Chromatographic conditions
To determine the validity period of each formulation according to its chemical stability a HPLC method was developed and validated. A C18 Kromasil column (150 mm x 4.6 mm, 5 μm) was used. The mobile phase consisted of a mixture of acetonitrile and water (75:25 v:v). The flow rate was 1 ml/min. The sample injection volume was 10 μL, the column temperature was 50ºC and the analysis time was 15 min. Rapamycin detection was processed at 280 nm.