POLYMER COMBINATION FOR PARENTERAL DRUG DELIVERY

The number of medical applications for natural or synthetic biomaterials contin\ues to expand. One particularly interesting development concerns the use of injectable polymeric biomaterials. The forms in which the biomaterials are injected can vary from particulate matter, e.g., microspheres or irregularly shaped particles, to gels and cements that are injected in liquid form and which harden inside the body. Polymers have played an integral role in the advancement of drug delivery technology by providing controlled release of therapeutic agents in constant doses over long periods, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs. The development of using polymer combination have attracted much attention because the biodegradation rate of the copolymer is easily controlled by altering its composition. In this review, the fundamental drug delivery systems from polymer blends including the origins and applications of  polymer blend systems and polymer blend  therapeutics are highlighted. The PCL microparticle-dispersed PLGA solution may be a good candidate as an injectable bulking agent. Using PCL–PLGA blend, the porous structure of the polymer blends dependent on the blend ratio under the same conditions other than the ratio. When blending PLGA with PEG, the in vitro release studies showed that the initial burst effect was dependent on the PLGA/PEG blend ratio. Moreover, the release rate increased in direct relation to PEG content. Blending PCL with poly(methacrylate) showed that the greater the poly(methacrylate) content, the less pronounced the burst effect and the more sustained the release effect. The latest developments in polymer blend capable of molecular recognition or directing intracellular delivery are surveyed to illustrate areas of research advancing the frontiers of drug delivery.