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dc.contributor.advisorMcGinity, James W.en
dc.creatorKucera, Shawn Anthony, 1974-en
dc.date.accessioned2008-08-29T00:11:26Zen
dc.date.available2008-08-29T00:11:26Zen
dc.date.issued2007-12en
dc.identifier.urihttp://hdl.handle.net/2152/3802en
dc.description.abstractThe influence of water soluble and insoluble stabilizing excipients on the physical stability of coated dosage forms was investigated in this study. The effect of the excipients on the thermal and physico-mechanical properties, and water vapor permeability of free films was studied, as was the influence of these excipients on the physical stability and release kinetics of coated pellets. The effect of water-soluble proteins, bovine serum albumin (BSA) and Type B gelatin, on the physical aging of Eudragit[trademark] RS/RL 30 D films was investigated. It was found that ionic interactions occurred above the isoelectric point of BSA and caused unstable films which showed accelerated decreases in drug release rate. The adjustment of the pH of the dispersion below the isoelectric point of BSA resulted in electrostatic repulsive charges that stabilized the drug release rate from coated dosage forms at both ambient and accelerated conditions. The addition of gelatin to the coating dispersion increased the drug release rate due to the formation of gel-domains through which the drug was able to easily diffuse. The influence of silicon dioxide on the stability of Eudragit[trademark] RS/RL 30 D films was investigated. Colloidal grades showed enhanced incorporation in the acrylic matrix; however, unstable films were formed. The addition of silicon dioxide with a larger particle size increased the permeability of the film and stabilization in drug release rate was attributed to constant water vapor permeability values of free films. The influence of ethylcellulose on the physical aging of Eudragit[trademark] NE 30 D coated pellets was studied. The two polymers were found to be substantially immiscible and the drug release rate of coated pellets was constant at both ambient and accelerated conditions which correlated to stabilizations in both the physico-mechanical properties and water vapor permeability of free films. Blending both Eudragit[trademark] NE 30 D and RS 30 D resulted in the formation of coherent films without the need of plasticizer. The two polymers were found to be miscible and both films and coated dosage forms were stable when stored below the glass transition temperature of the polymer blend. When films were stored above this temperature, instabilities occurred as a result of the further coalescence and densification of the polymer blend.en
dc.format.mediumelectronicen
dc.language.isoengen
dc.rightsCopyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.en
dc.subject.lcshExcipientsen
dc.subject.lcshDrug stabilityen
dc.subject.lcshDrugs--Coatingsen
dc.subject.lcshPolymeric drug delivery systemsen
dc.subject.lcshDrugs--Controlled releaseen
dc.titlePhysical and chemical properties of acrylic polymers influencing physical agingen
dc.description.departmentPharmacyen
dc.identifier.oclc221657739en
dc.type.genreThesisen
thesis.degree.departmentPharmacyen
thesis.degree.disciplinePharmacyen
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen


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