In Vitro Permeation Characteristics of Itraconazole from Oil Drops and Ophthalmic Ointment Through Excised Goat And Sheep Corneas

In vitro transcorneal permeation of itraconazole from oil drops and ophthalmic ointments was studied using freshly excised goat and sheep corneas. Permeation of itraconazole from castor oil was found maximum and minimum with kardi oil formulation. The higher permeation of itraconazole from castor oil formulation could be attributed to the lower partition coefficient of drug between oil and aqueous phase. The addition of benzyl alcohol, a preservative, in oil drops, increased the permeation of itraconazole. Partition experiments indicated increased partitioning of itraconazole in the aqueous phase in the presence of benzyl alcohol. The addition of phenyl mercuric acetate, phenyl mercuric nitrate and thiomersal as preservative, in castor oil drop decreased the permeation of itraconazole. Corneal hydration was within the desired limit below 80 %. Permeation of itraconazole from ointment containing dissolved drug was higher than the ointment containing solid drug. In antifungal study, the castor oil formulation showed maximum zone of inhibition against Candida albicans. Stability study conducted at 40 C and 70% RH indicated the formulations as quite stable to ensure 2 years shelf life.