Fig. 17. Conjunctival sac drug kinetics. The effect of drop volume and multiple drops on absorption of pilocarpine. A. Amount of drug lost from the precorneal tear film as a function of drop volume. Note the diminishing effect of very large drop size. B. Miotic effect of 25 μL of 0.25% pilocarpine when instilled (a) alone, (b) followed by a drop of saline within 2 minutes, and (c) followed by a drop of saline within 30 seconds. (Chrai SS, Makoid MC, Eriksen ST, Robinson JR: Drop size and initial dosing frequency problems of topically applied ophthalmic drugs. J Pharmaceut Sci 63:333, 1974)