SILOXANE-CONTAINING PHOSPHOLIPIDS AS POTENTIAL DRUG DELIVERY SYSTEMS

Abstract

Drug delivery systems (DDS) have become an important focus research over the past three decades with the emergence of new therapies based on biomolecules such as peptides, DNA, enzymes etc., with the aim of improving or optimising the potency of these biomolecules. Liposomes are colloidal vesicles derived from amphiphilic phospholipid biomolecules and have the capacity to encapsulate a broad spectrum of molecules. The promise of liposomes in regard to drug delivery relates to an increase in the bioavailability of drugs, a decrease in drug toxicity, an increase in the efficacy of the drug, and targeted delivery to areas of pathology. Different liposomes varying in their phospholipid composition present different characteristics in terms of entrapment capacity of drugs, stability of liposomes and drug release profile. Optimizing any of these characteristics will hence improve the efficiency of liposomes as DDS. This study reveals the potential for siloxane-containing phospholipids to display a higher entrapment capacity than conventional liposomes related to 1-palmitoyl-2-oleoyl-sn-glycero-3-phospcocholine (POPC) and controlled released when using the model compound, calcein. With the siloxane-phospholipids being studied, zero-order release was observed and in some instances appeared to be independent of the pH of the release media.