Increased partitioning of pilocarpine to the oily phase of submicron emulsion does not result in improved ocular bioavailability

Submicron emulsions containing pilocarpine as ion-pair with mono-dodecylpho sphoric acid were prepared. Physical stability of these preparations was co nfirmed during 4 months of storage at 4 degrees C. Approximately 50% of the drug was found in the aqueous phase of emulsion separated using an ultrafi ltration technique, while the rest was present in the oily phase and interp hase. The miotic effect observed in rabbits after application of the ion-pa ir in aqueous solution ol in submicron emulsion was the same; indicating th at the drug distribution into the oily phase of the colloidal vehicle does not improve ocular bioavailability. (C) 2000 Elsevier Science B.V. All righ ts reserved.