Polymeric compounds, drug delivery

Kwon GS. Polymeric micelles for delivery of poorly water-soluble compounds. Crit Rev Ther Drug Carrier Syst 2003 20(5) 357-403. 

Formulation of Insoluble Compounds, Liposomes in Solubilization, Micellization and Drug Solubility Enhancement, and Polymeric Micelles in V Mer-lnsoluble Drug Delivery. ... 

Polymeric micelles formed by Pluronics, PEG phospholipid conjugates, PEG-b-polyesters, or PEG-b-poly-L-amino acids were proposed for drug delivery of poorly water-soluble compounds, such as amphotericin B, propofol, paclitaxel, and photosensitizers [77,86,87]. It was also emphasized that using polymeric micelles can significantly increase the drug transport into the brain. 

In this review efflux pump inhibitors are classified into two groups low molecular mass inhibitors and polymeric inhibitors, because the high molecular mass of the polymeric excipients prevents absorption into systemic circulation after oral administration. In some cases, just a local inhibition of efflux transporters in the intestine is desired, whereas in other cases also an additional systemic modulation of efflux pumps can be of advantage. For chronical treatments, impact on the complex systemic efflux transporter system can result in severe complications. In this case, an enhanced intestinal absorption of efflux pump substrates can be achieved by using drug delivery systems based on polymeric inhibitors. On the other hand, in cancer therapy it would be of advantage to reduce efflux of anticancer compounds also in the systemic system because tumour tissues often overexpress these transporters. Then a low molecular mass efflux inhibitor could be useful. 

Subtypes of the LDL receptor can also be used for an improved drug delivery to the brain Coating of polymeric nanoparticles with surface-active compounds such as Tween 80 (polysorbate 80) leads to an association of plasma proteins such as apolipoprotein Al or apolipoprotein E with the particles and subsequently leads to an improved CNS efficiency of incorporated drugs. It has been suggested that coated particles are taken into endothelial cells via an LDL receptor [17, 125]. 

This degradation process is autocatalytic, since the g-hydroxybutyric acid that is produced catalyzes the hydrolysis reaction. To prevent abrupt degradation and erosion, a basic compound must be incorporated into the polymer. For example, sodium bicarbonate can be incorporated into a polymeric device composed of Alzamer to control the rate of polymer degradation and erosion. Although the polymer has been used for a number of drug delivery applications, it is difficult to produce and requires addition of significant amounts of a basic chemical to prevent uncontrolled degradation [21]. 

SLM combines the advantages of different drug delivery systems such as polymeric microparticles, fat emulsions, and liposome. In this respect, they have been successfully proposed for the delivery of a variety of drugs including antibiotics, anti-inflammatory compounds, vaccines, and adjuvant. Among the hpids, phospholipids, triacyl glycerols, waxes, fatty acids, or their mixtures can be used. SLM can be administered by subcutaneous, oral, intramuscular, topical, or pulmonary ways. 

The potential of polymeric nanoparticles as an ocular drug delivery system has been explored by a colloidal system consisting of an aqueous suspension of nanoparticles. These nanoparticles can be rapidly fabricated under extremely mild conditions with their ability to incorporate bioactive compounds. ... 

---