Preparation and characterization of the chitosan as a biomaterial to be used in the medical practice

Abstract

The reposition of orbitary volume can be done by autogenic tissues or biomaterials. In recent years new materials have begun to be suggested, such as porous polyethylene (Medpor) and natural hydroxyapatite (Bioeye), which are excellent materials. However, limitation of the use of commercialized spheres in our environment is related to its higher cost. Purpose: 1) to develop Chitosan spheres for utilization in anophthalmic cavities; 2) to evaluate biocompatibility of Chitosan spheres in enucleated cavities of rabbits. Material and Method: 40 male albino rabbits, aged three years, will be submitted to enucleation surgery. The animals will be anesthetized by intraperitoneal injection of sodium pentobarbital 3% (1 ml/kg of weight) and inter-orbitary infiltration of Proxymethacaine 2% (2 ml), with the help of a 30X7 needle. The right eye will be removed and then spheres implanted in the orbitary cavity. The conjunctiva will be sutured with continuous stitches of non-absorbable 6-0 thread. All procedures will be done under aseptic and antiseptic conditions. The animals will be maintained in individual cages under stable conditions of illumination, temperature and humidity; they will receive water and ration appropriate to the species ad libitum. Antibiotic eye drops will be administered 2x/day. Clinical evaluation will be done weekly, being attentive to signs of inflammatory reaction, extrusion or infection at the place of injection. During the research period, tests of hepatic and renal function will be realized to research possible systemic effects of the substance employed. The animals will be sacrificed using an overdose of Sodium Pentobarbital 3% intraperitoneally, occurring 30, 60, 90 and 180 days after implant placement. Exenteration of the orbitary content will be done, as the material should be fixed in Formol 10% and prepared for histological exam. With regard to the histological exam, evaluation will be made of tissue reparation, inflammatory reaction and evaluation of implanted material as to its integration, permanence and hospital response. The results will be submitted to statistical evaluation. (AU)