2.2.2. In Vitro Drug Release

To test the in vitro drug release, FTS-coated strings were individually placed in straight sided glass jars containing 20 mL of phosphate-buffered saline (PBS) (0.01 M with 2% Solutol HS, pH 7.4) under sink conditions at 37 ◦C. Sink conditions were defined as fluticasone (FTS) concentration at or below 1/5 of its maximum solubility (i.e., ≤0.11 mg/mL FTS) in PBS + 2% Solutol at 37 ◦C. The saturation solubility of FTS in PBS + 2% Solutol was determined by HPLC analysis. Sample aliquots (1 mL) were collected at 24 h time point, and FTS concentration was quantified by HPLC analysis. The amount of FTS released was quantified by HPLC analysis and was normalized to the total concentration of FTS coated on the string. All experiments were performed in triplicates.
