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Materials 2010, 3(12), 5195-5211; doi:10.3390/ma3125195

In vitro Evaluation of Acyclovir/Chitosan Floating Systems

 and 1,2,*
Received: 27 October 2010 / Revised: 24 November 2010 / Accepted: 25 November 2010 / Published: 6 December 2010
(This article belongs to the Special Issue Chitins)
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Abstract: Chitosan (CS) floating lyophilized formulations (L) for gastric drug delivery of acyclovir (ACV) have been developed. The freeze-dried formulations were obtained from acidic aqueous suspensions prepared with different ACV/CS ratios. No changes in ACV crystallinity were observed during X-ray diffraction powder studies as a consequence of the manufacturing process. Considering that fed and fasted states modified the intragastric pH, swelling and in vitro dissolution studies were carried out in different acidic media (0.1 M HCl and progressive pH medium) in order to understand the influence of these physiological states on ACV/CS formulations. Swelling behavior of the floating lyophilized formulations was dependent on CS and ACV proportions within L and on medium nature due to pH dependent CS solubility. Furthermore, no interactions between ACV and CS were detected in solid state according to the X-ray studies. In vitro dissolution of ACV from L was influenced by the swelling behavior. However, it is feasible to optimize the ACV/CS ratios to achieve a desired formulation that releases the total quantity of ACV at a specific time. Moreover, floatability was assessed by buoyancy tests. The results demonstrated that the freeze-drying process achieved effective floating systems capable of remaining within the stomach while the total amount of ACV is released from L.
Keywords: Acyclovir; chitosan; floating freeze-dried formulations; swelling behavior; controlled release Acyclovir; chitosan; floating freeze-dried formulations; swelling behavior; controlled release
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Ruiz-Caro, R.; Veiga, M.D. In vitro Evaluation of Acyclovir/Chitosan Floating Systems. Materials 2010, 3, 5195-5211.

AMA Style

Ruiz-Caro R, Veiga MD. In vitro Evaluation of Acyclovir/Chitosan Floating Systems. Materials. 2010; 3(12):5195-5211.

Chicago/Turabian Style

Ruiz-Caro, Roberto; Veiga, María D. 2010. "In vitro Evaluation of Acyclovir/Chitosan Floating Systems." Materials 3, no. 12: 5195-5211.

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