Formulation and Evaluation of Pluronic F127 Thermosetting Gels Containing Atorvastatin Calcium as Novel Ophthalmic Delivery Systems

Abstract

Aims: This study aims to formulate and evaluate ophthalmic thermo-sensitive gels containing atorvastatin calcium. The major problem of the drug is poor water solubility, and hence the ocular bioavailability, complexation with cyclodextrin is an attempt to solve this problem. The formulations based mainly on Pluronic F127 alone or combined with other viscosity-increasing polymers. Methodology: Atorvastatin calcium the proved effective anti-inflammatory agent used in ocular diseases was prepared and characterised in the form of hydroxypropyl beta-cyclodextrin complex. In this study, the possibility to formulate thermosetting gels containing either the free drug, drug-cyclodextrin physical mixture or complex was investigated by using heat sensitive polymers pluronic F127 alone or combined with other viscosity-increasing polymers such as methyl cellulose, PVP K25. All formulations were characterised physically for its colour, clarity, viscosity, pH, and drug contents. Also the effect of different polymeric composition on the in-vitro release profiles of Atorvastatin calcium from different preparations was investigated. Results: All preparations were found colourless, clear, and with accepted pH values, rheological properties and drug content. In vitro release studies of different formulations in Simulated tear, fluid indicated the possibility of altering the % drug release from thermosetting gels containing Atorvastatin calcium -HP-β-CyD complex relative to the free drug by modification the formulae prepared. Methyl cellulose in 2% was found to enhance the drug release profile of drug from Atorvastatin calcium -HP-β-CyD complex gels, while PVP K25 in 5% caused retardation of drug released from the prepared thermosetting gels. Conclusions: Ophthalmic thermosetting gels formulations containing Atorvastatin calcium -HP-β-CyD complexes are considered good and promising delivery systems. They showed good physical properties. Depending on the type and concentration of the viscosity increasing polymer incorporated into the formulations, it can be applied either for improving or retardation of Atorvastatin calcium release profile.