Influence of hydroxypropyl beta-cyclodextrin on the corneal permeation of pilocarpine

The influence of hydroxypropyl β-cyclodextrin (HPβCD) on the corneal permeation of pilocarpine nitrate was investigated by an in vitro permeability study using isolated rabbit cornea. Pupillary-response pattern to pilocarpine nitrate with and without HPβCD was examined in rabbit eye. Corneal permeation of pilocarpine nitrate was found to be four times higher after adding HPβCD into the formulation. The reduction of pupil diameter (miosis) by pilocarpine nitrate was significantly increased as a result of HPβCD addition into the simple aqueous solution of the active substance. The highest miotic response was obtained with the formulation prepared in a vehicle of Carbopol® 940. It is suggested that ocular bioavailability of pilocarpine nitrate could be improved by the addition of HPβCD.