Patent Application
20070238807
Embodiments of the present disclosure provide a film forming composition that includes a polymer having a hydrophobic component and a charged component, and optionally a bioactive agent, where the polymer and the bioactive agent are substantially dispersed in a solvent to form the composition. Upon application to a surface, such as a biological surface, most or all of the solvent preferably evaporates leaving the polymer and the bioactive agent as an adherent conformable water resistant film. As the bioactive agent remains homogeneously dispersed with the polymer in both the liquid state and the film state, the bioactive agent can provide a therapeutic and/or cosmetic benefit to the biological surface.
In addition, film forming compositions of the present disclosure retain these bioactive agents for delivery to a biological surface without compromising the mechanical characteristics, such as the wash resistance, of the resulting film. For example, the films formed from the film forming composition embodiments are elastic, have good flexural and elongation durability, and are resistant to being washed off or swelling during exposure to soap and water. In addition, solvents used in the film forming composition are relatively quick-drying at room temperature, non-irritating to surfaces such as skin, and substantially painless (e.g., non-stinging) when applied to an injury on the biological tissue. The resulting film is also substantially non-water-sensitive, waterproof, non-tacky, does not attract and/or hold dirt, and can help to control water vapor and/or oxygen gas transmission there through.
As will be discussed herein, polymer embodiments can have unique properties resulting from the combination of the hydrophobic component and the charged component that allow for the bioactive agent to remain dispersed in the composition even after the evaporation of the solvent. According to various embodiments, the bioactive agent can remain miscible with the polymer even when the bioactive agent is hydrophilic. Not to be limited by theory, it is believed that the use of the charged monomers in the polymers of the present disclosure help solubilize the bioactive agents having a hydrophilic character that would not necessarily be soluble in the absence of the charged monomers.
Polymer embodiments of the present disclosure generally includes from about 80 mole percent to about 100 mole percent of a hydrophobic component, and from about 0 to about 20 mole percent of a charged component. The film forming composition also optionally includes a bioactive agent and a solvent in which the polymer and the bioactive agent are substantially dispersed in the composition. The hydrophobic component and the charged component of the polymer can be materials comprising a polymerizable monomer, oligomer, or polymer.
In additional embodiments, the polymer of the film forming composition can include a hydrophilic component, where the polymer has about 0 to about 10 mole percent of the charged component, and the remaining mole percent of the polymer is the hydrophilic component and the hydrophobic component in a ratio of about 60/40 percent to about 80/20 percent. The hydrophilic component of the polymer can be materials comprising a polymerizable monomer, oligomer, or polymer.
In some embodiments of the polymers of the disclosure, a combination of the hydrophobic and hydrophilic components may be used, either randomly or in separate blocks of the polymer (e.g., thermoplastic elastomers, grafts, etc). One variation in the selection of monomers to be used in the polymer can be using more than one monomer within each category of hydrophobic, charged or hydrophilic.
The term “hydrophobic component” is recognized in the art and is intended to include those monomers, generally alkyl acrylates, alkyl(meth)acrylates, (meth)acrylamide, allyl esters, or vinyl ester monomers, that include a hydrophobic moiety, e.g., esters having branched or unbranched, substituted or unsubstituted alkyl or cycloalkyl chains of generally one or more carbon atoms.
Examples of monomers for the hydrophobic component as provided herein include, but are not limited to, substituted and unsubstituted styrenes, isoprene, butadiene, vinyl acetate and esters of acrylic acid and methacrylic acid, where the ester group has a carbon atom chain of one or more carbon atoms, such as ethyl acrylate or methacrylate, propyl acrylate or methacrylate, butyl acrylate or methacrylate, and C12 through C18 esters of acrylic acid or methacrylic acid.
Hydrophobic components also can include alkyl esters, wherein the alkyl portion is a branched or unbranched, substituted or unsubstituted alkyl chain of 2 or more carbon atoms or a substituted or unsubstituted aryl group. Dialkyl and monoalkyl acrylamides and methacrylamides are further contemplated as hydrophobic components. Dialkyl methacrylamides and acrylamides include alkyl chains having at least 2 or more carbon atoms that can be substituted or unsubstituted, branched or unbranched. Monoalkyl methacrylamide or acrylamides include an alkyl chain having at least 4 carbon atoms or more that can be branched or unbranched, substituted or unsubstituted.
Suitable monomers for the hydrophobic component may be listed above and include, but are not limited to, vinyl chloride; vinylidene chloride; vinyl propionate; alpha-methylstyrene; t-butylstyrene; butadiene; cyclohexadiene; ethylene; propylene; vinyl toluene, t-butyl acrylate, t-butyl methacrylate, and mixtures thereof. Additional hydrophobic monomers include methyl acrylate (MA), methyl methacrylate (MMA), ethyl acrylate (EA), ethyl methacrylate (EMA), 2-ethyl hexyl methacrylate (EHMA), 2-methoxyethyl acrylate (MEA), 2-methoxyethyl methacrylate (MEMA), styrene (Sty), vinyl acetate (VA), vinyl neodecanoate (VND), 2-ethylhexyl acrylate (EHA), butyl acrylate (BA), n-butyl methacrylate (BMA), isobutyl methacrylate, lauryl acrylate (LA), and mixtures thereof.
As used herein the term “hydrophilic component” is intended to include those monomers, generally hydoxyalkyl acrylates, hydoxyalkyl(meth)acrylates, (meth)acrylamide, and vinyl ester monomers, that include a hydrophilic moiety, e.g., alkoxyesters having alkyl or cycloalkyl chains having one or more hydroxyl, polyethoxy, polypropyloxy groups attached thereto. Hydrophilic components will, in general, be insoluble in the nonpolar, low boiling point solvents useful for solvation of the hydrophobic polymer.
Examples of monomers for the hydrophilic component as provided herein include, but are not limited to N-vinyl pyrrolidone (VPL); 2-hydroxyethyl acrylate (HEA) or 2-hydroxyethyl methacrylate (HEMA); N-tris(hydroxymethyl) acrylamide or N-[tris(hydroxymethyl)methyl]acrylamide (THMMAM); N,N-dimethyl acrylamide (DMA); N-acryloyl or methacryloyl morpholine; “PEGylated” or “ethoxylated” acrylates or methacrylates, such as polyethyleneglycol acrylate (PEGA), polyethyleneglycol methacrylate (PEGMA), 2-(2-ethoxyethoxy)ethyl acrylate or methacrylate; N-isopropyl acrylamide or methacrylamide; glycerol mono acrylate or methacrylate; N-(2-hydroxypropyl)acrylamide or methacrylamide and N-(2-hydroxyethyl)acrylamide and methacrylamide; methacrylamide, N-t-butyl acrylamide, the half esters of maleic anhydride, acrylamide, acrylate alcohols, hydroxyethyl methacrylate, vinyl ethers (such as methyl vinyl ether), maleimides, other polar vinyl heterocyclics, allyl alcohol, vinyl alcohol (such as that produced by the hydrolysis of vinyl acetate after polymerization), and mixtures thereof.
In one embodiment, the hydrophilic monomers include N-vinylpyrrolidone (VPL), 2-hydroxyethyl acrylate (HEA), 2-hydroxylethyl methacrylate (HEMA), N,N-dimethyl acrylamide (DMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMMAM), polyethyleneglycol acrylate (PEGA), polyethyleneglycol methacrylate (PEGMA), and mixtures thereof.
As used herein a “charged component” includes those monomers that contain a cationic or anionic charge associated with the molecule, or are not charged, but easily ionized (such as acrylic acid, methacrylic acid, and amine containing monomers). For example, the anions can include an ammonium ion, quaternary ammonium ions, halides, sulfate, carbonate, phosphate, phosphite, acetate and the like. Suitable cations include various metal ions such as sodium, potassium, calcium, etc.
In one embodiment, the monomers for the charged component may include, but are not limited to, N,N-dimethylaminoalkyl acrylate, such as N,N-dimethylaminoethyl acrylate (DMAEA), N,N-dimethylaminoalkyl methacrylate, such as quaternized dimethylaminoethyl methacrylate, [2(methacryloyloxy)ethyl]trialkylammonium salt, [2-(acryloyloxy)ethyl]trialkylammonium salt, such as [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETMAC), N,N-dimethylaminoalkyl methacrylamide, N,N-dimethylaminoalkyl acrylamide, N,N,N-trimethylaminoalkyl methacrylamide salt, N,N,N-trimethylaminoalkyl acrylamide salt, (vinylbenzyl)trialklyammonium salt, such as (vinylbenzyl)trimethylammonium chloride (VBTMAC), diallyldimethylammonium chloride, acrylic acid (AA), methacrylic acid (MAA), itoconic acid (IC), crotonic acid, maleic anhydride, maleic acid, fumaric acid, mono-2-(methacryloyl)ethyl succinate (MAES), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), vinylphosphonic acid (VPA), vinyl imidazole, vinyl pyridine, styrene sulfonate, and mixtures thereof.
Polymers of the present disclosure may be prepared, for example, by free-radical polymerization methods, including but not limited to bulk, solution, emulsion, and suspension polymerization methods. For example, polymers of the present disclosure can be prepared by emulsion polymerization. According to the emulsion polymerization method, polymers suitable for use in the present disclosure are prepared by forming an emulsion comprising the desired monomers and a water-soluble radical initiator system (such as a thermal initiator or a photoinitiator) in an inert atmosphere such as nitrogen or argon, and then heating the emulsion until a reaction exotherm occurs. The reaction mixture is stirred and cooled and the resulting polymer is collected. Optionally, an ionic or nonionic surfactant may be added to the reaction mixture. Reducing agents may optionally be added to form an oxidation-reduction “Redox” pair with the radical initiator.
During the emulsion polymerization reaction, a quantity of the monomers can be charged batchwise or in a continuous or semicontinuous manner to the reaction vessel. By semi-continuous it is meant that a plurality of batches of the monomer is charged to the vessel during the course of the polymerization. The independent rate at which the monomers are added to the vessel will depend on the consumption rate of the particular monomer with time. Typically, the rate of addition of monomer will be about equal to the rate of consumption of monomer, i.e., conversion of monomer into polymer.
For the reaction, the reaction vessel can be initially charged with a solvent. Suitable solvents for polymerization reactions of the disclosure include, for example, water, ketones, ethers, polar aprotic solvents, esters, aromatic solvents, and aliphatic hydrocarbons, both linear and cyclic. Exemplary ketones include methyl ethyl ketone (2-butanone) (MEK), acetone, and the like. Exemplary ethers include alkoxyalkyl ethers, such as methoxy methyl ether or ethyl ether, tetrahydrofuran, 1,4 dioxane, and the like. Polar aprotic solvents include dimethyl formamide, dimethyl sulfoxide and the like. Suitable esters include alkyl acetates, such as ethyl acetate, methyl acetate, and the like. Aromatic solvents include alkylaryl solvents, such as toluene, xylene, and the like and halogenated aromatics such as chlorobenzene, and the like. Hydrocarbon type solvents include, for example, isooctane, hexane, cyclohexane, and the like.
In the case of emulsion polymerizations, a surfactant can be added, typically in an amount of 0.01% by weight to 1% by weight. The polymerization is usually initiated after an initial charge of monomer by adding an initiator or initiator system to the solvent phase.
The phrase “free-radical initiator,” within the context of the disclosure, refers broadly to compounds or mixtures of compounds that can lead to the formation of radical species under appropriate working conditions (e.g., thermal activation, irradiation, redox conditions, etc.). Examples of free-radical initiators useful in the polymerization mixture according to the present disclosure include alkyl peroxides, substituted alkyl peroxides, aryl peroxides, substituted aryl peroxides, acyl peroxides, alkyl hydroperoxides, substituted alkyl hydroperoxides, aryl hydroperoxides, substituted aryl hydroperoxides, heteroalkyl peroxides, substituted heteroalkyl peroxides, heteroalkyl hydroperoxides, substituted heteroalkyl hydroperoxides, heteroaryl peroxides, substituted heteroaryl peroxides, heteroaryl hydroperoxides, substituted heteroaryl hydroperoxides, alkyl peresters, substituted alkyl peresters, aryl peresters, substituted aryl peresters, percarbonates, halide compounds, and azo compounds, for example. Initiation may also be by heat or UV light, depending on the embodiment being practiced. Specific initiators can include lauroyl peroxide.
In various embodiments, the amount of initiator employed is typically between 0.03 and 2 weight %, or between 0.05 and 1 weight % of the total weight of the monomer mixture. The full amount of initiator may be added at the start of the polymerization or the initiator can be added to the polymerization in a continuous way during the polymerization process. A part of the initiator could also be added at the start and the remainder in one or more separate additional portions during the polymerization. Further addition(s) may be done batchwise or the further addition may be continuous. Emulsion polymerization system may further comprise auxiliaries, such as buffers and complex-formers.
Polymerization conditions that may be used include temperatures for polymerization typically in the range of from about 20° C. to about 110° C., more specifically from about 40° C. to about 90° C., and even more specifically from about 50° C. to about 80° C. The atmosphere may be controlled, with an inert atmosphere such as nitrogen or argon being useful, for example.
Polymerization conditions can also include the time for reaction, which may be, in various embodiments, from about 0.5 hours to about 72 hours, more specifically from about 1 hour to about 24 hours, and even more specifically from about 2 hours to about 12 hours. Conversion of monomer to polymer can also be at least about 50%, at least about 75% and even at least about 85%.
In another embodiment, polymers of the present disclosure may be obtained by a non-free-radical polymerization mechanism, such as the polymerization of monomers, such as oxazoline monomers shown below in Structure I, by a (living) cationic ring-opening polymerization process. In a copolymerization involving several oxazolines, random copolymers can be obtained by a cationic polymerization with different R substituants affecting the balance of hydrophobicity/hydrophilicity in the system. An example of a hydrophilic oxazoline is 2-methyl-2-oxazoline. A typical example of a hydrophobic oxazoline is 2-nonyl-2-oxazoline. Block copolymers can also be obtained by this living cationic ring-opening polymerization mechanism. A typical synthetic protocol of the synthesis of poly (2-nonyl-2-oxazoline) is reported by Hoogenboom et al, J. Comb. Chem. 2005, 7, 10-13, the disclosure of which is hereby incorporated by reference, involving the use of methyl tosylate as an initiator in a solvent mixture of acetonitrile and dichloromethane.
wherein R is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, and combinations thereof. More specifically, R may be selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted aryl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted allenyl, optionally substituted aralkyl, optionally substituted acyl, optionally substituted, aroyl, optionally substituted alkoxy, optionally substituted heteroalkyl, optionally substituted heteroaryl, and optionally substituted heterocyclyl.
The polymers of the present disclosure can have a structure selected from the group consisting of random copolymers, block copolymers, graft copolymers and hyperbranched copolymers. As used herein, “block copolymer” includes a polymer comprising at least two segments of differing composition; having any one of a number of different architectures, where the monomers are not incorporated into the polymer architecture in a solely statistical or uncontrolled manner. Although there may be three, four or more monomers in single block-type polymer architecture, it is considered herein as a block copolymer. Block copolymers can be prepared a number of ways, including sequential addition of monomers or using multi-functional control agents that may form a linking group between one or more blocks of the copolymers. Graft copolymers can be generated using initiators capable of initiating multiple free radical polymerizations under the controlled conditions of the present disclosure.
In yet another aspect of the present disclosure, the polymer can be a blend of polymers having hydrophobic components, charged components, and optionally hydrophilic components as provided herein. Alternatively, the polymer can be a blend of polymers, such as a polymer with hydrophobic components and charged components blended with a polymer having hydrophobic components, charged components and hydrophilic components.
The polymer may have molecular weights from 50,000 to several million in various embodiments. In one embodiment, the molecular weight range is 50,000 to 1,000,000 weight average molecular weight (Mw). In certain aspects of the disclosure, the Mw of the polymer is between about 65,000 and about 500,000, more specifically between about 75,000 and about 500,000, and more specifically between about 200,000 and 500,000. The Mw of the polymer may be controlled by varying initiator, initiator concentration, monomer concentration, reaction temperature, reaction solvent, and/or reaction method.
As provided herein, the types and mole fractions of monomers used to form polymers of the present disclosure can be selected to adjust permeability, adhesion, elasticity, flexibility, toughness, and temperature stability, among other film qualities, to meet the requirements of a liquid bandage. For example, at least one glass transition temperature (Tg) of the polymer can be adjusted to allow the polymer once in film form to be flexible from about 37° C. (e.g., body temperature) to about 50° C. The Tg of a monomer is a known parameter. When combinations of monomers are used in forming random copolymer the resulting Tg of the polymer is a function of the Tg of the different monomers. For example, polymers of the present disclosure can combine monomers with a high Tg and monomers with a low Tg to provide a polymer tuned for the desired Tg to prevent the resulting film from cracking when applied to the biological surface.
Screening and analysis of polymers suitable for the embodiments of the present disclosure can be accomplished through the use of parallel material processing techniques, among other techniques. For the present disclosure “Library Studio®” software (Symyx Technologies, Inc., Santa Clara, Calif., USA) can be used to design monomer libraries for the polymer of the present disclosure. In designing the libraries, varying proportions of different monomers for the hydrophobic component, charged component, and optionally the hydrophilic component, can be selected in an array for the different libraries. The resulting libraries can then optionally be stored in a “Renaissance Application Server®” (Symyx Technologies, Inc., Santa Clara, Calif., USA) from which information and instructions can be provided to “Impressionist®” software (Symyx Technologies, Inc., Santa Clara, Calif., USA) or by other instrument-control software to create and execute the library on an Automated Synthesis Station that synthesizes the polymers in an array format. The resulting polymers can then be screened for certain physical and functional properties, including chemical, solubility, thermal, and mechanical attributes.
In one embodiment, a polymer of the present disclosure is formed by copolymerizing about 5 mole percent or less of methacrylic acid (MAA) for the charged component, with the remaining mole percent of 2-ethyl hexyl methacrylate (EHMA) and methyl methacrylate (MMA) for the hydrophobic component in a ratio of about 75/25 to about 50/50 mole percent EHMA/MMA. In an additional embodiment, the polymer is formed by copolymerizing about 2 mole percent or less of MAA for the charged component, with the remaining mole percent of EHMA and MMA for the hydrophobic component in a ratio of about 55/45 to about 50/50 mole percent EHMA/MMA. This polymer demonstrates excellent adhesion to biological surfaces, is flexible and waterproof, is soluble in therapeutically compatible solvents such as isooctane and isopropanol, as will be discussed herein, and is very compatible with many kinds of bioactive agents, including those that are hydrophilic in nature.
In another embodiment, the polymer is formed by copolymerizing about 0 to about 5 mole percent of MAA for the charged component, about 30 to about 45 mole percent of MMA, about 1 to about 15 mole percent of 2-methoxyethyl methacrylate (MEMA), with the remaining mole percent of the polymer being 2-ethyl hexyl methacrylate (EHMA), where MMA, MEMA and EHMA are the hydrophobic component. In an additional embodiment, the polymer is formed by copolymerizing about 0 to 2 mole percent MAA, about 35 to about 40 mole percent MMA, about 5 to 15 mole percent MEMA, with the remaining mole percent of the polymer being EHMA. This polymer demonstrates excellent adhesion to biological surfaces, is flexible and waterproof, is soluble in therapeutically compatible solvents such as isooctane and isopropanol, as will be discussed herein, and is very compatible with many kinds of bioactive agents, including those that are hydrophilic in nature.
In another embodiment, the polymer is formed by copolymerizing about 2.0 to about 7.5 mole percent of acrylic acid (AA) for the charged component, the remaining mole percent of a methyl acrylate (MA) for the hydrophobic component, and 2-hydroxyethyl methacrylate (HEMA) for the hydrophilic component in a ratio of about 40/60 percent MA/HEMA to about 20/80 percent MA/HEMA. This polymer demonstrates excellent adhesion to biological surfaces, is flexible and waterproof, is soluble in therapeutically compatible solvents such as water and ethanol, as will be discussed herein, and is very compatible with many kinds of bioactive agents, including those that are hydrophilic in nature.
Embodiments of the present disclosure further include various methods of making the film forming composition that include dissolving the polymer of the present disclosure with a bioactive agent in a solvent. Solvents for use with the film forming compositions are desirably therapeutically safe and skin tolerant. Such solvents can have a sufficiently low boiling point (e.g., 75° C. or less) at 1 atmosphere that a coating of the film forming composition is touch dry within 3 minutes, within 2 minutes, and even within 1 minute, after being coated onto a biological surface at ambient temperature, pressure, and humidity (e.g., 22° C., 1 atmosphere and 50% RH). This can be achieved by monomer choice, molecular weight control, and solvent system choice. In one embodiment, the polymer of the present disclosure has a limited solubility in water (less than 1 percent by weight (wt %) in deionized water at 40° C.).
Suitable solvents for the film forming compositions include those in which the polymer is soluble at a concentration of at least 1 wt % at 25° C. Typically, the polymer content of film forming composition is no more than about 50 wt %, and/or no more than about 20 wt %, based on the total weight of the solution. In one embodiment, the polymer content of film forming composition is about 8 wt %, based on the total weight of the solution. In an additional embodiment, the film forming compositions can include a solvent in which the polymer and/or bioactive agent are dispersed so as to form a slurry or a dispersion.
Solvents of the present disclosure can include one or more hydrophobic solvents. Examples of suitable hydrophobic solvents include non-polar solvents including one or more C4-C12 straight, branched, or cyclic alkanes, dimethyl formamide, dimethyl sulfoxide, tetrahydrofuran, chloroform, acetone, acetonitrile, dioxane, dimethyl acetamide, N-methyl pyrrolidone, or combinations thereof. Useful solvents for solution coating include, for example, n-pentane, n-hexane, isooctane, n-heptane; n-octane; n-nonane, and combinations thereof.
The solvent may also include a blend of solvents that are a mixture of one or more hydrophobic solvents as provided herein, with one or more non-aqueous polar solvents. Suitable non-aqueous polar solvents can include alcohols, esters (such as acetates), organic acids (such as acetic acid), and glycols. Examples include isopropanol, propanol, diethylene glycol, propylene glycol, ethylene glycol, N-methyl pyrrolidone, glycerol, combinations of these, and the like. By utilizing a solvent system of this nature, the films may dry more rapidly. Moreover, a minimal amount of the polar solvent is used in order to increase the solubility of polymer systems with hydrophilic and charged monomers.
In various embodiments, for polymers of the present disclosure having the hydrophobic components and the charged components, the solvent can include about 85 to about 100 weight percent of one or more non-polar solvents (e.g., alkanes) and about 0 to about 15 weight percent of one or more non-aqueous polar solvents. In one embodiment, the solvent includes about 90 to about 100 percent by volume of one or more non-polar solvents selected from the group consisting of pentane, hexane, isooctane, or mixtures thereof, and about 0 to about 10 percent by volume of one or more non-aqueous polar solvent selected from the group consisting of an alcohol (e.g., isopropanol), ethyl acetate, acetone, or mixtures thereof. In an additional embodiment, the solvent includes about 90 to 99 percent by volume of one or more non-polar solvents selected from the group consisting of pentane, hexane, isooctane or mixtures thereof, and about 1 to about 10 percent by volume of one or more non-aqueous polar solvent selected from the group consisting of an alcohol (e.g., isopropanol), ethyl acetate, acetone, or mixtures thereof. In a further embodiment, the solvent includes about 95 to 99 percent by volume of one or more non-polar solvents and about 1 to 5 percent by volume of one or more non-aqueous polar solvents. In some embodiments, the non-aqueous polar solvent is isopropanol, and the alkane is isooctane.
For polymers of the present disclosure having the hydrophobic components, the charged components and the hydrophilic components, the solvent can include about 60 to 85 percent by volume of water and about 15 to 40 percent by volume of ethanol. In an additional embodiment, the solvent includes about 65 to 75 percent by volume of water and about 25 to 35 percent by volume of ethanol. In a further embodiment, the solvent includes about 70 percent by volume of water and about 30 percent by volume of ethanol.
Additional compounds can be added to the solvent to enhance and/or increase the solubility of the polymer in the solvent. For example, for various embodiments of the polymers provided herein, solubility in an aqueous system can be improved by ionizing carboxylic acid groups on the polymer through the use of a volatile base compound. Examples of suitable base compounds for providing this ionization include, but are not limited to, ammonium hydroxide, 2-aminomethylpropanol (2-AMP), and mixtures thereof, which ionization can help to increase the solubility of the polymer. After application of the film forming composition, the solvent and the volatile base compound evaporate resulting in protonation of the carboxylic acid group on the polymer. The acid groups on the polymer can then strongly associate, giving strength to the resulting film and providing for greater wash resistance of the film. Other substances may be added to the solvent and/or the film forming composition for plasticization, improved adhesion, and/or rheology control, and the like.
The bioactive agent of the present disclosure may be incorporated into the film forming composition for ready or continual release to the biological surfaces to which the film is applied. As provided herein, the bioactive agents that are hydrophilic remain miscible with the polymer of the present disclosure in the liquid state and the film state. The bioactive agent can include, but is not limited to, a therapeutic agent that can be released to the underlying biological surface of the film and/or a cosmetic agent provided for aesthetic purposes. As used herein, a “therapeutic agent” is one that produces a local or systemic effect in a subject and is used to encompass substances intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease and/or in the enhancement of desirable physical development and conditions in a subject. The term “subject” used herein is taken to include mammals (e.g., humans) and non-mammals.
Examples of the therapeutic agent include, but are not limited to, therapeutically effective amounts of an antimicrobial, topical anesthetics, antifungals, antioxidants, and mixtures thereof. Additional examples of the therapeutic agent include synthetic or naturally occurring agents, and include, without limitation, pharmacologically active polypeptides (which is used herein to encompass a polymer of L- or D-amino acids of any length including peptides, oligopeptides, proteins, enzymes, hormones, etc.), saccharides (e.g., mono-, di-, poly-saccharides, and mucopolysaccharides), vitamins, and the like. Examples of cosmetic agents include, but are not limited to, pigments, dyes, and combinations thereof. Other types of bioactive agents which may be desirable to incorporate include UV and IR absorbers.
According to the present disclosure, the bioactive agent of the present disclosure is a hydrophilic material selected from the group consisting of the therapeutic agent, the cosmetic agent, and mixtures thereof. Suitable examples of bioactive agents can include antimicrobial agents such as antibiotics such as ciprofloxacin, norfloxacin, clofoctol, and the like, and antifungal and antiseptic agents such as chlorhexidine, sanguinarine extract, metronidazole, quaternary ammonium compounds, such as cetylpyridinium chloride and benzalkonium chloride (BZK), and the like; anti-inflammatory agents such as ibuprofen, fenbufen, cortisone, and the like; vitamins such as vitamins A, C and E; anesthetic agents such as benoxinate, benzocaine, lidocaine, procaine, and the like; antihistamines; antipyretics; biocides; bactericides; biomolecules such as bacteriocins, antibodies, enzymes, and the like; nonsteroidal anti-inflammatory drugs; proteinaceous materials, such as collagen; preservatives; opacifying agents; coloring agents such as pigments, dyes, and the like; pH-adjusting agents; surfactants, such as anionic, nonionic, cationic and zwitterionic or amphoteric surfactants; and buffers and salts to buffer the pH and ionic strength of the film forming composition.
Additives that can be combined with the film forming composition can include, but are not limited to, viscosity and flow control agents to adjust the viscosity and thixotropy of the mixture to a desired level, antioxidants to improve oxidative stability of the film, surfactants, emulsifiers, preservatives, stabilizers, diluents, and air release agents or defoamers, plasticizers, adhesion promoters, or combination of these, for example.
In one embodiment, each bioactive agent is present within (i.e., incorporated within) the film forming composition in an amount of at least about 0.1 weight percent (wt %), based on the total weight of the film forming composition and the bioactive agents. In an additional embodiment, the bioactive agent is present within the film forming composition in an amount of at least about 1 wt %, based on the total weight of the film forming composition and the bioactive agents. In a further embodiment, the bioactive agent is present within the film forming composition in an amount of at least about 5 wt %, based on the total weight of the film forming composition and the bioactive agents. Typically, the amount of each bioactive agent will be at or below its solubility limit in the film forming composition.
Film forming compositions of the present disclosure could also be used for applications such as sunscreens with the incorporation of UV absorbers. Still other uses include forming films for use in eliminating chapped lips, treating skin, and providing protection to skin and other surfaces which may be medicated prior to application of the film.
In some embodiments, films formed from the film forming composition can have a thickness of the film that is no greater than about 1000 microns, no greater than about 500 microns, and/or no greater than about 100 microns. A film can be as thin as desired (e.g., 1 nanometer or thinner), but are typically not thinner than about 10 nanometers to about 100 nanometers. Generally, the film thickness is limited by the process used to form the film. For the embodiments herein, the thickness of the film does not have to be constant or uniform. Furthermore, the thickness of the film can be used to tune the duration of time over which the biological agent is released.
Film forming compositions of the present disclosure can further be included in a kit. The kit can include a quantity of the film forming composition of the present disclosure provided in a dispensing container. In one embodiment, the dispensing container includes a bottle having an applicator that releasably attaches to the bottle. The kit can be provided in a package having instructions for use of the dispensing container and the film forming composition. Examples of a suitable applicator include, but are not limited to a brush, a rod, a sponge, a cloth, a dropper, a pump sprayer, or mist forming structure or any other usable technique or structure for applying a liquid to a surface.
The invention has been described with reference to various specific and preferred embodiments and will be further described by reference to the following detailed examples. It is understood, however, that there are many extensions, variations, and modifications on the basic theme of the present invention beyond that shown in the examples and detailed description, which are within the spirit and scope of the present invention.
A number of embodiments of the invention are illustrated by the following examples. However, the particular materials and amounts thereof recited in these examples, as well as other conditions and details, are to be interpreted to apply broadly in the art and should not be construed to unduly restrict or limit the invention in any way.
All reactions for Examples 3, 6 and 7 were performed in oven-dried glassware under a positive pressure of argon or nitrogen gas. The air- and moisture-sensitive solutions were transferred by means of a syringe into rubber-septum-capped reaction vessels. Reaction mixtures and chromatographically collected fractions were concentrated on a rotary evaporator (ca. 20° C./20 torr). Commercial grade reagents were used without further purification, except for monomers, which were degassed by applying a nitrogen- or argon-stream for 30 min. Monomer inhibitors were removed by distillation or filtration over Aldrich-inhibitor-remover [9003-70-07]. Polymerization mixtures were carried out and sealed in a glove box under a nitrogen or argon atmosphere, and performed at temperatures indicated herein. Size Exclusion Chromatography (SEC) was performed using automated gel permeation chromatography (GPC) systems and different sets of columns and eluents depending on the polarity of the polymers. In general, SEC was performed in accord with U.S. Pat. Nos. 6,296,771, 6,294,338, 6,265,226, 6,260,407 and 6,175,409, each of which is incorporated herein by reference. Molecular weight and polydispersity index (PDI) are referred to linear polystyrene standards. Monomer conversion was determined by 1H-NMR on a Brucker AC 400 (400 MHz) or by GC on a HP-6890 automated system. Glass transition temperatures for the polymers were measured using a Parallel DMTA Workflow (Symyx Technologies, Santa Clara, Calif.).
In the present examples, the following abbreviations are used: “EHMA” is 2-ethyl hexyl methacrylate, “MMA” is methyl methacrylate, “MAA” is methacrylic acid, and “MEMA” is 2-methoxyethyl methacrylate. Unless otherwise noted, reagents were purchased from Sigma-Aldrich of Milwaukee, Wis. 2-Ethyl hexyl methacrylate (EHMA) was purchased from Alfa Aesar of Ward Hill, Mass. The water used in all experiments was distilled and degassed prior to use.
Library Studio® software (Symyx Technologies, Inc., Santa Clara, Calif., USA) was used to design a monomer library for the random copolymerization of MAA, EHMA and MMA. Polymerization reactions were prepared by an emulsion process using a Parallel Polymerization Reactor® (Symyx Technologies, Inc., Santa Clara, Calif., USA) from the recipe information supplied by the Library Studio® software. Stock solutions for the monomers are as provided below in Table I.
Twenty-four reaction vessels of the Parallel Polymerization Reactor® were configured as follows: an array of twenty-four sealed stainless steel reactor chambers, each equipped with speed-controlled rotary shaft stirrer paddles, disposable glass liner reaction vessels with volume capacity of about 8 ml, nitrogen gas manifold inlet and outlet, thermostatically controlled heating, and inlet lines into each of the reactor vessels, supplied by pump and valve distribution systems. The feed lines of each distribution system were primed with the corresponding stock solutions described below (Table I). The reactor was assembled in a clean, empty state, and sealed. The reactor was flushed 5 times, where each flush cycle includes pressurizing with nitrogen to a pressure of 60 psig, followed by venting to flush air from the system. Finally, the system was maintained under an ambient (1 atm) nitrogen atmosphere during the course of the reaction.
For the array of twenty-four reaction vessels (four rows by six columns) the percent of total monomers for MAA was 2.76% for row one, 1.84% for row two, 0.92% for row three and 0.0% for row four, while the theoretical molar ratio of total monomers for EHMA/MMA was 55/45 for column 1, 58.1/41.9 for column 2, 61.6/38.4 for column 3, 65/35 for column 4, 70/30 for column 5, and 75/25 for column 6 of the array.
The addition protocol was as follows. In a first stage, the surfactant solution was added followed by the addition of the solvent. After 45 minutes to 1 hour, 10% of EHMA, and 9% of MMA and MAA stock solutions were added and the temperature was set to 58° C. and stirring was begun. After 20 minutes, 30% of the Asc solution and 5% of the t-BHP was added to each reaction vessel. The second stage began after 20 minutes, during which most of the remaining monomers (90% of EHMA, 90% MMA and 90% MAA) and initiators were added semicontinuously in 100 steps during 9 hours. The remaining 1% of MMA and MAA was then added in a single step. Heating was maintained for 1 hour at 58° C. The samples where then filtered over glasswool and directly precipitated in acetone. Solids were then washed several times with water and dried overnight.
The polymers synthesized in Example 1 were then subjected to a screening methodology to investigate various performance properties, including flexural durability, elongational durability, and wash resistance. The wash resistance test provided information on solubility of the films formed with polymers from Example 1 in soap water solutions and the thickness increase of non-soluble polymers due to water absorption. The objective of this test was to assess whether a polymer film dissolves in, or absorbs, water under conditions similar to those presented during personal hygiene or during household chore activities such as dishwashing. Polymer films were formed by dispensing 20 μl of a 20% polymer solution on a Kapton® (DuPont, Wilmington Del.) covered aluminum plate. After the films were dried by leaving them on a hot stage set at 37° C., the thickness (H1) of the films was read and recorded using a scanning laser profilometer (Symyx Technologies, Santa Clara, Calif.).
The effect of water on film integrity was assessed by immersing the plate (face down) in a detergent solution at 43° C. for 15 minutes. This solution was contained in a Petri dish in which gentle magnetic stirring was applied to homogenize the solution temperature and to apply some shear to the films. After the required time, the plate was washed with clean water and the excess water was eliminated by a gentle blow of compressed air. The thickness of the films (H2) was then measured immediately while the films were still wet. A decrease in thickness reflected partial dissolution of the polymer. An increase in thickness indicated swelling of the film. Samples that did not show changes in thickness were deemed wash resistant polymers. Intermediate cases (simultaneous partial dissolution and swelling of the film) will also result in thickness close to the original values, and may mislead the interpretation of the results. To clear any doubts arising from the wet thickness reading, a third reading (H3) was performed after the films were dried a second time. The ratio H3/H1 quantifies the extent to which the material resists dissolution, i.e. wash resistance; the ratio H2/H3 measures the degree of swelling upon immersion in the wash liquid.
The results of wash resistance of the films formed with the polymers from Example 1 are shown in Table II. All polymers exhibit good water resistance with all thickness changes within 2% (H3/H1).
In the flexural durability test, a film of each of the polymers was formed on a Viton® sheet (DuPont, Wilmington Del.). The Viton surface was first prepared by bead blasting to obtain a rougher surface and improve the adhesion of the resulting polymer film. The film was prepared by dispensing 40 μl of a 15 wt % polymer solution in Chloroform on the elastic substrate and allowing it to spread to cover approximately 1 cm2. The films were left to dry overnight on top of a hot stage at 37° C. The dry thickness of the polymer film was approximately 20 to 30 μm.
The films were then placed in an ambient controller chamber (35° C. at 50% relative humidity) for 6 hours for equilibration. The flexural test was carried out by rolling the elastic substrate with the film around a sharp angled pole so that every section of the film was bent at 90 degrees sometime during the experiment. This movement was repeated ten times (strokes). Any cracking or wrinkling of the polymer film was captured in images using a microscope. No changes were observed in the polymer films after 10 strokes.
For the elongational durability test, polymer films were prepared on bead blasted Viton® strips in the same way as in the flexural durability test. Once the films were dried and equilibrated as discussed above, the strips were subjected to elongation under mechanical and ambient controlled conditions (35° C. at 50% relative humidity). The strips were subjected to elongation to 100% stain from their original length (40 mm) (i.e., the films were stretched to twice their original length) at an elongation rate of 900%/minute. Once the elongation reached the maximum, results (cracking, delamination, etc.) were recorded. After the films were relaxed to the original length, pictures were taken with the microscope to record any structural change of the film after relaxation. The film of polymer A4 shows very slight edge delamination, and the film of polymer B6 shows some cracks after relaxation. No structure changes were observed for the rest of films.
A polymer formed from monomers of EHMA, MMA, and MAA was prepared, characterized and tested for solubility in mixtures of one or more hydrophobic solvents and one or more non-aqueous polar solvents. Molar percentages of the monomers EHMA, MMA and MAA for the reaction were 54 mol. %, 44.16 mol. %, and 1.84 mol. %, respectively. The polymer was prepared using a redox initiating system (peroxide initiator) at 0.3 weight percent based on total weight of the monomer in an emulsion free-radical polymerization process. The total polymerization reaction volume was one liter.
A 2 L, three-neck, round-bottom flask was equipped with mechanical stirring, a thermometer and adapters, heating mantle, and a flow control to provide an argon atmosphere and inlet (a septum) to lines from individual stock solutions (Table III). A surfactant mixture of 6.102 g of Tergitol 15S5 (Dow Chemical Company), 2.029 g of Tergitol 15S40 (Dow Chemical Company), 0.001 g of sodium acetate (Sigma Chemical), and 6.102 g of Dowfax 2A1 (Dow Chemical Company) was introduced into the flask. The flask was purged with argon for 30 minutes. Water (367.97 mL) was introduced in the flask via double-tip syringe needle on the surfactant mixture. The emulsion mixture was then stirred for 15 to 30 minutes. The emulsion mixture in the flask was then heated to a constant temperature of 58° C.
An initial charge of monomers of the MMA, EHMA and MAA stock solutions according to Table IV, below, was introduced into the flask. The emulsion mixture was left to equilibrate under stirring for 20 minutes at a constant temperature of 58° C. After 20 minutes, an initial charge of the Asc stock solution (Table IV) was added to the flask. An initial charge of the t-BHP stock solution (Table IV) was then added after an additional 10 minutes to provide the free-radical initiator. After an additional 20 minutes, a remaining volume of the free-radical initiator (Asc/t-BHP) and the MMA, EHMA and MAA stock solutions were fed to the flask in 100 equal steps over a 9 hour interval, as indicated in Table IV. A late charge of monomers of the MMA stock solution and the MAA stock solution according to Table IV was then added in the emulsion mixture in a single step after the 9 hour reaction time. The resulting emulsion mixture was then left under stirring at 58° C. for 1 hour before being cooled to room temperature.
The resulting emulsion mixture was then passed through glasswool to remove any solids. The emulsion mixture containing the polymer was precipitated by a dropwise addition of the mixture into methanol or acetone at room temperature. The resulting polymer was then filtered and thoroughly washed with water on a Büchner funnel until no foam was observed through the filter. The polymer was then freeze dried to remove adsorbed water. A further purification of the polymer was performed by a reverse precipitation technique during which the polymer was dissolved into the minimum amount of solvent and the non-solvent can be added dropwise to the solution. This process allows for removal of small molecules (unreacted monomers, initiators, surfactants or small polymeric chains).
During the process, the polymer (300 g) was then divided into two lots of 150 g each (for convenience only) and dissolved in 500 mL of a mixture isopropanol-isooctane (50/50 vol/vol) in a beaker. Ethanol (4 L) was then added dropwise to the mixture of the polymer and the isopropanol-isooctane that resulted in a cloudy mixture. The cloudy mixture was left under stirring for 1 hour and then placed in a refrigerator (3° C.) overnight. A resulting supernatant was then discarded and the polymer collected as a gummy material at the bottom of the beaker. The polymer was then washed several times with ethanol, and then transferred to a plastic container. The polymer was then dried at 85° C. for 16 hours before analysis.
The polymer was then characterized by H1 NMR and gel permeation chromatography (GPC). The molar ratio of EHMA/MMA units in the polymer was determined by 1H NMR to be 53 mol % EHMA, and 47 mol % MMA. The molecular weight obtained by GPC showed a broad peak with a weight average molecular weight (Mw) of 495,000 g/mol and a polydispersity index (PDI) of 2.35. The glass transition temperature (Tg) for the EHMA/MAA/MMA polymer was determined to be Tg=42.0° C. using a Parallel DMTA Workflow (Symyx Technologies, Santa Clara, Calif.).
The polymer 0.15 g from Example 3 was mixed with 1 ml of isooctane containing 5 wt % isopropanol to make a 15 wt % solution of the polymer. Polymer films were prepared from the 15 wt % solution of the polymer in the same way as in Example 2 for water resistance test, and for durability test. The thickness change of the polymer film was less than 2% after the film was washed in hot soap water and re-dried for the thickness measurement. No changes to the film surface were observed during the flexural and elongational durability tests.
The polymer 0.15 g from Example 3 was mixed with 1 ml of isooctane containing 5 wt % isopropanol and 0.13 wt % of Benzalkonium Chloride (Aldrich) to make a 15 wt % solution of the polymer. Polymer films were prepared from the 15 wt % solution of the polymer in the same way as in Example 2 for water resistance test, and for durability test. The thickness change of the polymer film was less than 2% after the film was washed in hot soap water and re-dried for the thickness measurement. No changes to the film surface were observed during the flexural and elongational durability tests.
A polymer formed from monomers of EHMA, MMA, MAA, and MEMA was prepared, characterized, and tested for solubility in mixtures of one or more hydrophobic solvents and one or more non-aqueous polar solvents. Molar percentages of the monomers EHMA, MMA, MEMA, and MAA for the reaction were 49 mol. %, 39 mol. %, 11 mol. %, and 1 mol. %, respectively. The polymer was prepared as a free-radical polymerization process using a thermal initiating system (peroxide initiator) at 0.8 mole % based on total moles of the monomer in isooctane solution at 80° C. The total polymerization reaction volume was 0.4 liter.
A 1 L three-neck round bottom flask was prepared with mechanical stirring, a thermometer and adapters, and a flow control to provide inert atmosphere and inlet (a septum) to lines from individual stock solutions (Table V). The flask was also provided with a heater.
An initial charge of monomers of the EHMA, MMA, MEMA, and MAA stock solutions, the solvent and an initiator (lauroyl peroxide) according to Table VI, below, were introduced into the flask and stirred. The mixture was then heated to a constant temperature of 80° C. After 10 minutes, a feed of the monomer stock solutions was added in 100 steps and a feed of the initiator was added in 10 steps over a 5 hour interval. After the reagents were added, the mixture was left under stirring at 80° C. for 1 more hour. Before cooling, the mixture was diluted with 200 ml of isopropanol. Once at room temperature, the polymer was precipitated by a slow addition of ethanol (up to 3 liters). The precipitate was washed several times with ethanol then re-dissolved in isooctane/isopropanol 50/50 vol % and the precipitation with ethanol was repeated. After several washes with ethanol the precipitate was placed in a plastic flask and dried under vacuum at a temperature of 65° C. for 48 hours.
The EHMA/MMA/MEMA/MAA polymer was then characterized by H1 NMR and gel permeation chromatography (GPC). The molar ratio of the incorporated EHMA, MMA, and MEMA units was determined by 1H NMR to be 48 mol. % EHMA, 41 mol. % MMA, and 11 mol. % MEMA. Analysis of the polymer with GPC showed a broad peak with a weight-average molecular weight (Mw) of 129,000 g/mol and polydispersity index (Mw/Mn) of 1.90. The glass transition temperature for the EHMA/MMA/MEMA/MAA polymer was found to be Tg=41.2° C.
A polymer formed from monomers of EHMA, MMA, MAA, and MEMA was prepared, characterized and tested for solubility in mixtures of one or more hydrophobic solvents and one or more non-aqueous polar solvents. Molar percentages of the monomers EHMA, MMA, MEMA, and MAA for the reaction were 60 mol. %, 32 mol. %, 7 mol. %, and 1 mol. %, respectively. The polymer was prepared as a free-radical polymerization process using a thermal initiating system (peroxide initiator) at 0.8 mole percent based on total moles of the monomers in isooctane solution at 80° C. The total polymerization reaction volume was 0.4 liter.
A 1 L three-neck round bottom flask was prepared with a mechanical stirring, a thermometer and adapters: a flow control to provide inert atmosphere and inlet (a septum) to lines from individual stock solutions (Table VII). The flask was also provided with a heater.
An initial charge of monomers of the EHMA, MMA, MEMA, and MAA stock solutions, isooctane, the lauroyl peroxide (initiator), as indicated in Table VIII, were added to the flask. The mixture was heated to a constant temperature of 80° C. After 10 minutes, a feed of the monomer stock solutions was added in 100 steps and a feed of the initiator was added in 10 steps over a 5 hour interval. After the reagents were added, the mixture was left under stirring at 80° C. for 1 more hour. Before cooling, the mixture was diluted with 200 ml of isopropanol. Once at room temperature, the polymer was precipitated by a slow addition of ethanol (up to 3 liters). The precipitate was washed several times with ethanol then re-dissolved in isooctane/isopropanol 50/50% volume and the precipitation with ethanol was repeated. After several washes with ethanol the precipitate was placed in a plastic flask and dried under vacuum at 65° C. for 48 hours.
The polymer was then characterized by H1 NMR and gel permeation chromatography (GPC). The molar ratio of the incorporated EHMA, MMA, and MEMA units contents in the polymer were determined by 1H NMR to be 60 mol. % EHMA, 33 mol. % MMA, and 7 mol. % MEMA. Analysis of the polymer with GPC showed a broad peak with a weight-average molecular weight (Mw) of 182,000 g/mol and polydispersity index (Mw/Mn) of 2.08. The glass transition temperature for the polymer was found to be Tg=32.0° C.
The following additional polymer libraries were synthesized and screened as described herein.
A) MAA (2 to 0.5 mol %) and EHMA/MMA (from 50/50 to 62/37 mole ratio).
B) MAA (1 mol %), MMA (from 32 to 42 mol %), MEMA (from 1 to 11 mol %), EHMA (remaining mol %).
All reactions were done on an 8 mL scale. For polymer library A, water was used as the solvent. For polymer library B, isooctane was used as the solvent. The total monomeric concentration for both reactions was 10 wt %. The amount of initiator used was 1 wt % compared to the total monomer in the mixture. The hydrophobic and charged monomer stock solution has a concentration of 15 wt % in the solvent.
The complete disclosures of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.
This application claims the benefit of U.S. Provisional Application No. 60/789,757, filed Apr. 6, 2006, the entire content of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60789757 | Apr 2006 | US |
