Solid as solvent-Novel Spectrophotometric Analytical Method for Metronidazole Tablets using Solids (Eutectic Liquid of Phenol and Niacinamide) as Solubilizing Agents (Mixed Solvency Concept) Maheshwari Rajesh Kumar1,*, Khan Masheer Ahmed2, Maheshwari Nupur1, Maheshwari Neelesh3 1Department of Pharmacy, Shri G S Institute of Technology and Science, Indore (India) 2School of Pharmacy, Devi Ahilya Vishwavidyalaya, Indore 3School of Pharmaceutical Sciences, RGPV, Bhopal *Corresponding Author E-mail: rkrkmaheshwari@yahoo.co.in
Online published on 21 July, 2016. Abstract The researchers are doing much work to give eco-friendly solutions for the pollution and toxicity caused by most of the organic solvents. Maheshwari has given a nice concept, known as mixed-solvency concept by the application of which, innumerable solvent systems can be developed. Maheshwari is of the opinion that each substance possesses solubilizing power. He has given several eco-friendly methods in the area of drug estimations and formulations precluding the use of toxic organic solvents. The present research work also provides an eco-friendly method to estimate spectrophotometrically, the metronidazole drug in tablet formulations without the help of organic solvent. The present investigation is an attempt to show that solids can also be wisely used to act as solvent precluding the use of organic solvents. The main objective of the present study is to demonstrate the solvent action of solid. Solid excipients can nicely be employed as solubilizers in the development of pharmaceutical dosage forms in solution form of poorly soluble drugs (mixed solvency concept). Present study describes the application of solvent character of eutectic liquid consisting of phenol and niacinamide in 25:10 ratio (PNM 2510) on the weight basis for spectrophotometric estimation of metronidazole tablets. Solubility of metronidazole in distilled water was found to be 7.28 mg/ml at room temperature. More than 80 mg of metronidazole dissolves in 1 ml of PNM 2510. In the present investigation, PNM 2510 was utilized to extract out (dissolve) the drug from tablet powder of metronidazole tablets. Distilled water was used for dilution purpose. Absorbance was noted at 320 nm against reagent blank to calculate the amount of drug in the tablets. Proposed method is novel, eco-friendly, rapid, free from toxicity of organic solvent, accurate and reproducible. Recovery studies and statistical data proved the accuracy, reproducibility and precision of the proposed method. The presence of phenol, niacinamide and tablet excipients did not interfere in the spectrophotometric estimation of metronidazole at 320 nm. Phenol and niacinamide do not interfere above 300 nm in spectrophotometric analysis. Top Keywords Mixed-solvency concept, metronidazole, phenol, niacinamide, eutectic liquid, spectrophotometric analysis. Top |