In vitro characterization & Pharmacokinetic evaluation of ion activated in situ gelling system for Betaxolol Hydrochloride

Formulation of Betaxolol HCl in-situ gelling system by ion activated method for the treatment of glaucoma with the aim to improve patient compliance as the dosage regimen is one drop of the dosage form twice a day. Betaxolol HCl in-situ gelling system was prepared by using gelrite for ion activated method. The gelrite was selected as polymer, when instilled as a liquid solution in to the cul-de-sac can be initiated gelation by the electrolytes (Na + , Ca +2 and Mg +2 cations) present in tear fluid. The preparation was subjected to physico chemical evaluation, in-vitro diffusion study, sterility study, isotonicity testing, eye irritation testing, stability testing, in-vivo studies, pharmacokinetic parameters such as Cmax, tmax and AUC and the comparative evaluation of in-vitro and in-vivo studies with marketed product. A significant ocular bioavailability (relative bioavailability 119.96) was observed in 0.6 % gelrite containing 0.25% betaxolol HCl of formulation F3 exhibited sustained release of drug from formulation over a period of 8hrs thus increasing residence time of the drug, nonirritating with no ocular damage or abnormal clinical signs to the eye. Therefore, it was concluded that the selected formulation satisfies the entire necessary requisite for a stable, sterile and sustained release formulation with enhanced bioavailability.