New UV-Visible Spectrophotometric Methods for the Determination of Levetiracetam in Bulk and Pharmaceutical Formulation
S. Ganapathy, G.V.H. Raju*, D.G. Sankar and Pettla Y. Naidu
Department of Pharmaceutical Sciences, Andhra University, Visakhapatnam-530003
*Corresponding Author E-mail: gadepalli_raj@yahoo.com
ABSTRACT:
A three simple, sensitive and reproducible UV-Visible spectrophotometric methods (Method A to Method C) are developed for the determination of Levetiracetam (LEVT) in pure and dosage forms. Method A is based on the formation of colored species on treatment of Levetiracetam (LEVT) with 3-Methyl-2-benzo thiazolinone hydrazone (MBTH) and Cerric Ammonium Sulphate (CAS). Method B is based on the formation of colored species on treatment of Levetiracetam(LEVT) with Fecl3 and 1,10 PTL. Method C represents UV Spectrophotometric determination of Levetiracetam and its dosage forms in Methanol at 210nm.
Levetiracetam is a anticonvulsant drug used in the treatment of epilepsy. It is S-enantiomer of etiracetam, structurally similar to the prototypical nootropic drug piracetam. Along with other anticonvulsants like gabapentin it is also sometimes used in the treatment of neuropathic pain Levetiracetam is a white to off-white crystalline powder with a faint odor and a bitter taste. It is very soluble in water. It is freely soluble in chloroform and in methanol, soluble in ethanol, sparingly soluble in acetonitrile and practically insoluble in n-hexane.
It is official in US pharmacopoeia and no UV Visible spectrophotometric analytical reports are found in literature for its quantitative estimation in bulk and tablet dosage forms. In the present investigation a three simple, sensitive and reproducible UV-Visible spectrophotometric methods are developed for the determination of Levetiracetam (LEVT) in pure and its dosage forms using MBTH- Fecl3 and Fecl3 -1,10PTL. In Method A the formation colored species is due to the Oxidative Coupling reaction with MBTH in Presence of Fecl3 to form a green Colored complex having λmax at 630nm. In Method B the formation of Colored species having λmax at 510nm is due to reaction of Reduced Ferric ion to Ferrous ion with 1,10 Phenanthorline. Method C represents determination of Levetiracetam and its dosage forms in methanol which is having absorption maxima at 210nm.
EXPERIMENTAL: 5-8
Instrument: A Systronics UV-VIS Spectrophotometer model 107 was used for absorbance measurements
Reagents:
All the Chemicals used were of analytical grade
Method A:
i. MBTH (0.2%): 200mg of MBTH was dissolved in 100ml of distilled water
ii. CAS (1%): 1g of Cerric ammonium Sulphate (CAS) was dissolved in 0.72M Sulphuric acid
iii. Diluent: water
Preparation of Standard solution(100µg/ml): About 100mg of Levetiracetam(LEVT) working standard was accurately weighed and transferred into 100ml volumetric flask, 70ml of diluent was added sonicated to dissolve and made up to volume with diluent. Further 5ml of the resulting solution is taken into 50ml volumetric flask and made upto volume with diluent
Preparation of Test Solution: Twenty tablets were taken weighed and powdered .Sample equivalent to About 100mg of Levetiracetam (LEVT)was accurately weighed and transferred into 100ml volumetric flask,70ml of diluent was added sonicated to dissolve and made up to volume with diluent. 10ml was taken and centrifuged at 2500rpm. Further 5ml of the resulting solution is taken into 50ml volumetric flask and made up to volume with diluent.
Method B:
i) Fecl3 (0.9%):900mg of Fecl3 was dissolved in 100ml of distilled water
ii) 1, 10 PTL (0.2%):200mg of 1, 10 PTL was dissolved in 100ml of distilled water
iii) Diluent: Water
Preparation of Standard solution (50µg/ml): About 100mg of Levetiracetam (LEVT) working standard was accurately weighed and transferred into 100ml volumetric flask, 70ml of diluent was added sonicated to dissolve and made up to volume with diluent. Further 5ml of the resulting solution is taken into 100ml volumetric flask and made up to volume with diluent
Preparation of Test Solution: Twenty tablets were taken weighed and powdered .Sample equivalent to About 100mg of Levetiracetam (LEVT)was accurately weighed and transferred into 100ml volumetric flask, 70ml of diluent was added sonicated to dissolve and made up to volume with diluent. 10ml was taken and centrifuged at 2500rpm. Further 5ml of the resulting solution is taken into 100ml volumetric flask and made upto volume with diluent.
Method C:
i) Diluent: Methanol
Preparation of Standard solution(100µg/ml): About 100mg of Levetiracetam (LEVT) working standard was accurately weighed and transferred into 100ml volumetric flask ,70ml of diluent was added sonicated to dissolve and made up to volume with diluent. Further 5ml of the resulting solution is taken into 50ml volumetric flask and made upto volume with diluent
Preparation of Test Solution: Twenty tablets were taken weighed and powdered .Sample equivalent to About 100mg of Levetiracetam (LEVT)was accurately weighed and transferred into 100ml volumetric flask, 70ml of diluent was added sonicated to dissolve and made up to volume with diluent. 10ml was taken and centrifuged at 2500rpm. Further 5ml of the resulting solution is taken into 50ml volumetric flask and made up to volume with diluent.
Assay Procedures:
For Method A Volumes of standard solution ranging from (0.5-3ml; 1ml=100µg) were transferred into a series of 10ml graduated volumetric flasks. A 1ml portion of MBTH was added to each flask and shaken gently for 5 min. Then 1ml of CAS solution was added to each flask and kept aside for 10min for maximum color development .Appropriate volume of distilled water was added to each flask to bring the total volume 10ml.The absorbance was measured at 630nm against reagent blank. The Test solution was treated in the same manner as standard and measured the absorbance at 630nm
For Method B Volumes of standard solution ranging from (0.5-4ml; 1ml=50µg) were transferred into a series of 10ml graduated volumetric flasks. Then 0.5ml portion of FeCl3 and 2.0ml of 1, 10 PTL were added successively and the volume made up to 5ml with diluent and set aside for 10min. To that 2.0ml of o-PA was added and the total volume was made up to 10ml with distilled water. The absorbances of the colored complex solutions were measured after 5min at 510nm against reagent blank prepared similarly. The Test solution was treated in the same manner as standard and measured the absorbance at 510nm.
For Method C Volumes of standard and test solution ranging from (0.5-2.5ml; 1ml=100µg) were transferred into a series of 10ml graduated volumetric flasks and made up to volume with diluent. The resulting solutions were measured the absorbance at 210nm using the diluent as blank.
The amount of Levetiracetam (LEVT) present in the sample solutions(X) using the proposed methods was calculated by formula given below and the results are given in Table-2
AT Ds Aw P
X = ---- X ------X ---- X ----- X 100
As DT L 100
AT = Absorbance of sample solution
As = Absorbance of standard solution
Ds= Dilution factor for Standard
DT = Dilution factor for Test Solution
Aw = Average weight of sample in mg
L = Label Claim
P =Potency of Standard on as is basis
RESULTS AND DISCUSSION:
The UV-Visible spectrum of standard solutions of Levetiracetam (LEVT) for Method A, Method B and Method C was illustrated in Figure 1, Figure 2 and Figure 3. The optical characteristics such as Beer’s law limits(µg/ml), Sandell’s sensitivity (µg/cm2/0.001 A.U), Correlation coefficient (r), % Relative standard deviation (Calculated from six determinations), % Range of error (0.05 confidence limits and 0.01 confidence limits), Regression equation (I+ ac) for the proposed methods are calculated and summarized in Table-1.
|
Method Parameters |
Method A |
Method B |
Method C |
|
λmax |
630nm |
510nm |
210nm |
|
Beer’s law limits(µg/ml) |
5-30 |
2.5-25 |
5-20 |
|
Sand ell’s Sensitivity(µg/cm2/0.001 A.U) |
0.032 |
0.030 |
0.027 |
|
Regression equation(I + ac) Slope (a) Intercept (I) |
0.0313 0.0017 |
0.0337 0.0002 |
0.0368 0.0083 |
|
Correlation coefficient(r) |
0.999 |
0.999 |
0.999 |
|
%RSD |
0.462 |
0.447 |
0.569 |
|
% Range of error Confidence limits with 0.05 level Confidence limits with 0.01 level |
0.386 0.572 |
0.374 0.553 |
0.476 0.704 |
* Mean of six determinations
TABLE-2 EVALUATION OF LEVETIRACETAM IN PHARMACEUTICAL PREPARATIONS
|
Label Claim Mg/tablet |
Amount Obtained(mg)* |
%Recovery ** |
|||||
|
Proposed method |
Reference Method (HPLC) |
||||||
|
Method A |
Method B |
Method C |
Method A |
Method B |
Method C |
||
|
500 |
497.5 ± 2.288 |
502.283 ± 2.220 |
500.983 ± 2.853 |
499.3 ± 1.571 |
99.3 ± 0.239 |
99.9 ± 0.519 |
99.8 ± 0.364 |
*Mean ±SD of six determinations. ** Mean ±SD of six determinations(100mg of Levetiracetam was added and recovered)
Figure 1. Visible Spectrum of Levetriacetam - Method A (MBTH-CAS)
Figure 2. Visible Spectrum of Levetriacetam - Method B (FeCl3-1,10 PTL)
Figure 3. UV Spectrum of Levetriacetam in Methanol
Figure 4. Calibration Curve of Levetriacetam - Method A (MBTH-CAS)
Figure 5. Calibration Curve of Levetriacetam - Method B (FeCl3-1, 10 PTL)
The results obtained with the proposed methods for dosage forms is Compared with the results obtained with HPLC method and presented in Table-2.The Proposed method is Validated and found to be Specific, Accurate, Precise and Linear.
The Calibration Curve Figure 4, Figure 5 and Figure 6 for the Proposed methods was illustrated in the Concentration range 5 to 30 µg mL-1 of Levetiracetam(LEVT) for Method A , 2.5 to 25 µg mL-1 for Method B and 5 to 20 µg mL-1 for Method C. Interference studies revealed that the common excipients used in the dosage forms do not interfere in the estimation of Levetiracetam(LEVT)using the proposed methods. To Check the recovery using the proposed method known amount of pure drug was added to the Placebo used in the pharmaceutical preparation of Levetiracetam and the mixtures were analyzed by the proposed method and the %Recoveries are given in the table-2. In conclusion the proposed methods are simple, sensitive and accurate and can be used for the routine determination of Levetiracetam (LEVT) in pharmaceutical preparations.
Figure 6. Calibration Curve of Levetriacetam in Methanol
ACKNOWLEDGEMENTS:
The authors wish to thank the Orchid Healthcare for providing the samples of Levetiracetam.
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Received on 31.03.2010 Modified on 13.04.2010
Accepted on 20.04.2010 © AJRC All right reserved
Asian J. Research Chem. 3(3): July- Sept. 2010; Page 724-727