A method for detecting the in vitro release of ophthalmic implants

Abstract

This invention discloses a method for detecting the in vitro release of ophthalmic implants, comprising: incubating a container containing the ophthalmic implant and a release medium in an instrument providing constant temperature, and sampling at predetermined time points to detect the release of the ophthalmic implant, wherein the release medium is 1,4-dioxane. This method uses 1,4-dioxane as the release medium and employs a dissolution apparatus or a shaker, shortening the release time of the ophthalmic implant, and is low in cost and simple to operate.

Description

Technical Field

[0001] This invention belongs to the field of ophthalmic medicine, and more specifically, this invention generally relates to a method for detecting the in vitro release rate of an ophthalmic implant. Background Technology

[0002] Cyclosporin A (CsA) is a highly effective, non-myelotoxic immunosuppressant with highly selective inhibitory effects on cellular immunity and humoral immunity caused by thymus-dependent antigens; it is a third-generation immunosuppressant. Its systemic or topical efficacy in reducing immune rejection after corneal transplantation and treating certain autoimmune eye diseases is widely recognized. However, systemic CsA administration is not only expensive but may also cause complications such as liver and kidney toxicity and hypertension. Currently, CsA treatment for eye diseases is primarily done with eye drops. However, due to its large molecular weight and hydrophobic nature, CsA has poor permeability within the eye and is affected by tear dilution and flushing, making it difficult to achieve effective therapeutic concentrations within the eye.

[0003] Therefore, researchers in this field are dedicated to developing ophthalmic implants. In addition to avoiding the adverse reactions of systemic medication, CsA ophthalmic implants also have the characteristics of accurate dosage, sustained release and long-lasting effect, and can effectively improve the bioavailability of CsA. They can be used to treat a variety of chronic ophthalmic diseases that require long-term medication.

[0004] Since intraocular implants are a novel type of drug formulation, requiring very small doses and capable of slow release within the eye over a long period, achieving a high level of therapeutic effect, ensuring their effective release is of paramount importance. Therefore, it is necessary to develop an accurate and effective method to detect the actual extent of their release within the eye. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for accurately and effectively detecting the release rate and / or release extent of ocular implants in the eye.

[0006] The present invention provides an ocular implant comprising: incubating a container containing an ocular implant and a release medium in an instrument providing a constant temperature, and sampling and detecting the release of the ocular implant at predetermined time points, wherein the release medium is 1,4-dioxane.

[0007] In a preferred embodiment of the present invention, the ophthalmic implant may comprise an active ingredient and a pharmaceutically acceptable carrier, preferably, the weight ratio of the active ingredient to the pharmaceutically acceptable carrier is 1:5 to 5:1 (e.g., 1:4, 1:3, 1:2, 1:1, 2:1, 3:1 or 4:1, etc.), more preferably 1:2 to 2:1.

[0008] In a preferred embodiment of the present invention, the active ingredient of the ophthalmic implant may be selected from cyclosporine, atropine, aflibercept, conbercept, or tetracycline, but is not limited thereto.

[0009] In a preferred embodiment of the invention, the pharmaceutically acceptable carrier may be selected from polyglycolic acid (PGA), polylactide (PLA), polycaprolactone (PCL) or polylactic acid-glycolic acid copolymer (PLGA), preferably polylactic acid-glycolic acid copolymer.

[0010] In a preferred embodiment of the present invention, the release medium may be an aqueous solution of 1,4-dioxane at a concentration of 10% to 40% (e.g., 10%, 15%, 20%, 25%, 30%, 35%, 40% or any value therebetween), preferably a 40% aqueous solution of 1,4-dioxane.

[0011] In a preferred embodiment of the present invention, the instrument providing constant temperature can be a water bath constant temperature dissolution apparatus or a water bath constant temperature oscillator, preferably a water bath constant temperature oscillator.

[0012] In a preferred embodiment of the present invention, the rotation speed of the oscillator can be 50-100 rpm (e.g., 50 rpm, 75 rpm or 100 rpm, etc.), preferably 75 rpm.

[0013] In a preferred embodiment of the present invention, the constant temperature can be maintained within 37°C ± 0.5°C.

[0014] In a preferred embodiment of the present invention, the incubation time can be 12-24 hours (e.g., 12 hours, 18 hours, or 24 hours).

[0015] In a preferred embodiment of the present invention, the sampling can be performed at time points with intervals of 0.5-2 hours (e.g., 0.5 hours, 1 hour, or 2 hours). More specifically, taking an incubation time of 12 hours as an example, samples can be taken at time points of 1, 3, 5, 7, 9, and 11 hours, with each sample being, for example, 1 ml, and fluid can be added or not after sampling.

[0016] In a preferred embodiment of the present invention, the detection of the release of the ophthalmic implant can be performed by high-performance liquid chromatography (HPLC). More specifically, octadecylsilane-bonded silica gel can be used as the packing material; acetonitrile-water (65:35) can be used as the mobile phase; the flow rate is 0.35 ml per minute; the column temperature is 65°C; and the detection wavelength is 210 nm.

[0017] Compared with the prior art, the in vitro release method for ophthalmic implants of the present invention uses 1,4-dioxane as the release medium and employs a dissolution apparatus or a shaker, which shortens the release time of ophthalmic implants and is lower in cost and simpler to operate. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 Release curves determined by a dissolution apparatus method according to an embodiment of the present invention are shown; and

[0020] Figure 2 The release curve measured by the oscillator method according to one embodiment of the present invention is shown. Detailed Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] Example

[0024] Example 1: Screening of Release Media

[0025] To more accurately and effectively detect the release of ophthalmic implants, it is necessary to screen release media that meet the leakage conditions. As used in this article, the term "leakage condition" refers to the concentration of the drug in the release medium being much lower than its saturation concentration. Physiologically, this means that the drug is rapidly absorbed in the body. In vitro assays of formulations, including release rate measurements, need to mimic in vivo physiological conditions to satisfy the drug dissolution-absorption process. The leakage condition plays a corrective role. Generally, the volume of the release medium is 3-5 times the volume of the medium required for a saturated drug solution.

[0026] Specifically, cyclosporine (CsA) ophthalmic implants were first prepared according to the composition and process in Table 1 below.

[0027] Table 1

[0028] Material ratio Preparation process Implant appearance Specification PLGA:Cyclosporin A = 54.5%:45.5% freeze-drying + stamping cylindrical implant 1mg

[0029] The solubility of the CsA ophthalmic implant prepared above was tested in different media, and the results are shown in Table 2 below.

[0030] Table 2

[0031] medium Solubility / μg / mL 10 mmol / L PBS (phosphate buffer) 5.9 10 mmol / L PBS + 0.1% SDS (sodium dodecyl sulfate) 8.9 10 mmol / L PBS + 0.2% SDS 25.8 10% 1,4-dioxane aqueous solution 75.1 20% 1,4-dioxane aqueous solution 218.9 40% 1,4-dioxane aqueous solution 556.56

[0032] Among them, 10 mmol / L PBS + 0.2% SDS is a commonly used medium for in vitro release testing of implants. However, as can be seen from Table 2 above, cyclosporine A has significantly better solubility in 1,4-dioxane. Therefore, using 1,4-dioxane as the release medium will be more helpful in detecting the in vitro release of cyclosporine A ophthalmic implants.

[0033] Example 2: Screening of release medium volume

[0034] Furthermore, the CsA ophthalmic implant prepared above was tested using a dissolution apparatus at a medium temperature of 37°C and a rotation speed of 75 rpm, using different media and volumes. The results are shown in Table 3 below.

[0035] Table 3

[0036]

[0037]

[0038] Based on the solubility of CsA ophthalmic implants in different media and volumes, as well as the leakage conditions in Table 3, 100 mL of 40% 1,4-dioxane aqueous solution will be selected as the release medium for subsequent experiments.

[0039] Example 3: Instrument Screening

[0040] 1) Take self-made implant samples with different process parameters. The sample information is shown in Table 4 below.

[0041] Table 4

[0042] Sample number Preparation process Extrusion appearance Implant No. 6 Hot melt extrusion once cylindrical rod Implant No. 7 Hot melt extrusion twice cylindrical rod

[0043] 2) Dissolution tests were performed using a dissolution apparatus and a shaker, respectively. The test parameters are shown in Table 5 below.

[0044] Table 5

[0045]

[0046]

[0047] 3) After sampling, octadecylsilane-bonded silica gel was used as the packing material, with acetonitrile-water (65:35) as the mobile phase, a flow rate of 0.35 mL / min, a column temperature of 65℃, and a detection wavelength of 210 nm. The release rate detection results are shown in Tables 6 and 7 below, and the release curve results are shown in Tables 6 and 7 below. Figure 1 and Figure 2 As shown;

[0048] Table 6

[0049]

[0050] Table 7

[0051]

[0052]

[0053] From Table 6-7 and Figure 1-2 The results show that when using the shaker method, the cumulative release rates at 11 hours were 93.85% and 84.55%, respectively, which were higher than the 83.78% and 68.61% of the dissolution apparatus method. Furthermore, the RSD of the six parallel tests of the same batch was smaller. A smaller RSD indicates better repeatability. Compared with the dissolution apparatus, the shaker has a higher cost-performance ratio and is easier to operate.

[0054] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0055] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0056] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for detecting the in vitro release of an ophthalmic implant, comprising: A container containing an ophthalmic implant and a release medium is incubated in a temperature-controlled instrument, and samples are taken at predetermined time points to detect the release of the ophthalmic implant, wherein the release medium is 20% to 40% 1,4-dioxane, and the active ingredient of the ophthalmic implant is cyclosporine A.

2. The method according to claim 1, wherein, The ophthalmic implant contains an active ingredient and a pharmaceutically acceptable carrier.

3. The method according to claim 2, wherein, The weight ratio of the active ingredient to the pharmaceutically acceptable carrier is 1:5 to 5:

1.

4. The method according to claim 2, wherein, The weight ratio of the active ingredient to the pharmaceutically acceptable carrier is 1:2 to 2:

1.

5. The method according to claim 2, wherein, The pharmaceutically acceptable carrier is selected from polyglycolic acid (PGA), polylactide (PLA), polycaprolactone (PCL), or polylactic-co-glycolic acid copolymer (PLGA).

6. The method according to claim 5, wherein, The pharmaceutically acceptable carrier is a polylactic acid-hydroxyacetic acid copolymer.

7. The method according to claim 1, wherein, The instrument providing constant temperature is a water bath constant temperature dissolution apparatus or a water bath constant temperature oscillator.

8. The method according to claim 7, wherein, The oscillator rotates at a speed of 50-100 rpm.

9. The method according to claim 7, wherein, The oscillator rotates at 75 rpm.

10. The method according to claim 1, wherein, The constant temperature is maintained within 37℃±0.5℃.

11. The method according to claim 1, wherein, The incubation period is 12-24 hours.

12. The method according to claim 1, wherein, The sampling was carried out at time points ranging from 0.5 to 2 hours.

13. The method according to claim 1, wherein, The release of the ophthalmic implant was detected by high-performance liquid chromatography.

Images