Bentonite clay incorporated topical film formulation for delivery of trimetazidine: Control of ocular pressure and in vitro-in vivo correlation

Bentonite clay based film formulation has been prepared for topical delivery of trimetazidine (TZ) for the control of ocular pressure. Trimetazidine ophthalmic film formulation has been prepared incorporating bentonite at 1: 0.0001 to 1: 0.00005 ratio in hydroxylpropyl methylcellulose (HPMC) matrix by solvent casting method. Film formulation showed controlled release of drug and thereby extending the ophthalmic permeation for more than 6 h. Permeation has been extended with the decrease of bentonite amount in the film. Sustained trimetazidine delivery has been characterized by the area under the decreased intraocular pressure (IOP) versus time curve after topical administered film formulation. In rabbits treated with film formulation TB3, the peak IOP dropped of almost 30% from the baseline at 240 min and persisted until 360 min and a good in vitro-in vivo correlation has also been established. The matrix formulation containing bentonite has shown higher negative biding energy values compared to the formulation without containing bentonite indicating stable interaction with improved bioavailability and sustained effect. Bentonite incorporated trimetazidine film formulation could be utilised in the control and management of intraocular pressure in rabbit.