| CA, which is a 23-member macrolide lactone with potent immunosuppressive activity, was isolated from Streptomyces tsukubaensis. Lots of animal experiments and clinical trials indicate that CA has better immunosuppressive activity than cyclosporine A (10～100 fold), and has less adverse effect. In clinic, it is used primarily in prevention of transplant rejection but also for the treatment of autoimmune disorders, And it is effective for treating ocular disease such as corneal transplant rejection, dry eye disease, intractable uveitis, scleritis, allergic conjunctivitis and so on. At present, the listed dosage forms of CA are capsule, injection and ointment. Its eye drops was not listed at home and abroad. Because its eye drops belongs to the national second class new drug, So developing its eye drops is of important significance, this will bring enormous social and economic benefits. However, CA is scarcely solved and its solubility is only about 2μg/ml and it is very unstable in water, so the aim of this study is to prepare CA ophthalmic suspension. In this study, in order to obtain the high-quality ophthalmic suspension, firstly its solid dispersion formulation (SDF) was prepared, then to prepare CA ophthalmic suspension using its SDF as an intermediate. This method is superior to the traditional technologies such as mechanical crush or powder, the appearance of the eye drops is homogeneous with small particles, the scope of particle size distribution was narrow, and it has minor irritation and better security and compliance than its oil solution and eye ointment.Objective:To select the appropriate water-soluble carriers, the SDFs of CA were prepared, further the CA ophthalmic suspension was prepared. The prescription and preparation processing of the eye drops were designed and studied.The methods of qaulity control was established. The stability, irritation and pharmacodynamics of the eye drops were evaluated.Methods:Preparation of CA Ophthalmic Suspension: On the basis of references, three different SDFs with hydroxypropyl-β- cyclodextrin (HP-β-CD), hydroxypropylmethylcellulose (HPMC3cp) and Polyvinylpyrrolidone(PVPK30) with different proportions were prepared. The SDFs were prepared by conventional solvent method and a new preparation method which does not need dichloromethane, because no use of dichloromethane is recommended by International Conference on Harmonization (ICH) harmonized tripartite guideline. Adding additives such as suspending agent, osmotic regulation agent, humectants, flocculant to prepare the CA ophthalmic suspension. The appearance, pH, particle size, sedimentation ratio, redispersibility, stability and so on were studied, the best prescription was certained.Study of quality evaluation and stability: Determining particle diameter by optical microscope and laser light scattering particle size analyzer; Determining viscosity by rotary viscometer; Determining Zeta electric potential by microiontophoresis apparatus; The content and related substances were determined by HPLC.The chemical and physical stability of ophthalmic suspension were investigated in high temperature test, strong light test, accelerative test and long-term test.Ocular irritation studies: The ocular irritation tests were performed according to Draize technique on ten albino rabbits. Multiple dosing eye stimulation were observed, recorded and evaluated. The ophthalmic suspension was topically administered to the left eyes of ten rabbits and the right eyes have no drug administered as the blank group. Evaluation was done as per Draize technique.Pharmacodynamics:This part investigated the effect of CA ophthalmic suspension on dry eye syndrome. The aim is to develop a simple dry eye model in the rabbits, induced by daily repeated instillations of 1.0% atropine sulphate. The evolution of the dry eye syndrome in the animals was assessed by the Schirmer I Test and by examination of the cornea after fluorescein staining, then evaluate the effect of the eye drops.Results:From the particle size, physical and chemical stability and the bioavailability of the ophthalmic suspension considerations, the best formulation of the eye drops was: 100ml eye drops containing CA 0.1g HPMC(3CP) 0.3g Tween-80 0.1 g Anhydrous Monosodium Citrate 2.25g Sodium Chloride 0.15g Ethylparaben 0.03g HPMC(K10M) 0.4g NaOH q.s. Water for injection q.s. pH 6.0～6.5The standard curve of HPLC for determining dissolution rate of SDFs was: A=7.5848×104C–1.1405×103 (r=0.9998,n=7), the dissolution mediator was distilled water. The average value of relative recovery was 99.9%, within-day precision were 1.32%, 0.73%, 0.47%, between-days precision were 2.31%, 1.46%, 1.05%, consistent with the regulation of ChP.The standard curve of HPLC for assay of ophthalmic suspension was: A= 1.5656×107C + 1.0752×104(r=0.9999, n=7), The average value of relative recovery was 100.6%, precision was 1.59%, consistent with the regulation of ChP.Study of quality evaluation and stability: Prepare 3 bathes of samples according to the best prescription, the appearance of the samples was white, well-distributed, thin suspension, particle size, sedimentation ratio, redispersibility, pH, osmotic pressure, content consistent with the regulation of ChP. At the temperature of 60℃, the appearance, content and related substances have no significant changes. The strong light experiment found that with strong light 4500±500lx the appearance have no significant changes, but related substances raised slightly; Results of accelerative test (40℃) and long-term test (25℃) indicate that ophthalmic suspension has no caking, aggregation; the particle size, pH, content have no significant changes.Ocular irritation studies: No phenomena such as cornea surface damage; conjunctival congestion, red swelling, iris injury to occur. The results indicated that CA ophthalmic suspension has favourable biocompatibility and has no ocular irritation.Pharmacodynamics: The results indicated that CA ophthalmic suspension can enhance value of lacrimal secretion of the rabbits with dry eye syndrome, promote the healing of the ocular region, so it was markedly efficacy in the treatment of the dry eye syndrome.Conclusion:To prepare the CA-HPMC SDF by the new method , the using of dichloromethane can be avoided. The ophthalmic suspension prepared from the SDF of CA was homogeneous with small particles and the scope of particle size distribution was narrow, the redispersibility and physical and chemical stability were good, no agglutination phenomenon occurred. The preparation processing was simple and reproducible. The ophthalmic suspension has no irritation, can increase secretion of tears, promote the healing of the ocular region, so it was markedly efficacy in the treatment of the dry eye syndrome. |
PDF Full Text Request