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Comparison of cyclodextrins and urea as hosts for inclusion of drugs

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Abstract

Cyclodextrins have been extensively used for inclusion of various drugs for improvement of pharmaceutical characteristics of diverse nature. Numerous derivatives of cyclodextrins are currently available and are being subjected to continuous investigations. On the other hand, urea was previously being used as host for inclusion of straight chain linear compounds. However, development of a modified technique has opened flood gates for inclusion of non-linear drugs containing cyclic moieties. Cis-retinoic acid, nicorandil, vitamin E, amiloride, glipizide, enalapril maleate, simvastatin, lafutidine and ezetimbe are some of the drugs which have already been investigated for improvement of pharmaceutical characteristics. These characteristics include improvement of stability, content uniformity, dissolution profile and rheological behavior. Recently, pesticide-fertilizer combination has also been reported to serve the dual purpose of pesticide cum fertilizer and for improvement in safe handling and formulation characteristics. All FDA approved cyclodextrins are safe chemicals for human use within permissible limits. Urea is a component of normal physiological processes of body in human beings and other mammals. Urea is far cheaper when compared to cyclodextrins. Studies reveal that despite unique characteristics of urea like high solubility, non-toxicity, stability, inexpensiveness, biodegradability and easy availability, the use of urea as a host for inclusion of drugs has been grossly overlooked by researchers. Immense potential of urea as a host for inclusion of drugs need to be explored for improvement of pharmaceutical characteristics. The relative use of both cyclodextrins and urea as hosts for inclusion of drugs has been briefly reviewed in the present article.

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Dhall, M., Madan, A.K. Comparison of cyclodextrins and urea as hosts for inclusion of drugs. J Incl Phenom Macrocycl Chem 89, 207–227 (2017). https://doi.org/10.1007/s10847-017-0748-y

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