Hui H W, Zeleznick L, Robinson J R
Curr Eye Res. 1984 Feb;3(2):321-30. doi: 10.3109/02713688408997216.
Aqueous solutions of pyrilamine, cimetidine, and histamine were instilled into the eyes of albino rabbits and drug levels determined as a function of time in the cornea, conjunctiva, aqueous humor, and iris-ciliary body. For all three drugs, less than 1% of the applied dose penetrates to the aqueous humor. Moreover, cimetidine and histamine are significantly less bioavailable than pyrilamine. Both cimetidine and histamine appear to bind to precorneal mucin and thus exhibit binding to conjunctival tissue with subsequent low penetration into the cornea and prolonged peak times in the aqueous humor. In addition, both drugs show binding to the iris-ciliary body as well. The influence of solution pH on the penetration of these compounds was also investigated, and a factor of two increase in aqueous levels was noted for the pH range 5-8, which encompasses the pKa's for these compounds.
将吡苄明、西咪替丁和组胺的水溶液滴入白化兔眼内，并测定角膜、结膜、房水和虹膜睫状体中药物浓度随时间的变化。对于这三种药物，给药剂量中不到1%能穿透进入房水。此外，西咪替丁和组胺的生物利用度明显低于吡苄明。西咪替丁和组胺似乎都与角膜前粘蛋白结合，因此表现出与结膜组织的结合，随后进入角膜的渗透率较低，房水中的峰值时间延长。此外，这两种药物也显示出与虹膜睫状体的结合。还研究了溶液pH对这些化合物渗透的影响，发现在pH值5 - 8范围内（该范围涵盖了这些化合物的pKa值），房水中的药物浓度增加了两倍。
