European Journal of Biomedical and Pharmaceutical Sciences

“SOLID AS SOLVENT” - NOVEL APPROACH FOR SPECTROPHOTOMETRIC ESTIMATION OF SOLID DOSAGE FORM OF NALIDIXIC ACID USING SOLIDS (EUTECTIC LIQUID OF PHENOL AND NIACINAMIDE) AS SOLUBILIZING AGENTS (MIXED SOLVENCY CONCEPT)

R K Maheshwari, Akshay Fouzdar*

ABSTRACT

The pollution and toxicity caused by most of the organic solvents is a big challenge. The researchers are doing much work to give ecofriendly solutions for this challenge. Maheshwari has given a nice concept, known as mixed-solvency concept. By application of this concept, 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 nalidixic acid 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. In the present study, a eutectic liquid (PNM 2510) obtained by triturating phenol crystals and niacinamide in 25:10 ratio on weight basis was employed to extract (dissolve) nalidixic acid drug from fine powder of tablets. Dilution was made with distilled water to carry out spectrophotometric estimation at 330 nm without the help of organic solvent. The solubility of nalidixic acid in distilled water at room temperature was found to be 0.21 mg/ml. The solubility of nalidixic acid in PNM 2510 was more than 138 mg per ml (of PNM 2510). Proposed spectrophotometric analytical method is novel, economic, 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 tablet excipients, phenol and niacinamide did not interfere in the spectrophotometric estimation at 330 nm. Phenol and niacinamide do not interfere above 300 nm.

Keywords: Mixed-solvency concept, nalidixic acid, phenol, niacinamide, spectrophotometric analysis, eutectic liquid.