title: Measurements of non-uniform water content in hydroxypropyl-methyl-cellulose based matrices via texture analysis.
abstract: The use of hydrogels in the preparation of controlled release pharmaceutical forms is extensively diffused. The main feature of these polymers is their ability to swell forming a gel layer when they enter in contact with fluids. Once the gel layer is formed, the drug contained in the matrix can easily diffuse ensuring a controlled release from the tablet. Measurement of water content within a hydrating matrix based on hydrogels is a key topic in the study of pharmaceutical solid dosage forms. The aim of this work is to evaluate the water content of swollen matrices composed by HPMC and theophylline both in axial and in radial direction, as a function of time, using a texture analysis. A relationship between water content and slope of the force-penetration curves has been obtained using a simplified system in which the water uptake is allowed only in radial direction, obtaining thus partially hydrated matrices with the water content varying only along the radial direction. Once the relationship has been validated, it has been applied in a more complex system in which the polymer swelling takes place in both axial and radial direction. Thus, using the texture analysis it has been possible to determine the water in each position within the hydrated matrices.
authors: Dipartimento di Ingegneria Industriale (DIIn), Università di Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
authors: Sara
authors: S
authors: Cascone
authors: Dipartimento di Ingegneria Industriale (DIIn), Università di Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy. Electronic address: glamberti@unisa.it.
authors: Gaetano
authors: G
authors: Lamberti
authors: Dipartimento di Ingegneria Industriale (DIIn), Università di Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy.
authors: Giuseppe
authors: G
authors: Titomanlio
authors: Dipartimento di Farmacia (DIFARMA), Università di Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano SA, Italy.
authors: Matteo
authors: M
authors: d'Amore
authors: Dipartimento di Farmacia (DIFARMA), Università di Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano SA, Italy.
authors: Anna Angela
authors: AA
authors: Barba
keywords: Hydrogels; Texture analysis; Water content