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International Journal of Research in Pharmaceutical and Biomedical Sciences
ISSN: 2229-3701
_________________________________________Research Article
Visible Spectrophotometric Estimation and Validation of
Metformin HCl in Bulk and Pharmaceutical Dosage Forms
M. Manoranjani1* and M. Kamala Karuna2
1Department of Chemistry, PG Centre, P.B. Siddartha College of Arts & Science, 2Government Junior College, Guntur, Andhra Pradesh, India. ABSTRACT
A simple, rapid, novel and sensitive spectrophotometric method was developed for the determination of
Metformin HCl in pharmaceutical formulation. This method is based on formation of pale yellow coloured ion
pair complex between metformin HCl and Bromocresol green reagent, which is readily extracted into
dichloromethane solvent and showed maximum absorbance at 416nm.
The reaction has been evaluated to obtain optimum experimental conditions. Linear responses were exhibited
over the range 10-140µgmL-1. A high sensitivity is recorded at 0.14683µg/cm3 per 0.001 absorbance unit. The
developed method was applied for the assay of the drug in its commercial formulations.
Key Words: Metformin HCl, spectrophotometry, ion-pair complex, validation, Commercial dosage forms.

INTRODUCTION
MATERIALS AND METHODS
Metformin HCl is an anti-hyperglycemic drug used All the chemicals used were of analytical and to manage type -2 diabetes. It is a unique and chemically pure grade and deionised water was widely used anti hyper glycemic drug throughout used throughout the study. Pure MetforminHCl was provided by Reddy’s lab. Pharmaceutical pharmacologically related to the other classes of oral anti hyper glycemic agents. Inhibition of Gluformin were purchased from the local market. glyconeogenesis appears to be an important Bromocresol green 0.1% w/v was prepared. 1M component of the drug’s activity. The IUPAC orthophosphoric acid buffer solutions was prepared name for Metformin HCl is 1,1—Dimethyl formula,C4H11N5.HCl.The structure is given below. Preparation of standard drug solution
Accurately weighed quantity of the drug equivalent to 100mg was dissolved in few ml of methanol and the volume was made up to 100ml with methanol to get concentration of about 1000µgmL-1. From the stock solution working standards were prepared by taking 10ml of the solution in 100ml volumetric flask and made up to the mark with methanol to get concentrations of about 100µgmL-1. Preparation
solution
commercial
Very few physico-chemical methods appear in formulations
literature for determination of metformin HCl in Twenty tablets of Metformin HCl were finely bulk and formulations. Formation of ionpair powdered and the powder equivalent to 100mg of complex with ninhydrin11 and determination of drug was accurately weighed and dissolved in metfomin by HPLC12methods were also reported. It 100ml of the methanol to get 1000µgmL-1 stock is simple, sensitive and rapid since it is a single solution. From the above stock solution working step procedure and low cost without loss of standards were prepared to get the concentration of EXPERIMENTAL
Procedure for determination
A double beam UV/visible spectrophotometer with Aliquots of Metformin HCl standard solution 0.2ml 1cm quartz cells was used for the absorbance to 2ml were transferred into a series of 10ml measurements. A systronic pH meter was used. volumetric flasks, to each flask 1ml of the Vol. 4 (2) Apr– Jun 2013 www.ijrpbsonline.com 680
International Journal of Research in Pharmaceutical and Biomedical Sciences
ISSN: 2229-3701
Bromocresol green indicator and 3ml of ortho applications in the field of drug analysis by phosphoric acid buffer (1M) were added and diluted to 10ml with distilled water. The yellow In the present work the drug Metformin HCl forms coloured chromogen was extracted into 5ml of an ion pair complex with Bromocresol green. The dichloromethane solvent and the absorbance was interaction and subsequent formation of the ion pair measured at 416nm, against the reagent blank complex occurred in acidic medium via the prepared simultaneously omitting the drug solution. protonated nitrogen atoms of the drug. The organic A calibration curve is constructed by plotting the solvent like chloroform, CCl4, benzene failed to absorbance against the concentration (µg/ml), extract the coloured chromogen but the drug was showed a good linearity in range of 10-140µg/ml. Procedure for dosage forms
The optimum conditions were established by Aliquots of the dosage form standard solution were varying each parameter at a time keeping the others transferred to 10ml volumetric flasks and analysis constant, the effect of each parameter on the was completed as previously mentioned method. absorbance of coloured species were observed The nominal content of the tablet was calculated various parameters like volume of the reagent, from the previously plotted calibration graph. effect of PH, stability of the colour, volume of the buffer were optimized before development of the RESULTS AND DISCUSSION
The formation of ion pair complex between amino groups of many drugs with dyes has found wide Optical characteristics, precision and
accuracy of the proposed methods for Metformin
Assay and Recovery studies of the drug in commercial dosage forms
% recovery by
Pharmaceutical formulation
Labeled amount
Amount found in mg
proposed Method
Vol. 4 (2) Apr– Jun 2013 www.ijrpbsonline.com 681
International Journal of Research in Pharmaceutical and Biomedical Sciences
ISSN: 2229-3701
CONCLUSION
The proposed method described in this paper is simple, rapid and applicable for routine analysis of Metformin HCl in pharmaceutical formulations 4. Instrumental Methods of analysisWillard, Merritt Dean,Settle,7thedition,pg159-172 interference from common excipients. Moreover, it exhibits the advantage of being convenient at low cost without losing accuracy. Therefore, the method should be useful for routine analytical and quality control assay of the investigated drug in ACKNOWLEDGEMENT
Siddhartha Academy of General and technical education for providing the necessary facilities. 11. Spectrophotometric methodfor analysis of We are thankful to Prof. K. Saraswathi, Retd. Prof, S.V. University, Tirupathi for her guidance. REFERENCES
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