Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Stability studies of a mixture of paracetamol and ascorbic acid, prepared extempore, at elevated temperature and humidity conditions

Iwona Golonka, Andrzej Kawacki, Witold Musial

Department of Physical Chemistry, Wroclaw Medical University, ul. Borowska 211A, 50-556 Wroclaw, Poland;

For correspondence:- Witold Musial Email: witold.musial@umed.wroc.pl Tel:+48717840231

Received: 12 February 2015 Accepted: 5 July 2015 Published: 30 August 2015

Citation: Golonka I, Kawacki A, Musial W. Stability studies of a mixture of paracetamol and ascorbic acid, prepared extempore, at elevated temperature and humidity conditions. Trop J Pharm Res 2015; 14(8):1315-1321 doi: 10.4314/tjpr.v14i8.1

© 2015 The authors.
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Abstract

Purpose: To determine the effect of the temperature of water used for the preparation of paracetamol and ascorbic acid mixture on its stability, as well as to assess the influence of humidity on the stability of single components and their mixtures.

Methods: The stability of the mixtures in aqueous medium was evaluated with the aid of UV–Vis spectrophotometer interfaced with a computer. Spectral analysis was adapted to monitor changes in the aqueous medium of a commercial paracetamol and ascorbic acid mixture, an extemporaneously prepared mixture of paracetamol and ascorbic acid, and the individual preparations of paracetamol and ascorbic acid.

Results: The degradation rate was lower in commercial preparation (6.80 × 10^-3 min^-1), compared to that of the extemporaneously prepared ascorbic acid/paracetamol mixture (2.30 × 10^-2 min^-1). The decomposition of the commercial product in aqueous medium was 3.38 times slower than that of the extemporaneously prepared mixture. Ascorbic acid, tested under the same conditions as the commercial product, was unstable in aqueous solutions, with a degradation rate of 1.17×10^-2 min^-1. Ascorbic acid, dissolved in water, degraded completely within 4 h at room temperature, whereas paracetamol remained stable under the same conditions for 11 days.

Conclusion: The individual drugs in their original form retained their stability for 72 h, but some of the mixtures, in particular, the extemporaneously prepared ones showed more rapid degradation. Extemporaneous preparation of paracetamol/ascorbic acid liquid mixtures should not be encouraged.

Keywords: Paracetamol, Ascorbic acid, Stability, Degradation, Over the counter drugs, Extemporaneous preparations