Evaluation of Ocular Bioavailability of Four Formulations of Pilocarpine Using the Albino Rabbit Eye Model by RP-HPLC

• 1、Department of Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University
• 2、Department of Ophthalmology，The Hangzhou First Hospital

Abstract：In this paper, the ocular bioavailability for four formulations of pilocarpine was compared using the albino rabbit eye model in the aqueous humor by RP-HPLC method. The 120 albino rabbits were divided into 40 groups, each consisting of 3 animals. Every 10 groups received 50 μL of (A) 1% generic pilocarpine, (B) 1% mixture pilocarpine solution consisting of aqueous sample and liposome sample, (C) 1% liposome pilocarpine, (D) 4% gel pilocarpine, respectively. The aqueous humor was withdrawn at 5, 10, 30, 40, 60, 90, 120, 180, 240 and 360 min. Pilocarpine was extracted from aqueous humor with dichloromethane. The results showed that the pilocarpine formulations: B, C and D gave higher aqueous humor concentration of drug than formulation A at all time periods tested. The areas under curve of formulation B, C or D were several times as much as formulation A. Measurable amounts of drug following formulation B, C and D were still observed at 180, 360 and 240 min, respectively. Our study demonstrated the significantly increase in ocular bioavailability pilocarpine due to the therapy with liposome or gel. It shows that a novel topical formulation of pilocarpine in liposome or gel might serve as a long acting antiglaucoma agent, and less frequent applications are necessary with them than with commercial drops.

Keywords： Pilocarpine Pharmacokinetics Bioavailability Aqueous humor RP-HPLC