Controlled release of drugs is a dynamic activity of pharmaceutical companies, due to the indisputable advancement provided by delivery technology to pharmacotherapy. In addition, this activity gives rise to new patented products for a market in which new substances are reducing and the approved ones more and more face administration problems. Today, no drug product enters the market without its own delivery program built in. In front of this requirement, pharmaceutical technology researchers proposed the so called drug delivery “technology platform,” i.e., drug administration based on the use of devices capable to contain, meter and deliver the drug at appropriate rate and duration. Typically, without considering drug conjugates, drug delivery devices are classified reservoirs or matrices. The choice between them depends on drug properties and delivery kinetics sought. In general, matrices are considered more reliable in term of delivery, less costly as manufacturing and easier to formulate. They are also less exposed to malfunctioning problems. Matrices are monolithic systems constituted of active substance dispersed and entrapped in a continuum of excipient (adjuvant), i.e., the “matrix forming” substance. The matrix requisite is the non-immediate disintegration of the monolith in contact with dissolution media. The usual appearance of this device is the tablet form, commonly manufactured by compression, that introduced in water does not apparently disintegrate. The maintenance of the solid structure permits the establishment of the mechanism for drug release control. Matrix keeps a substantial integrity or structure for the time needed to release the dispersed or dissolved drug. This does not mean that the matrix has not to dissolve but simply that dissolution is slowed down by its typical release mechanism. This behavior differentiates the disintegrating tablets from the matrices, the first promptly providing drug for dissolution and absorption, the second controlling in time drug dissolution and absorption. Here, drug release is obtained by elution from the polymeric (in general) continuum that can actively or passively participate to the release. Swellable matrices will be the subject of this chapter with the main focus on the swelling phenomenon and on the related drug release kinetics, in dependence on the components and matrix geometry used.

Swellable and Rigid Matrices: Controlled Release Matrices with Cellulose Ethers

COLOMBO, Gaia;
2008

Abstract

Controlled release of drugs is a dynamic activity of pharmaceutical companies, due to the indisputable advancement provided by delivery technology to pharmacotherapy. In addition, this activity gives rise to new patented products for a market in which new substances are reducing and the approved ones more and more face administration problems. Today, no drug product enters the market without its own delivery program built in. In front of this requirement, pharmaceutical technology researchers proposed the so called drug delivery “technology platform,” i.e., drug administration based on the use of devices capable to contain, meter and deliver the drug at appropriate rate and duration. Typically, without considering drug conjugates, drug delivery devices are classified reservoirs or matrices. The choice between them depends on drug properties and delivery kinetics sought. In general, matrices are considered more reliable in term of delivery, less costly as manufacturing and easier to formulate. They are also less exposed to malfunctioning problems. Matrices are monolithic systems constituted of active substance dispersed and entrapped in a continuum of excipient (adjuvant), i.e., the “matrix forming” substance. The matrix requisite is the non-immediate disintegration of the monolith in contact with dissolution media. The usual appearance of this device is the tablet form, commonly manufactured by compression, that introduced in water does not apparently disintegrate. The maintenance of the solid structure permits the establishment of the mechanism for drug release control. Matrix keeps a substantial integrity or structure for the time needed to release the dispersed or dissolved drug. This does not mean that the matrix has not to dissolve but simply that dissolution is slowed down by its typical release mechanism. This behavior differentiates the disintegrating tablets from the matrices, the first promptly providing drug for dissolution and absorption, the second controlling in time drug dissolution and absorption. Here, drug release is obtained by elution from the polymeric (in general) continuum that can actively or passively participate to the release. Swellable matrices will be the subject of this chapter with the main focus on the swelling phenomenon and on the related drug release kinetics, in dependence on the components and matrix geometry used.
2008
9780849390159
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/533407
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