Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

New Spectrophotometric Methods for the Determination of p-Aminosalicylic Acid in Tablets

MGH Laghari , Y Darwis, AH Memon

School of Pharmaceutical Sciences, University Sains Malaysia, 11800, Penang, Malaysia;

For correspondence:- Laghari Email: fairyrose25@yahoo.com Tel:+601124055956

Received: 9 September 2013 Accepted: 30 April 2014 Published: 25 July 2014

Citation: Laghari M, Darwis Y, Memon A. New Spectrophotometric Methods for the Determination of p-Aminosalicylic Acid in Tablets. Trop J Pharm Res 2014; 13(7):1133-1139 doi: 10.4314/tjpr.v13i7.18

© 2014 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To develop a new spectrophotometric method with improved sensitivity and at higher wavelength for the determination of p-aminosalicylic acid in tablets.

Methods: Two simple and sensitive spectrophotometric methods (methods A and B) were developed using p-dimethylaminobenzaldehyde (DAB), and p-dimethylaminocinnamaldehyde (DAC) as derivatizing reagents for the determination of p-aminosalicylic acid (PAS) in tablets. The derivatization was carried out using 3M HCl-KCl buffer for DAB and 5M HCl-KCl buffer solutions.

Result: The new derivatives of PAS absorbed maximally with bathochromic shift to 460 and 555 nm in the linear concentration range of 0.4 – 2.0 µg/mL with molar absorptivities of 2.4 × 10⁴ and 3.8 × 10⁴ L/mole/cm, respectively, compared to pure PAS which absorbed at λ_max of 264 nm with molar absorptivity 7.65 × 10³ L/mole/cm in the linear concentration range of 2 - 10 µg/mL. The developed methods were successfully applied to assay PAS in tablets with % recovery of 97.6 ± 1.71 and 98.4 ± 1.45 for methods A and B, respectively.

Conclusion: Both PAS derivatives absorb in the visible spectral region. The presence of excipients in pharmaceutical preparations did not interfere in the determination of PAS as PAS-DAB and PAS-DAC derivatives. Both methods can be applied to determine PAS from bulk and various pharmaceutical dosage forms.

Keywords: p-Aminosalicylic acid, p-dimethylaminobenzaldehyde, p-dimethylaminocinnamaldehyde, Spectrophotometry