CAPILLARY ELECTROPHORESIS ANALYSIS OF POLYHEMATOPORPHYRIN, A PHOTOSENSITIZER USED IN PHOTODYNAMIC THERAPY

Free solution capillary electrophoresis and micellar electrokinetic ca pillary chromatography are used to separate components in polyhaematop orphyrin (PHP), a preparation similar to Photofrin which is used as a photosensitizing agent in photodynamic therapy. PHP is known to contai n haematoporphyrin (HP), protoporphyrin (PP), hydroxyethylvinyldeutero porphyrin (HVD) and a mixture of ester, ether and carbon-carbon linked oligomers. The use of reference samples of HP and PP, together with p artially dehydrated HP, has allowed assignment of HP and HVD peaks in the electropherograms of PHP in 20 mM phosphate pH 6.9 and 20 mM disod ium tetraborate pH 9.2 buffers using sodium dodecyl sulphate in the ra nge 0-100 mM. Changes in the pattern and areas of monomer peaks and ol igomer distribution following base hydrolysis (which cleaves ester lin kages) and acid hydrolysis (which cleaves ester and ether linkages) yi elds information consistent with that from HPLC studies.