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The study of polydimethylsiloxane (P...

Gao, Zongming.

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The study of polydimethylsiloxane (PDMS) coatings for controlled drug release.

Record Type:	Electronic resources : Monograph/item
Title/Author:	The study of polydimethylsiloxane (PDMS) coatings for controlled drug release./
Author:	Gao, Zongming.
Description:	115 p.
Notes:	Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3478.
Contained By:	Dissertation Abstracts International65-07B.
Subject:	Chemistry, Polymer. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3141363
ISBN:	0496884956

The study of polydimethylsiloxane (PDMS) coatings for controlled drug release.
Gao, Zongming.

The study of polydimethylsiloxane (PDMS) coatings for controlled drug release. - 115 p.

Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3478.

Thesis (Ph.D.)--University of Cincinnati, 2004.

For some twenty years now, polydimethylsiloxane (PDMS) elastomers have already been used in some pharmaceutical coating materials. In particular, water-based PDMS latex with addition of colloidal silica and polyethylene glycols (PEG) as channeling agents has been successfully used to control drug release from pharmaceutical solid oral dosage forms. However, to improve the mechanical properties and decrease the tackiness of silicone coating, a large amount of colloidal silica had to be added before the coating process. This resulted in an increased solid content of the coating dispersion, which complicated the spray coating process and reduced the stability of the coating dispersion. Additionally, toxic material, organic tin, was employed as catalyst to produce PDMS coating material.

ISBN: 0496884956Subjects--Topical Terms:

1018428
Chemistry, Polymer.

The study of polydimethylsiloxane (PDMS) coatings for controlled drug release.
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100 1 $a Gao, Zongming. $3 1935505
245 1 4 $a The study of polydimethylsiloxane (PDMS) coatings for controlled drug release.
300 $a 115 p.
500 $a Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3478.
500 $a Chair: James E. Mark.
502 $a Thesis (Ph.D.)--University of Cincinnati, 2004.
520 $a For some twenty years now, polydimethylsiloxane (PDMS) elastomers have already been used in some pharmaceutical coating materials. In particular, water-based PDMS latex with addition of colloidal silica and polyethylene glycols (PEG) as channeling agents has been successfully used to control drug release from pharmaceutical solid oral dosage forms. However, to improve the mechanical properties and decrease the tackiness of silicone coating, a large amount of colloidal silica had to be added before the coating process. This resulted in an increased solid content of the coating dispersion, which complicated the spray coating process and reduced the stability of the coating dispersion. Additionally, toxic material, organic tin, was employed as catalyst to produce PDMS coating material.
520 $a The present study has developed a new method to prepare stable PDMS latexes suitable for spraying-coating drug tablets without the need for colloidal silica and organic tin catalyst. The approach taken consisted of preparing water-based emulsions of hydroxyl-terminated PDMS with sodium lauryl sulfate (SLS) as surfactant, and then cross linking on restriction of the pH of the system to the acidic range with HCl.
520 $a Optimizing the coatings for drug-release applications requires a better understanding of their properties and thus clarification of the mechanism through which the cross-linking reaction takes place. The present study also approaches this goal by documenting the effects of anionic, cationic and nonionic surfactants at various concentrations, and in acidic, neutral, or basic media. Analytical methods were set up to monitor the transport of crosslinker from the water phase into the hydrophobic PDMS phase. A possible mechanism for the PDMS cross-linking reaction in emulsion without organic tin as catalyst has been developed. Additionally, to prepare coated tablets for controlled drug release studies, an economical and efficient lab-scale coating system has been developed.
520 $a Furthermore, in-vitro evaluations were performed to study the effects of the amount of channeling agents, the addition of colloidal silica, and the pH of the dissolution media used. The study involved hydrochlorothiazide (as a marker drug) released from compressed tablets, which had been spray coated using PDMS latexes with various polyethylene glycols (PEG) loadings as channeling agents. The dissolution results showed that coated tablets containing up to 25% (w/w) PEG could have constant release rates. Higher amounts of PEG resulted in non-linear release patterns. Also, the addition of colloidal silica decreased the rates of drug release. Since the pH of dissolution media affected the structures of the exposed PDMS films, it had significant effects on the drug release behavior.
590 $a School code: 0045.
650 4 $a Chemistry, Polymer. $3 1018428
650 4 $a Health Sciences, Pharmacy. $3 1017737
690 $a 0495
690 $a 0572
710 2 0 $a University of Cincinnati. $3 960309
773 0 $t Dissertation Abstracts International $g 65-07B.
790 1 0 $a Mark, James E., $e advisor
790 $a 0045
791 $a Ph.D.
792 $a 2004
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3141363