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Characterization and Dissolution Study of Chitosan Freeze-Dried Systems for Drug Controlled Release
Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040-Madrid, Spain
Unidad de Biotransformaciones Industriales, Parque Científico de Madrid, Tres Cantos, Madrid, Spain
* Author to whom correspondence should be addressed.
Received: 8 September 2009; in revised form: 14 October 2009 / Accepted: 28 October 2009 / Published: 30 October 2009
Abstract: Freeze-dried systems (L) comprising chitosan (CS) and caffeine (CAF) have been developed for oral administration. Different proportions of CS and CAF have been used in the preparation of the systems. Hot stage microscopy (HSM), differential scanning calorimetry (DSC) and X-ray diffraction powder have been used to characterize the systems prepared. X-ray diffraction patterns showed that there were no interactions between CAF and CS molecules within the freeze-dried systems and the crystallinity of CAF was decreased. Swelling and dissolution tests were carried out in two different media (demineralized water and pH progressive medium) in order to establish their influence over CAF/CS system behaviour. Characteristic swelling behaviour of freeze-dried CS systems (imbibition and dissolution processes) was influenced by the proportions of CS and CAF in the formulations, and by the nature of the medium due to the pH-dependent solubility of CS. Release of CAF from lyophilized systems was conditioned by the swelling process and it should be possible to obtain a CAF/CS binary system with a specific time for total drug release including concrete proportions of both components. Furthermore, the freeze-drying process allowed us to obtain feasible systems for controlled release of CAF until the total amount of drug was released.
Keywords: caffeine; chitosan; freeze-dried systems; swelling and dissolution behaviour; controlled release
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Ruiz-Caro, R.; Veiga-Ochoa, M.D. Characterization and Dissolution Study of Chitosan Freeze-Dried Systems for Drug Controlled Release. Molecules 2009, 14, 4370-4386.
Ruiz-Caro R, Veiga-Ochoa MD. Characterization and Dissolution Study of Chitosan Freeze-Dried Systems for Drug Controlled Release. Molecules. 2009; 14(11):4370-4386.
Ruiz-Caro, Roberto; Veiga-Ochoa, María Dolores. 2009. "Characterization and Dissolution Study of Chitosan Freeze-Dried Systems for Drug Controlled Release." Molecules 14, no. 11: 4370-4386.