INTRODUCTION:

Domperidone is a dopamine D₂ – receptor antagonist used as an antiemetic. It has also been used to stimulate lactation. It is also prescribed along with paracetamol for the symptomatic relief in migraine with aura ^{1, 2, 3}. It is official in EP⁴. Chemically it is 5-chloro-1-[1-[3-(2,-3-dihydro-2-oxo-1H-benzimidazol-1-yl)-propyl]-4-piperidinyl]-1,3-dihydro-2H-benzimidazol-2-one ⁵. The review of the literature revealed that no method is yet reported for the UV spectrophotometric estimation of domperidone in tablet dosage forms. This paper describes a simple, rapid, accurate and reproducible method for the estimation of domperidone in tablet formulations.

MATERIALS AND METHODS:

Instrument:

Perkin-Elmer UV-Visible Spectrophotometer was used for spectral measurements with spectral band width 1 nm, wavelength accuracy is 0.5 nm and 1 cm matched quartz cells.

Analytical procedure:

Standard stock solution (100 mcg/ml) of DOM was prepared by dissolving 10 mg of pure DOM in 100 ml Methanol and aliquot of this solution was further diluted to get a concentration of 20 mcg/ml. This solution was then scanned in the wavelength range of 220-380 nm.

The wavelength selected for the analysis of domperidone was 287.5 nm as absorption maxima was observed at this wavelength (figure 1). Domperidone showed linearity with absorbance in the range of 6-36 mcg/ml. Coefficients of Correlation was found to be 0.9998 (Table 1).

In order to see the feasibility of proposed method for estimation of DOM in marketed pharmaceutical formulations, the method was first tried for estimation of drug in standard bulk sample. Accurately weighed 10 mg of DOM was dissolved in methanol by vigorous shaking and volume was adjusted to 100 ml by the same solvent. Appropriate aliquots 2.0 ml were transferred to 10 ml glass volumetric flasks and volume was adjusted to mark with same solvent i.e. conc. 20 mcg/ml. The absorbances of the solutions were recorded at 287.5 nm against blank, % amount of the DOM (equivalent to % label claim) was determined and results are reported in Table 2.

Analysis of tablet formulation:

For analysis of commercial formulation; twenty tablets were weighed, average weight determined and crushed into fine powder. A quantity of tablet powder equivalent to 10 mg of DOM was transferred into 100 ml glass volumetric flask containing 50 ml methanol, shaken manually for 10 min, volume was adjusted to mark with same solvent and filtered through whatmann filter paper no. 41. The appropriate aliquots 2.0 ml were transferred to 10 ml glass volumetric flask; volume was adjusted to the mark with same solvent. The absorbances of the solutions were recorded at 287.5 nm and the concentration of the DOM was determined by linear regression equation, % label claim was then calculated; results are shown in Table 2.

Validation:

Recovery studies were performed by adding a known amount of standard drug to preanalysed sample and contents were reanalyzed by proposed method. The other validation parameters (precision and ruggedness) were also studied. Precision of the method was assessed by repeatability studies whereas ruggedness was studied as intra-day and inter-day variations in analysis. Ruggedness of the proposed method was also determined by analysis of aliquots from homogenous slot by two analyst using same operational and environmental conditions. The results of validation studies for estimation of domperidone are given in Table 3.

Figure 1: UV Spectrum of DOM in Methanol

Table 1: Regression and Optical characteristics of domperidone

S.No.	Parameters	Results
1	Selected analytical wavelength	287.5 nm
2	Beer’s law range	6-36 mcg/ml
3	Coefficient of correlation	0.9998
4	Slope	0.0339
5	Intercept	0.0011

Table 2: Results of analysis of standard bulk sample and tablets

S. No.	Sample	Statistical data	% Label claim
1.	Bulk sample	Mean	99.79
1.	Bulk sample	S.D.	0.25
2.	Tablet	Mean	99.78
2.	Tablet	S.D.	0.31

RESULTS AND DISCUSSION:

The method developed for spectrophotometric determination of domperidone in tablet formulation was found to be simple and convenient for the routine analysis. Beer-Lambert law was obeyed in the concentration range of 6-36 mcg/ml. Co-efficient of variation was found to be 0.9998. The percentage recoveries were found in the range of 99.5 to 100.1% while the method was found to be precise with standard deviation of ± 0.24. The method was found to be rugged with no significant changes on test results upon change of analytical conditions like different time (Intraday), different day (Interday) and different analysts.

CONCLUSION:

The proposed method is simple, precise, accurate and rapid for the determination of domperidone in tablet dosage forms. Analysis of authentic samples containing domperidone showed no interference from the common additives and excipients. Hence, recommended procedure is well suited for the assay and evaluation of drugs in pharmaceutical preparations. It can be easily and conveniently adopted for routine quality control analysis.

Table 3: Validation Studies

S. No.	Parameters	Results
1	Mean % recovery	99.89 ± 0.34
2	Precision (as standard deviation)	± 0.24
3	Intraday % Label claim	99.82 ± 0.14
4	Interday % Label claim	99.67 ± 0.04
5	% Label claim by different analysts	99.83 ± 0.05

REFERENCES:

1. Kasper DL, Fauci AS, Longo DL, Braunwald E, Hauser SL, Jameson JL. Harrison's Principles of Internal Medicine. Sixteenth Edition. McGraw-Hill, 219-222

2. Tripathi KD. Essentials of Medical Pharmacology. Fifth Edition. Jaypee Brothers, 604

3. Domperidone monograph available at the site of pharmascience at the URL www.pharmascience.com/pms_en/healthcare/_MSINFO/mono_0223646.pdf

4. British Pharmacopoeia 2007. Vol 1, 732-735

5. Drug card for Domperidone (DB01184) available at http://www.drugbank.ca

6. Beckett AH, Stenlake JB. Practical Pharmaceutical Chemistry. Fourth Edition-Part Two 2007. CBS Publishers and Distributors, 282-288.

Received on 30.05.2009 Modified on 27.07.2009

Asian J. Research Chem. 2(4):Oct.-Dec. 2009 page 432-433