Drug Release Characteristics of Lipid Based Benzoporphyrin Derivatives
Chowdhary, R.K., Shariff, I. and David Dolphin
The purpose of this study was to examine the transfer of verteporfin (BPDMA) from its lipid based formulation to serum proteins. As a result of BPDMA being confined to the lipid phase, it was found that fluorescence from the photosensitizer was highly concentrated quenched. This phenomenon was used to demonstrate rapid transfer of lipid-based drug to various plasma components such as albumin and lipoproteins. Gel electrophoresis was used to show transfer of drug to lipoproteins. Loss of fluorescence quenching showed rapid transfer of the drug from its lipid based formulation to serum proteins. Gel electrophoresis showed that both the drug and phospholipid components were transferred to the lipoprotein fraction concurrently. The electrophoretic mobility of plasma lipoproteins was increased as a result of their interaction with lipid-based BPDMA. It was also shown that the lipid-based structures were readily destabilized in the presence of relatively low concentration of plasma, and that liposomes of this lipid composition were highly unlikely to be found intact in the circulation following i.v. injection. Verteporfin is rapidly transferred from its lipid based formulation to serum proteins. This rapid transfer, particularly to lipoproteins, provides a mechanism for its rapid delivery to cells.