Preparation and testing of buffered eye drops containing pilocarpine chloride with timolol maleate

Abstract

Background/Aim. In glaucoma therapy ?-blocator, timololmaleate, is the firsk-line medicine of selection, whereas a miotic, pilocarpine chloride, is one of the oldest medicines used for the treatment of this illness. They are applied as eye drops. In order to achieve a better therapeutic effect and improve life quality of the ill, we produced and tested eye drops formulations based on combining pilocarpinechloride and timolol maleate in buffers of different pH values. Methods. Following the general pharmacopoeial eye drops preparation regulation, we prepared formulations, of solution type, of pilocarpine chloride and timolol maleate combination, of pilocarpine choloride alone and of timolol maleate alone. A modified phosphate buffer according to Sorensen at 7.4, 7.7 and 8.0 pH values was used as a solvent. The quality of the produced formulations was examined using physical and physic-chemical methods and biological tests. Following pharmacopoeial regulations, we examined clarity, pH value and sterility. Pilocarpine chloride level was determined by means of ion-par (High Performance Liguid Chromatography) RP-HPLC method, whereas UV/VIS absorption spectrophotometry was used for determining the level of both timolol maleate, and timolol. Results. Results showed that monocomponent and combined preparations complied with the regulation demands. With the increase in the pH value of the solution pilocarpine chloride level decreased in relation to its initial content, whereas timolol level showed a tendency of moderate increase. Conclusion. Magistrally prepared pilocarpine chloride eye drops with timololmaleate have satisfied all the required conditions for an ophtalmological preparation. A modified phosphate buffer according to Sorensen at 7.4 pH value proved to be the most optimal solvent.