Polymeric materials and its matrix systems are one of most important factors to determine the drug delivery mechanisms. Most of current long action drug delivery systems are solid forms. Thus their usage is limited to insert into orifice, otherwise surgical implantation should be taken. To prevent the surgical implantation, the semi-solid polymer matrix (injectable gel) should be an ideal form to pass through the hypodermic needles. Injectable gel should be a biocompatible and biodegradable polymer matrix to avoid the surgical removal of gel. For this reason polymeric material, collagen, was selected for this study. Rigid and transparent gels of collagen closely resembling human vitreous have been developed. Method of formation of gel matrix will be discussed.