Water-soluble polymeric drug delivery

Poor water solubility of drugs and new chemical entities presents major challenges in the development of clinically useful formulations. Of the various approaches used for enhancing the solubility of poorly soluble drugs, polymeric delivery systems have been used effectively. Paclitaxel has been used as a model hydrophobic drug to show the effectiveness of solubility-enhancing properties of various polymeric delivery systems. Recently, hydrotropic polymers were developed based... 

Kopecek J. The potential of water-soluble polymeric carriers in targeted and site-specific drug delivery. J Cont Rel 1990 11 279-290. 

Grim Y, Kopecek J. Bioadhesive water-soluble polymeric carriers for site-specific oral drug delivery. Synthesis, characterisation and relesae of 5-aminosalicylic acid by Streptococcus faecium in vitro. New Polym Mater 1991 3 49-59. 

Wang D, Miller S, Sima M, Kopekova P, Kopecek J. Synthesis and evaluation of water-soluble polymeric bone-targeted drug delivery systems. Bioconj Chem 2003 14 853-859. 

The release kinetics of peptides and proteins from any polymeric drug delivery system are a function of many factors including the type of peptide or protein used, its water solubility, crystallinity, water content, etc., and the characteristics of the polymer system. We have found that the release rates of peptides and proteins from the atrigel m system may be affected by varying a number of parameters of the polymer formulations. These parameters include the type of polymer, the concentration of polymer, the molecular weight of the polymer, the type of solvent, the amount of protein loaded in the formulation, and the addition of additives. 

Fig. 30 Types of nanocarriers for drug delivery, (a) Polymeric nanoparticles polymeric nanoparticles in which drugs are conjugated to or encapsulated in polymers, (b) Polymeric micelles amphiphilic block copolymers that form nanosized core-shell structures in aqueous solution. The hydrophobic core region serves as a reservoir for hydrophobic drugs, whereas hydrophilic shell region stabilizes the hydrophobic core and renders the polymer water-soluble.

Continuous aqueous phase emulsion polymerization is one of the most widely used procedures to make nanoparticles for drug delivery purposes, especially those prepared from the alkylcyanoacrylate monomers. An oil-in-water emulsion system is employed where the monomer is emulsified in a continuous aqueous phase containing soluble initiator and surfactant [39, 40]. Under these conditions, the monomer is partly solubilized in micelles (5-10 nm), emulsified as large... 

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

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. 

---