| Fungal keratitis is a kind of severe disease that often causes blindness. Most of the disease pathogens are aspergillus and fusarium. Topical administration of antifungal agents is main method in the treatment of fungal keratitis. Be- cause antifungal agents have poor intraocular penetration, high toxicity and side effects, therapeutic efficacy of antifungal agents are not satisfied. The treatment of fungal keratitis has already become a problem all over the world. It is necessary to research new drugs that have good curative effect, broad-spectrum and strong penetration, and change the formulation of antifungal agents to advance therapeutic efficacy, for curing fungal keratitis more effectively. Ketoconazole, an imidazole fungistic agent with broad-spectrum activity, is effective against many ocular fungi. It inhibits ergosterol synthesis in fungi, thus damaging the fungal cell wall. The foreign ophthalmologists have studied intraocular pharmacokinetics of ketoconazole in topical, oral and subconjunctival use, but conclusions about its intraocular penetration were not consistent. Since 1997, the Pharmacologic and pharmaceutic Department of He Nan Institute of Ophthalmology has developed and manufactured triturated ketoconazole 3%, and its usage has achieved a certain effect curing fungal keratitis. In order to enhance the antifungal action of the ketoconazole eye drops, theDepartment has improved formulation and preparation method to develop two new advanced ketoconazole eye drops by increasing its solubility and intraocular penetration.Objective: To investigate intraocular penetration andpharmacokinetics of these two advanced ketoconazole eye drops and the triturated ketoconazole by high-pressure liquid chromatography(HPLC). And to provide basis to choose more effective antifungal agents for curing fungal keratitis.Methods: Three studies were included. The first one is HPLC assay of ketoconazole. The cornea and aqueous were separated from the globe after rabbit was sacrificed. All of the specimens were extracted and evaporated to dryness. The residue was reconstituted with mobile phase, and subjected to HPLC analysis. Methanol-distilled water (27:73 v:v) was used as mobile file. Flow rate was 1.5ml/min. The ultraviolet detector was set at 241nm wave- length. The concentration was calculated by peak area. The second one was the study of intraocular penetration of three ketoconazole eye drops. Nine New Zealand rabbits (eighteen eyes ) were divided into three groups in random: triturated ketoconazole 0.8% eye drops (Group one), advanced ketoconazole-1 0.8% eye drops (Group two) and advanced ketoconazole- II 0.8% eye drops (Group three). There were three rabbits (six eyes) in each group. One 50- μ1 drop was instilled in each eye for a total of eight applications in each group. Half an hour after the last dose, the rabbits were killed. Corneas and aqueous samples were obtained. The ketoconazole levels were determined by HPLC assay. The third one was the study of pharmacokinetics of advanced ketoconazole- II. Fifty-four New Zealand rabbits were divided into two groups, tweety-seven animals (fifty-four eyes) each. Advanced ketoconazole-II 0.8% eye drops was usedin Group one, and triturated ketoconazole eye drops was used in Group two. One 50 u 1 drop was instilled into the eyes of rabbits in each group. Aqueous and corneas samples were obtained at 5, 15, 30 minutes, 1,2,4, 8, 12, 24 hours after single topical administration. At each time point, three animals were killed. The drug concentrations were assayed by HPLC.Results: In HPLC assay of ketoconazole, under those experimental conditions, ketoconazole had a good relationship between the concentration and peak area in the range of 0.2-20.0μg/ml, (r=0.9991). The retention time was about 8.5min and the peak of ketoconazole was well separated with the peak of globe. The average recovery of ketoconazole in cornea was 74.62%. The average recovery of ketoconazole in aqueous was 76.17%. The intra-day and inter-day im...
|
PDF Full Text Request