UV spectrophotometric estimation of Duloxetine hydrochloride in tablet dosage form

 

N. Tamilselvi*, Tejaswi Bhavanam, Tessy Susan Thomas, Dona Sara Kurian, K. Sruthi, Manasvi Sunkara, M.R. Deepthi

KMCH College of Pharmacy, Kovai Estate, Kalapatti Road, Coimbatore 641048

*Corresponding author-Email: tamildeiva@gmail.com

 

A simple, precise, accurate and economical UV spectrophotometric methods have been developed and validated for the estimation of  Duloxetine  hydrochloride in tablet dosage form. Standard stock solution was prepared in water. The resulting solutions were then scanned in the UV range (200-400nm) in a double beam UV Visible spectrophotometer. The drug shows maximum absorption at 218nm. In these methods the drug obeyed Beer-Lambert’s law in the concentration range of 5.0-30μg/ml. The linear regression equations were calculated to be y = 0.100x+0.039, R=0.999. The results of estimation of marketed tablet formulations were found to be 99.1±0.001 with their %RSD less than 2. Recovery studies were carried out by addition of known amount of standard drug to the powdered tablet. The % recovery was found to be 99.16±0.44, which indicates accuracy and reliability of the validated methods as well as non-interference from excipients to the developed methods. The intraday and interday assay was within 2%. The method was then validated statistically as per the ICH guidelines which yielded good results concerning range, precision, accuracy, specificity, robustness and ruggedness.

 

 

INTRODUCTION:

Duloxetine  hydrochloride, chemically known as (+) - (S) - N-methyl - γ- (1- naphthyloxy) -2-thiophenepropylamine hydrochloride¹ is an antidepressant agent². It is indicated for the treatment of major depressive disorder (MDD).It is a selective serotonin and nor-epinephrine reuptake inhibitor (SSNRI) for oral administration. A survey of literature showed few analytical methods has been reported for determination of duloxetine hydrochloride in human serum and biological fluids using tandem MS and LC-MS methods³ and HPLC^4-5 method for the estimation of duloxetine hydrochloride in pharmaceutical preparations. Determination of duloxetine hydrochloride by spectroflourimetric method^6-7 has also been reported. To the best of our knowledge, there is no report on UV–Visible spectrophotometric method for its estimation. Therefore, an attempt was made  to develop a simple, rapid, accurate and sensitive UV spectrophotometric method for the estimation of duloxetine hydrochloride in pharmaceutical formulations.

 

MATERIALS AND METHODS:

Double beam UV-VIS spectrophotometer 1700 (Shimadzu) was used for measured absorbance. Analytical grade solvents were used in the present study. Drug sample of duloxetine hydrochloride was procured from Torrent Pharmaceuticals Ltd. Commercial tablets of duloxetine hydrochloride were purchased from the local market.

 

DETERMINATION OF LINEARITY RANGE:

Weighed accurately 10mg of duloxetine hydrochloride, transferred into a 10ml standard volumetric flask, dissolved and made up to the volume with distilled water. The final solution had a concentration of 1000µg/ml (solution A). Accurately pipetted out 0.5 ml of solution a into a 10 ml standard flask and made up to the volume using distilled water to get a concentration of 50mg/ml (solution B). Accurately pipetted out 1, 2, 3, 4, 5 and 6ml of solution C into a 10ml standard flask and made up to the volume using distilled water to get the concentration of 5.0, 10, 15, 20, 25 and 30µg/ml. The absorbance of each solution was measured at 218 nm. Calibration curve was plotted between absorbance vѕ concentration. (Figure 2). Duloxetine hydrochloride showed linearity range from 5.0-30 µg/ml at the selected wavelength. Optical characteristics are presented in table-1.

 

Fig 1: UV spectrum of  Duloxetine hydrochloride

 

TABLE 1: Optical characteristics and precision data of  Duloxetine hydrochloride

PARAMETERS	VALUES
λ max(nm) Beer’s law limit (μg/mL) Molar absorptivity(L/mol cm) Correlation coefficient (R) Sandell sensitivity(μg/cm2/0.001AU) Regression equation(y=mx+c) Intercept (a) Slope (b)	218 5.0-30 0.97x104 0.999 0.036 y = 0.100x+0.039 0.039 0.100

 

Fig 2:     Calibration curve of  Duloxetine hydrochloride

 

TABLE-2: Results of the estimation of duloxetine hydrochloride in tablet

Tablet Formulation	Label claim (mg/tablet)	Amount found (mg)	Recovery (%)	RSD  %
Tablet 1	30	29.70	99.16	0.027
Tablet 2	30	29.69	99.14	0.026

 

ANALYSIS OF DULOXETINE HYDROCHLORIDE:

Twenty tablets were accurately weighed and finely powdered in a mortar. A weight equivalent to 30mg was accurately weighed out and transferred into a 25ml volumetric flask. The volume was made up with distilled water to acquire a final concentration of 1200µg/ml. (Solution A).Accurately pipetted out 1ml of the solution A and transferred into a 100ml standard flask and made up to the volume with distilled water to acquire a final concentration of 12µg/ml. Accurately pipetted out 1.5 and 2.0ml of the above solution (solution A) and transferred to a 100 ml standard flask and made up to the volume with distilled water. The solution had a final concentration of 18µg/ml and 24µg/ml respectively. The absorbance of each solution was measured at 218nm using distilled water as blank. (Figure 1).

 

RECOVERY STUDIES:

Recovery studies were carried out at two different levels by adding 18 and 24 μg/ml of pure drug solution to different samples of tablet powder solution containing the equivalent 30mg/ml of drug. From the amount of drug found, percentage recovery was calculated (Table 2).

 

RESULTS AND DISCUSSION:

The proposed method for determination of showed linear regression of absorbance on concentration gave the equation y = 0.100x+0.039, with a correlation (R) of 0.999.  Duloxetine hydrochloride exhibited maximum absorption at 218 nm and obeyed Beer’s law in the range of 5.0-30µg/ml. The percentage recovery values 99.23% and 99.16% indicates there is no interaction of the excipients present in the formulations. The study was made to test ruggedness of the method through an interday and intraday analysis of samples.

 

CONCLUSIONS:

Based on the results obtained, it is found that the proposed method of analysis is accurate, precise, reproducible and economical and can be employed for the routine quality control of duloxetine hydrochloride in pharmaceutical formulations.

 

ACKNOWLEDGEMENT:

The authors are thankful to the Director of K.M.C.H. College of Pharmacy for providing facility regarding work.

 

REFERENCES:

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3.     Johnson J T, Oldham S W and Lantz R J, J Liq Chromatogr Rel Technol.19, 1996,1631- 1635.

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5.     Laura Mercolini, Roberto Mandrioli and Roberto Cazzolla,  J Chromatogr. B, 2007, 81-87.

6.     Xiangping Liu, Yingxiang Du and Xiulan Wu,  Spectrochimica Acta Part A: Mol Biomol    Spectrosc. 2008, 915-920.

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Received on 16.02.2012          Modified on 02.03.2012

Accepted on 09.03.2012         © RJPT All right reserved