Nitto Medic Co., Ltd.

A review.Levofloxacin hydrate is a new quinolone antibacterial agent, showing the antibacterial activity by inhibition of DNA replication occurring due to the inhibition of the activity of bacterial DNA gyrase.Since the generic drug ensures the same therapeutic quality in the patient as the original drug, the objective of bioequivalence studies of generic drugs is to show it as a guideline for test methods.Further, as the germicidal power of the antibacterial agent is defined by its drug concentration, MIC (min. inhibitory concentration) is used to compare the effectiveness of the drug.On the other hand, in the case of ophthalmic solutions, as the drug passes through the cornea and enters the aqueous humor, it has been reported that the the highest concentration of the drug in the aqueous humor after the instillation of an ophthalmic solution can be used as an index to show the migration of the drug to the target tissue.Hence it is thought that it may be possible to evaluate the therapeutic equivalence of the drug by comparing its concentration in the aqueous humor after the elapse of a predetermined time period subsequent to the instillation of the ophthalmic solutionBy statistical methods, using a confidence interval of 90%, if the difference in the average values of the logarithm of the index showing the bioeqivalence of the original and generic drugs is in the range of log(0.80)-log(1.25), then they are judged to be biol. equivalentWhen the target is the ocular tissue, it is difficult to carry out bioequivalence tests of ophthalmic solutions in humans.Therefore, after instillation of the generic drug and the original drug in the left and right eyes of the rabbit, which is often used in the development of ophthalmic solutions, the bioequivalence test to estimate the 90% confidence interval of difference between the average values of the logarithm of the concentration of levofloxacin in the aqueous humor was conducted.The original drug used for this purpose was 0.5% Cravit ophthalmic solution and the generic drugs used were: 0.5% [NP] levofloxacin ophthalmic solution (Nitto Medic Co., Ltd. Sales: Nipro Pharma Corporation), 0.5% [CH] levofloxacin ophthalmic solution (Choseido Pharmaceutical Co., Ltd., Sales: Tanabe Seiyaku Sales Co., Ltd) and 0.5% levofloxacin ophthalmic solution [Towa] (Towa Pharmaceutical Co., Ltd).The same formulations, as they were jointly developed by all three companies and hereinafter referred to as 0.5% levofloxacin ophthalmic solution