抄録
Particle dosage forms have been receiving much attention in drug delivery systems because of such features as controlled release, absorption improvement and drug targeting. In addition, unlike polymer drugs and prodrugs, particles have the advantage of ability to carry many drug molecules. Most particle formulations have been designed to reduce toxicity and to increase accumulation at target sites, to some extent being used for in a number of clinical applications. Especially lipid-based particles such as liposomes, emulsions and solid particles composed of lipids (solid lipid particles, SLN) have been focused on use for drug delivery systems. Currently, Lipid-based particles are mostly used for controlled release of drugs, whereas cationic liposomes and emulsions are used as vectors for gene delivery. The introduction of polyetyleneglycol derivative (PEG) to lipids, i. e. “PEGlated” as long-circulating liposomes and the “remote loading” method for drug loading into the liposomes has produced liposome-encapsulated drugs for chemotherapy. PEGlated technique has also been applied to injectable microemulsions and solid lipid particles. The area of liposome targeting, e. g. use of antibody-targeting liposomes, has been extensively studied. In gene delivery, the role of helper lipids such as cholesterol and DOPE as well as that of PEG lipids in cationic liposomes in improving transfection efficiency in vivo has been reported. The study of drug distribution in particles, and design of particles targeted at tissues and cells with ligands and biosenser induced to nucleus are needed for the clinical use of lipid-based particles.
