Practical Implication of Chromatographic Method for Estimation of Aceclofenac and Pregabalin in Bulk and Pharmaceutical Dosage Forms

Background. Aceclofenac and Pregabalin in combination significantly reduce pain as compared to individual drug in chronic low back pain. Literature reveals that all the reported spectrophotometric methods either need tedious extraction procedures, do not offer high sensitivity, use nonspecific reagent, or recommend the measurement of absorbance in the near UV region where interference most probably occurs that does not offer suitable linearity range. Result. A selective, sensitive, accurate, and precise, high performance liquid chromatographic method with UV detector analysis of Aceclofenac and Pregabalin was investigated. Good chromatographic separation was achieved using an ODS-BP hypersil C18 column (250？mm × 4.6？mm, i.d., 5？μm) and a mobile phase consisting of 0.05？M phosphate buffer (KH2PO4) (pH 6.0)？:？methanol (60？:？40, v/v) at a flow rate 1？mL/min. The ultraviolet detector was set at wavelength 218？nm. Retention time for Aceclofenac and Pregabalin was found to be 3.220 and 5.910？min, respectively. Rectilinear relationship with good regression coefficients 0.999 and 0.999 was found over the concentration ranges of 5–25？μg/mL and 3.75–18.75？μg/mL for ACF and PGB, respectively, with detection limits 0.64 and 0.35？μg/mL and quantitation limits 1.95 and 1.06？μg/mL. Conclusion. The mean percentage recoveries were in the range of 98.45–100.08 and 99.69–100.48 for ACF and PGB, respectively. The developed method was successfully applied to the analysis of the drugs in their commercial tablets. 1. Introduction ACF is 2-[2-[2-[(2,6-dichlorophenyl) amino] phenyl] acetyl] oxy acetic acid. It is a nonsteroidal anti-inflammatory drug with good analgesic effect [1] (Figure 1). PGB is S-3-(amino methyl)-5-methylhexanoic acid. It is an anticonvulsant drug for neuropathic pain and adjunct for partial seizures. It can be used in generalised anxiety disorders [2] (Figure 2). ACF is official in British Pharmacopoeia, 2009, Indian Pharmacopoeia, 2010, and European Pharmacopoeia, 2005 [1, 3, 4]. PGB is official in Indian Pharmacopoeia, 2010 [1]. The literature survey revealed that few analytical methods have been published concerning the simultaneous estimation of ACF and PGB either alone or in combination with other drugs, namely, spectrophotometric [5, 6] and chromatographic [7–9] methods for ACF and spectrophotometric [10], chromatographic [11], and also spectrofluorimetric [12, 13] methods for PGB. Spectrofluorimetries are not available in many labs. Regarding spectrophotometric methods for determination of PGB, some of them do not offer high sensitivity or need