Macromolecules, polymeric drug

Polymeric drugs are macromolecules that elicit biological activity (7). Many synthetic polymers are biologically inert. However, some exhibit toxicity, while others exhibit a wide range of therapeutic activities. There are three kinds of polymer drugs polycations, polyanions, and polynucleotides. 

Probably the most promising polymeric drug carrier system involves polysaccharide molecules. These are natural polymers and are often biodegradable to products that are useful to the host or easily eliminated by the host. Dextrans have been the most extensively used polysaccharide for macromolecular prodrug preparations (79). These materials are biocompatible and the in vivo fate is directly related to their molecular weight. Moreover these macromolecules can be easily targetted to the hepatocytes with D-mannose or L-fucose (20). 

Macromolecular drugs, in general, can be divided into four types (a) polymeric drugs—these represent macromolecules that themselves display pharmacological activity, and polymers that contain therapeutically active groups as an integral part of the main chain ... 

Huval CC, Bailey MJ, Braunlin WH, Holmes-Farley SR, Mandeville WH, Petersen JS, Polomoscanik SC, Sacchiro RJ, Chen X, Dhal PK. Novel cholesterol lowering polymeric drugs obtained by molecular imprinting. Macromolecules 2001 34 1548-1550. 

Macromolecules as drug carriers may be divided into degradable and nondegradable types based on their fate within the organism. Biodegradable polymeric drug carriers are traditionally derived from natural products polysaccharides, poly(amino acids) in the hope that the body s natural catabolic mechanisms will act to break down the macromolecular structure into small,... 

L.R.Brown, C.L.Wei and R.Langer,/ vivo and in v/ft-o release of macromolecules from polymeric drug delivery... 

Kopecak J, Duncan R. Poly A-(2-hydroxypropyl) methacrylamide macromolecules as drug carrier systems. In Ilium L, Davies SS, eds. Controlled Release of Drugs from Polymeric Particles and Macromolecules. Bristol, UK Adam Hilger, 1988. 

Brown, L.R., C.L. Wei, and R. Langer, In vivo and in vitro release of macromolecules from polymeric drug delivery system. Journal of Pharmaceutical Research, 1983,72, 1181-1185. 

Ulbrich K, Subr V, Strohalm J, Plocova D, Jelinkova M, Rihova B. Polymeric drugs based on conjugates of synthetic and natural macromolecules. 1. Synthesis and physicochemical characterisation. J Cont Rel 2000 64 63-69. 

The EPR effect can be observed with macromolecules having apparent molecular size larger than 40-800 kDa [14-22, 29-31], or more to the size of bacteria [32]. Namely, biocompatible polymeric drugs having size larger than the renal clearance threshold (more than 40 kDa) exhibit the EPR effect [14-22]. 

The area of applied bioactive polymeric systems includes such diverse entities as controlled release systems (erodable systems, diffusion controlled systems, mechanical systems and microcapsules), and biologically active polymers, such as natural polymers, synthetic polypeptides, pseudo-enzymes, pseudo-nucleic acids and polymeric drugs. The area can also include immobilized bioactive materials, such as immobilized enzymes, antibodies and other bioactive agents and the area of artificial cells. This Chapter reviews the general field of biologically active synthetic and modified natural macromolecules with an emphasis on their common characteristics, problems and applications. The areas reviewed include both medical and non-medical applications for both controlled release systems and polymers that exhibit direct biological activity. 

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