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Dept. of Pharmaceutical Chemistry,
Padmashree Dr.D. Y.Patil College of Pharmacy, Akurdi, Pune INDIA


A simple, sensitive, spectrophotometric method in UV region has been developed for the determination of oxaprozin in bulk and tablet dosage form. Solution of oxaprozin in Methanol shows maximum absorbance at 282 nmin zero order spectrum method (method A), in first order derivative spectra (method B) show sharp peak at 270 nm when n=1, and in method C calculation of area under curve (AUC) for analysis of Oxaprozin in wavelength range 292-270nm. The drug followed the Beer-Lambert’s law in the concentration range of 4-32 µg/ml. Result of analysis were validated statically and were found to be satisfactory.

Keywords: Oxaprozin, Zero order, First order, Area under curve.


Oxaprozin, chemically 4, 5-diphenyl-2-oxazole propionic acid1, 2, is best known as a non-steroidal anti-inflammatory agent which is used for the treatment of pain, inflammation and rheumatic conditions. The empirical formula is C18H15NO3 and its molecular weight is 293.317.A few HPLC methods3-8 have been reported for estimation of oxaprozin in biological fluids.

However, there is no visible and UV methods have been reported in the literature for estimation of oxaprozin. The present study is to develop an accurate and reliable UV method for determination of oxaprozin in bulk and its solid dosage forms. Our present investigation aimed to develop a simple, rapid precise, accurate and economical visible spectrophotometric method for the analysis of oxaprozin in bulk and solid dosage forms.



A shimazdu uv/vis spectrophotometer was used with 1cm matched quartz cells and spectral bandwidth of 2 cm.


Standard gift sample of oxaprozin was procured from Emcure pharmaceutical Ltd. Pune. Tablet of Oxaprozin were procure from marketed commercial brand i.e.Oxapro.

Solvent used

Methanol was used solvent as a solvent in the study.

Stock solution

Accurately about 5mg of Oxaprozin was weighed and transferred to 50 ml volumetric flask. To it 20 ml of Methanol was added to dissolve the drug completely with vigorous shaking. Then the volume was made up to the mark with the Distilled water to give the drug stock solution of concentration 50mg/ml.

Method A2, 5, 11

From the stock solution of Oxaprozin appropriate volumes were pipette out and transferred to 10ml volumetric flasks. Keep it 15-20min ultrasonicator. The volume was made up to the mark with Distilled water to give the samples of desired concentrations like 4, 8, and 12up to 32mg/ ml. The absorbance maxima of these solutions were found at 282 nm. (Fig.1) a linear graph of absorbance vs. concentration was obtained. The concentration range over which the drugs obeyed Beer-Lambert’s law was found to be 4-32mg/ml for Oxaprozin. The concentration of sample solution was determined from calibration curve.

Figure 1:- Zero order spectrum of Oxaprozin

Method B3,15

The first order derivative spectra at n=1 (method b) showed a sharp peak at 270nm (figure 2).The absorbance difference at n=1 is calculated by the inbuilt software of the instruments which was directly proportional to the concentration of the standard solution .The standard drug solution was diluted so as to get the final concentration in the range of 4-32µg/ml and scanned in the first order derivative spectra. The calibration curve of Oxaprozin absorbance difference against concentration of the drug showed linearity.

Figure2: First order derivative spectrum of Oxaprozin

Method C3, 4

The Auc (Area under curve) method involves theSuitable concentrations of solutions were prepared accurately to determine the range of Oxaprozin for analysis. The standard solutions were scanned in the spectrum mode of the instrument from 400 nm to 200nm. The absorbance maxima of these solutions were obtained at wavelength 270nm. The area under the curve between 292nm to 270 nm was selected (Fig.3) for the calculation because the linearity was obtained within these areas with good reproducibility of results.

Figure3: Wavelength range selected by AUC method of Oxaprozin

 Table 1: Optical Calibration Curve of Oxaprozin

Parameters  Method A Method B Method C
Wavelength range (nm) 282 270 270-292
Beer- Lambert’s range (mg /ml)


4-32mg /ml 4-32mg /ml 4-32mg /ml
Coefficient of correlation ( r2)c

Regression equation Y = mx + c


0.999 0.998 0.998
Slope (m) 0.0271 0.001 0.588


Intercept ( c) 0.000 0.00 -0.032


LOD 0.0328 0.117 0.00709
LOQ 0.990 0.536 0.02151

Analysis of tablet formulation 5,12,15

For estimation of Oxaprozin in tablet formulation by three methods, twenty tablets were weighed. The tablet content was weighted and triturated to fine powder. Tablet powder equivalent to 10 mg. of Oxaprozin was weighed and transferred to 100 ml volumetric flask and dissolved in 40 ml of methanol. It was kept for ultrasonification for 30 min. finally the volume was made up to the mark with methanol; this was then filtered through whatman filter paper no. 41 to get tablet stock solution of concentration of 10 μg/ml. various dilution of the tablet solution were prepared and analyzed for six times and concentration was calculated by using the calibration curve for three method.

All these method were validated according to ICH guidelines by carrying out analysis of six replicate samples of the tablets (table 2), Recovery studies were carried out at two different level i.e80%100%, 120%by adding the pure drug (8, 10, and 12 mg respectively) to previously   Analysed tablet powder sample from the amount of drug found percentage recovery was calculated (Table3).

Method Tablet formulation Label claim Amount found %mean S.D C.O.V S.E
A T1 600 598.48 99.74 0.1179 0.118 0.0482
B T1 600 597.15 99.51 0.1643 0.165 0.06914
C T1 600 598.11 99.69 0.1973 0.198 0.08056

Table 2: Estimation of Oxaprozin formulation tablet

Table 3: Recovery Study Data

Method Tablet Formulation Level Of % Recovery Label Claim Amount of std drug added %*     Mean %* Mean S.D C.O.V S.E
A T1 80 10 8 18.04 99.98 0.4055 0.4058 0.2314
100 10 10 20.04 100 0.1323 0.1317 0.0763
120 10 12 22.01 100.05 0.2946 0.2937 0.1701
B T1 80 10 8 18.06 99.98 0.6892 0.6896 0.3979
100 10 10 20.05 100 0.6759 0.6774 0.3902
120 10 12 22.01 99.96 0.5128 0.5103 0.2960
C T1




80 10 8 17.75 99.50 0.6971 0.6990 0.4025
100 10 10 20.03 100.03 0.2611 0.2616 0.1508
120 10 12 22.03 100.03 0.6312 0.6315 0.3644


The Methods A, B, C for estimation of Oxaprozin in tablet dosage form were found to be accurate and reproducible .beer- lambert’s was obeyed in the concentration range of 4-32ug/ml. in all these methods .The values of standard deviation were satisfactory and the recovery studies were close to 100%.hence These method can be useful in the routine analysis of Oxaprozin in bulk drug and formulation.


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