Patent Application
20080161234
The present invention relates to a composition comprising lactic acid for the treatment and/or prophylaxis of conditions in the urogenital tract.
It also relates to the use of such a composition for the preparation of a medicament for the treatment and/or prophylaxis of conditions in the urogenital tract as well as to a method for the treatment and/or prophylaxis of conditions in the urogenital tract.
Acidity is believed to be one of the protective mechanisms of the vagina. This acidity has been associated with a decreased risk of infections such as chlamydia, genital mycoplasma, trichomoniasis, urinary tract infection and a decreased carriage of bacteria in the introitus (Hanna, N et al 1985, 1975, Stamey T A and Kaufman M F 1975, Stamey T A and Timothy M M 1975).
In contrast, imbalance of the vaginal microbiota, bacterial vaginosis (BV), has been associated with premature birth, increased risk of sexually transmitted diseases, increased risk of HIV infection, and pelvic inflammatory disease (Schwebke, J R, 2003, Obstet Gynecol Clin North Am. 30:685-94; Eschenbach, D A, 1993, Am J Obstet Gynecol, Vol 169:441-5; Taha et al, Aids, 1998, Vol 12:1699-706, Hillier, S L, et al, 1996, Am J Obstet Gynecol, Vol 175: 435-41).
During the perinatal period and from menarche to menopause the vagina is most acidic. The vagina is believed to be acidified by the anaerobic metabolism of vaginal glycogen to acidic products, predominantly acetic and lactic acids. Whether this metabolism is performed by vaginal bacteria and/or epithelial cells is still under debate (see review Pybus and Onderdonk 1999).
A favourable environment for the lactate producing microbiota is generally present, and results in a pH of approximately 4 in the mucousal secretions. However, the environment can be disturbed by factors such as variations in the oestrogen concentration during certain periods of the menstrual cycle and during the menopause, and also by an increasing occurrence of secretions of various types, for example from protracted menstrual haemorrhages, premenstrual bloody discharges, mid-cycle bleeding and ejaculate. Foreign bodies in the vagina, for example coils, pessaries and those inserted, for example, in connection with antibiotic treatment and on washing can also lead to a disruption of the healthy microbiota which is such that the pH rises. When the pH rises above 4.5 there is an increased tendency towards growth of anaerobic bacteria.
Disruptions of the normal microbiota in the vagina without inflammatory reactions in the mucous membrane are referred to as BV and lead to offensive discharges and pH's over 4.5, but they are not generally regarded as an actual disorder. However, BV is an indication that the defense against infection, which is partly conferred by a low pH, has been weakened and, under unfavourable circumstances, this leads to actual infection.
Shifts in the microbiota are associated with shifts in vaginal pH (Caillouette J C et al 1997). During BV the vaginal pH rises and a shift from being lactobacillus dominated to a biota in which Gardnerella vaginalis and anaerobic bacteria predominate is observed. The presence of anaerobic bacteria gives rise to offensive discharges and volatile amines at the increased pH (above 4.5).
The odour produced by an increased pH of vaginal fluid in BV is due to the presence of amines. The discharge in BV contains an increased concentration of several amines which are produced by anaerobic bacterial decarboxylation. Amines become volatile and thus odourous when they exist in the unprotonated form (free base). However, after addition of a strong acid the amines are converted to a protonated form (salt) and are not volatile. Lactic acid is a strong acid and thus suitable to diminish malodorous discharge.
By lowering the pH of the vagina with lactic acid it would make it easier for lactobacillus species to recolonize the vagina and thereby restore the natural resistance toward overgrowth by bacteria connected with BV. Lactate (i.e. salt of lactic acid) given in a gel containing growth substrate (glycogen) for lactobacillus has shown to be effective against elevated pH and bad odour in BV. (See EP 0 257 007)
The lactate-gel provides an acidic lactic acid cream containing glycogen without preservatives. Glycogen is found in abundance in the vaginal epithelial cells in fertile women and is an important nutrient substrate for the lactobacilli.
Compared with creams which contain only lactic acid or acidic creams with preservatives, the lactate-gel has been shown in vitro to have twice as favourable an effect on the survival of the lactobacilli. It can thus be used for re-establishing a normal environment in cases of BV.
The lactate gel has also been shown to have some antibacterial effect against certain BV-associated bacterial species due to its low pH. (See Andersch B et al; “Treatment of Bacterial Vaginosis with an Acid Cream: A Comparison between the Effect of Lactate-Gel and Metronidazole”, Gynecol obstet Invest 21: 19-25 (1986)). However, no effects have been observed against yeast, such as C. albicans and C. krusei.
Conventional methods for treating fungal infections in the vagina generally involve the administration of antibiotics, e.g. imidazole derivatives. There are of course many incentives for reducing the use of antibiotics, e.g. due to the development of resistance.
Further, it is difficult to diagnose whether a patient suffers from BV or a fungal infection. This leads to the prescription of antibiotics as a matter of precaution, resulting in unnecessary excessive administration of antibiotics.
It would of course be very useful to obtain a non-antibiotic treatment, which beside having the abovementioned characteristics of lowering the vaginal pH and diminishing odour, also is effective for treating or preventing BV and/or fungal infections, particularly yeast infections. Ideally, the treatment should be effective irrespective of whether a patient suffers from, or is at risk of contracting, BV or fungal infection. Until now, no such possibility has been provided.
An aim of the present invention is to provide a more efficient composition for the treatment of urogenital conditions, which lowers pH and is effective against bad odour, and which is also effective for treating bacterial vaginosis and fungal infections, in particular fungal infections caused by yeast species.
This aim is achieved by a composition comprising lactic acid, characterized in comprising lactoferrin (LF) and/or a peptide fragment thereof.
The incorporation of LF, and/or a peptide fragment thereof, enhance the antimicrobial activity of the composition and it may thus be used for the purpose of inhibiting the growth of and/or killing undesired bacteria and fungi in the urogenital tract, in particular the vagina.
The concentration of LF and/or a peptide fragment thereof may be in the range of 0.0001 to 100 mg/ml, in particular 0.001 to 10 mg/ml or 0.01 to 5 mg/ml, and said LF may be recombinant human LF. Said peptide fragment of lactoferrin may be synthetic or recombinant.
The concentration of lactic acid may be in the range of 0.1 to 10% (i.e. 1 to 100 mg/ml).
The composition may further comprise a neutralizing substance, and the content of lactic acid and neutralizing substance is preferably such that the pH lies within the range of 3.5 to 4.5.
The composition may further comprise a growth substrate for lactic acid bacteria, and the weight ratio of lactic acid to growth substrate is preferably in the range of 20:1 to 500:1, more particularly about 50:1.
The composition may further comprise an inert vehicle and/or a consistency agent.
The composition may be e.g. in the form of a cream, a gel, a vaginal suppository, a tablet or a spray.
Furthermore, the invention relates to the use of a composition according to the above for the preparation of a medicament for the prophylaxis and/or treatment of conditions in the urogenital tract. The medicament has an antimicrobial activity.
The conditions to be treated and/or prevented comprises an elevated pH and/or a disturbed microbiota in the urogenital tract. A disturbed vaginal microbiota is characterized by abnormally high levels of BV-associated bacteria (anaerobic gram-negative bacteria, anaerobic gram-positive cocci, staphylococci streptococci, E. coli) and/or Candida, in combination with abnormally low levels of lactobacilli.
The invention also relates to a method for the prophylaxis and/or treatment of the abovementioned conditions.
There are several advantages with the composition according to the present invention:
Lactoferrin (LF), which is described as an antibacterial agent, a modulator of the inflammatory response, and an immunoregulatory protein, is a single chain iron-binding glycoprotein. LF is found in colostrum and mature milk at levels of 2-7 g/l. In colostrum, LF makes up 43% of the total protein content. Other exocrine secretions like saliva, tears, bronchial mucus, and cervicovaginal fluid also contain LF (table 1).
It is remarkably resistant to proteolytic degradation by trypsin and trypsin-like enzymes. Pepsin digestion, however, give rise to a peptide fragment, lactoferricin, which is strongly bactericidal against a wide spectrum of bacteria in vitro. Both LF and lactoferricin are bactericidal and fungicidal in vitro.
It is of great importance to maintain the balance between the microorganisms in the vagina. In the treatment of BV (offensive discharges caused by imbalance in the vaginal biota without inflammation) it is important to re-establish the lactobacillus-dominated biota.
In the research work leading to the present invention, it was found that surprisingly good synergy effects could be obtained by combining the known lactate, described above, with LF and/or peptide fragments thereof.
Thus, the present invention provides an acidic lactic acid composition containing LF and/or peptide fragments thereof. The composition according to the present invention reinforces the natural protection mechanisms of the vaginal mucosa by helping to re-establish the productive environment for lactobacilli, lowering the pH and also by exerting an antimicrobial activity on a number of microbes, e.g. C. albicans, E. coli, S. aureus, G. vaginalis, and Prevotella species.
LF for use in the present invention may be human LF, recombinant human LF (rHLF), or bovine LF.
By human LF is meant LF purified from humans, e.g. from human milk.
By recombinant human LF is meant LF produced in pro- or eucaryotic cells (bacteria, fungal cells, plants, or animals) by hybride-DNA technology.
Peptide fragments of LF may also be used in the present invention, either alone or in combination with LF. It is possible to use either one kind of peptide fragment or two or more different kinds of peptide fragments.
By “peptide fragments of LF” is meant peptides of various sizes, based on the antimicrobial region of the LF molecule from the N-terminal end. The peptide fragment sequence is based on the sequence constituted of the amino acids (a.a.) 1-40, in particular the amino acids 12-40, of human LF counted from the N-terminal end. Synthetic as well as recombinant peptides may be used. An example of a LF peptide is lactoferricin. Another one could be the 25 or 23 amino acid long peptide starting from a.a.residue at position 16 or 18, respectively, from the N-terminal end. LF peptides suitable to be used in the present invention are described in the international application having publication number WO 00/01730.
The concentration of LF and/or a peptide fragment thereof may e.g. be in the range of 0.0001 to 100 mg/ml, 0.0001 to 1 mg/ml, 0.001 to 10 mg/ml, 0.01 to 5 mg/ml, or 1 to 50 mg/ml. In particular, the concentration of LF and/or a peptide fragment thereof is in the range of 0.001 to 10 mg/ml, or in the range of 0.01 to 5 mg/ml.
The concentration of lactic acid may e.g. be in the range of 1 to 100 mg/ml or 10 to 100 mg/ml.
Furthermore, lactate, i.e. salt of lactic acid, may be used in the present invention.
The composition may comprise a neutralizing substance for buffering the pH of the lactic acid. Examples of neutralizing substances are sodium hydroxide and ammonia.
The content of lactic acid and neutralizing sub-stance may be such that the pH lies within the range from 3.5 to 4.5, preferably close to 3.8. The pH is advantageously not so low that the acid irritates the tissues or impairs the environment for the lactobacilli which require a moderately acid environment. A pH of 3.7-3.9 has been shown to be particularly advantageous.
The composition may further comprise a growth substrate for lactic acid bacteria. The growth substrate is preferably α(1-4) glucans containing α(1-6) branches.
An example of a suitable growth substrate is glycogen, which is found in abundance in the vaginal epithelial cells in fertile women and is an important nutrient substrate for lactobacilli. Glycogen is used as the growth substrate for the lactobacilli, so that the treatment not only results in adjustment of the pH level to a lower figure by means of supplying lactic acid, but also to re-establishment of an advantageous environment for the growth of the lactobacilli in order to regenerate the natural conditions. Other examples of growth substrates are lactose, dextrose, glucose, and amylopectin.
Lactic acid is incorporated in a considerably greater weight proportion than the growth substrate, for example in weight ratios of 20:1 to 500:1, in particular 50:1.
The composition according to the invention may be in the form of a cream, a gel, a spray, a tablet or a vaginal suppository. The composition according to the present invention consequently has a cream or gel consistency, a tablet consistency, a consistency suitable for spray administration, or is given the form of a vaginal suppository or a tablet.
The composition according to the invention may be vaginally, perorally or transdermally administered.
A vehicle for the active constituents of the composition may be added to form a usable pharmaceutical product. The composition according to the present invention may contain vehicles which are of a type which is inert in this connection, and which provide cream- or gel-like consistency, or a consistency suitable for spray administration. Alternatively, the inert vehicle is a substance which melts at body temperature and in body fluid.
If a vaginal suppository is to be produced, a vehicle is required which makes it possible to form an article which is relatively solid at room temperature and in a dry environment, but which melts at body temperature and in contact with body fluid. In this connection there may be used polyethylene glycol, PEG, which gradually melts in the vaginal environment.
One suitable vehicle for a cream is propylene glycol, but other substances of an inert nature are also known to be of use in this connection as vehicles, e.g. triglycerides.
The composition according to the present invention may further comprise a consistency agent such as, in the case of creams and gels, methyl hydroxypropyl ether of cellulose. As an example of a commercial product that may be mentioned is Hypromellosum® 90 HG 4000. Another example of a consistency agents is corn starch.
By a “condition in the urogenital tract” is meant any disturbance or disorder in the urinary tract or in the genital organs in a female and/or male. In particular, the invention is suited for the treatment of conditions in the vagina.
A condition to be treated according to the invention may involve an elevated pH and/or a disturbed microbiota in the urogenital tract. By an “elevated pH” is meant a pH above 4.5.
By a “disturbed microbiota” is meant a biota having abnormally high levels of BV-associated bacteria, such as G. vaginalis, anaerobic gram-negative bacteria (Prevotella-, Bacteroides-, and Fusobacterium species), anaerobic gram-positive cocci, Mobiluncus species, and/or abnormally high levels of E. coli, staphylococci (S. aureus), and streptococci, all in combination with abnormally low levels of lactobacilli. Also high levels of Candida, which may result in vaginitis are considered a disturbed vaginal microbiota.
By an “abnormally high level” is meant a level which is 100 to 1000 fold higher than the level in a normal person.
By an “abnormally low level” is meant not predominating, i.e. not present or less than one lactobacillus morphotype per microscopical immersion field, or less or equal to other morphotypes per immersion field. (Assessment according to the “Nugent scoring system”, used internationally to describe bacterial imbalance in vaginal secretion. See Nugent R P et al 1991, J Clin Microbiol 29:297-301.)
By an “antimicrobial activity” is meant a bacteriostatic, fungistatic, bactericidal and/or fungicidal activity, i.e. the ability to retard the growth of and kill certain bacteria and fungi, respectively.
By “prophylaxis and/or treatment of a condition” is meant any treatment in order to cure or alleviate a condition according to the above, or to prevent the development of such a condition.
Examples of conditions to be treated with the composition according to the invention are bacterial vaginosis, intermediate vaginal microbiota, and yeast infections, e.g. Candida-infections (Candida vaginitis, Candida balanitis).
Further, the composition according to the invention may be used in the treatment of chlamydia, genital mycoplasma, trichomoniasis, urinary tract infection, pelvic inflammatory disease, and infections caused by human papillomavirus (HPV). In addition, any combinations of the aforementioned conditions may be treated with the composition according the invention.
The composition according to the invention may also be used e.g. in the treatment of fungal eczema, ulcerous nipples, as a profylaxis against sexually transmitted diseases, or as a glidant.
The composition according to the invention may also be used to treat bacterial and/or viral infections in the mouth, throat and/or nose. Further, it may be used to treat skin infections caused by bacteria and/or virus.
By a “pharmaceutically effective amount” is meant an amount of the composition according to the invention, which will lead to the desired pharmacological and/or therapeutic effect. The desired pharmacological and/or therapeutic effect is, as stated above, to cure or alleviate and/or prevent the development of conditions in the urogenital tract.
By a “patient” is meant any human or non-human mammal, female or male, in need of being treated with the composition and/or method according to the invention.
The composition according to the invention may further contain other substances, such as adjuvants, carriers, preservatives, vitamins, minerals, oestrogen etc, which are well known to persons skilled in the art.
Furthermore, it is possible to combine the composition according to the invention with other conventional pharmacological treatments of conditions in the urogenital tract, e.g. the treatment with antibiotics and/or antimycotics, such as imidazol preparations.
The composition may be in the form of a concentrate, intended to be diluted by the user before use. Such a concentrate is suitably diluted with e.g. pure water, aqueous solutions or saline.
Specific examples of a composition according to the present invention emerges from the following examplary compositions.
The bacterial strains S. aureus 1800 (CCUG 1800), E. coli 06, and the yeast C. albicans (ATCC 64549) have been used in the microplate assay. All microorganisms were cultured in brain heart infusion medium (BHI) on a shaker over night at 37° C. A volume of the culture was transferred to a new tube with BHI and incubated for two more h on the shaker. The bacteria were harvested in the log phase, washed once and thereafter suspended in the broth used for the microplate assay. The suspension was adjusted spectrophotometrically and diluted to a concentration of approximately 4×106 cells per ml at 650 nm.
L. gasseri and L. jensenii were cultured on chocolate-agar plates for 24 h in 5% CO2/95% air. They were thereafter harvested and added to BHI (0.34%). After washing the bacterial solutions were adjusted spectrophotometrically and diluted to 8×106 bacteria/ml.
G. vaginalis and P. bivia were cultured on chocolate-GL-plates for 48 h in anaerobic milieu. The bacteria were harvested and suspended in BHI for further incubation (4 hours at 37° C.). The bacteria were washed twice in Bactopeptone (BP, 0.2%). The concentration was adjusted spectrophotometrically and diluted to 1×107 bacteria per ml.
LF from human milk was purchased from Sigma (Saint Louis, USA). Recombinant human LF was obtained from Agennix. A peptide fragment composed of 23 amino acids based on the antimicrobial region of human LF was synthesized by the fmoc-strategy.
Washed cells were suspended in 0.2% BP (pH 7.0) or BHI medium diluted 1/10 (0.34%, pH 6.7-6.9) (Difco, USA). The concentration of bacterial or fungal cells was spectrophotometrically adjusted. LF or peptide, serially diluted in BHIdil or BP by twofold steps (unless otherwise stated), were added in triplicate to the wells of a microtiterplate (200 ul per well). The bacterial or yeast cell solutions were added in 10 ul volumes to give a final concentration of approximately 2×105 cells per ml. The concentration of the stock solution was always checked by viable counts. The microplate was incubated at 37° C. in a humid chamber for 2 h unless otherwise stated. Five ul were taken from each well and added as a drop onto a blood agar plate and incubated over night at 37° C. In some experiments more thorough viable counts were performed and the killing was expressed as remaining colony forming units in relation to the inoculum. The lower limit for detection of microorganisms was 200 CFU/ml.
The procedure for the microbicidal assay with regard to G. vaginalis and P. bivia was as described above except that the microplate was incubated under anaerobic conditions (2 h). Thereafter droplets of the solutions were analyzed for viable bacteria on blood agar plates after 48 h of anaerobic incubation at 37° C.
The antimicrobial activity of human LF was analysed by the microbicidal assay described above. Different microbes such as C. albicans, E. coli and S. aureus were analysed with respect to their survival in lactate (not containing the inert gel base, which makes the gel unsuitable for the microbicidal assay) containing LF.
Our results showed that LF enhanced the antimicrobial effect of lactate against C. albicans when lactate was diluted fivefold or more (≦1%) for all LF concentrations except 0.5 mg at dilution 1% of lactate (
The antibacterial activity of lactate towards E. coli and S. aureus was good both in the absence or presence of LF (Table 2 and 3).
The effects of LF and lactate was also analysed with two Lactobacillus strains (L. gasseri and L. jensenii) frequently found in the vagina (
In the next experiment a comparison between E. coli and L. gasseri was done in order to find out if different incubation conditions (0.34% BHI, CO2 incubator) would change the effects of LF. Thus E. coli was treated in the same way as L. gasseri.
As found earlier E. coli was sensitive for lactate, and L. gasseri was more resistant than E. coli in lactate with or without LF (
E. coli killing
S. aureus killing
The experiment indicated that L. gasseri was more resistant than E. coli to the effects of lactate and LF in combination, despite the poor survival of L. gasseri in LF without lactate.
The antibacterial activity of LF on G. vaginalis and P. bivia was also analysed. In this experiment the bacterial strains did not survive in our test system, despite the anaerobic condition. (See example 2 below for further experiments)
In summary, LF enhanced the antimicrobial activity of lactate against C. albicans, and E. coli. (although the magnitude of the activity was somewhat dependent on the LF as well as lactate concentrations regarding C. albicans).
At the undiluted lactate concentration the antimicrobial activity was complete without LF when analysed against C. albicans, S. aureus, and E. coli. It can also be concluded that it is not only the pH, which is important for the antimicrobial activity, but also the type of molecule giving rise to the low pH. Thus the α-hydroxipropionic acid, lactate, is more active in the presence of LF than HCl (
It may seem that LF in combination with lactate could be beneficial for the host against both unpleasant odours and antimicrobial imbalance.
The microbicidal assay was modified in order to obtain survival conditions for G. vaginalis and P. bivia. Instead of 0.2% BP 0.34% BHI was used. The bacterial strains were analyzed with only LF added in various concentrations to the wells (no lactate present). The plate was incubated for 20 hours.
Growth inhibition by LF was seen for all strains tested (
In a second series of experiment the minimal bactericidal concentration (MBC) at 99% killing was measured for seven strains of G. vaginalis (table 4). Out of those only one showed some growth when incubated with 2.5 mg of LF. Thus, an antimicrobial activity of LF on P. bivia and G. vaginalis as well was confirmed.
G. vaginalis, strain code:
The aim was to test whether rHLF would enhance the antimicrobial effects of lactate to the same extent as LF purified from human milk (Sigma).
The antimicrobial activity of lactate (not including gel base) containing rHLF was analysed by the microplate assay. The microorganisms C. albicans, E. coli and S. aureus were analysed.
In our first experiment rHLF and LF were compared under conditions without lactate (not shown). Analysis with the microplate assay showed that both LF preparations were similar in their microbicidal activity against E. coli, while LF was somewhat more active against S. aureus and C. albicans at concentrations of 0.25 and 0.125 mg/ml (2 h of incubation).
In the presence of lactate the strongest activities against C. albicans were obtained with undiluted lactate (5%), since no yeast cells survived (
In the following experiment higher concentrations of LF and rhLF were studied with regard to fungicidal effect on C. albicans (
Based on the results obtained with 2 mg of rHLF (see
To summarize, synergy effects were obtained by adding rHLF to the lactate. rHLF appeared somewhat weaker in its antimicrobial activity compared with LF when tested in a weak BHI medium (0.34%). In contrast, rHLF was somewhat stronger than LF in the presence of lactate (1 or 0.2%), except when using lactobacilli. This opposite effect on lactobacilli is beneficial for the host, since lactobacilli belong to the healthy normal microbiota. The results indicate that 2 mg/ml of rHLF could be a suitable concentration in lactate.
A peptide fragment based on the antimicrobial region of the LF molecule containing 23 a.a. was analysed for its fungicidal activity in the presence of lactate. As seen in
Thus, a short LF peptide fragment added antifungal activity to the lactate solutions.
To summarize the examples, the addition of LF to lactate enhanced the antimicrobial effect of it.
A synergy effect was obtained when combining lactate with LF/rHLF with regard to bacteria such as E. coli (
This synergy effect was unexpected since the addition of negatively charged molecules (lactate) would be expected to compete with the negatively charged groups on the bacterial surface for the interaction with the cationic LF. It is generally believed that electrostatic interaction with the negatively charged surfaces of microorganisms is the first step in the microbicidal activity of LF. For instance, it has been shown that increasing concentrations of phosphate and bicarbonate may decrease the fungicidal activity of human LF (Soukka et al., 1992, FEMS Microbiology letters 90:223-228).
It should also be emphasized that lactobacilli such as L. gasseri unexpectedly survived equally well in the lactate whether or not rHLF (
| Number | Date | Country | Kind |
|---|---|---|---|
| 0401631-7 | Jun 2004 | SE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SE05/00989 | 6/23/2005 | WO | 00 | 9/17/2007 |
