Studies on tolfenamic acid-chitosan intermolecular interactions:Effect of pH, polymer concentration and molecular weight

Ahmed, S. and Sheraz, M.A. and Rehman, I.U. (2013) Studies on tolfenamic acid-chitosan intermolecular interactions:Effect of pH, polymer concentration and molecular weight. AAPS PharmSciTech, 14 (2). pp. 870-879. ISSN 1530-9932

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Abstract

Solid-state properties of tolfenamic acid (TA) and its complexes with chitosan (CT) have been studied. Effect of medium pH, molecular weight of polymer and its different concentrations on these TA-CT complexes were studied in detail. Low and medium molecular weight CT have been used in different ratios at pH ranging from 4 to 6 and freeze-drying technique has been employed to modify the appearance of crystalline TA. Physical properties of the formed complexes have been studied by employing X-ray diffraction, differential scanning calorimetry and scanning electron microscopy; chemical structure has been studied using Fourier transform infrared spectroscopy. The results showed that both forms of the polymer exhibited complete conversion in 1:8 ratio at pH 4, 1:4 at pH 5 and 1:1 at pH 6 indicating a marked effect of pH on drug-polymer complexation. The percent crystallinity calculations indicated low molecular weight CT slightly more effective than the other form. No changes in the complexes have been observed during the 12 week storage under controlled conditions. Both forms of CT at different pH values indicated retardation of recrystallization in TA during cooling of the melt from 1:1 ratios exhibiting formation of strong intermolecular hydrogen bonding between the drug and the polymer. © 2013 American Association of Pharmaceutical Scientists.

Item Type:
Journal Article
Journal or Publication Title:
AAPS PharmSciTech
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3000/3003
Subjects:
ID Code:
132936
Deposited By:
Deposited On:
17 Apr 2019 09:00
Refereed?:
Yes
Published?:
Published
Last Modified:
01 Jul 2020 05:45