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AAPS PharmSciTech. 2002 June; 3(2): 55–63.
Published online 2002 March 27. doi:  10.1208/pt030212
PMCID: PMC2750314

In vivo evaluation of modified gum karaya as a carrier for improving the oral bioavailability of a poorly water-soluble drug, nimodipine


This work examines the influence of modified gum karaya (MGK) on the oral bioavailability of a poorly water-soluble drug, nimodipine (NM), in comparison with that of gum karaya (GK). A cogrinding method was selected to prepare mixtures of NM and GK or MGK in a 1:9 ratio (NM:GK/MGK). Differential scanning calorimetry (DSC), Fourier transmission infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), solubility studies, and in vitro release studies were performed to characterize the properties of the cogrinding mixtures. No drug-carrier interactions were found, as confirmed by DSC and FT-IR studies. The XRD study revealed that the crystallinity of NM was identical in both the cogrinding mixtures and was decreased when compared to that of physical mixtures or pure NM. The in vitro release rate of NM from both cogrinding mixtures was significantly higher than that of physical mixtures or pure NM. The in vivo study revealed that the bioavailability of NM from pure drug was significantly lower when compared to the cogrinding mixtures. The oral bioavailability was found to be NM powder < cogrinding mixtures of NM and GK < cogrinding mixtures of NM and MGK < NM solution. It can be inferred from the above results that MGK, an economical carrier, could be used for the dissolution enhancement of NM.

Key Words: gum karaya, modified gum karaya, nimodipine, dissolution enhancement, cogrinding method, oral bioavailability studies

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
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