Solid-phase extraction method for the separation of amphotericin B from the lipids dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol
A solid-phase extraction method is described for separating amphotericin B from the lipids used in a liposomal amphotericin B formulation. The drug was bound on to a silica sorbent extraction column and the lipids dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol were removed by using a solvent consisting of chloroform, methanol and ammonia solution. The lipid-free amphotericin B was eluted from the column by using a slightly acidic methanol solution. Drug recoveries averaged 95% as measured by microbiological assay and high-performance liquid chromatography. The precision of the method was demonstrated by a coefficient of variation of 1.38–1.65%.