Showing papers on "Drug carrier published in 1998"
Journal Article•
TL;DR: When a pharmaceutical agent is encapsulated within, or attached to, a polymer or lipid, drug safety and efficacy can be greatly improved and new therapies are possible.
Abstract: When a pharmaceutical agent is encapsulated within, or attached to, a polymer or lipid, drug safety and efficacy can be greatly improved and new therapies are possible. This has provided the impetus for active study of the design of degradable materials, intelligent delivery systems and approaches for delivery through different portals in the body.
2,195 citations
TL;DR: In vivo selection of phage display libraries was used to isolate peptides that home specifically to tumor blood vessels that enhanced the efficacy of the anticancer drug doxorubicin and reduced its toxicity.
Abstract: In vivo selection of phage display libraries was used to isolate peptides that home specifically to tumor blood vessels. When coupled to the anticancer drug doxorubicin, two of these peptides-one containing an alphav integrin-binding Arg-Gly-Asp motif and the other an Asn-Gly-Arg motif-enhanced the efficacy of the drug against human breast cancer xenografts in nude mice and also reduced its toxicity. These results indicate that it may be possible to develop targeted chemotherapy strategies that are based on selective expression of receptors in tumor vasculature.
2,176 citations
2,057 citations
TL;DR: A summary of the achievements in the field to date of non-ionic surfactant vesicles (niosomes) as immunological adjuvants, anti-cancer/anti-infective drug targeting agents and carriers of anti-inflammatory drugs is presented.
958 citations
TL;DR: Experimental data show that sustained release of growth factor from the gelatin hydrogels is very effective in exerting the biological functions of the growth factor.
787 citations
TL;DR: The aim of this review is to give an insight into the many potential applications of chitosan as a pharmaceutical drug carrier.
Abstract: The aim of this review is to give an insight into the many potential applications of chitosan as a pharmaceutical drug carrier. The first part of this review concerns the principal uses of chitosan as an excipient in oral formulations (particularly as a direct tableting agent) and as a vehicle for parenteral drug delivery devices. The use of chitosan to manufacture sustained-release systems deliverable by other routes (nasal, ophthalmic, transdermal, and implantable devices) is discussed in the second part.
745 citations
TL;DR: In this paper, the authors focus on three representative areas of ophthalmic drug delivery systems: polymeric gels, colloidal systems, cyclodextrins and collagen shields.
665 citations
TL;DR: In this paper, the interaction between chitosan microspheres and mucus glycoprotein was evaluated by turbidimetric measurements and the measurement of mucin adsorbed on the micro-spheres.
634 citations
TL;DR: Although the transfection efficiency of the nanospheres was typically lower than that of lipofectamine and calcium phosphate controls in cell culture, the beta-gal expression in muscle of BALB/c mice was higher and more sustained than that achieved by naked DNA and lip ofectamine complexes.
544 citations
TL;DR: The carrier-mediated transcutaneous insulin delivery is unlikely to involve shunts, lesions or other types of skin damage, and is inferred to be transported into the body between the intact skin cells with a bio-efficiency of at least 50% of the s.c. dose action.
505 citations
TL;DR: New approaches for the modification of CS are presented as well as a new system with a great potential for colonic drug delivery, which combines specific biodegradability and pH-dependent release.
TL;DR: A novel nanoparticulate system has been developed with excellent characteristics for the transport of proteins through the nasal mucosa with a much greater penetration of TT into the blood circulation and the lymph nodes than PLA nanoparticles.
Abstract: Purpose. The aim of the study was to encapsulate a model protein antigen, tetanus toxoid (TT), within hydrophobic (PLA) and surface hydrophilic (PLA-PEG) nanoparticles and to evaluate the potential of these colloidal carriers for the transport of proteins through the nasal mucosa.
TL;DR: This article will focus on the experiences with liposome-blood protein interactions and how alterations in the chemical and physical properties of the carrier system influence the interactions with blood proteins and circulation times.
TL;DR: The results indicated that the drug-loaded nanospheres could be useful as a novel drug carrier in injectable delivery systems for hydrophobic drugs.
TL;DR: The study demonstrated the utility of proniosomal transdermal patch bearing levonorgestrel for effective contraception and developed and extensively characterized both in vitro and in vivo.
TL;DR: An AB block copolymer of oligo(methyl methacrylate) (oMMA) and poly(acrylic acid) (PAAc) has been synthesized and can be useful for prolonged mucosal drug delivery of hydrophobic drugs.
TL;DR: The selected solvents used to prepare micelles by dialysis in water affect the size of polymeric micelle, and an increase of molecular weight and hydrophobic components of diblock copolymer produced larger micells.
TL;DR: The thermally sensitive block copolymer system synthesized by ring-opening polymerization of dl-lactide initiated from hydroxy-terminated poly (N-isopropylacrylamide) (PIPAAm-PLA) is interesting from both applied and fundamental perspectives, particularly for active targeting as drug carriers.
TL;DR: The roles of the mucus and mucosal cell layers are discussed along with technologies and strategies that may be used to improve uptake, including attempts to determine the mechanisms of microparticulate uptake into enterocytes and membranous epithelial (M) cells.
TL;DR: Protein release from PLGA microspheres is not only governed by the PLGA erosion rate and protein diffusion through the water-filled channels, but is highly affected by the protein properties and its possible interaction with PLGA and its degradation products.
TL;DR: Different preparation techniques of various drug-loaded PLGA devices, with special emphasis on preparing microparticles are presented, and issues about other related biodegradable polyesters are discussed.
Abstract: There has been extensive research on drug delivery by biodegradable polymeric devices since bioresorbable surgical sutures entered the market two decades ago. Among the different classes of biodegradable polymers, the thermoplastic aliphatic poly (esters) such as poly(lactide) (PLA), poly(glycolide) (PGA), and especially the copolymer oflactide and glycolide referred to as poly(lactide-co-glycolide) (PLGA) have generated tremendous interest because of their excellent biocompatibility, biodegradability, and mechanical strength. They are easy to formulate into various devices for carrying a variety of drug classes such as vaccines, peptides, proteins, and micromolecules. Most importantly, they have been approved by the United States Food and Drug Administration (FDA) for drug delivery. This review presents different preparation techniques of various drug-loaded PLGA devices, with special emphasis on preparing microparticles. Certain issues about other related biodegradable polyesters are discussed.
TL;DR: The incorporation of polymer-lipid conjugates, initially using PEG and subsequently other selected flexible, hydrophilic polymers, into lipid bilayers gives rise to sterically stabilized liposomes that exhibit reduced blood clearance and concomitant changes in tissue distribution largely because of reduction in phagocytic uptake.
TL;DR: An understanding of how liposome association can alter drug properties can lead to their rational development in the treatment of many diseases.
Abstract: Liposomes are versatile drug carriers which can be used to solve problems of drug solubility, instability and rapid degradation. Both hydrophilic and hydrophobic drugs can be associated with liposomes and special techniques have been developed for the efficient loading of weak acids and weak bases into liposomes. Liposomes can function as sustained release systems for drugs and the rate of release can be manipulated. Advantage can be taken of the substantial changes in pharmacokinetics which often accompanies the association of drugs with liposomes. New formulations of liposomes, sterically stabilised with substances like surface-grafted polyethylene glycol have circulating half-lives in humans of up to 2 days. These long circulation times allow concentration of liposomal drug in regions of increased vascular permeability like solid tumours an decreased delivery of drug to normal tissues. Alterations of the biodistribution of drugs, when they are liposomes-associated, in general leads to significant overall decreases in drug toxicity but can also increase toxicity in some tissues. The use of targeting ligands to increase the selectivity of delivery of liposomal drugs to target tissues is currently under development. An understanding of how liposome association can alter drug properties can lead to their rational development in the treatment of many diseases.
TL;DR: The results illustrate the usefulness of guar gum as a potential carrier for colon-specific drug delivery and reveal that the use of 4% w/v of rat caecal contents in PBS, obtained after 7 days of enzyme induction provide the best conditions for in vitro evaluation of Guar gum.
TL;DR: The field of long-circulating microparticulate drug carriers is reviewed, and the protective effect of certain polymers including poly(ethylene glycol) on nanoparticulated carriers (liposomes, nanoparticles, micelles) is considered in terms of statistical behaviour of macromolecules in solution.
Abstract: The field of long-circulating microparticulate drug carriers is reviewed. The protective effect of certain polymers including poly(ethylene glycol) on nanoparticulate carriers (liposomes, nanoparticles, micelles) is considered in terms of statistical behaviour of macromolecules in solution. Using liposomes as an example, the mechanism is discussed assuming that surface-grafted chains of flexible and hydrophilic polymers form dense 'conformational clouds' preventing other macromolecules from interaction with the surface even at low concentrations of the protecting polymer. The scale of the protective effect is interpreted as the balance between the energy of the hydrophobic anchor interaction with the liposome membrane core or with the particle surface and the energy of the polymer chain free motion in solution. The possibility of using protecting polymers other than poly(ethylene glycol) is analysed, and examples of such polymers are given, based on polymer-coated liposome biodistribution data. General requirements for protecting polymers are formulated. Sterically protected nanoparticles and micelles are considered, and differences in steric protection of liposomes and particles are discussed. The problem of the preparation of drug carriers combining longevity and targetability is analysed. The biological consequences of steric protection of drug carriers with surface-grafted polymers are discussed, and possible clinical applications for long-circulating pharmaceutical carriers are considered.
TL;DR: The results of this study suggest the potential of the enzyme-degraded xyloglucan gels as vehicles for rectal delivery of drugs.
TL;DR: In vitro release studies show that the BSA release from the nanoparticles can be prolonged to 30 h and follows a diffusion-controlled mechanism, and the number of freezing-thawing cycle and release temperature both influence BSArelease rate considerably.
TL;DR: Polymeric latex particles with strongly differing surface properties were synthesized as models for colloidal drug carriers for tissue-specific drug targeting via the intravenous route and protein-nanoparticle interactions were studied.
Abstract: Plasma protein adsorption patterns on colloidal drug carriers acquired after iv administration depend on their surface characteristics and are regarded as key factors for their in vivo organ distribution. Polymeric latex particles with strongly differing surface properties were synthesized as models for colloidal drug carriers for tissue-specific drug targeting via the intravenous route. Physicochemical char- acterization was performed for size, surface charge density, zeta potential, and surface hydrophobicity. The interactions with human plasma proteins were studied by way of two- dimensional polyacrylamide gel electrophoresis (2-D PAGE). Considerable differences in protein adsorption on the latex particles were detected with regard to the total amount of surface-bound protein on the various particle types as well as specific proteins adsorbed, for example, fibrinogen, albumin, and a recently identified plasma glyco- protein. Possible correlations between protein adsorption patterns and the physicochemical characteristics and topog- raphy of the polymeric surfaces are shown and discussed. Knowledge about protein-nanoparticle interactions can be utilized for the rational design of colloidal drug carriers and also may be useful for optimizing implants and medical devices. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 478-485, 1998.
TL;DR: Investigation of nanoparticle surface modifications to enhance their arterial uptake concluded that surface modified nanoparticles have potential applications for intra-arterial drug delivery to localize therapeutic agents in the arterial wall to inhibit restenosis.
TL;DR: The present review discusses the advantages and limitations of incorporating drugs in the lipid domain of the vesicle, which include ion pair formation and pharmacosomes.