Grund J, Koerber M, Walther M, Bodmeier R. The effect of polymer properties on direct compression and drug release from water-insoluble controlled release matrix tablets.
Int J Pharm 2014;
469:94-101. [PMID:
24746409 DOI:
10.1016/j.ijpharm.2014.04.033]
[Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/08/2014] [Accepted: 04/12/2014] [Indexed: 11/15/2022]
Abstract
The objective of this study was to identify and evaluate key polymer properties affecting direct compression and drug release from water-insoluble matrices. Commonly used polymers, such as Kollidon(®) SR, Eudragit(®) RS and ethyl cellulose, were characterized, formulated into tablets and compared with regard to their properties in dry and wet state. A similar site percolation threshold of 65% v/v was found for all polymers in dry state. Key parameters influencing polymer compactibility were the surface properties and the glass transition temperature (T(g)), affecting polymer elasticity and particle size-dependent binding. The important properties observed in dry state also governed matrix characteristics and therefore drug release in wet state. A low T(g) (Kollidon(®) SR<Eudragit(®) RS) decreased the percolation threshold, particle size effect and tortuosity, but increased permeability and sensitivity to heat/humidity treatment. Hence, lower permeability and higher stability are benefits of a high-T(g) polymer (ethyl cellulose). However, release retardation was observed in the same order as matrix integrity (Eudragit(®) RS<ethyl cellulose<Kollidon(®) SR), as the high permeability was counteracted by PVP in case of Kollidon(®) SR. Therefore, the Tg and composition of a polymer need to be considered in polymer design and formulation of controlled-release matrix systems.
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