Spectrophotometric Determination of Mosapride Citrate in Pharmaceutical Formulations

M. Purushotham Reddy¹, P. Ravindra Reddy² and N. Rami Reddy³

¹Department of Chemistry, Government College for Men, Kurnool-518002, India

²Department of Chemistry, S. K. University, Anantapur-515003, India

³Department of Chemistry^,S.B.S.Y.M. Degree College, Kurnool-518218, India

*Corresponding Author E-mail: mpreddy50@gmail.com

ABSTRACT:

A simple spectrophotometric method has been developed for the estimation of mosapride in tablet formulations. The method is based on the formation of a orange coloured azo product by the diazotization of mosapride followed by a coupling reaction with resorcinol. The absorbance of orange coloured solution is measured at 470 nm against reagent blank. Beer’s law is obeyed in the concentration of 20-100 mg/ml of drug. The method is successfully employed for the determination of mosapride in tablets formulations.

KEYWORDS: Spectrophotometry, mosapride citrate, resorcinol, diazotization Formulations

INTRODUCTION:

Mosapride citrate chemically, (±)-4-amino-5chloro-2-ethoxy-N [4-(4-fluorobenyl)-2-morpholinyl [methyl] benzamide citrate dihydrate. It is used in gastrointestinal symptoms associated with chronic gastritis. Few methods are reported in the literature for the determination of mosapride citate in pharmaceutical formulations, which include Spectrophotometry ^1-3 HPLC^4-6. The absorption maximum in the visible range of the spectrum, for the product was found to be 470 nm shown in figure 1.

In the present work, the amino group in mosapride is diazotized with sodium nitrite and hydrochloric acid at 0ºc temperature. After diazotization, the diazonium salt is coupled with resorcinol. The orange coloured chromogen formed in the method is stable for more than 24 hours. The orange coloured chromogen was measured at 470 nm against reagent blank prepared similar manner omitting drug solution. An attempt has been made to develop simple sensitive and economical method for estimation of mosapride in bulk and pharmaceutical formulations. The probable mechanism of the reaction was given in the Scheme 1.

EXPERIMENTAL:

Apparatus:

A Milton Roy 1001 plus spectrophotometer with 1 cm quartz cells were used for all absorbance measurements.

Chemicals and reagents:

All the chemicals and reagents used were of AR grade. Double distilled water was used throughout the investigation. Hydrochloric acid (0.1N) was prepared and standardized with standard procedure. Sodium nitrite (0.1 N) was prepared by dissolving 0.69g in 100 ml distilled water. Sodium carbonate (0.5 N) was prepared by dissolving 5.3 g in 100 ml distilled water. resorcinol (1%) and urea (1%) solution were prepared.

Preparation of standard drug solution:

Pure mosapride (50 mg) was dissolving in 50 ml methanol. This stock solution was further diluted with methanol to get working concentration of 100 mg/ml.

Calibration curve procedure:

Various aliquots (0.2, 0.4, 0.6, 0.8, 1.0 ml) of mosapride were transferred into a series of 10 ml volumetric flask. To each flask, 1.0 ml of 0.1 N hydrochloric acid and 1.0 ml of 0.1 N sodium nitrite solutions were added with swirling and kept aside for 5 min., at 0-50⁰c temperature for complete diazotization. Then 1.0 ml of 1% urea solution was added in each flask and shaken frequently to allow nitrogen gas to escape. After 2 min. 1.0 ml of 0.5 N sodium carbonate solution and 1.0 ml of 1% resorcinol solution were added.

Fig. 1: Absorption spectrum of masopride citrate with resorcinol at 470 nm

Fig. 2: Linearity curve for mosapride citrate

The volume in each flask was adjusted to 10 ml with methanol. After 10 min., the absorbance of orange coloured solution was measured at 470 nm against reagent blank prepared by similar manner omitting drug solution. The concentration of the mosapride was read from calibration curve, which was .shown in fig.2.

Pharmaceutical formulations:

Ten tablets of mosapride were weighed and powdered. The powdered equivalent to 50 mg of mosapride was transferred into 50 ml volumetric flask, shaken thoroughly with 25 methanol and filtered. The filtrate was diluted to 50 ml with methanol. This stock solution is further diluted to obtain the working concentration of 100 mg/ml. Different aliquots of solutions were taken and analyzed by using the procedure described earlier and the amount of mosapride present in sample was read from calibration graph. The results are tabulated in Table 1.

Table 1: Optical characteristics of proposed method.

Parameters	Proposed method
λ _max(nm)	470
Beer’s law limit (µg/ml)	20-100
Molar absorptivity (l mole-1 cm-1)	6.89x10³
Sandell’s sensitivity (µg cm-2 / 0.001 absorbance unit)	0.068
Regression equation (Y = a + bC)	Y=0.015x+0.009
Slope (b)	0.015
Intercept (a)	0.009
Correlation coefficient (r)	0.999

*Y = a+bX, where Y is the absorbance and X concentration in μg / ml

a= Intercept

b= Slope

Table 2: Assay and recovery of mosapride citrate in table formulation

Sample

Labelled

Amount (mg)

Amount found in mg

% Recovery^*

^*t_cal

Proposed method ±S.D^*

Official method^*

Tablet 1

Tablet 2

Tablet 3

Tablet 4

5.04 ±0.23

4.98 ±0.33

9.98±0.19

10.02±0.21

5.0

4.90

9.94

9.98

99.98

99.96

99.99

100.2

0.3887

0.1336

0.2305

0.2063

^*Average of five determinations based on label claim.

RESULTS AND DISCUSSIONS:

The method developed in the present investigation may perhaps be used for the analysis of mosapride from tablets. In this method mosapride underwent diazotization when treated with sodium nitrite and hydrochloric acid. The excess nitrous acid during the diazotization could be removed by the addition of urea solution. The solution was shaken frequently to allow the nitrogen to escape. For the diazotization process, mosapride readily diazotized in acidic medium and that the diazonium cation would then react with a coupling reagent of resorcinol to produced a orange coloured azo product. This orange colour shows maximum absorbance at 470 nm. The proposed method is advantageous over many spectrophotometric methods as heating or extraction is avoided. The results obtained from the proposed method are in good agreement with label claim of the tablets. As a check on accuracy of the method, recovery experiment was performed and percent recovery was found to be close to 100%. The additives and recipients usually present in tablets do not interfere under these conditions. The optical characteristics such as absorption maxima, Beer´s law limits, molar absorptivity and Sandell´s sensitivity are presented in Table 1. The regression analysis using method of least squares was made for the slope (b), intercept (a) and correlation (r) obtained from different concentrations and results are summarized in table 1

The standard deviation and student’s ’t’ test values calculated from the five measurements of mosapride citrate are presented in Table 2. The standard deviation were low that indicates the reproducibility of the proposed method. In the student’s ’t’ tests, no significant differences were found between the calculated and theoretical values of both the proposed methods at 95% confidence level. This indicated similar precision and accuracy in the analysis of zidovudine in its tablets

The proposed method was found to be simple, precise, accurate and time saving, reproducible and can be conveniently adopted for routine analysis of estimation of mosapride in bulk drugs samples and from pharmaceutical formulations.

REFERENCES

1. Appala Raju, S, Shobha, M, A simple and sensitive UV spectrophotometric method for the estimation of mosapride citrate in bulk drug and its formulations Asian Journal of Chemistry, 15, 529, 2003.

2. Kuchekar, BS, Usha Adagale, M, Nagar, Bhise, B, colorimetric method for the estimation of mosapride citrate in solid dosage forms Indian Journal of Pharmaceutical Sciences, 65, 165, 2003.

3. H. D. Revanasiddappa and M. A. Veena, Spectrophotometric determination of mosapride in pure and pharmaceutical preparations, Eclética Química, 32, 2007.

4. Patel, et al, High-Performance Liquid Chromatography and Thin-Layer Chromatography for the Simultaneous Quantitation of Rabeprazole and Mosapride in Pharmaceutical Products, Journal of Chromatographic Science, 46, 10-14, 2008

5. Dong Fang, Ma Chuan-jiang , Determination of Mosapride Citrate by HPLC, Shangdong Pharmaceutical Industry, 12, 2005

6. SHAO Hong, Determination of mosapride citrate and its preparations by HPLC, Chinese Pharmaceutical Journal, 05, 2002.