Simultaneous Spectrophotometric Estimation of Ofloxacin and Satranidazole in Tablet Dosage Form

 

Wankhede SB*, Prakash A and Chitlange SS

Pad. Dr. D. Y. Patil Institute of Pharmaceutical Sciences and Research, Sant Tukaram Nagar, Pimpri, Pune-18.

*Corresponding Author E-mail:  sagar2277@rediffmail.com

 

ABSTRACT

Two accurate, precise, rapid and economical methods were developed for the estimation of Ofloxacin and Satranidazole in tablet dosage form. First method is first order derivative spectroscopy, wavelengths selected for quantitation were 259.0 nm for Ofloxacin (zero cross for Satranidazole) and 227.0 nm for  Satranidazole (zero cross for Ofloxacin). Second method is area under curve method; area under curve in the range of 292.5-282.5 nm (for Ofloxacin) and 325.0-315.0 nm (for Satranidazole) were selected for the analysis. In both the methods linearity for detector response was observed in the concentration range of 5-40 µg/ml for Ofloxacin and Satranidazole, both. The proposed methods were successfully applied for the simultaneous determination of both drugs in commercial tablet preparation. The results of the analysis have been validated statistically and by recovery studies.

 

 KEY WORDS               Ofloxacin; Satranidazole; derivative spectroscopy; area under curve method.                                                                                                                                                                

 

INTRODUCTION:

Ofloxacin (OFL) is a fluoroquinolone derivative. Chemically, it is (±)-9-fluoro-2, 3-dihydro-3-methyl-10- (4-methyl-1-piperazinyl)-7-oxo-7H-pyrido-[1,2,3-de]-

1,4-benzoxazine -6-carboxylic acid.¹  It is mainly used as   antibacterial   for   the   treatment   of   urinary   tract infection      and      sexually      transmitted      diseases.

Satranidazole    (SAT),    is    a    novel    nitroimidazole

derivative. Chemically, it is 1-methylsulfonyl-3-(1- methyl-5-nitro-2-imidazolyl)-2-imidazolidinone². It is used as antiprotozoal and antibacterial agent in the treatment of amoebiasis³. Ofloxacin is official in USP⁴ and BP⁵ whereas Satranidazole is not official in any pharmacopoeia.   Both   the   drugs   are   marketed   as combined  dose  tablet  formulation  and  the  ratio  is

200:300 mg OFL: SAT. Literature survey revealed that a number of methods have been reported for estimation of Ofloxacin individually or in combination with other drugs^6-12 and Satranidazole is estimated individually^13-15. However,  there  are  two  analytical  methods: simultaneous equation and absorption ratio method¹⁶, reported for the simultaneous estimation of Ofloxacin and Satranidazole in a combined dosage formulation. Present work describes two simple, accurate, reproducible, rapid and economical methods for simultaneous estimation of OFL and SAT in tablet formulation.

MATERIAL AND METHODS:

Instrument: A double-beam Shimadzu UV- Visible spectrophotometer,  1700  Pharmaspec,  with  spectral bandwidth of 2 nm, wavelength accuracy ± 0.5 nm and a pair of 1-cm matched quartz cells was used to measure absorbance of the resulting solution.

 

Materials: Standard gift sample of Ofloxacin and Satranidazole were provided by Alkem Laboratories Limited, Baddi. Combined dose Ofloxacin and Satranidazole tablets (SATROGYL-O, 200 mg Ofloxacin and 300 mg Satranidazole; manufacture by Alkem Laboratories Limited, Baddi), were purchased from local market.

 

Solvent used: Double distilled water was used as a solvent. Stock solution: Standard stock solutions of OFL (100 µg/ml) and  SAT  (100  µg/ml)  were  prepared  and  used  for  the analysis.

 

Procedure

Method A-          First Order Derivative Spectroscopy

In this method solutions of OFL and SAT (25 µg/ml, each), were prepared separately by appropriate dilution of standard stock solution and scanned in the spectrum mode from 400 nm to 200 nm. The absorption spectra thus obtained were derivatized from first to fourth order. First order derivative spectra were selected for analysis of both drugs. From the overlain spectra of both drugs (Fig. 1), wavelength selected for quantitation were 259.0 nm for OFL (zero cross for SAT) and 227.0 nm for SAT (zero cross for OFL). The calibration

 

_{Table No. 1: Results of Analysis of Tablet Formulation}

Method	Drug	Label Claim	Amount of drug estimated (mg/tab)	% Label Claim*  ± S.D.	% Recovery*
A	OFL	200	198.80	99.41 ± 0.4883	99.58
	SAT	300	298.31	99.44 ± 0.3802	99.61
B	OFL	200	198.04	99.02 ± 0.5318	99.74
	SAT	300	298.11	99.37 ± 0.7166	100.01

* indicates mean of six determinations.

curves for OFL and SAT were plotted in the concentration range of 5-40 µg/ml at wavelength 259.0 nm and 227.0 nm, respectively. The concentration of the individual drug present in the mixture was determined against the calibration curve in quantitation mode.

 

Fig.-1:    Overlain    Spectra    of    Ofloxacin    (OFL)    and

Satranidazole (SAT) in Method- A

 

Method B-          Area Under Curve Method

For the selection of analytical wavelength, solutions of OFL   and   SAT   (25   µg/ml,   each),   were   prepared separately by appropriate dilution of standard stock solution and scanned in the spectrum mode from 400 nm to  200  nm.  From  the  overlain  spectra  of  both  drugs (Fig. 1), area under the curve in the range of 292.5-282.5 nm (for OFL) and 325.0-315.0 nm (for SAT) were selected for the analysis. The calibration curves for OFL and SAT were prepared in the concentration range of 5-

40 µg/ml at their respective AUC range. The ‘X’ values of the drugs were determined for both the drugs at the selected AUC range. The ‘X’ is the ratio of area under the curve at selected wavelength ranges with the concentration of component in gm/lit. These ‘X’ values were the mean of six independent determinations. A set of two simultaneous equations obtained by using mean

‘X’ values are given below.

 

A₁ =   615.60 C_OFL +164.21 C_SAT -(at λ_292.5-282.5 nm)-- (1) A₂ = 268.78 C_OFL+ 302.12 C_SAT -(at λ_325.0-315.0 nm) -- (2)

 

Where A₁ and A₂ were area under curve of sample at the wavelength range 292.5-282.5 nm and 325.0-315.0 nm, respectively, 615.60 and 268.78 were ‘X’ values of OFL at wavelength range 292.5-282.5 nm and 325.0-315.0 nm, respectively. Similarly 164.21 and 302.12 were ‘X’ values of SAT at the wavelength range 292.5-282.5 nm and 325.0-315.0 nm, respectively. C_OFL  and C_SAT  were concentration  of   OFL   and   SAT,   respectively.   The

 

concentration of OFL and SAT in sample was determined by using the equation (1) and (2).

 

Application of the proposed method for the determination of OFL and SAT in tablets

For the estimation of drugs in the commercial formulations, twenty tablets were weighed and average weight was calculated. The tablets were crushed to obtain fine powder. Tablet powder equivalent to 50 mg OFL was transferred to

100.0 ml volumetric flask and volume made up to the mark with double distilled water and ultrasonicated for 20 minutes. The  solution  was  then  filtered  through  a  Whatmann  filter paper (No. 41). From the filtrate 5.0 ml was transferred to a

100.0 ml volumetric flask and diluted to the mark with the same solvent. The solution was further diluted with double distilled water to obtain 10 µg/ml OFL and 15 µg/ml of SAT. In Method-A, the concentration of both OFL and SAT were determined by measuring the absorbance of the sample at

259.0 nm and 227.0 nm in first order spectrum mode. The results of the tablet analysis were calculated against the calibration curve in quantitation mode. For Method-B, the concentration of both OFL and SAT were determined by measuring area under curve in the range of 292.5-282.5 nm (for OFL) and 325.0-315.0 nm (for SAT) and values were substituted in the respective formula to obtain concentrations. Results of tablet analysis are shown in Table No. 1.

 

Fig.-2: Overlain Spectra of Ofloxacin (OFL) and Satranidazole

(SAT) in Method- B

 

VALIDATION:

The   methods   were   validated   with   respect   to   linearity, accuracy, precision and selectivity.

Accuracy:   To   ascertain   the   accuracy   of   the   proposed methods, recovery studies were carried out by standard addition  method  at  three  different  levels  (80%,  100%  &

120%).  Percent  recovery  for  OFL  and  SAT,  by  both  the methods, was found in the range of 98.74 % to 100.95 %. Linearity: The linearity of measurement was evaluated by analyzing different concentration of the standard solution of

 

OFL  and  SAT.  For  both  the  methods,  the  Beer- Lambert’s  concentration  range  was  found  to  be  5-40

µg/ml for OFL and SAT, both.

Precision: The reproducibility of the proposed method was determined by performing tablet assay at different time intervals (morning, afternoon and evening) on same day (Intra-day assay precision) and on three different days (Inter-day precision). Result of intra-day and inter- day precision is expressed in % RSD. Percent RSD for Intraday assay precision was found to be 0.7023 (for OFL) and 0.5280 (for SAT) in first order derivative spectroscopy method; 0.5439 (for OFL) and 0.0749 (for SAT) in area under curve method. Inter-day assay precision was found to be 0.7429 (for OFL) and 0.6998 (for SAT) in first order derivative spectroscopy method;

0.5849 (for OFL) and 0.6352 (for SAT) in area under the curve method.

 

RESULTS AND DISCUSSION:

The methods discussed in the present work provide a convenient and accurate way for simultaneous analysis of OFL and SAT. In first order derivative spectroscopy, wavelengths selected for quantitation were 259.0 nm for OFL (zero cross for SAT) and 227.0 nm            for SAT (zero cross for OFL). In area under curve method, the area under curve in the range of 292.5-282.5 nm (for OFL) and 325.0-315.0 nm (for SAT) were selected for the analysis. In both the methods linearity for detector response was observed in the concentration range of 5-

40 µg/ml for OFL and SAT, both. In method A, concentration  of  the  individual  drug  present  in  the mixture was determined against the calibration curve in quantitation mode. In method-B, ‘X’ values were calculated for both the drugs at selected wavelengths and substituted in equations for determining concentration of OFL and SAT in tablet sample solution. Percent label claim for OFL and SAT in tablet analysis, by both the methods, was found in the range of 98.35 % to 100.34

%. Standard deviation and coefficient of variance for six determinations of tablet sample, by both the methods, was found to be less than ± 2.0 indicating the precision of both the methods. Accuracy of proposed methods was ascertained by recovery studies and the results are expressed as % recovery. Percent recovery for OFL and SAT, by both the methods, was found in the range of

98.74 % to 100.95 %., values of standard deviation and coefficient of variation was satisfactorily low indicating the accuracy of both the methods. Based on the results

obtained,  it  is  found  that  the  proposed  methods  are

accurate, precise, reproducible & economical and can be employed for routine quality control of Ofloxacin and Satranidazole in combined dose tablet formulation.

 

ACKNOWLEDGEMENTS:

The authors are very thankful to Dr. Avinash D. Deshpande, Director of Pharmacy, Pad. Dr. D. Y. Patil Institute of Pharmaceutical Sciences and Research, Pimpri, Pune for providing necessary facilities. The authors are also thankful to Alkem Laboratories Limited,

Baddi,   for   providing   gift   samples   of   Ofloxacin   and

Satranidazole.

 

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Received on 20.08.2008    Modified on 30.08.2008

Accepted on 10.09.2008    © AJRC All right reserved