2.3.10. In Vitro Cumulative Drug Release

To test the in vitro drug release, FTS-loaded rings (pre- and post-loaded) were individually placed in straight sided glass jars containing 200 mL of PBS (0.01 M with 2% (*w/w*) Solutol, pH 7.4) and incubated at 37 ◦C under sink conditions for 30 days. Sample aliquots (1 mL) were collected at various time points and replaced with fresh release medium. The release medium was completely removed and replaced with fresh medium every week to maintain sink conditions. FTS concentration in release samples was quantified by HPLC analysis. Cumulative drug release was normalized to the total concentration of drug in the ring determined by HPLC analysis. All experiments were performed in triplicates.
