The dissolution profile of orally delivered drugs can be controlled through the use of osmotically controlled drug delivery devices. The most commonly used device is the osmotic tablet, which is essentially a tablet core that is coated with a rate-limiting semipermeable membrane. The feasibility of applying a coating onto a tablet using dense gas techniques was studied. Two different coating materials, polymethymethacrylate (PMMA, Mw = 120,000 g/mol) and cellulose acetate (CA, 39.8 wt% acetyl content) were applied onto an 8 mm osmotic tablet core using the Gas Anti-solvent (GAS) process. For PMMA, the pressurisation rate, coating temperature and volumetric expansion of up to 250% had minimal effect on the coating quality. The concentration, solvent type and the use of polyethylene glycol (Mw = 200 g/mol) had a more pronounced effect on the coating. The coating process was optimised to apply a smooth and uniform coating with a 50 ??m thickness. For CA, the pressurisation rate and the coating temperature had little effect on the coating that was applied. The process was more sensitive to a change in the concentration of the solution and the volumetric expansion that was used. It was found that the concentration could not be increased too much without affecting the coating quality. A CA coating was applied onto a PMMA-coated tablet using the optimised conditions. The thickness in the tablet coating increased by 10 ??m. Dissolution tests of the uncoated and coated tablets were carried out. The CA coatings were found to be insufficient in limiting the rate of water entering the tablet and performed similarly to an uncoated tablet core. The PMMA coatings were found to limit the rate of delivery of the model drug. However, variations in the PMMA coatings resulted in an inconsistent delivery profile across batches. The tablets coated with both PMMA and CA had a delivery rate in between that of uncoated and PMMA-coated tablets, indicating that the application of the second coating had compromised the initial PMMA coating.

Thesis (M.S.)--West Virginia University, 1998. / Title from document title page. "November 13, 1998." Document formatted into pages; contains x, 121 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 105-110).

Thesis (M.S.)--California Polytechnic State University, 2009. / The letter x is subscripted in the title. Title from PDF title page; viewed on October 23, 2009. Major professor: Dr. Richard Savage. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Materials Engineering." "September 2009." Includes bibliographical references (p. 115-121). Also available on microfiche.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xxi, 282 p.; also includes graphics (some col.). Includes bibliographical references (p. 262-282).

Thesis (doctoral)--Helsinki University of Technology, 2002. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Rutgers University, 2007. / "Graduate Program in Ceramic and Materials Science and Engineering." Includes bibliographical references (p. 49-50).

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Public Health." Includes bibliographical references.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 191-198.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Released for public view from 10 November 2008. Includes bibliographical references: leaf 136-146.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 64-70). Also available via the Internet.