Patent Application
20130301043
The invention relates to the field of monitoring the nature of samples by Raman spectroscopy. In particular, the invention can be particularly used for the analytical quality control (AQC) of products prepared extemporaneously in hospital pharmacies.
The “certification of therapeutic objects (OT)” via the legal in situ AQC concept, aims in fact to guarantee the parameters, identity, purity and concentration of the molecules of interest. These products can be of high added value (for example monoclonal antibodies), or require precautions for use (for example a cytotoxity for products intended for chemotherapies).
In the best case, this analysis should be fast (result in a few minutes and before perfusion to the patient), have no effect on the sample, and not require the sample to be sampled for control purposes (some samples cannot be sampled without being destroyed).
With this in mind, Raman spectroscopy offers a certain number of advantages:
The use of Raman technology also makes it possible to identify, and still non-intrusively, the vehicle (NaCl 0.9%, G5%, water ppi etc.) conveying the molecule of interest.
The principle of Raman spectroscopy is as follows: the radiations of a powerful monochromatic source (laser) are conducted in an optical fiber, and focused on the sample to be analyzed, thus provoking its excitation. The light scattered by the sample is collected by a sensor, then routed by an optical fiber to the separator (monochromator). Coupled to a detector, the latter then supplies data concerning the sample which has then only to be processed by computer. Generally, the light scattered either at 180° or at 90° is collected.
By comparison with reference spectra, it thus becomes possible to characterize the nature of the product present in the sample, its concentration, as well as the presence of any impurities.
It is a local measurement technique: the laser beam is focused on a small part of the sample, and makes it possible to study the properties of this sample on a volume of a few cubic microns.
This technology has already been used to analyze gelatine capsules, or injectable solutions, and, in particular, directly in plastic bottles.
The particular issue that arises in the hospital environment for the implementation of AQC is the diversity of the therapeutic objects to be studied, both in their composition and in the nature and the form of the container. In practice, these therapeutic objects, when injectable solutions are involved, can be present in syringes (of varying volumes), perfusion bags, bottles, beakers or similar vessels, ampoules or portable infusers.
Portable infusers are light and disposable devices for allowing a slow and continuous perfusion of chemotherapy. The chemotherapy product is contained in a flexible balloon tank, which is itself placed inside a rigid container.
The wide variety of the therapeutic objects and of their geometry demands the availability of a system that makes it possible to apply the Raman spectroscopy method to these objects, easily. Moreover, since hospital pharmacies prepare many therapeutic objects, it is necessary to be able to replace one object with another rapidly, without the parameterizing of the excitation light source being difficult to perform. Finally, the operators should also be protected from any exposure to the laser beam or the scattered light.
The invention thus relates to a chamber for analyzing a sample by Raman spectroscopy, characterized in that it in the form of an opaque parallelepiped, having
The terms “vertical”, “bottom” are linked to the way in which the chamber is preferentially put in place during its use for analyzing a sample. De facto, this clearly means that the hatch for introducing a sample is located on a first wall. The first orifice and the means (4) for fastening a light source to supply an excitation radiation and a lens (22) allowing for the convergence of the excitation radiation in order to define a focal point of the excitation radiation are located on a second wall which is therefore at right angles (perpendicular) to the first wall.
The second orifice and the fastening means of a sensor making it possible to detect the Raman scattered light are located on a wall which is not parallel to (facing) the second wall.
In this embodiment, the light source (laser head) and the lens are located on the bottom wall of the chamber according to the invention. The light is thus sent from bottom to top. This embodiment is preferred because it makes it possible to characterize the sample placed on the base plate of the bottom wall, above the first orifice.
However, in other embodiments which also form part of the invention, it is possible to locate the head of the laser on a flank (the first orifice then being in a side wall of the chamber), this amounting in fact to “turning” the chamber during its use. It is also possible to locate several laser heads, for the acquisition of Raman data in different points of the sample. In this case, it should however be checked that there is no interference between the different detectors, in order for each of them to detect the light scattered after excitation by a specific head.
As has been seen, Raman spectroscopy amounts to collecting and analyzing the light scattered by the sample after excitation, generally at 90° or 180° from the axis of the excitation laser beam.
In a preferred embodiment, the second orifice is combined with the first orifice. In this embodiment, the scattered light is collected at 180°. In this embodiment, the fastening means (4) and the fastening means of said sensor are also combined. They then contain two optical fibers (one bringing the light permitted via the laser head, and the second conveying the light scattered by the sample to the monochromotor and the detector).
Because of the great variability of the therapeutic objects to be tested, and in particular the thickness of the containers, it should be possible to move the focal point of the excitation light, in order for it to be located in the sample, at approximately 1 cm above the container of the therapeutic object. This distance in particular makes it possible to avoid the “edge effects” linked to the container.
As mentioned above, the laser (parallel monochromatic light source) is coupled to a lens allowing for the convergence of the light beams in a small volume of the sample that is to be analyzed. The distance between the lens and the point of convergence is known to the operator and is expressed by the focal length of the lens.
In one embodiment, the fastening means (4) make it possible to move, together, both the light source (the laser head) and the lens.
In another embodiment, the laser head is fixed relative to the bottom wall of the analysis chamber, and only the lens can move on the vertical axis.
In a preferred embodiment, said fastening means (4) of said light source and of the lens comprise a light-tight sleeve, fastened to the bottom wall of the chamber.
In a particular embodiment, this sleeve is screwed to the bottom wall of the illumination chamber. In this embodiment, recesses can be machined in the base plate, to introduce the screws, in order to maintain the flatness of the base plate after fastening the sleeve.
The light-tightness of the sleeve is obtained by producing the latter in an opaque material (such as polycarbonate). This makes it possible to both avoid the “contamination” of the light beam by the ambient light and protect the operators.
In a particular embodiment, the adjustment means of the moving assembly (which is the light source and the lens when these two elements are attached together or the lens alone) comprise a millimetric screw. The use of a millimetric screw thus makes it possible to move on the elements that have to be able to move on the vertical axis very accurately. It is thus possible to use a millimetric screw allowing for positioning to within a hundredth of a millimeter. The principle of the millimetric screw is to induce a translational movement from a rotational movement of the screw. The screw pitch makes it possible to define the accuracy of the screw (translational movement for each turn of the screw).
In a preferred embodiment, this screw is linked to a counter making it possible to know the movement of the screw, equal to that of the moving assembly, and therefore the height of the focal point within the chamber according to the invention.
By way of illustration, it is assumed that the focal length of the lens is 20 mm, and that the moving assembly is flush with the base plate of the chamber at the point 0 of the counter. This means that the focal point of the light is located 20 mm above the base plate.
If the aim were to analyze a sample present in a plastic container 1 mm thick, it would therefore be necessary to obtain the focus at 11 mm above the base plate (approximately 1 cm into the sample), which would therefore mean lowering the mobile object by 9 mm.
If the sample is present in a syringe having a thickness of 3 mm, the moving object is lowered by 7 mm.
The person skilled in the art thus determines the adjustment to be made to the moving object as a function of the focal length of the lens, and of the nature of the therapeutic object, and in particular the thickness of the container.
The chamber according to the invention (Raman illumination chamber) may be fastened on a frame comprising feet.
This frame may also comprise means making it possible to adjust the height of the chamber relative to the frame (for example adjustable feed on screw jack). In this case, it may be advantageous for the chamber to include flatness measuring means, such as a spirit level, in order to check that the base plate is perfectly horizontal.
The walls of the chamber are machined from any opaque material. It should be noted that the different walls may be made of different materials. In a preferred embodiment, a material is used, at least for the base plate, that makes it possible to guarantee the best possible flatness, by avoiding relief irregularities on the base plate to the greatest possible extent. It is thus possible to use polycarbonate or carbon material. The thickness of the walls of the chamber according to the invention is defined by the person skilled in the art, is generally greater than 0.5 cm and generally does not exceed a few centimeters. It is thus possible to use walls of carbon 1 cm thick.
The opacity of the chamber makes it possible to avoid measurement interference that might be due to the ambient light when implementing the Raman spectroscopy measurement. It also makes it possible to protect the operators.
The hatch for introducing the sample into the chamber according to the invention can be of any kind. It is, however, important for it to preserve the opacity of the chamber once closed. A seal can therefore be provided for this purpose.
The hatch may thus slide guillotine-fashion along a side wall (from top to bottom or from bottom to top). It may also be open via a system of hinges, or a rack (motorized or not). It is also possible to envisage return systems (such as springs) making it possible to assist the operator in closing this hatch after the sample has been put in place. It may be fastened in the closed position by any means (magnet, hook etc.).
The invention also relates to a method for analyzing a sample present in a container comprising the steps of
Obviously, the excitation radiation is emitted via a light source fixed to the fastening means (4).
The detection of the Raman scattered light is obviously performed via a sensor fixed to the fastening means of a sensor of said chamber.
As has been seen, this method is particularly useful when said sample is a liquid solution, and said container is chosen from a syringe, a perfusion bag, a bottle, a beaker or similar vessel, an ampoule, a portable infuser.
In another embodiment, the method is implemented with a sample which is solid, said container being chosen from a gelatin capsule, a capsule, a solid cladding.
It is, however, also possible to implement this method on solid samples with no container, and in particular tablets. This embodiment also falls within the framework of the invention.
In one embodiment, the excitation radiation is emitted for a duration of between 1 second and one minute.
The excitation duration is defined by the operator and depends in particular on the power of the laser, and on the nature of the sample to be analyzed.
In order to increase the analysis quality, the sample is often subjected to a number of excitation radiations, and the average of the data collected for each excitation is taken.
It should be noted that the present invention also covers the use of Raman spectroscopy, in general, for characterizing the content of a portable infuser.
The invention also covers the use of Raman spectroscopy, in general, for characterizing a cancer treatment, as described in the examples.
A range of intensity of linear peaks is obtained as a function of the concentration (1 to 20 mg/mL); r2>0.99 (n=9); significant slope (P<0.001−Test F)
The variation of the slopes of the reference ranges<5% and a same-day and between-day reproducibility of the data is observed.
These results show that this technology is applicable to oxazaphosphorines.
The same hardware is used as in example 1.
Application of Raman spectroscopy (SR) to AQC for syringes of doxorubicin and epirubicin, in an NaCl 0.9% or glucose 5% vehicle.
These molecules exhibit epimerization: inversion of steric configuration of the fourth carbon of the glucidic fraction and of the UV spectra: identical (λmax 254 nm).
The results obtained show that the Raman spectroscopy makes it possible to measure the concentration of the two products in solution, regardless of the vehicle used, with a good linearity.
Moreover, two characteristic wavelengths (465 cm−1 and 350 cm−1) can be observed for the doxorubicin, making it possible to differentiate it from epirubicin.
The nature of the spectra observed also makes it possible to differentiate the vehicle used.
The same hardware is used as in example 1.
The problem with portable infusers is that it is impossible to sample the sample once introduced in the infuser without destroying the infuser. Moreover, the presence of two containers surrounding the sample reduces the strength of the excitation signal (each container absorbing a portion of the excitation energy).
It was possible to show that, despite the presence of the two containers, the Raman spectrometry makes it possible to qualify the nature of the product contained in the portable infusers.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10581167 | Oct 2010 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP11/67533 | 10/7/2011 | WO | 00 | 7/10/2013 |
