The term “hydrotropy” has been used to designate the increase in aqueous solubility of various poorly water-soluble compounds due to the presence of large amount of additives. Various hydrotropic agents have been used to enhance the aqueous solubility of a large number of drugs. Sodium benzoate, sodium salicylate, niacinamide, and urea have been employed to enhance the aqueous solubility of poorly water-soluble drugs. Various organic solvents like methanol, chloroform, ethanol, benzene, hexane, acetone, diethyl ether and acetonitrile are widely used in spectrophotometric estimations of poorly water-soluble drugs. Most of these organic solvents are toxic, costlier and sources of pollution. Inaccuracy in spectrophotometric estimations due to volatility of organic solvents is another drawback of these solvents. A novel, safe and sensitive method of spectrophotometric estimation in ultraviolet region is developed using 7.5 M N,N’-Dimethylurea .solution for the quantitative determination of metronidazole (poorly water-soluble drug) in tablet dosage form. There was more than 4 times enhancement in the aqueous solubility of metronidazole in 7.5M N’Ndimethyl urea solution (an inexpensive chemical used here as solubilizing hydrotropic agent). Metronodazole shows maximum absorbance at 320 nm. N’Ndimethyl urea sodium does not absorb above 260 nm. Results of the analysis were validated statistically and by recovery studies. Using 7.5 M N’Ndimethyl urea solution for analysis of two different tablet formulations of metronidazole, the percent label claims and recoveries estimated were close to 100 with low values of standard deviation, percent coefficient of variation and standard error. Thus method is ecofriendly, less toxic, inexpensive more accurate.
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