Simple Extractive Spectrophotometric Determination of Mesalamine by Acid-Dye Complexation Methods in Solid Dosage Form
Venugopal Darak*, Arvind B. Karadi, Md. Arshad and S. Appal Raju
Department of Pharmaceutical Analysis, HKES’s College of pharmacy, Sedam road, Gulbarga, Karnataka-585105, India.
*Corresponding Author E-mail: Venu.darak@gmail.com
ABSTRACT:
Two simple and sensitive ion-pairing spectrophotometric methods have been developed for the assay of Mesalamine in pure form and in pharmaceutical formulations. The developed methods involve formation of colored chloroform extractable ion-pair complexes of the drug with Bromo Cresol Green (BCG) and Bromo Cresol purple (BCP) in acidic medium. The extracted complexes showed absorbance maxima at 429, 413 nm for BCG, BCP, respectively. Beer’s law was obeyed in the concentration ranges 20-100 and 25-125 μg/ml for both the methods. These methods have been successfully applied for the analysis of drug in pharmaceutical formulations. No interference was observed from common pharmaceutical adjuvants. Results of analysis were validated statistically and through recovery studies.
KEYWORDS: Mesalamine, Spectrophotometry, Bromo Cresol Green (BCG), Bromo Cresol purple (BCP).
INTRODUCTION:
Mesalamine is chemically known as 5 – amino – 2 – hydroxy benzoic acid[1-4], is an anti-inflammatory drug used to treat inflammation of the digestive tract (crohn’s disease) and mild to moderate ulcerative colitis. It is a bowl-specific amino salicylate drug that is metabolized in the gut and has its predominant actions there, thereby having fewer systemic side effects[5-6]. The literature survey reveals that few analytical methods for this drug are reported, which include chromatographic[7], and spectrophotometric methods[8]. Extractive spectrophotometric methods are popular for their sensitivity in the assay of drugs and, therefore, ion-pair extractive spectrophotometry has received considerable attention for the quantitative determination of many pharmaceutical compounds. The aim of this study was to determine the amount of Mesalamine by extractive spectrophotometric method and the application to the solid dosage forms.
MATERIALS AND METHODS:
Apparatus:
All spectral measurements were made on Shimadzu 1800 UV-Visible spectrophotometer with 1 cm matched quartz cells were used.
Materials:
Pure drug of Mesalamine was obtained from Cosmo pharmaceutical Pvt Ltd, Goa and commercial formulations were procured from local market. All the chemicals used Acid pthalate buffer (pH 2.2), BCP and BCG are of analytical grade. Solvents and other chemicals were of analytical grade.
Preparation of Standard solution:
Weigh accurately 100 mg of Mesalamine and transferred in to 100 ml volumetric flask and dissolve in 100 ml of 0.1N HCl to obtain a concentration of 1mg /ml. From this suitable dilutions were made to obtain the working standard concentration of 100μg/ml.
Preparation of sample solution:
Two brands of commercially available tablets were taken, twenty tablets each weighing 400mg were weighed and powered. A tablet powder equivalent to 100 mg was weighed accurately and transferred in to 100 ml volumetric flask containing 50 ml of 0.1N HCl, the flask was sonicated for 5 min, the volume was made up to mark with 0.1N HCl, and the solution was filtered through whatmann filter paper 41, from the above stock solution, working standard solution of 100μg/ml were prepared by further dilution with 0.1N HCl, the above procedure was applied for analysis.
Procedure:
Method A:
Fresh aliquots of Mesalamine ranging from 0.25 to 1.25ml (1ml=1000µg/ml) were transferred into a series of 10ml volumetric flasks. To each flask 2.0ml of Bromo Cresol Green and 2.0ml of acid pthalate buffer (pH 2.2) was added and the volume of aqueous phase were brought to 10ml of distilled water. Then aqueous phase were transferred to a 125ml separating funnel separately. The flasks were shaken gently for 5min. Then 10ml chloroform was added to each separating funnel and the contents were shaken for 5min and allowed to stand, so as to separate the aqueous layer and chloroform layer. The yellow colored chloroform layer was collected and absorbance was measured at 429nm against reagent blank (Fig.1). The amount of Mesalamine present in the sample solution was computed from its calibration curve (Fig.2).
Fig 1: Absorption Spectrum of Mesalamine by BCG
Fig 2: Calibration Curve of Mesalamine by BCG
Method B:
Fresh aliquots of Mesalamine ranging from 0.2 to 1-0ml (1ml=1000µg/ml) were transferred into a series of 10ml volumetric flasks. To each flask 2.0ml of Bromo Cresol Purple and 2.0ml of acid pthalate buffer (pH 2.2) were added and the volume of aqueous phase was brought to 10ml of distilled water. Then aqueous phase were transfered to a 125ml separating funnel separately. The flasks were shaken gently for 5min. Then 10ml chloroform was added to each seperating funnel and the contents were shaken for 5min and allowed to stand, so as to separate the aqueous layer and chloroform layer. The yellow colored chloroform layer was collected and absorbance was measured at 413nm against reagent blank (Fig.3). The amount of Mesalamine present in the sample solution was computed from its calibration curve (Fig.4).
Fig 3: Absorption Spectrum of Mesalamine by BCP
Fig 4: Calibration Curve of Mesalamine by BCP
RESULTS AND DISCUSSION:
The optical characteristics such as Beer’s law limits, Molar absorptivity, and relative standard deviation were calculated and the results are summarized in Table 1.Regression characteristics like slope, intercept and correlation co-efficient were calculated and are presented in Table 1.Commercial tablets of Mesalamine were successfully analyzed by the proposed methods and the results are presented in Table 2. Comparison of the results obtained with the proposed and UV methods for dosage forms (Table 2) confirms the suitability of these methods for Pharmaceutical dosage forms. To evaluate validity and reproducibility of the methods recovery experiments were conducted and the results are summarized in Table 2. The other active ingradients and excipients usally present in pharmaceutical dosage forms did not interfere.
Table 1: Optical Characteristics and Precision
|
Parameters |
Method A |
Method B |
|
lmax (nm) |
429 |
413 |
|
Beer’s law limits (mg/ml) |
25-125 |
20-100 |
|
Molar absorptivity (lit. mol-1 cm-1) |
0.3244×104 |
0.1939×104 |
|
Limit of Detection (LOD/ mcgml-1) |
0.6539 |
0.576 |
|
Limit of Quantification (LOQ/ mcgml-1) |
1.981 |
1.778 |
|
Sandell’s sensitivity (mg/ml 0.001 abs unit) |
0.00198 |
0.00477 |
|
Regression equation (Y*) Slope (b) |
0.00763 |
0.00616 |
|
Intercept (a) |
-0.0026 |
0.0014 |
|
Correlation coefficient (r) |
0.9999 |
0.9998 |
|
% RSD |
0.336 |
0.322 |
|
**Confidence limits with 0.05 level |
0.001590 |
0.002099 |
|
Confidence limits with 0.01 level |
0.002360 |
0.002056 |
*Y=bC+a, where Y is the absorbance unit and C is the concentration of Mesalamine in mg/ml,
**Average of eight determinations,
Table-2 Evaluation of Mesalamine in Tablet Dosage formulations .
|
|
Label Claim (mg) |
Amount of drug obtained by proposed methods (mg) |
Reference method UV** |
% Recovery* |
% Recovery** |
||
|
A |
B |
|
A |
B |
UV |
||
|
M1 |
400 |
398.14 |
398.64 |
398.64 |
99.49 |
99.37 |
99.37 |
|
M2 |
400 |
399.92 |
399.58 |
398.74 |
99.46 |
99.54 |
99.28 |
*mean of six determinations, ** UV method developed in our laboratory
M1= Mesacol (Unipharma Pvt Ltd), M2= Walasa (Wallace Pvt Ltd)
CONCLUSION:
The proposed extractive spectrophotometric methods for the estimation of Mesalamine are simple, sensitive, accurate and can be used for the routine quality control of the drug in bulk as well as its pharmaceutical formulations.
ACKNOWLEDGEMENTS:
The Authors are thank full to Cosmo Pharma Pvt Ltd, Goa for providing gift sample of drug for research and Principal, Management, HKES’s College of Pharmacy, Gulbarga Karnataka (India) for providing necessary laboratory facilities to carry out the present work.
REFERENCES:
1. O’ Neil M.J, editor. The Merck Index. An Encyclopedia of Chemicals, Drug and Biologicals. Merck& Co. Inc. 2006; 14th ed: pp. 613.
2. Sweetman S C, editor. Martindale. The Complete Drug Reference, Pharmaceutical press, London (U.K). 2007; 35th ed: pp. 1573.
3. BertamKatzung G, editor. Basic and Clinical Pharmacology. Mc. Graw Hill, Singapore. 2008; 10th ed: pp.1030.
4. The United State Pharmacopeial Convection, editor. United State Pharmacopeia. NF, Asian Edition. 2007; 3rd ed: pp.2584.
5. K.D.Tripathi. Essentials of Medical Pharmacology,Jaypee Brothers Medical Publishers (P) Ltd, New Delhi. 2004; 5th ed: pp. 620-621.
6. Janice AR, Jose RJ, Rubia Casagrande. Validation of HPLC, DPPH and Nitrosation metods for Mesalamine determination in pharmaceutical dosage forms. Brazillian journal of Pharmaceutical Sciences. 43(1); 2007: 97-103.
7. Patel KM, et-al. Development and validation of spectrophotometric methods for the estimation of mesalamine in tablet dosage forms. J Young Pharmacists.2; 2010: 284-288.
8. Navyasloka S,et-al. Sensitive spectrophotometric method for determination of Mesalamine in bulk and pharmaceutical formulations. Der Pharma Chemica. 2(4); 2010: 389-396.
Received on 26.03.2011 Modified on 04.04.2011
Accepted on 09.04.2011 © RJPT All right reserved
Research J. Pharm. and Tech. 4(6): June 2011; Page 962-964