Development and Validation of UV Spectrophotometric Method for the Estimation of Strontium Ranelate in Sachet Formulation
*K. Mythili, S. Gayatri, E. Mukesh Kumar, T. Adi Reddy, K. Chitra and C. Uma Maheswara Reddy
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Sri Ramachandra University, Porur, Chennai, Tamil Nadu, India
*Corresponding Author E-mail: mythilisrmc@yahoo.co.in
ABSTRACT:
A new simple and reproducible UV spectrophotometric method for the estimation of strontium ranelate in bulk and sachet formulation has been developed. Strontium ranelate is used to treat osteoporosis in women who have passed the menopause. Standard solution of strontium ranelate in monobasic potassium phosphate buffer (pH 3) showed maximum absorbance at 323 nm. Beer-Lambert’s law obeyed in the concentration range of 2-20 μg / ml with correlation coefficient of 0.9981. The percentage recovery was found to be 103.21 %, which reflect that the method is free from interference of impurities during the estimation of drug in formulation. The developed method was validated with respect to linearity, accuracy, precision and specificity.
KEYWORDS: UV spectrophotometric method, strontium ranelate, buffer
INTRODUCTION:
Literature survey revealed the availability of method of estimation of strontium ranelate by RP-HPLC (4). As of our knowledge, no report has been mentioned in the literature for the estimation of strontium ranelate by UV mehod. Therefore a new simple, selective and reproducible method for the estimation of strontium ranelate in bulk and sachet formulation was developed.The developed method was validated with respect to linearity, accuracy and precision.5,6
Fig 1: Chemical Structure of strontium ranelate
Shimadzu double beam UV spectrophotometer (model Lamda 25) with 1 cm matched quartz cells was used for the studies. Schimadzu electronic balance (model A X 200) and pH meter (model 335) were also used. The chemicals such as hydrochloric acid and monobasic potassium phosphate (pH 3) were of analytical grade (7). Strontium ranelate (standard drug) and Strotas sachet (Strontium ranelate-2 gm) were procured from Sai Adventium Pharma Ltd., Hyderabad.
Preparation of standard solution:
About 100 mg of pure sample was weighed accurately and dissolved in 5 ml of hydrochloric acid (0.1 N) and the volume was made up to 100 ml with monobasic potassium phosphate buffer (stock solution I). A solution of 100 μg/ml of strontium ranelate was prepared by diluting stock solution I, using buffer (stock solution II). The stock solution II was suitably diluted with the buffer to get the concentration ranging from 2-20 μg/ml. Stock solution II was scanned in the UV range of 200-400 nm and the wavelength of maximum absorption for strontium ranelate was found to be 323 nm.
The optical characteristics for strontium ranelate (standard drug) are given in Table I
Table-I: Optical characteristics for strontium ranelate (standard drug)
|
S.N |
PARAMETERS |
OBSERVATION |
|
1. |
Wavelength of maximum absorption |
323 nm |
|
2. |
Linearity range |
2-20 µg/ml |
|
3. |
Slope |
0.0044 |
|
4. |
Intercept |
0.0432 |
|
5. |
Regression Equation |
Y= (0.0044)X + 0.0432 |
|
6. |
Molar Absorptivity |
1.09 x103 |
|
7. |
Standard Deviation |
0.6761 |
|
8. |
Relative Standard Deviation |
0.0676 |
|
9. |
Coefficient of Variation |
6.7617 |
|
10. |
Standard Error |
0.2138 |
|
11. |
Correlation Coefficient |
0.9981 |
Table-II: Results for recovery studies (Accuracy)
|
Sample |
Labeled amount (gm / sachet) |
Amount found (gm) |
Percent content (%) |
Recovery studies |
||
|
Amount added (gm) |
Amount recovered (gm) |
Percent recovery (%) |
||||
|
S1 |
2 |
2.0593 |
102.96 |
0.5 |
0.5243 |
104.86 |
|
S2 |
2 |
2.1080 |
105.40 |
1.0 |
1.0150 |
101.53 |
|
S3 |
2 |
2.0670 |
103.35 |
1.5 |
1.5480 |
103.25 |
Preparation of sample solution:
The average weight of the contents of three sachets was determined. The powdered sample equivalent to 0.1 gm was dissolved in 5 ml of hydrochloric acid (0.1 N) and the solution was made up to 100 ml with the buffer and filtered. The filtrate was diluted suitably with the buffer to get the concentrations within the linearity range.
METHOD VALIDATION:
Linearity:8, 9
The absorbance of all the solutions ranging from 2-20 μg / ml was measured at 323 nm against the blank solution. The calibration curve was plotted and it was found to be linear in the range.The calibration plot is shown in figure II.
Fig 2: Calibration plot for strontium ranelate
Accuracy:
To validate the accuracy of the method recovery studies were carried out by addition of known quantities of standard drug at 80, 100 and 120 % to the pre-analyzed sample and the mixtures were analyzed by the proposed method. The percentage recovery was calculated and the results are given in Table II
Table-III: Results for determination of intraday and inter day precision
|
Precision parameter |
% RSD |
LIMIT |
|
|
Intraday
|
Initial |
0.551 0.532 0.546 |
Not more than 2 % |
|
After 3 hrs |
|||
|
After 6 hrs |
|||
|
Inter-day
|
Day 1 |
0.526 0.548 0.537 |
|
|
Day 2 |
|||
|
Day 3 |
|||
Precision:
The precision of the method was done by analysing 3 concentrations of strantium ranelate in three independent replicates on the same day and on three different days over a period of one week. The intra-day and inter day variations were calculated in terms of percentage relative standard deviation and the results are given in Table III
RESULTS AND DISCUSSION:
The optical characteristics of strontium ranelate were calculated and all are with in the limits. The proposed method obeys Beer's law in the concentration range of 2 to 20 μg / ml. The recovery study was carried out to ascertain the accuracy. The Percent recovery of strontium ranelate was found to be 101.53 to 104.86 %, which indicates, high degree of accuracy of the method. The percentage relative standard deviation were calculated for intraday and inter day precision and found to be less than 2 %. The analysis results of the marketed formulation are in good agreement with the label claim. Hence, the proposed method can be successfully used for routine quality control analysis of drug in marketed preparations.
ACKNOWLEDGEMENT:
Authors thank the management of Faculty of Pharmacy, Sri Ramachandra University for providing all the necessary facilities to carry out this work.
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Received on 24.06.2011 Modified on 01.07.2011
Accepted on 08.07.2011 © RJPT All right reserved
Research J. Pharm. and Tech. 4(9): Sept. 2011; Page 1468-1470