Rapamycin extraction
For the extraction of rapamycin from ointment, emulsion and gel formulations 0.100 g of cream was introduced in a glass tube with 4 ml of a mixture of acetonitrile, hexane and WFI and stayed in the vortex for 10 seconds. The samples were then centrifuged at 3500 rpm for 10 minutes. The resulting supernatant was removed and 1 ml was aliquoted for HPLC analysis. For the extraction of rapamycin from liposomes 0.100 g of cream was introduced in a glass tube with 4 ml of methanol. The samples stayed in the vortex for 10 seconds, 50 μL was aliquoted and after 1/20 dilution with methanol was analyzed with HPLC method.