Hydrogels are three dimensional networks of hydrophilic homopolymers or copolymers generally covalently or ionically crosslinked. They interact with aqueous media by swelling to some equilibrium value by retaining the aqueous media in their structures. This study concerns the investigation of the swelling and the controlled drug release behaviour of hydrogels synthesized via the photopolymerisation process. The study of hydrogels in this project was oriented towards their biomedical applications as controlled drug delivery devices. It is a known fact that the complete conversion of monomers to polymers may not be achieved in the polymerisation process thus there is always a certain component of unreacted toxic monomers still remained in the polymer matrix. These monomers have the tendency to leach out of the polymer matrices when the polymers are in contact with an aqueous medium thus rendering the hydrogel to be nonbiocompatable. The polymers synthesized in this work were washed thoroughly in milli-Q-water and then evaluated in vitro for any possible toxic effect on human keratinocyte (HaCaT)v cells using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diaphenyl tetrazolium bromide (MTT) cell proliferation assay. The cytotoxicity results indicated that the hydrogels understudy sustained and allowed a positive growth of the HaCat cells in the duration of the cytotoxicity experiment, thus proving to be satisfactorily compatible. / Doctor of Philosophy (PhD)

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 86-92).

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Titles called 1,2,3, and 4. Includes bibliographical references (leaves 276-286). Also available on the World Wide Web.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Chemistry." Includes bibliographical references.

Not available / text

Not available / text

No description available.

There exists a demand to re-engineer pre-existing pharmaceuticals to provide improved drug delivery, new dosage forms and increased drug safety and efficacy. Furthermore, the development of novel methods and formulations allows for the patent life of pre-existing drugs to be extended, which has obvious economic benefits for pharmaceutical companies. Dense gas technology provides a means to achieve these aims and to overcome the distinct limitations of traditional technologies. A novel formulation of the antifungal drug itraconazole has been developed using gas antisolvent processes. The new itraconazole-polymer formulation displayed a significant improvement in dissolution rate achieving 89.8 % dissolution compared to 52.5 % for the commercial formulation. The results of this study demonstrate the great opportunity to use dense gases for the creation of novel drug-polymer composite formulations with improved dissolution properties. The impregnation of an active ingredient into a polymer matrix is another method that can be used to improve the dissolution of poorly water soluble drugs. Dense gas technology has been incorporated into traditional methods for the formation of porous polymer matrices decreasing process residence times. However, some issues still need to be overcome including high operating temperatures and the use of class 3 solvents. A novel dense gas process for the formation of a porous polymer hydrogel matrix has been developed to improve upon current methodologies; Dense Gas Solvent Exchange Process (DGSEP). The Dense Gas Solvent Exchange Process was used to create a porous chitosan hydrogel impregnated with a stable amorphous form of the drug griseofulvin. Furthermore, the process was extended to include a hydrophilic polymer into the matrix. The resulting formulation had a dramatically improved dissolution rate achieving complete dissolution within 70 minutes compared with the commercial formulation which achieved less than 40 %dissolution in the same time. There is great potential for DGSEP to be applied to the formation of a variety of polymer hydrogels impregnated with active ingredients and incorporating polymers and other compounds. The significance of these results is that a simple and effective processing method has been developed to produce hydrogel systems that are suitable for the development of a diverse range of drug delivery systems.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 245-259). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xv, 172 p.; also includes graphics (some col.). Includes bibliographical references (p. 161-172).