Controlled drug delivery biodegradable systems

Pitt, C. G., and Schindler, A., The design of controlled drug delivery systems based on biodegradable polymers, in Biodegradable and Delivery Systems for Contraception, Progress in Contraceptive Delivery Systems, Vol. 1 (E. S. E. Hafez and W. A. A. van Os, eds.), MTP Press Ltd., Lancaster, England, 1980, pp. 17-46. 

Biodegradable polyurethanes have been proposed and studied before (9-72). The difference in our study is the inclusion of a phosphoester linkage instead of the commonly used polyester component. This seems to provide more flexibility as the side chain of the phosphate or phosphonate can be varied. For controlled drug delivery applications, drugs can be linked to this site to form a pendant delivery system. Moreover, for certain medical applications, fast degradation rate is obtainable by the introduction of these hydrolyzable phosphoester bonds. With the LDI based polyurethanes, drugs or other compounds of interest can also be coupled to the ester side chain of the lysine portion. 

Nondegradable subcutaneous implants as diffusion-controlled drug delivery systems, including Norplant, have been reviewed.89 99 Unlike biodegradable implants with long-term toxicological concern for metabolism of the polymer, nondegradable implants cannot avoid removal of the... 

Leong, K. Synthetic biodegradable polymer drug delivery systems, in Polymer for Controlled Drug Delivery, ed. P. Tarcha. Boca Raton FL CRC Press, 1991, pp. 127-148. 

The majority of controlled drug delivery systems now being marketed or under development are based on diffusion of the drug through a semipermeable membrane to achieve the requisite release rate. Diffusion control is particularly important to transdermal delivery, where biodegradation and dissolution are not viable mechanisms of controlling the release rate. Provided the process is Fickian, the rate of diffusion through the semipermeable polymer is determined by... 

Heller, J. Biodegradable polymers in controlled drug delivery. Critical Reviews in Therapeutic Drug Carrier Systems 1984, 1 (1), 39-90. 

The microparticle system has become an indispensable part of the controlled drug delivery fields for the past few decades since it can readily be adapted for various administration methods. In particular, biodegradable polymeric microparticles can provide a number of advantages over conventional parenteral formulations ... 

Drug release from biodegradable polymer microparticles is determined by the polymer degradation kinetics, structural features of the microparticles, and distribution of the drugs within the particle matrix. The ultimate goal of microparticle systems in the controlled drug delivery is to achieve readily tunable release profiles, which has been pursued in various perspectives. 

Peri D, Bogdansky S, Allababidi S, Shah JC. Development of an implantable, biodegradable, controlled drug delivery system for local antibiotic therapy. Drug Dev Ind Pharm 1994 20 1341-1352. 

Poly (e-caprolactone), poly lactides, and polyglycolides have quite unusual properties of biodegradability and biocompatibility. The majority of polymers used in the biomedical field to develop implants, sutures, and controlled drug-delivery systems are the aforesaid resorbable polyesters produced by ring-opening polymerization of cyclic (di)esters. 

PLA is a non-toxic and biodegradable material that is extensively used in coating membranes [10] and as carrier compounds [11-18]. The application of PLA in controlled drug-delivery systems is often limited due to its poor wettability. It has... 

To enhance the desirable properties of a polymer as a matrix for a controlled drug delivery system, efforts have been made to improve its hydrophilicity, biodegradation rate, and drug stability. Hydrophilic blocks play vital role in polymeric drug delivery systems, for example, poly(ethylene oxide)... 

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