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Abstract
An in vitro technique for quantitatively assessing the rate of transport of topically applied pilocarpine HCl through the rabbit cornea under conditions simulating normal physiology is described. The method separates corneal transport from events in the internal eye which influence aqueous pilocarpine concentration. Transport is very small relative to loading dose (0.16 per cent), but it continues through 90 minutes under ambient conditions. Loss of pilocarpine into a controlled "tear" flow system occurs in the first 10 minutes of the experiments and is consistently close to 70 per cent of the loading dose. Of the remaining 30 per cent, only about 0.5 per cent eventually penetrates the cornea to appear in the anterior chamber analog. The findings suggest rapid corneal uptake of topical pilocarpine with sustained transport of a small fraction to the aqueous.