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Abstract #27323 Published in IGR 12-4
Cyclodextrin solubilization of carbonic anhydrase inhibitor drugs: Formulation of dorzolamide eye drop microparticle suspension
Jansook P; Stefansson E; Thorsteinsdottir M; Sigurdsson BB; Kristjansdottir SS; Bas JF; Sigurdsson HH; Loftsson TEuropean Journal of Pharmaceutics and Biopharmaceutics 2010; 76: 208-214
Topically applied carbonic anhydrase inhibitors (CAIs) are commonly used to treat glaucoma. However, their short duration of action requiring multiple daily dosing can hamper patient compliance. The aim of this study was to develop novel aqueous CAI eye drop formulation containing self-assembled drug/cyclodextrin (D/CD) microparticles that enhance and prolong drug delivery to the eye. Phase-solubility of each drug tested (i.e. methazolamide, brinzolamide and dorzolamide HCl) was determined in either pure water or an aqueous eye drop medium. The pH was adjusted to maximize the fraction of unionized drug. Dorzolamide had the highest affinity for (gamma)-cyclodextrin ((gamma)CD) and, thus, was selected for further investigation. Hydroxypropyl methylcellulose (HPMC) was the most effective polymer tested for stabilization of the dorzolamide/(gamma)CD complexes and gave the highest mucoadhesion at 0.5% w/v concentration. Thus, the dorzolamide eye drop vehicle containing (gamma)CD (18% w/v) and HPMC (0.5% w/v) was developed. The physicochemical properties of this formulation complied with the specifications of the eye drop suspension monograph of the European Pharmacopoeia. The in vivo testing of the formulation showed that the drug was delivered to the aqueous humor in rabbits for at least 24. h with the maximum drug concentration at 4. h. Furthermore, this formulation delivered the drug to the posterior segment of the eye after topical administration. These results indicate that this CAI eye drop formulation has the potential of being developed into a once-a-day product. (copyright) 2010 Elsevier B.V.
T. Loftsson. Faculty of Pharmaceutical Sciences, University of Iceland, Hofsvallagata 53, IS-107 Reykjavik, Iceland. thorstlo@hi.is
Classification:
11.16 Vehicles, delivery systems, pharmacokinetics, formulation (Part of: 11 Medical treatment)
11.5.2 Topical (Part of: 11 Medical treatment > 11.5 Carbonic anhydrase inhibitors)
