Generating and loading of liposomal systems for drug-delivery applications

Techniques involved in generating liposomal-drug systems in a manner compatible with clinical demands are reviewed. Recent advances include extrusion procedures for the rapid and reproducible generation of liposomes, and new techniques for the efficient and stable entrapment of drugs at high drug/lipid ratios. Notable examples include the freeze-thaw protocol which can allow drug-trapping efficiencies approaching 90%. Active trapping procedures, utilizing drug uptake in response to ion gradients, can result in extremely high drug/lipid ratios and trapping efficiencies approaching 100%. These and other advances suggest no major difficulties for the manufacture of liposomal drug systems for pharmaceutical applications.