Poly delivery system

Associations can be of physical nature too. Chitosan blends with hydrophilic polymers including polyvinylalcohol, polyethyleneoxide and poly-vinylpyrrohdone, were investigated as candidates for oral gingival delivery systems. Chitosan blends were superior to chitosan alone in terms of comfort, ease of processing, film quality, and flexibihty [325]. 

Poly[(4-carboxylatophenoxy)(methoxyethoxyethoxy)phosphazene] copolymers of variable compositions were synthesized by Allcock [645] in 1996. These polymers were found to be soluble in alkaline solutions. When crosslinked (by y-rays or by addition of CaCl2 to the polymer solution) the resulting hydrogels were found able to contract or expand as a function of the pH of the solution and their utilization as pH-responsive materials for drug delivery systems could be envisaged. 

Various antimalarial drugs have been studied in biodegradable delivery systems. Wise (89) reported the use of a lactide/glycolide copolymer and also poly(L-lactic acid) for release of drugs such as quinazoline and sulfadiazine. Although in vitro data and experiments in mice were somewhat encouraging, these early formulations failed to reach significant clinical status. 

T., Katutani, Y., and Kitsugi, T., Release of antibiotics from composites of hydroxyapatite and poly(lactic acid), in Advances in Drug Delivery Systems (J. M. Anderson and S. W. Kim, eds.), Elsevier, New York, 1986, pp. 179-186. 

G. W., Poly(lactic-co-glycolic) acid mance in controlled release delivery systems of LHRH analogues, Proc. Int. Symp. Control. Rel. Bioact. Mater., 12, 177, 1985. Hutchinson, F. G., U.S. Patent 4,767,628, 1988. 

Pitt, C. G., Jeffcoat, A. R., Zweidinger, R. A., and Schindler, A., Sustained drug delivery systems. I. The permeability of poly(e-caprolactone), poly(DL-lactic acid), and their copolymers, J. Biomed. Mater. Res., 13. 497-507, 1979. 

Heller, J., Penhale, D. W. H., Fritzinger, B. K., and Ng, S. Y., Controlled release of contraceptive agents from poly(ortho ester), in Long Acting Contraceptive Delivery Systems (G. I. Zatuchni, A. Goldsmith, J. D. Shelton, and J. Sciarra, eds.), Harper and Row, Philadelphia, 1984, pp. 113-128. 

Sparer, R. V., Chung, S., Ringeisen, C. D., and Himmelstein, K. J., Controlled release from erodible poly(ortho ester) drug delivery systems, J. Control. Rel.. 23-32, 1984. 

Beck, L. R., and Tice, T. R., Poly (lactic acid) and poly(lactic-co-glycolic acid) contraceptive delivery system, in Long Acting Steroidal Contraception (D. R. Mishell, ed.). Raven Press, New York, 1983, pp. 175-199. 

Kohn, J., and Langer, R., Non-peptide poly(amino acids) for biodegradable drug delivery systems, in Proceedings of the 12th International Symposium on Controlled Release of Bioactive Materials (N. A. Peppas and R. J. Haluska, eds.). Controlled Release Society, Lincolnshire, IL, 1985, pp. 51-52. 

In this paper, then, the previously developed model (7) is extended to the calculation of erosion characteristics of a well described polymeric delivery system, the acid-catalyzed erosion of poly (ortho ester)s (2-6). This system is chosen as the example system because of the completeness of the data package in the open literature. It is expected that this modelling approach is also useful for other hydrolytically unstable polymeric drug delivery systems. 

New drug delivery systems are of great scientific and commercial interest. Amphiphilic networks composed of about 50/50 hydrophobic PIB and hydrophilic poly(2-(-dimethylamino)ethyl methacrylate) (DMAEMA) polymer segments were found to be biocompatible and to a large extent avascular (7). These PHM-PDMAEMA networks (i, in line with propositions of Weber and Stadler (2), and Sperling (J), denotes PDMAEMA chains linked by PIB chains) gave pH dependent... 

In the previous paper (7) we have described the synthesis, characterization, and certain diffusional characteristics of poly(N V-methylacrylamide)-l -polyisobutylene amphiphilic networks exhibiting a relatively high degree of swelling in both water and n-heptane. It was of interest to prepare further neutral amphiphilic networks of lower water swelling for sustained drug delivery systems. One candidate for this... 

JT Jacob-LaBarre, HE Kaufman. (1990). Investigation of pilocarpine loaded poly-butylcyanoacrylate nanocapsules in collagen shields as a drug delivery system. Invest Ophthalmol Vis Sci 31(Suppl) 485-488. 

Poly-j3-malate is readily degraded completely to L-malic acid under both acid and base conditions [108], and it can also be hydrolyzed by enzymes within the cell [105,106]. Recently, several bacteria were isolated which were able to utilize poly-/i-malate as sole carbon source for growth [109]. Because the polymer is biodegradable and bioadsorbable, it is of considerable interest for pharmaceutical applications, especially in controlled-release drug delivery systems [97,98]. Chemical routes to poly-/ -malate are expected to provide materials with various properties [110]. 

Brus C, Petersen H, Aigner A, Czubayko F, Kissel T (2004) Physicochemical and biological characterization of polyethylenimine-graft-poly(ethylene glycol) block copolymers as a delivery system for oligonucleotides and ribozymes. Bioconjug Chem 15 677-684... 

Erdmann et al. (2000) report the fabrication of devices for the localized delivery of salicylic acid from the poly(anhydride-co-ester)s mentioned in Section II.C. A unique feature of this drug delivery system is that the drug compound is part of the polymer backbone. Devices were implanted intraorally and histopathology was reported (Erdmann et al., 2000). Chasin et al. (1990) review fabrication and testing of implantable formulations for other drugs including angiogenesis inhibitors for treatment of carcinomas and bethanechol for the treatment of Alzheimer s disease. 

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