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.

Selective tumor localization and improved therapeutic index of anthracyclines encapsulated in long-circulating liposomes

Abstract: We have investigated the tissue distribution, toxicity, and antitumor activity of anthracyclines encapsulated in hydrogenated phosphatidylinositol (HPI)-containing liposomes which show a characteristic long circulation time in plasma (J. Natl. Cancer Inst., 81: 1484-1488, 1989). Phosphatidylglycerol (PG)-containing liposomes were used for comparison. Doxorubicin (DOX) or epirubicin (EPI) was encapsulated in the aqueous interior of small (65-100 nm mean diameter) HPI or PG liposomes. The DOX and EPI levels in i.m. tumor implants of the J6456 lymphoma were significantly raised by delivery in HPI liposomes but not by delivery in PG liposomes. No such increase was observed in normal muscle tissue. When DOX encapsulated in HPI liposomes was injected i.v. into BALB/c mice bearing an ascitic form of the J6456 lymphoma, more than 10% of the injected dose was recovered in the ascitic fluid in liposome-associated form. No significant accumulation of liposomal drug was observed in peritoneal washes from tumor-free mice. DOX encapsulation in either PG- or HPI-containing liposomes reduced the lethal toxicity of the drug in mice. However, only the HPI-DOX formulation was significantly more active than free DOX in the treatment of the ascitic J6456 tumor at all dose levels tested. Therapeutic results with EPI encapsulated in HPI liposomes also showed an efficacy superior to that of free EPI. These studies provide evidence that anthracyclines delivered in long-circulating liposomes extravasate with relative selectivity in tumor areas, improving the overall therapeutic index.

Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery.

Abstract: Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally occurring polysaccharide next to cellulose, is a biocompatible and biodegradable mucoadhesive polymer that has been extensively used in the preparation of micro-as well as nanoparticles. The prepared particles have been exploited as a potential carrier for different therapeutic agents such as peptides, proteins, vaccines, DNA, and drugs for parenteral and nonparenteral administration. Therapeutic agent-loaded chitosan micro- or nanoparticles were found to be more stable, permeable, and bioactive. In this review, we are highlighting the different methods of preparation and characterization of chitosan micro- and nanoparticles, while reviewing the pharmaceutical applications of these particles in drug delivery. Moreover, the roles of chitosan derivatives and chitosan metal nanoparticles in drug delivery have been illustrated.

Size-dependent bioadhesion of micro- and nanoparticulate carriers to the inflamed colonic mucosa

Abstract: Purpose. The size-dependent deposition of microparticles and nanoparticles after oral administration to rats using an experimental model colitis was examined. Local delivery of an entrapped drug could reduce side effects and would be a distinct improvement compared with existing colon delivery devices.

Drug-polymer conjugates: potential for improved chemotherapy.

Abstract: Use of polymeric drug delivery systems is rapidly becoming an established approach for improvement of cancer chemotherapy. Zoladex, a poly lactide-co-glycolide subcutaneous implant that delivers a luteinizing hormone releasing hormone analog over 28 days, is now the treatment of choice for prostate cancer, and a polyanhydride matrix containing BCNU is currently in phase III evaluation for treatment of glioma multiforme. Soluble polymers were first proposed as targetable drug carriers in the mid-1970s, and although the first conjugates are still at an early stage of development some, e.g. SMANCS (styrene maleic acid-neocarzinostatin) and monomethoxypolyethyleneglycolasparaginase, are now undergoing clinical evaluation and show considerable promise. Polymeric drug delivery systems are usually designed to produce an improved pharmacokinetic profile of an antitumor agent (controlled release) and in addition soluble carriers can achieve either first-order (organ specific) or second-order (tumor specific) drug targeting by virtue of the fact that they are usually administered intravenously and should theoretically access primary and secondary disease. Soluble polymeric carriers have the potential to improve the activity of conventional antitumor agents, peptide and protein drugs, and have recently been used in constructs for delivery of oligonucleotides. With increased awareness that the successful design of a polymeric drug delivery systems can only be achieved with prior consideration of the pathology and stage of the disease, tumor accessibility, biochemistry and cell biology of the target site, choice of appropriate therapeutic agent(s) and understanding of their fundamental mode of action, we have seen the emergence of a number of exciting and potentially more selective antitumor therapies based on polymer technologies. Here, the basic principles for design of soluble polymeric drug delivery systems are explained and illustrated using examples drawn from our studies on the development of N-(2-hydroxypropyl)methacrylamide copolymer conjugates for use in cancer chemotherapy. Those soluble polymeric carriers that are undergoing clinical evaluation are briefly reviewed.