Page3643 Indo American Journal of Pharmaceutical Research, 2015 ISSN NO: 2231-6876 UV SPECTROPHOTOMETRIC ANALYSIS FOR THE DETERMINATION OF MEFENAMIC ACID IN PHARMACEUTICAL FORMULATION Bhagyashree R. Dhumal 1, Kishore P. Bhusari 1, Mahavir H. Ghante 1, Nishant S. Jain* 2 1 Sharad Pawar College of Pharmacy, Hingna Road, Wanadongari, Nagpur-441110, India. 2 Institute of Pharmaceutical Sciences, Guru Ghasidas University (A Central University), Bilaspur-495009 (C.G.), India. ARTICLE INFO Article history Received 25/11/2015 Available online 30/11/2015 Keywords UV; Mefenamic Acid; Spectrophotometer. ABSTRACT The present study investigated a UV spectrophotometric method for the determination of mefenamic acid in the tablet formulation. The UV spectrophotometric analysis for mefenamic acid using the suggested methods was performed at 285.0 nm dissolved in 0.1N NaOH with linearity in the concentration range of 5-25 μg/ml. The validation for specificity, precision, robustness and recovery of the method was also performed. The results of the employed methods were found to be simple, linear, precise, accurate and sensitive and can be used for routine quality control analysis for the estimation of mefenamic acid in bulk and tablet dosage form. Corresponding author Nishant S. Jain Institute of Pharmaceutical Sciences, Guru Ghasidas University (A Central University), Koni, Bilaspur, Chhattisgarh, India 495009 +918827989653 nishant.s.jain@hotmail.com Please cite this article in press as Bhagyashree R. Dhumal et al. Uv Spectrophotometric Analysis For The Determination of Mefenamic Acid in Pharmaceutical Formulation. Indo American Journal of Pharmaceutical Research.2015:5(11). Copy right 2015 This is an Open Access article distributed under the terms of the Indo American journal of Pharmaceutical Research, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Page3644 INTRODUCTION Mefenamic acid as drug belongs to the category of a non-steroidal anti-inflammator, analgesic, antipyretic agent with molecular formula C 15 H 15 NO 2 (M.W.: 241,29) and chemical name as 2-(2,3-dimethylphenyl)aminobenzoic acid 1,2,3,4. The chemical structure of Mefenamic acid is depicted below 1. Structure: Chemical structure of Mefenamic acid. Mefenamic acid is commonly used for the management of pain, fever and menstrual pain. It is typically prescribed for oral administration. However, its exact mechanism of action on inflammation (swelling) and uterine contractions is a still unknown. Studies have ascribed it to the ability of mefenamic acid to inhibit the prostaglandin synthesis. Indeed, some investigations have proposed the mechanism for antipyretic and analgesic effects of mefenamic acid via inhibition of prostaglandin synthesis by competitive blocking of the enzyme cyclooxygenase (COX) 2,3. The literature survey revealed the analysis for mefenamic acid using HPLC/UV with chromatographic separation performed on a C18 column (250 4.6 mm I.D.) and with the employed mobile phase of acetonitrile water (50:50, v/v, ph 3 ) or using 10 mm phosphoric acid acetonitrile (40:60, v/v) at the detection wavelength of 280 nm 5,6,7,8 Investigations have been carried out for alone mefenamic acid with acid solvent system 9. However, no study till date has performed the UV determination of mefenamic acid with the alkali as solvent. Therefore, the present study aims to develop a method for determination of mefenamic acid in bulk and tablet formulation using UV spectrophotometric analysis with alkali as solvent. EXPERIMENTAL Chemicals and reagents Mefenamic acid was generously gifted by Torrent Research center, Varodra, India. All other solvents and reagents were purchased from S.D. Fine or Loba chemicals, India and were of analytical grade. Instrumentation Spectral runs were made with a Shimadzu UV-Visible spectrophotometer, model- 1600/1700 (Japan) was employed with a spectral bandwidth of 1 nm and wavelength accuracy of ± 0.3 nm with automatic wavelength corrections with a pair of 10 mm quartz cells. Glasswares used in each procedure were soaked overnight in a mixture of chromic acid and sulphuric acid rinsed thoroughly with double distilled water and dried in hot air oven. Location of λ max The working standard solution was scanned in UV range (200-400 nm) in 1.0 cm quartz cell against solvent blank. The UV spectra of the drug show the spectrum wavelength selected for the estimation of drug was 285 nm as λ max of mefenamic acid. At 285 nm mefenamic acid shows maximum absorbance (Fig. 1). Fig. 1. UV spectrum of Mefenamic acid.
Page3645 Standard solution Standard stock solution An accurately weighed quantity of mefenamic acid (10 mg) was dissolved in 0.1N NaOH to make a 10 ml solution (1000 μg/ml). Working standard solution A stock standard solution (1.0 ml) was transferred to the volumetric flask (10 ml) and the volume was made up to the mark with 0.1N NaOH so to obtain a final concentration of 10 μg/ml. The solution was used for spectral studies. Linearity and Calibration curve of mefenamic acid hydrochloride An accurately weighed quantity of Mefenamic acid equivalent to 10 mg of Mefenamic acid was dissolved in 0.1N NaOH to to obtain the concentration in the range of 1000 6000 ng. Study of Beer-Lambert s law Accurately measured standard stock solution was diluted up to 10 ml with 0.1N NaOH to get the concentration range 5 to 25 μg/ml. The absorbance of each of the solutions was measured at 285.0 nm against blank (0.1N NaOH). A calibration curve was found to be linear (Fig. 2). Fig.2 Study of Beer-Lambert s law (conc: μg/ml). Determination of absorptivity value, A (1%, 1 cm), of Mefenamic acid at selected wavelength The resulting stock a solution (1 ml) was added to a volumetric flask (10 ml) and the volume was made up to the mark with 0.1N NaOH to get the final concentrations of 10 μg/ml of the drug. The absorbance of each of the solutions was measured in 10 mm cell against solvent blank at 285.0 nm and A (1%, 1cm) values were calculated. The same procedure was repeated for five observations. The results are shown in Table 1. Where, A Absorptivity Conc. Concentration in g/100ml B Path length Table 1. A ( 1%, 1cm) Values of Mefenamic acid at 285.0 nm. Sr. No A ( 1%, 1cm) 1 937 2 942 3 946 4 934 5 941 Mean 940
Page3646 Analysis of marketed formulation: (Mefenamic acid- Meftal (Blue cross Laboratories)-label claimed 250 mg) Twenty tablets were weighed and finely powdered. An accurately weighed tablet, powder equivalent to 10 mg of mefenamic acid was taken into volumetric flask containing 0.1N NaOH. The flasks content was sonicated for 10 min. The volume was adjusted with 0.1N NaOH up to 100 ml. The solution was filtered through whatman filter paper. The filtrate (1 ml) was transferred to volumetric flask (10 ml) and the volume was made up to the mark with 0.1N NaOH up to get the final concentration of 10 μg/ml of mefenamic acid. The absorbances of final solutions were measured in 1.0 cm cell at 285.0 nm against solvent blank. The content of Mefenamic acid was calculated using the following methods: Method A: Using Absorptivity A (1%, 1cm) value Where, At Absorbance of sample DF Dilution factor Lc Labeled claim A (1%,1cm) Absorptivity Method B: Direct comparison method Where, At Absorbance of sample A std Absorbance of standard Lc Labeled claim Table 2. Results of estimation of Mefenamic acid in Tablet. Mefenamic acid Tablet (Avg. wt 435.0 mg for 250 mg of mefenamic acid) Sr. No Sample weight (mg) Std conc (µg/ml) Abs at 285 nm % Drug estimation Std Sample Method A Method B 1 17.40 0.942 0.937 99.47 99.48 2 17.40 0.942 0.933 99.04 99.10 3 17.40 10 0.942 0.932 98.93 98.99 4 17.40 0.942 0.943 100.10 100.11 5 17.40 0.942 0.940 99.78 99.76 Mean 99.46 99.48 ±SD 0.4922 0.4635 % RSD 0.4949 0.4659 Validation of proposed UV-spectrophotometric method. Accuracy Accuracy of the proposed method was ascertained on the basis of recovery studies performed by standard addition method. Standard solution: Standard solution was prepared as per described in standard solution. Sample solution An accurately weighed quantity of pre analyzed powder content of tablet equivalent to 10 mg of Mefenamic acid and 8 12 mg of standard Mefenamic acid was taken into volumetric flask (100 ml) and 0.1N NaOH was added to it. The content in the flask was sonicated for 10 min and the volume was adjusted with 0.1N NaOH (100 ml). This (1.0 ml) portion was diluted with 0.1N NaOH to get 10 μg/ml of Mefenamic acid. The absorbances of final solutions were measured in 1cm cell at 285 nm against solvent blank. The recovery of Mefenamic acid was calculated by following formula. The results of this study are shown in Table 3.
Page3647 Where, A = Total drug estimated (mg) B = Wt. (mg) of drug contributed by tablet powder C = Amount of pure drug added (mg) Table 3. Result of recovery study. Wt of Tablet (mg) & Amount of std TotalAmount Total Amount of Sr ABS at % Actual drug content added (mg) Of drug Amount std Found No 285 nm Recovery A B taken A+B found C (mg) C-A 1 17.40 (10) 08.00 18 0.426 17.95 7.95 99.37 2 17.40 (10) 08.00 18 0.440 17.96 7.96 99.50 3 17.40 (10) 10.00 20 0.491 19.98 9.98 99.80 4 17.40 (10) 10.00 20 0.492 19.96 9.96 99.60 5 17.40 (10) 12.00 22 0.540 21.97 11.97 99.75 6 17.40 (10) 12.00 22 0.538 22.98 11.98 99.83 Mean 99.64 ±SD 0.1832 % RSD 0.1838 Precision Studies: The precision of any analytical method is expressed as SD and %RSD of series of measurements (Table 2-5). Standard solution: The standard solution was prepared as per described in the standard solution. Sample solution: An accurately weighed tablet powder equivalent to 10 mg of Mefenamic acid was taken into volumetric flask (100 ml) containing 0.1N NaOH. The flasks content was sonicated for 10 min. The volume was adjusted with 0.1N NaOH (100 ml) and solution was filtered through whatman filter paper. The filtrate (1.0 ml) was transferred to volumetric flasks (10.0 ml). The volume was made up to the mark with distilled water to get the final concentration of 10 μg/ml of Mefenamic acid. The absorbances of final solutions were measured in 1.0 cm cell at 285.0 nm against solvent blank. The content of Mefenamic acid was calculated and is given below. Different analysts The Mefenamic acid samples solutions were analyzed using the proposed methods by three different analysts. The results of this study are depicted in Table 4. Table 4. Results of precision studies (Different analysts). Sr. No. Different % Drug estimation Analysts Method A Method B 1. I 99.95 100.03 2. II 98.99 99.08 3. III 99.41 99.52 Mean 99.45 99.54 ±S.D 0.4812 0.4754 %RSD 0.4839 0.4776 Different instruments The Mefenamic acid samples solutions were analyzed using the proposed methods by three different instruments (Results shown in Table 5).
Page3648 Table 5. Results of precision studies (Different instruments). Sr. Instruments Observation % Drug estimation No. Method A Method B 1. UV -1800 1 99.27 99.33 2. UV-1700 2 99.15 99.23 Mean 99.34 99.21 ±S.D 0.7990 0.0848 %RSD 0.8042 0.0855 Different days 1) Interday 2) Intraday The Mefenamic acid samples solutions were analyzed using the proposed methods on three different days. The results of the inetrday and intraday studies are shown in Table 6. Table 6. Results of precision studies (Different days). Different % Drug estimation Sr. days Interday Intraday No. Method A Method B Method A Method B 1. I 100.30 100.37 99.73 99.84 2. II 99.68 99.78 99.62 99.71 3. III 99.93 100.04 99.47 99.55 Mean 99.97 100.06 99.60 99.7 ±S.D 0.3119 0.2956 0.1305 0.1452 %RSD 0.3120 0.2955 0.1310 0.1456 Specificity Studies: Accurately weighed six quantities of finely powdered tablet equivalent to about 10 mg Mefenamic acid were transferred to different volumetric flasks (100 ml). All these solutions were stored for 24 h under following different conditions like 1. Normal (control) 2. At room temp. after addition of 1.0 ml of 0.1N HCl (Acid) for 16 h. 3. At 60 after addition of 1.0 ml of 0.1N NaOH (Alkali) for 24 h. 4. At room temp. after addition of 1.0 ml of 3% H 2 O 2 (Oxide) for 16 h. 5. At 60 (Dry heat) for 24 h.6. Sunlight (UV) for 24 h. After 24 h, distilled water was added to each flask, sonicated for 10 min and volume was made up to 100 ml (100 μg/ml). From each flask, The solution (1 ml) was diluted up to 10ml with distilled water to get 10 μg/ml of Mefenamic acid. The absorbance of each of the resulting solution was measured at 285 nm using the solvent blank (Table 7). Table 7. Results of specificity studies. Sr. Treatment % Drug estimation No Method A Method B 1 Normal 99.91 99.98 2 Acid 99.45 99.49 3 Base 99.97 98.79 4 Oxide 98.97 99.98 5 Heat 99.88 99.76 6 UV 99.88 99.71 Mean 99.18 99.68 ±SD 0.3964 0.5373 % RSD 0.3996 0.5389 Linearity range: The study was performed over the series of concentrations ranging from 5-25 μg/ml of Mefenamic acid, (as detailed under the study of Beer s law). The graphs of concentration v/s absorbance were found to be straight line over the concentration range of Mefenamic acid (5-25 μg/ml). The results of linearity range are shown in Table 8. Table 8. Result of linearity range. Drug Coefficient of correlation Slope Range μg/ml Mefenamic Acid 0.999 0.020 5-25
Page3649 Robustness Studies: Change in wavelength (±2 nm): The Mefenamic acid sample solution was analyzed using proposed methods after a deliberate change in detection wavelength for estimation by ±2 nm (Table 9). Table 9. Results of Robustness. Sr. Wavelength % Drug estimation No Method A Method B 1. 283.0 99.04 99.10 2. 285.0 100.10 100.11 3. 287.0 98.93 98.99 Mean 99.35 99.4 ±SD 0.6460 0.6173 %RSD 0.6502 0.6210 CONCLUSION The spectrum of Mefenamic acid tablet formulation in 0.1N NaOH showed the absorption at 285.0 nm. The calibration curves studies indicated by a high level of precision for the proposed methods, as evidenced by the low value of coefficient of variation of Mefenamic acid in pure solution. The linearity range was observed between 5 25 ug/ml of Mefenamic acid with straight line and plot passing through the origin. The validation of the methods of estimation used in the present study was supported by the low values of % RSD and standard error. Thus, it is reasonable to contemplate that the results are precise with recovery studies result pointing towards the accuracy of the proposed methods. The robustness of the analysis of mefenamic acid by the proposed methods were ascertained by varying the instrument, time of study and analyst with a reproducible results, confirming the reproducibility of the proposed methods. All the procedure followed in the present study are as per the ICH guidelines 10. Thus, it can be concluded that the method described in the present investigation for the determination of Mefenamic acid in the bulk and tablet formulation is economical, simple, accurate, sensitive and reproducible. Therefore, the proposed method could be routinely used for the analysis in quality control laboratories.
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