Drug carrier

About: Drug carrier is a research topic. Over the lifetime, 18276 publications have been published within this topic receiving 997718 citations. The topic is also known as: drug carriers & drug vehicle.

In vitro and in vivo study of two types of long-circulating solid lipid nanoparticles containing paclitaxel.

Abstract: Paclitaxel, a diterpenoid derived from the needles and bark of the Pacific yew tree, is a potent inhibitor of cell replication, blocking cells in the late G 2 -mitotic phase of the cell cycle by stabilizing the microtuble cytoskeleton. Clinical trials have shown that paclitaxel has antineoplastic activity, particularly against primary epithelial ovarian carcinoma, breast cancer, colon, head and neck cancers and non-small cell lung cancer. 1) Paclitaxel is a hydrophobic molecule and poorly soluble in water, for which reason it is solubilized in a 50 : 50 mixture of Cremophor EL (a polyethoxylated castor oil) and ethanol. Cremophor EL is associated with a number of side effect, including hypersensitivity, nephrotoxicity and neurotoxicity. Furthermore, Cremophor EL dissolves phthalate plastics from commonly used polyvinyl chloride bags and intravenous infusion lines. 2) The use of Cremophor EL as a vehicle also appears to alter the biochemical properties of lipoproteins, such as high-density lipoprotein; it has also been shown to mediate partially the cytotoxic activities of paclitaxel in primary cultures of tumor cells from patients. 3) Although a premeditation regimen with corticosteroids and antihistamine reduces the incidence of serious hypersensitivity reactions, milder reactions have still been found to occur in 5—30% of treated patients. 3) Colloidal drug carriers such as liposomes and nanoparticles can be used to improve the therapeutics index of both established and new drugs by modifying their distribution, thus increasing their efficiency and/or reducing their toxicity. This is because the drug distribution then follows the carrier, rather than depending on the physicochemical properties of the drug. 4)

Thermosensitive sterically stabilized liposomes : formulation and in vitro studies on mechanism of doxorubicin release by bovine serum and human plasma

Abstract: Purpose. To formulate thermosensitive sterically stabilized liposomes and to study the effects of plasma and serum components in vitro. Methods. The rate of release of encapsulated doxorubicin (Dox) from liposomes of various compositions was followed by fluorometric assay at 37°, 42° and 45°C, in buffer and also in both calf serum and human plasma up to 50% by volume. Results. The optimal composition for the maximal differential release of doxorubicin between 37°C and 42°C in human plasma was a mixture of dipalmitoylphosphatidylcholine/hydrogenated soy phosphatidylcholine/cholesterol and distearoylphosphatidylethanolamine derivatized with polyethylene glycol at a molar ratio of 100:50:30:6. In experiments designed to study the mechanism causing increased permeability of liposomes in bovine serum, we found two different distinct release patterns: a slow linear rise of rate of Dox release for fluid liposomes and fast exponential rise reaching plateau within 5 minutes for solid phase (rigid) liposomes. This release of Dox from rigid but not fluid liposomes was inhibited by pre-heating serum at 55°C for 30 minutes or by addition of EDTA (but not EGTA) or antiserum to the C3 component of complement. Conclusions. A formulation of sterically stabilized liposomes with the proper thermal sensitivity in human plasma has been obtained. In addition, the results suggest that complement may play an important role in the interaction of rigid but not fluid liposomes with bovine serum. Human plasma did not show this effect.