Preparation and In-vitro Evaluation of Timolol Maleate Loaded Ocular inserts by using various polymers

Abstract

The anatomy physiology and biochemistry of the eye render this organ impervious to foreign substances. Ocusert system was firstly developed in 1975 in the USA. It is a flat, flexible, solid and semisolid device which consists of drug reservoir by using various polymers. In the present study Timolol maleate loaded ocular inserts were prepared using different polymers (Methylcellulose, Hydroxypropyl methylcellulose, Eudragit, Ethyl cellulose, Polyvinyl pyrrolidone) by solvent casting method for the treatment of glaucoma. Glycerin, Polyethylene glycol and Dibutyl phthalate were used as plasticizers in different ratios. The prime objective of ocuserts formulating is to enhance therapeutic effect through continuous controlled delivery of ophthalmically active drug to the eye. The physiochemical parameters like thickness, weight, surface pH, folding endurance, % moisture absorption, % moisture loss and drug content were evaluated. In-vitro drug release studies were carried out using a Franz diffusion cell like model. Drug-polymer interactions were investigated by Fourier transform infrared (FTIR) spectroscopy. It was found that the higher the polymer percentage in the formula, the greater the weight and thickness of the film. The mechanical properties of the films reveal that the formulations (F2, F3, F4, F5, F6, F7 and F8) were strong, elastic with smooth surface and appropriate weight for ocular use. In addition to having surface pH that matches the requirements of the ocular dosage forms. It has also been shown that the formulas with hydrophobic polymers have low ability to absorb moisture as well as low moisture content. F4 (Eudragit RL 100 10%) gave sustained drug release with most of the drug being released after 8 hours (95.331%). The release profile of F4 followed the Korsmeyer-Peppas model and correlation coefficient (R2 = 0.992). FTIR studies did not show any evidence of interaction between the drug and the polymers.