HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF MITOXANTRONEIN LIPOSOME PREPARATIONS USING SOLID-PHASE EXTRACTION AND ITS APPLICATION IN STABILITY STUDIES

A method for the determination of the entrapped mitoxantrone in liposo me preparations was developed. The method consists of a solid-phase ex traction procedure followed by HPLC analysis. A C-18 cartridge was use d for solid-phase extraction and 0.5 M methanolic HCl was used for elu tion. The extraction demonstrated a good separation of the mitoxantron e from the phospholipid. A C-18 column and a mobile phase containing a cetonitrile-0.01 M monopotassium phosphate (40:60) with the pH adjuste d to 3.0 with orthophosphoric acid were employed. The detection wavele ngth was 242 nm. The HPLC method was stability indicating and was appl ied to determine the degradation of the entrapped mitoxantrone in lipo somes. A pseudo-first-order reaction was found for the degradation of the entrapped mitoxantrone. The half-life of the mitoxantrone decrease d with increasing pH of the medium. The results demonstrate that the p roposed method is satisfactory for the determination of the stability of mitoxantrone in liposome preparations.