Ocular penetration of pilocarpine in rabbits.
Aqueous humor pilocarpine hydrochloride concentration was measured at 15, 30, 60, and 120 minutes after instillation in the rabbit eye of a radioactively labeled 2% pilocarpine solution in various vehicles. Maximum concentrations were found with a vehicle containing 1.67% polyvinylpyrrolidone and other water-soluble polymers (Adsorbotears) and 1% hydroxypropyl methylcellulose. These produced pilocarpine concentrations during the first two hours after administration three times greater than those found with either saline, 1.4% polyvinyl alcohol, or 0.5% hydroxypropyl methylcellulose. Benzalkonium chloride, 0.01%, enhanced pilocarpine penetration into the aqueous by as much as 50% at all time intervals. The vehicle viscosity was unrelated to efficacy of pilocarpine penetration into the aqueous. The equally effective 1% hydroxypropyl methylcellulose and Adsorbotears have viscosities of 112 and 20 centistokes, respectively, while 0.5% hydroxypropyl methylcellulose (13 centistokes), 1.4% polyvinyl alcohol (3 centistokes), and sodium chloride solution (0.85 centistokes) are much less efficacious.
D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism*; D001548:Benzalkonium Compounds / Q000494:pharmacology; D008747:Methylcellulose / Q000031:analogs & derivatives; D014677:Pharmaceutical Vehicles; D010862:Pilocarpine / Q000378:metabolism*; D011108:Polymers / Q000494:pharmacology; D011142:Polyvinyl Alcohol / Q000494:pharmacology; D011205:Povidone / Q000378:metabolism; D011817:Rabbits; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D013997:Time Factors; D014783:Viscosity; D014867:Water
D001548:Benzalkonium Compounds; D014677:Pharmaceutical Vehicles; D011108:Polymers; D010862:Pilocarpine; D014867:Water; D012965:Sodium Chloride; D011142:Polyvinyl Alcohol; D008747:Methylcellulose; D011205:Povidone