INTRODUCTION:

Dexibuprofen, [S (+) - Ibuprofen] is considered as the pharmacologically active enantiomers of racemic Ibuprofen¹. It is chemically-2-[4-(2-methyl propyl) phenyl] propanoic acid². It is a widely used non steroidal anti-inflammatory drug. It is used as symptomatic treatment for osteoarthritis, primary dysmenorrhoea, muscular skeletal pain and dental pain. It reduces gastric damage and improves analgesic and anti-inflammatory effect than racemic ibuprofen³. Dexibuprofen is not official in any pharmacopoeia, but one HPTLC method⁴ and UV spectrophotometric methods in tablets⁵ and few HPLC methods in gel formulation⁶, in urine⁷ and in tablets⁸. Our present study aimed to develop a simple accurate and reproducible RP-HPLC method for the estimation of Dexibuprofen in tablet formulation.

EXPERIMENTAL:

Chemicals and Reagents:

HPLC grade acetonitrile were used for the analysis. Water obtained from Milli-Q RO water system. Pharmacological grade Dexibuprofen was purchased from A to Z chemical Laboratory, Chennai. Commercial formulation, Xflam tablets containing 300mg of Dexibuprofen were obtained form local market.

Instrumentation:

Chromatographic separation was performed on SHIMADZU-LC 2010HT system equipped with quaternary pump; Variable wavelength programmable UV/Visible detector SPD-20A and Rheodyne (772 5i) with 20µL fixed loop are used and data analysis is done by LC solution software. Weighing was done on Shimadzu AY-120 balance.

Chromatographic condition:

Chromatographic separation was achieved on WATERS symmetry C₁₈(250 x 4.6mm., 5µm.,) column. The mobile phase consisting of acetonitrile and water (55:45% v/v) adjusted to pH 2.5 with orthophosporic acid. The mobile phase was filtered through a 0.45µm membrane filter and sonicated for 15 minutes. The mobile phase was delivered at flow rate of 1.5mL/min. Detection was performed at 214nm.

Preparation of standard solution:

Accurately weighed quantity of Dexibuprofen (50mg) was transferred to 50mL volumetric flask and dissolved in 25mL of acetonitrile and diluted to the mark with the same solvent. The further dilution was made to get 100µg/mL concentration. The drug solution was filtered through a 0.45µm membrane filter before injection.

Sample preparation and assay:

About 20 tablets were weighed and the powdered sample equivalent to 50mg was taken and transferred to 50mL volumetric flask. The contents of the flask were dispersed in 25mL of acetonitrile and shaken well to dissolved, and sonicated for 30 minutes. Finally the dilution was made to 50mL with acetonitrile and further dilution was made to get 100µg/mL concentration. The drug solution was filtered through a 0.45µm membrane filter before injection. All determinations were conducted in triplicate. Both the standard and sample preparation was injected separately, and the peak area response were recorded. The percentage label claim was calculated and given in table-1.

Table-1:Determination of Dexibuprofen in tablet dosage form

PARAMETERS	VALUE
Label claim in mg/capsule	300mg
% Drug content ± SD	99.68±0.76
%RSD	0.82

RESULTS AND DISCUSSION:

The estimation of Dexibuprofen in tablet dosage form was carried out by RP-HPLC. The results of system suitability parameters such as tailing factor, asymmetry and number of theoretical plates are indicated satisfactory results and given in table-2. The retention time for Dexibuprofen was found to be 7.65minutes. The linearity was studied in the concentration range form 40-160µg/mL. the regression co-efficient value was found to be 0.9991. The mean recovery for Dexibuprofen was 99.0 to 102.0 % which is largely within the 90-110% range that is considered acceptable and it reveals that the method is accurate⁶. The validation of the proposed method was verified by system precision and method precision. The system precision was evaluated by measuring by the peak area responses for five replicate injections of the standard solutions. The method precision was determined by quantifying the sample solution as per the proposed method. The %RSD was found to be less than 2 indicate the proposed method is precise. The specificity of the method was confirmed by injecting the placebo and observed that there was no interference due to placebo. Robustness of the method is determined by analyzing the sample in duplicate with varying the method conditions, i.e, very small changes in flow rate, showed there were no marked changes in chromatographic behavior and content of the drug, as evident from the low value of RSD indicating the method is robust. The method was also confirmed by ruggedness study, analyzing the product day to day, analyst to analyst and instrument to instrument.

Table -2 System suitability parameters

PARAMETERS	VALUE
Theoretical plates	5237
Tailing factor	1.02
Asymmetry	1.06
%RSD of peak retention time	0.146

Table-3 Summary of Validation parameter

PARAMETERS	OBTAINED VALUE
Linearity Range	70-120µg/mL
Correlation Co-efficient	0.9991
Limit of Detection	2 µg/mL
Limit of Quantitation	10 µg/mL
%Recovery (n=6)	99.0-100.2%
System Precision (%RSD)	0.69%
Method Precision (%RSD)	0.58%
Robustness (%RSD)	0.71%
Ruggedness (%RSD)	0.73%

The data for ruggedness also found to be within the acceptance limit. Different validation parameters for the proposed HPLC method were summarized in table-3. The result obtained was in agreement with the labeled value of Dexibuprofen in tablet dosage form. The determined validation parameters are in the acceptable range.

CONCLUSION:

The developed RP-HPLC method with UV-Visible detection for the estimation of Dexibuprofen offers simplicity, selectivity, precision and accuracy. So this method can be applicable for the estimation of Dexibuprofen in quality control studies for the routine analysis.

REFERENCE:

1. Sweetman and Sean, Martindale, The complete drug reference, 37^th Edition, April 2011.

2. The Merck Index, 12^th edn, Merck Research Lab., Division of Merck and co., Inc., Whitehouse station, N.J., 1996.

3. Bonabello A. et al, Dexibuprofen (S(+)-Isomer Ibuprofen) Reduces damage and improves analgesic and anti-inflamatory effects in rodents, Anesth Analg. 97(3); 2003: 402-408.

4. Selvadurai Muralidharan et al, Validated HPTLC method of analysis of Dexibuprofen in its formulation, Jr of Planar Chromatography – Modern TLC. Vol 22, No.3; June 2009: 207-210.

5. S.Gayatri, K.Mythili, K.Chitra, and C.Umamaheswara reddy, UV Spectrophotometric estimation of Dexibuprofen in bulk drug and its pharmaceutical formulation, Research Jr. of pharmaceutical biological and chemical science. April-June vol 2, issue 2; 2011: pp 885.

6. WANG Wen-qing et al, Herald of medicine. content determination of dexibuprofen in the GEL preparation by HPLC. 27(7); 2008: 835-837.

7. De Olivaria AR, Cesarino EJ, and Bonatod.S, Jr. of Chromatography and bioanalytical techniques, biomed life science. april 2005: pp-285-291.

8. Selvadurai Muralidharan, Subramania nainar Meyyanathan, Development and validation of a HPLC and an UV spectrophotometric methods for determination of Dexibuprofen in pharmaceutical preparations. Int.Scholarly Research Network, ISRN Pharmaceutics. Article ID 948314: 2011.

Received on 15.09.2011 Accepted on 26.10.2011

Asian J. Pharm. Ana. 1(4): Oct. - Dec. 2011; Page 98-99