Validated Spectrophotometric Simultaneous Estimation of Nimesulide and Dicyclomine Hydrocloride in Combined Tablet Dosage Form

 

Lokesh Singh1 and Sanju Nanda2

1Swami Keshvanand Institute of Pharmacy, Bikaner (RAJ.) INDIA

2Dept. of Pharmaceutical Sciences, Maharishi Dayanand University, Rohtak (HR.) INDIA

*Corresponding Author E-mail: lokeshshekhawat@in.com

 

ABSTRACT:

Two novels, simple, rapid and sensitive spectrophotometric method has been developed for simultaneous estimation of Nimesulide and dicyclomine HCl. The first method involved determination of Nimesulide and Dicyclomine HCl using the Q analysis method and second method involved simultaneous equation method. Nimesulide has absorbance maxima at 300.8 nm, Dicyclomine HCl has absorbance maxima at 217.6 nm and isoabsorptive point is at 232.4 nm in methanol. Linearity was obtained in the concentration ranges 10-100 g/ml and 900-3000 g/ml for Nimesulide and Dicyclomine HCl, respectively. These methods were successively applied to pharmaceutical formulation because no interferences from tablet excipients were found. Accuracy and reproducibility of proposed method was statistically validated by recovery studies. The suitability of these methods for the quantitative determination of the compounds was proved by validation.

 

KEYWORDS: Nimesulide, Dicyclomine HCl, Simultaneous equation method, Q analysis method, Spectrophotometric.

 


INTRODUCTION:

Chemically, Nimesulide is 4- Nitro- 2- phenoxy- methanesulfonanilide1. It is a non-steroidal anti inflammatory drug. It is used for chronic arthritis (Such as rheumatoid arthritis and osteoarthritis); surgery and post- traumatic acute pain and inflammation; otorhinolaryngological inflammation resulting in pain; dysmenorrheal; fever5. It is official in B.P.2 and Merck1 .Nimesulide alone or in combination with other drugs is reported to estimate by spectrophotometric method6-8. HPLC9, HPTLC10, GC11 and capillary chromatographic method12.

 

Chemically, Dicyclomine hydrochloride is 2-(Diethylamino) ethyl [bicyclohexyl]-1-carboxylate hydrochloride1. Dicyclomine hydrochloride is an antispasmodic and anticholinergic (antimuscarinic) agent. Dicyclomine relieves smooth muscle spasm of the gastrointestinal tract4. It is official in USP3 and Merck1. Literature survey reveals that potentiometric method13 and gas chromatography method14.

 

Since no spectrophotometric method is reported for simultaneous estimation of Nimesulide and Dicyclomine HCl in combination therefore, in the present work, a successful attempt has been made to estimate both these drugs simultaneously by two simple UV- spectrophotometric methods (Q-Analysis Method and Simultaneous Equation Method).

 

EXPERIMENTAL:

MATERIALS AND METHODS:

UV visible double beam spectrophotometer, Shimadzu model-1700, with 1cm quartz cells was used. Pure sample of Nimesulide and Dicyclomine HCl were obtained as gift sample from Ind swift laboratories. The tablet dosage form, NELSID-D (Ind-Swift, Claim: 100 mg Nimesulide + 20 mg Dicyclomine HCl) and SPASMONICE (Wockhardt, Claim: 100 mg Nimesulide + 20 mg Dicyclomine HCl) were procured from local medical store. Methanol AR grade was purchased, made by Loba chemi.

 

PREPARATION OF STOCK SOLUTION:

Accurately weighed quantity of Nimesulide (5 mg) was dissolved in sufficient quantity of methanol in a 50 ml volumetric flask. Similarly accurately weighed quantity of Dicyclomine HCl (75 mg) was dissolved in sufficient quantity of methanol in 25 ml volumetric flask. Both the solutions were sonicated and the volume was adjusted up to the mark with methanol to obtain a stock solution of 100 g/ml (Nimesulide) and 3000 g/ml (Dicyclomine HCl) respectively.

Q- ANALYSIS (METHOD I):

For the selection of analytical wavelength for Q absorbance method, the stock solution of Nimesulide and Dicyclomine HCl were separately diluted in methanol to get concentration of 10 g/ml (Nimesulide) and 900 g/ml (Dicyclomine HCl) respectively.

 

From the overlain spectra (Fig-3) wavelength 232.4 nm (Isoabsorptive point) and 217.6 nm (λmax of Dicyclomine HCl) were obtained. Absorptivity values of Dicyclomine HCl were measured at 232.4 nm and 217 nm wavelengths. Similarly Absorptivity values of Nimesulide were also measured at same wavelengths. Six estimation were performed for obtain mean values. These values are mention in table no. 1.

 

TABLE 1: Absorptivity values (e1%, 1cm) of nimesulide and dicyclomine HCl at 232.4nm (isoabsorptive point) and 217.6 nm (Q- analysis -method-i)

S. No.

Absorptivity at 232.4 nm

Absorptivity at 217.6 nm

NIM

DCM

NIM

DCM

1

0.015712

0.015770

0.002212

0.002881

2

0.015717

0.015781

0.002225

0.002887

3

0.015719

0.015773

0.002231

0.002883

4

0.015716

0.015763

0.002211

0.002879

5

0.015715

0.015782

0.002213

0.002885

6

0.015716

0.015773

0.002235

0.002869

*Mean

0.015715

0.015773

0.002221

0.002880

*S.D.

0.0248

0.0712

0.1055

0.0641

*R.S.D.

0.01578

0.04514

0.4750

0.2225

*Mean - Average of six estimation, * S.D. - Standard Deviation, *% R.S.D. Percent Standard Deviation

 

TABLE 2: Absorptivity values (e1%, 1cm) of nimesulide and dicyclomine HCl (Simultaneous equation method-method-ii)

S. No.

Absorptivity at 217.6 nm

Absorptivity at 300.8 nm

 

ax1

ay1

ax2

ay2

1

0.01130

0.0542

0.002881

0.002212

2

0.01135

0.054215

0.002887

0.002225

3

0.01140

0.054222

0.002883

0.002231

4

0.01135

0.054266

0.002879

0.002211

5

0.011342

0.054285

0.002885

0.002213

6

0.011310

0.054266

0.002869

0.002235

*Mean

0.011342

0.054242

0.002880

0.002221

*S.D.

0.00003544

0.00003433

0.00000641

0.00001055

*%R.S.D.

0.3124

0.0632

0.2225

0.4750

*ax1- Absorptivity of Nimesulide at 217.6 nm, *ax2- Absorptivity of Nimesulide at 300.8 nm, *ay1-Absorptivity of Dicyclomine HCl at 217.6 nm, *ay2- Absorptivity of Dicyclomine HCl at 300.8 nm, *Mean - Average of six estimation, * S.D. - Standard Deviation, *% R.S.D. Percent Standard Deviation

 

 

A series of standard solutions ranging from 10-100 g/ml (Nimesulide) and 900-3000 g/ml (Dicyclomine HCl) were prepared and the absorbance of solution was recorded at 232.6 nm and 217.6 nm to plot a calibration curve were found to be linear in the concentration range under study. Absorptivity values of Nimesulide and Dicyclomine HCl were determined at selected wavelength and are presented in table no 1.

The absorbance and Absorptivity at these wavelengths were substituted in the following equation to obtain the concentration of both the drug.

CDicyclomine = (QM - QY) / (QX-QY) X A1/ax1

CNimesulide= A1/ax1 - CDicyclomine

CDicyclomine = (QM 0.1408) / (0.0427) X A1/0.01571

CNimesulide = A1/0.01571 - CDicyclomine

Where, CNimesulide and CDicyclomine were concentration of Nimesulide and Dicyclomine HCl respectively, A1 was the absorbance of sample at 232.4 nm (Isoabsorptive point), ax1 was the absorptivity of Dicyclomine at 232.4 nm.

QX = Absorptivity of Dicyclomine HCl at 217.6 nm/ Absorptivity of Dicyclomine HCl at 232.4 nm

QY = Absorptivity of Nimesulide at 217.6 nm/ Absorptivity of Nimesulide at 232.4 nm

QM = Absorptivity of sample at 217.6 nm/ Absorptivity of sample at 232.4 nm

 

SIMULTANEOUS EQUATION METHOD (METHOD-II):

For selection of analytical wavelengths for simultaneous equation method, the wavelength 217.6 nm (λmax of Dicyclomine HCl) and 300.8 nm (λmax of Nimesulide) were selected. The absorbance of Nimesulide and Dicyclomine HCl were measured at 217.6 nm and 300.8 nm. The absorptivities of both the drug at both the wavelengths were also measured.

 

The absorbance and the Absorptivity values at these particular wavelengths were calculated and substituted in the following equation, to obtain respective concentration.

CNimesulide = (A1ax2-A2ax1) / (ax2ay1-ax1ay2)

CDicyclomine = (A2ay1-A1ay2) / (ax2ay1-ax1ay2)

CNimesulide = A1 (0.01134)-A2 (0.00288) / (0.000131)

CDicyclomine = A2 (0.05424)-A1 (0.00222) / (0.000131)

 

ASSAY OF TABLET FORMULATION BY METHOD I and II:

20 tablets were weighed and crushed to obtain fine powder. An accurately powdered tablet weight weighed equivalent to about 100 mg of Nimesulide and 20 mg of Dicyclomine HCl was transferred to 100 ml volumetric flask, dissolved in 50ml methanol and sonicated for 40 min. the volume was then made up to mark using methanol. The resulting solution was filtered through whatman filter paper grade I and filtrate was appropriately diluted to get approximate concentration of 50 g/ml (Nimesulide) and 10 g/ml (Dicyclomine HCl).1.8 mg/ml of Dicyclomine HCl was added externally to bring concentration in linearity range (0.9 mg/ml-3mg/ml). Absorbencies of sample solution were recorded at 217.6 nm (λmax of Dicyclomine HCl), 232.4 nm (Isoabsorptive point) and 300.8 nm (λmax of Nimesulide). The concentration of two drugs in the sample were determined by respective equations, mention in method-I and method-II.

 

The analysis procedure was repeated six times with tablet formulation. The results of analysis of tablet formulations are presented in table no. 4.


 

TABLE 4: RESULTS OF SIMULTANEOUS ESTIMATION OF MARKETED FORMULATION

Method

NELSID-D

Tablet Content

Label Claim mg/tab

% Label Claim Found*

S.D.*

R.S.D.* (%)

I

Nimesulide

100

99.98

0.1495

0.1495

Dicyclomine HCl

20

100.21

0.2091

0.2086

II

Nimesulide

100

99.99

0.1728

0.1728

Dicyclomine HCl

20

100.14

0.1912

0.1909

Method

SPASMONICE

Tablet Content

Label Claim mg/tab

% Label Claim Found*

S.D.*

R.S.D.* (%)

I

Nimesulide

100

100.3

0.1109

0.1105

Dicyclomine HCl

20

100.24

0.2175

0.2169

II

Nimesulide

100

100.52

0.1717

0.1708

Dicyclomine HCl

20

100.27

0.2363

0.2356

*Indicate mean of six determinations

 

TABLE 5: RESULTS OF RECOVERY STUDIES

Recovery

Level

Drug

Quantity of drug added g/ml

Method-I

Method-II

Recovery*

(%)

S.D.*

R.S.D.*

(%)

Recovery*

(%)

S.D.*

R.S.D.*

(%)

100%

Nimesulide

40

100.14

0.0937

0.0935

99.97

0.1213

0.1213

Dicyclomine HCl

1500

100.33

0.1587

0.1581

100.74

0.1421

0.1410

* Indicate mean of six determinations

 

 


RESULTS AND DISCUSSIONS:

Linearity and Precision:

In quantitative estimation the calibration curve was constructed for both Nimesulide and Dicyclomine HCl, after analysis of consequently increase concentration. To check the precision and reproducibility of the method, six sample of the same concentration (n=6) of Nimesulide and Dicyclomine HCl were prepared and analyzed. The low % RSD values obtained for Nimesulide (0.2225) and Dicyclomine HCl (0.0632) indicated that the method had high precision and reproducibility. The regression equation, slope, intercepts, correlation coefficient, precision and linearity range are given in table no 3.

 

 

TABLE 3: VALIDATION PARAMETERS FOR STANDARD NIMESULIDE AND DICYCLOMINE HCl

Parameters

Nimesulide(300.8nm)

Dicyclomine HCl(217.6nm)

Linearity range

10-100 g/ml

0.9-3 mg/ml

Regression equation

Y=14.75 X - 0.004

Y=0.542X

Intercept

-0.004

0.000

Slope

14.75

0.542

Correlation Coefficient (r2)

0.999

0.999

Precision (% RSD)

0.2225

0.0632

*Indicate means of six determinations, Y= mX+C

 

Reproducibility:

The accuracy and specificity of proposed method was tested by recovery studies. The recovery studies were carried out at 100% level by adding a known quantity of pure drug to the preanalyzed formulation. From the quantity of drug recovered, the percentage recovery was calculated (Mention in Table no. 5). The % recovery for Nimesulide and Dicyclomine HCl were found to be 100.14(%RSD 0.0935), 100.33(%RSD 0.1581) for Method I and 99.97(%RSD 0.1213), 100.74 (%RSD 0.1410) for Method- II. The high recovery rate with low % RSD values indicated that the methods had a good accuracy and specificity, as there was no interference from the excipients present in formulations.

FIG 1: UV Spectra for Nimesulide

 

FIG 1: UV SPECTRA FOR DICYCLOMINE HCl

 

FIG 1: UV OVERLAY SPECTRA FOR NIMESULIDE AND DICYCLOMINE HCl

 

CONCLUSION:

The proposed method was successfully applied to the simultaneous determination of Nimesulide and Dicyclomine HCl form bulk and tablet formulation. The presented method was found to be simple, accurate, precise and reproducible. The developed methods can be directly and easily applied to the analysis of the combined pharmaceutical tablet formulation of Nimesulide and Dicyclomine HCl. The developed methods are quick and cost effective as compared to chromatographic techniques.

 

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Received on 08.12.2009 Modified on 29.01.2010

Accepted on 25.02.2010 RJPT All right reserved

Research J. Pharm. and Tech. 3(2): April- June 2010; Page 562-565