Online - 2455-3891 Vol 11, Issue 12, 2018 Print - 0974-2441 Research Article STABILITY-INDICATING REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR SIMULTANEOUS ESTIMATION OF METHYLCOBALAMIN, ALPHA-LIPOIC ACID, PYRIDOXINE HCL, AND FOLIC ACID IN BULK AND COMBINED DOSAGE FORM PADMAJA V1*, PRASANTHI M1, MAYURI P2 1Department of Pharmaceutical Analysis, Nirmala College of Pharmacy, Atmakuru, Mangalagiri, Guntur, Andhra Pradesh, India, 2Departmen of Pharmaceutics, Nirmala College of Pharmacy, Atmakuru, Mangalagiri, Guntur, Andhra Pradesh, India. Email: [email protected] Received: 16 April 2018, Revised and Accepted: 02 August 2018 ABSTRACT Objectives: The purpose of the research is to develop a simple, precise, economical, accurate, reproducible, and sensitive method for the estimation of methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and folic acid drug product by reversed-phase high-performance liquid chromatography (RP-HPLC) method. Methods: New analytical method was developed for the estimation of methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and folic acid in drug product by RP-HPLC. The chromatographic separation was achieved on the Inertsil C18, 250 mm × 4.6 mm, 5 µm at ambient temperature. The separation achieved employing a mobile phase consists of buffer (added 5.05 g hexane-1-sulfonic acid is dissolved into 1000 mL of distilled water):acetonitrile in the ratio of 10:90% v/v. The flow rate was 1 mL/min and UV-visible spectrophotometer at 285 nm. The average retention time for methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and folic acid was found to be 3.5, 6.7, 8.5, and 9.3, respectively. Results: The developed method was validated as per ICH guidelines. All validation parameters were within the acceptable ranges. The assay methods were found to be linear from 0 to 2130 µg/mL for methylcobalamin, 0 to 142.5 μg/mL for alpha-lipoic acid, 0–4.54 µg/mL for pyridoxine hydrochloride, and 0–2 µg/mL for folic acid. The correlation coefficient was 0.999 for all drugs, respectively. The mean percentage values for the developed method Conclusion:were found to It be is concludedwithin the thatrange developed of 98–100.6%. method The was developed accurate, method precise, was linear, also reproducible, found to be robust. robust, and sensitive. Keywords: Alpha-lipoic acid, Folic acid, Methylcobalamin, Pyridoxine hydrochloride and Reversed-phase high-performance liquid chromatography, Validation. © 2018 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2018.v11i12.26715 INTRODUCTION for the estimation of methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and folic acid in bulk and combined dosage form by Methylcobalamin is a cobalamin, a form of Vitamin B . It differs from 12 reverse-phase high-performance liquid chromatography (Figs. 1-4). cyanocobalamin in that the cyano at the cobalt is replaced with a methyl MATERIALS AND METHODS ofgroup peripheral [1] and isneuropathy, chemically diabeticCoα-[α-(5,6-dimethylbenz-1H-imidazolyl)]- neuropathy, and as a preliminary Equipment treatmentCoβmethyl for cob amyotrophic amide. Methylcobalamin lateral sclerosis is [2].also The used alpha-lipoic in the treatment acid is The chromatographic technique was performed on a Waters, 2695 chemically (R)-5-(1,2-dithiolan-3-yl)pentatonic acid. Alpha-lipoic acid separation module, Empower, Version 2.0, reversed-phase C18 column is easily absorbed and transported across cell membranes; thus, free (Inertsil, 250 mm × 4.6 mm, 5 µm) as stationary phase, with Sartorius radical protection occurs both inside and outside of cells. Pyridoxine, also known as Vitamin B6, is a form of Vitamin B6 found commonly in membrane filter. food and used as dietary supplement [3]. Pyridoxine responsiveness analytical balance and vacuum microfiltration unit with 0.45 μ is associated with two particular missense mutations in the AGT gene Materials which lead to Gly170Arg and Phe152Ile amino acid replacements [4-6]. Pharmaceutically pure samples of methylcobalamin, alpha-lipoic acid, Folic acid, also known as Vitamin B9, is a form of synthetically produced pyridoxine hydrochloride, and folic acid were obtained from ICON water-soluble vitamin found in fortified food and supplements. Folate Laboratories, Vijayawada, India. is naturally derived from food, particularly from dark green leafy vegetables [7]. Folate and the biologically active folic acid, which is High-performance liquid chromatography grade methanol and converted to dihydrofolic acid in the liver, are essential in meeting acetonitrile were procured from on laboratories, Vijayawada, India. the requirements of the function of the human body. Folate is used to Selection of wavelength (for detection) literature review some methods are developed and validated by using In setting up the conditions for the development of assay method, the differentsynthesize, techniques repair, and likemethylate High deoxyribonucleicperformance liquid acid chromatography[8]. According to choice of detection wavelength was based on the scanned absorption [9,10], ultra performance liquid chromatography [11], ultravoilet- spectrum for methylcobalamin, alpha-lipoic acid, pyridoxine visible [12] technique with other combination of drugs. The proposed hydrochloride, and folic acid. The UV spectrum of methylcobalamin, method aimed to develop and validate a stability-indicating method alpha-lipoic acid, pyridoxine hydrochloride, and folic acid was obtained Padmaja et al. Asian J Pharm Clin Res, Vol 11, Issue 12, 2018, 302-307 Fig. 1: Chemical structure of methylcobalamin Fig. 2: Chemical structure of alpha-lipoic acid Fig. 5: UV spectrum of methylcobalamin, alpha-lipoic acid, pyridoxine HCL, and folic acid (285 nm) Chromatographic conditions The sample separation was achieved on a C18 (Inertsil, 250 mm × 4.6 mm, 5 µm) column, aided by mobile phase mixture of buffer: acetonitrile (10:90%v/v). The flow rate was 1 mL/min and Fig. 3: Chemical structure of pyridoxine hydrochloride at ambient temperature. ultraviolet detector at 285 nm, injection volume is 10 μL and maintained Preparation of mobile phase Buffer preparation: An accurate amount of 5.05 g hexane-1-sulfonic acid is dissolved into 1000-mL distilled water and adjusted to pH - 2.5 Mobilewith OPA. phase: Then Then, it was 10 filtered volumes through of buffer 0.45-μ and 90 membrane volumes offilter. acetonitrile were added and sonicated for 10 min. Preparation of standard stock solution Fig. 4: Chemical structure of folic acid Weighed accurately about 1500 mg methylcobalamin, 100 mg alpha- lipoic acid, 3 mg of pyridoxine, and 1.5 mg folic acid and transferred into 100-mL volumetric flask, added 70 mL of diluent, sonicated to 400 nm against blank as methanol. After thorough examination of the dissolve, and diluted up to volume with diluents to give a primarily spectra,separately the by wavelength scanning the 260 sample nm was over selected the wavelength for further range analysis. of 200– The stock solution containing 150 µg/mL of methylcobalamin, 10 µg/mL of overlay spectrum for methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and folic acid is shown in Fig. 5. of folic acid. alpha-lipoic acid, 0.3 μg/mL of pyridoxine hydrochloride, and 15 μg/mL 303 Padmaja et al. Asian J Pharm Clin Res, Vol 11, Issue 12, 2018, 302-307 Table 1: System suitability parameters for methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and folic acid Parameters Methylcobalamin Alpha-lipoic acid Pyridoxine hydrochloride Folic acid Acceptance criteria Retention time (min) 13.505 14.399 3.544 6.732 ±10 Theoretical plates 43409 19674 117890 3951 >2000 Tailing factor 1.22 1.89 1.61 1.81 <2 RSD 0.777 0.100 0.047 0.047 <2 RSD: Relative standard deviation Table 2: Method precision values for methylcobalamin Table 5: Method precision values for folic acid Rt (min) Area USP plate USP tailing Rt (min) Area USP plate USP tailing 13.505 5962 52654 1.21 6.732 158056 3954 1.81 13.512 5973 51764 1.27 6.738 158808 3944 1.84 13.505 5984 45180 1.57 6.732 157872 3957 1.80 13.512 5945 52104 1.27 6.738 157920 3957 1.84 13.505 5898 53121 1.21 6.732 158224 3951 1.81 13.512 5979 51792 1.26 6.738 158808 3944 1.84 Mean: 5957 Mean: 158281 %RSD: 0.534 %RSD: 0.269 Rt: Retention time, %RSD: Percentage relative standard deviation Rt: Retention time, %RSD: Percentage relative standard deviation Table 3: Method precision values for alpha-lipoic acid Table 6: LOD and LOQ values calculated from calibration curve Rt (min) Area USP plate USP tailing Parameters LOD=3.3 (SD/S) LOQ=10 (SD/S) 14.399 218860 19674 1.89 (µg/mL) (µg/mL) 14.409 218860 19470 1.88 Methylcobalamin 40.631 123.12 14.399 218652 19685 1.89 Alpha-lipoic acid 4.55 13.815 14.409 217920 19518 1.87 Pyridoxine Hcl 0.087 0.264 14.399 218845 19677 1.89 Folic acid 0.0447 0.135 14.409 218367 19496 1.89 LOD: Limit of detection, LOQ: Limit of quantitation, SD: Standard deviation, Mean: 218584 S: lope %RSD: 0.173 Rt: Retention time, %RSD: Percentage relative standard deviation Accuracy The accuracy of the method was determined by calculating the recoveries of Table 4: Method precision values for pyridoxine hydrochloride methylcobalamin, alpha-lipoic acid, pyridoxine hydrochloride, and Rt (min) Area USP plate USP tailing and 150% of the working strength of methylcobalamin, 3.544 117890 6272 1.33 alpha-lipoicfolic acid by analyzingacid, pyridoxine solutions hydrochloride, containing approximately and folic acid. 50%, 100%, 3.547 117967 6014 1.33 3.544 117478 6274 1.42 Robustness 3.547 117785 6018 1.36 Robustness is the measure of method remains unaffected by small 3.544 117769 6275 1.33 3.547 117967 6014 1.33 deliberate changes in method parameters such as flow rate and detection Mean: 117809 of wavelength on assay of the analyte of interest.