Evaluation of the Release Behavior of the Dexamethasone Embedded in Polycarbonate Polyurethane Membranes: An In Vitro Study

ABSTRACT

PURPOSE: To evaluate the release behavior of dexamethasone embedded in a polycarbonate polyurethane membrane. MATERIALS AND METHODS: Both water-soluble and water-insoluble dexamethasone were tested, and the release behavior of five water-insoluble dexamethasone films of different thickness (78 to 211 micrometer) was also evaluated. The amount of Dexamethasone used was 10% of the total weight of the polyurethane film mass. Each film was placed in a centrifuge tube containing 25 ml of 0.1-M neutral phosphate buffer, and the tubes were placed in a shaking incubator to quantify the amount of drug released into the buffer, absorption spectroscopy (lambda max=242 nm) was employed. RESULTS: In the test involving water-soluble dexamethasone, 60% of the drug was released during the first two hours of the study. Films containing water-insoluble Dexamethasone, on the other hand, released 40%, 60% and 75% of the dexamethasone in one, three and seven days, respectively. Both types of film maintained low-dose drug release for 28 days. When release behavior was compared between water-insoluble films of different thickness, thicker film showed less initial burst and more sustained release. CONCLUSION: Dexamethasone release behavior varies according to drug solubility and membrane thickness, and may thus be conrolled.