Block copolymer micelles have become accepted as a viable strategy for drug formulation and delivery. Block copolymer micelles may serve as solubilizers and/or true drug carriers depending on their drug retention properties in vivo. Indeed the formulation of hydrophobic drugs in these micelle systems has been shown to provide up to a 30,000 fold increase in the water solubility of some compounds. In addition, the administration of drugs in copolymer micelles has been shown to reduce their toxicity and improve their therapeutic efficacy. The present review is focused on the drug loading and release properties of block copolymer micelles. Specifically, the properties of the drug, properties of the micelle core and the presence of interactions between the drug and the core-forming block are discussed in terms of their influence on the drug loading and release properties of the micelles. The various methods employed to prepare drug-loaded micelles are reviewed and the in vitro release assays used to predict the in vivo release characteristics of the formulations are discussed. The balance between drug loading and micelle stability is highlighted as a critical factor in the optimization of micelle-based formulations. The in vivo performance of micelles as delivery systems is evaluated by comparing the pharmacokinetics of free drug and drug administered in micelle-based formulations. Overall, the composition-property and property-performance relationships outlined in this review may aid in guiding the rational design of block copolymer micelles for drug delivery. In addition, suggestions for future research in this area are provided as a means to assist in furthering block copolymer micelles as one of the leading advanced drug delivery technologies for the systemic administration of drugs.

Magnetic poly(ethyl-2-cyanoacrylate) (PECA) nanoparticles containing anti-cancer drugs (Cisplatin and Gemcitabine) were prepared by inter-facial polymerization. The spherical nanoparticles (d = 250 +/- 15 nm) with smooth surfaces and moderately uniform size distributions were obtained. The amount of magnetite encapsulated inside the polymer matrix was increased up to 14.26% (w/w) by controlling the initial weight ratio of monomer/magnetite. It was found that the amount of Cisplatin encapsulated in the magnetic nanoparticle is much higher than that of Gemcitabine because Cisplatin (hydrophobic) is highly soluble in the oil phase and encapsulated easier inside nanoparticles compared to Gemcitabine (hydrophilic). The presence of magnetite and its super-paramagnetic characteristic were confirmed by FTIR spectra and VSM. In-vitro experiments of drug release and magnetic mobility under external magnetic field demonstrated that magnetic poly(ethyl-2-cyanoacrylate) (PECA) nanoparticles can be a highly versatile magnetic drug carrier with sustained release behaviour and sufficient magnetic susceptibility.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

1997ketones ketones (acyclic compounds) P 0200 -091Chelation-Assisted Intermolecular Hydroacylation: Direct Synthesis of Ketone from Aldehyde and 1-Alkene.-The work describes a general direct intermolecular hydroacylation -not reported so far -of 1-alkene with aldehyde using the cocatalyst system of the transition metal complex and 2-amino-3-picoline. Some other metal complexes are also catalytically active. Without the addition of the picoline derivative, the decarbonylation product anisole is obtained exclusively in 46% yield, e.g., from the reaction of (Ia) and (II). This result indicates that hydroacylation competes with the decarbonylation of the aldehyde. In the reaction of a chiral olefin such as (Ie) with (II), the resulting ketone (IIIe) retains an asym. center in the 3-cyclohexenyl group. Aliphatic and aromatic aldehydes show comparable activity. The reaction of a sterically hindered aliphatic aldehyde, e.g. (IVe) affords a low yield of ketone ( Ve) compared with those of prim. and sec. aliphatic aldehydes. -(JUN, C.-H.; LEE, H.; HONG, J.-B.; J.