OXAPROZIN Bioanalytical method development and Validation using HPLC

Transcription

1 OXAPROZIN Bioanalytical method development and Validation using HPLC 4.1 DRUG PROFILE Oxaprozin Oxaprozin is a non-narcotic and non-steroidal anti-inflammatory drug (NSAID) used to relieve the inflammation, swelling, stiffness and joint pain associated with osteoarthritis and rheumatoid arthritis. 1, 2 Chemistry: Molecular formula : C 18 H 15 NO 3 with molecular weight Chemical name : 3-(diphenyl-1, 3-oxazol-2-yl) propioanoic acid The drug is official in USP with the monograph CAS in USP30 Description: Oxaprozin occurs as a white to yellowish crystalline powder Solubility: It is sparingly soluble in methanol and ethanol (95%), slightly soluble in diethyl ether and practically insoluble in water. Storage: Should be stored below 30 C and protected from light. 101

2 Mechanism of action Oxaprozin is a non-selective NSAIDS with a cell assay system showing lower COX-2 selectivity implying higher COX-1 selectivity. Oxaprozin acts as antiinflammatory agent as it inhibits cyclo oxygenase in platelets which tends blockage of prostaglandin synthesis. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilatation and subsequent heat dissipation. Indications It is indicated for the treatment and control of inflammation, swelling, stiffness and joint pain associated with rheumatoid arthritis and osteoarthritis. Adverse effects Rash, ringing in the ears, headache, dizziness, drowsiness, abdominal pain, nausea, diarrhoea, constipation, heartburn and shortness of breath. 3 Dosage and Administration The recommended dosage is 600 mg tablet once daily with food. Contraindications 4 It is contraindicated in patients who are hypersensitive to the product. Oxaprozin should not be given to patients who have experienced asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. It is not given to patients who are experiencing asthma, urticaria or allergic type reactions after taking aspirin or other NSAIDS. 102

3 4.2. LITERATURE REVIEW: OXAPROZIN YU Li-Li et al (2011) 5 reported a new and effective method for the quantitative analysis of Oxaprozin in human urine samples by the incorporation of excitation-emission matrix fluorescence (EEM) and second-order calibration methodologies based on self-weighted alternating trilinear decomposition (SWATLD) and alternating normalization-weighted error (ANWE) algorithms, respectively. Małgorzata S et al (2010) 6 reported a new, simple and rapid Thin-layer chromatographic method was developed and validated for analysis of Oxaprozin and its degradation products. Chromatography was performed on silica gel plates with n -hexane-chloroform-glacial acetic acid 4:1:1 (v/v) as mobile phase. Densitometric analysis of Oxaprozin was performed in absorbance mode at 286 nm. The method was validated for linearity, accuracy and precision. Marland A et al (2009) 7 reported an HPLC-UV method for the extraction of Oxaprozin from equine urine and serum. Confirmation of Oxaprozin in post administration extracts was accomplished by gas chromatographic- mass spectrometric analysis of methylated extracts or liquid chromatography with tandem mass spectrometry. The peak average urinary concentrations of Oxaprozin were 25.1 and 17.0 µg/ml at collection times of 8-10 and hrs. Ganesh M et al (2008) 8 reported a simple and sensitive extractive spectrophotometric method for the assay of Oxaprozin (OXA) either in pure form or in pharmaceutical solid dosage form. The method involves formation of colored chloroform extractable ion-pair complex of OXA with bromocresol green in 103

4 aqueous acidic medium. The extracted complexes showed absorbance maxima at 421 nm. The beer s law is obeyed in the concentration range of µg/ml. Ganesh M et al (2008) 9 reported a rapid, simple and validated reversedphase High-performance liquid chromatographic method for analysis of Oxaprozin in pharmaceutical dosage forms. Separation was carried on an ODS analytical column with a 45:55 (v/v) mixture of acetonitrile and triethanolamine solution (5 mm, ph 3.5 ± 0.05, adjusted by addition of 85% phosphoric acid) as mobile phase at a flow rate of 2.0 ml/min. SunShaofa et al (2007) 10 reported two spectroscopic methods which include fluorescence and UV-Vis absorption spectroscopy to study the interaction between a kind of NO-releasing Oxaprozin (Oxaprozin-P) and bovine serum albumin (BSA). The quenching mechanism of fluorescence of BSA by Oxaprozin-P was found to be a dynamic quenching. Reddy KV et al (2000) 11 reported a reversed phase linear gradient liquid chromatographic method for the quantitative determination of the seven known process related impurities and one degraded product of Oxaprozin in the bulk drug material. An Inertsil-ODS 3V (150 x 4.6 mm), 5 micron column was Operated with a phosphate buffer and acetonitrile. Detection was carried out on a UV detector at 254 nm. In addition to its ruggedness and robustness, this method offers identification of all eight impurities in a single run. 104

5 Yang G et al (1994) 12 reported three methods for the quantitative determination of Oxaprozin. Potentiometry method is simple, rapid and accurate. The coefficient of variation was 0.1%. UV Spectrophotometry was applied for determination of Oxaprozin, its precision was less than potentiometry method's. But the relative deviation was below 1%. In HPLC method, a chemical bonded phase column (WGC-C (18), 10µm, 15cm 4.6mm) was used. The mobile phase was methanol water solution (75:25) and its flow rate was 1.0ml/min. The wavelength of the detection was 254 nm. 105

6 4.3 EXPERIMENTAL: METHOD DEVELOPMENT MATERIALS AND METHODS Materials Oxaprozin and Nevirapine were obtained from CIPLA Pharmaceuticals, Mumbai. HPLC grade Acetonitrile, Ethyl tertiary butyl methyl ether and Methanol were purchased from SD fine chemicals, Mumbai, India. Analytical grade Potassium dihydrogen phosphate was purchased from SD fine chemicals, Mumbai, India. Pooled drug free expired human plasma was donated by Red Cross Society, Warangal. Instrumentation The HPLC system consisted of Alliance Waters 2695 with dual λ Absorbance UV detector. Separation was carried out on Inertsil C 18 column (4.6x250mmx5µm). A vortex-mixer (Remi), ultrasonic bath (Bransonic), a model C- 30 centrifuge (Remi) and a model cool safe 110-4/scan speed 32 were used for sample preparation. Preparation of Stock solutions Stock solutions of Oxaprozin (500 µg/ml) and Nevirapine (1000 µg/ml) internal standard were prepared in Methanol. Further dilutions were carried out in Methanol. Preparation of calibration standards Calibration standards were prepared freshly by spiking drug free plasma with Oxaprozin stock solution to give the concentrations of 0.78, 1.56, 3.12, 6.25, 12.5, 25.0, 50.0 and 100.0µg/ml they were stored at c till the time of analysis. 106

7 Preparation of quality control standards Quality control standards were prepared at three levels namely LQC, MQC and HQC. These standards were prepared freshly by spiking drug free plasma with Oxaprozin stock solution to give the concentrations of 2.0, 40.0 and 80.0µg/ml respectively. They were stored at c till the time of analysis. Detailed procedure for the preparation is shown in Table 26. Sample preparation method Drug free human plasma (250 µl) was spiked with appropriate volume of drug stock. To the above prepared sample, 25µl of Nevirapine (100µg/ml) was added as an IS. The sample was vortex mixed for 4 minutes to assure complete mixing. Analytes were extracted by adding with 2.5ml of tertiary butyl methyl ether followed by vortex mixing for 4 minutes and centrifugation at 2000 rpm/min in a cooling centrifuge for 15min at 4 0 C. The organic phase containing analytes were separated and analytes were obtained as dried residues after drying in lyophilizer. The analytes residue obtained was reconstituted with 300µl of mobile phase and analysed using HPLC system according to parameters optimized. Detailed procedure for preparation is shown in Table 22, calibration data is shown in Table 23, calculated concentrations of calibrated standards and mean concentrations of calibration standards data were showed in Table 24 and 25. Chromatographic conditions The HPLC system consisted of Alliance Waters 2695 with dual λ Absorbance UV detector. The detection wavelength for analysing drug was set at 240 nm. Separation was carried out on Inertsil C 18 column (4.6 x 250mm x 5µm) using 40:60 v/v Phosphate buffer (ph-3.0) and Acetonitrile as mobile phase at a 107

8 flow rate of 1.0 ml/min. The mobile phase was filtered through nylon Millipore (0.22 µm) membrane filters and degassed with ultra sonicator for 15 minutes prior to use. Chromatograms were obtained and integrated using Empower software which was provided along with the HPLC system. 4.4 EXPERIMENTAL: METHOD VALIDATION VALIDATION PARAMETERS Specificity A solution containing 0.78µg/ml Oxaprozin was injected onto the column under optimized chromatographic conditions to show the separation of Oxaprozin from the impurities from the plasma. The specificity of the method was checked for the interference from plasma. Linearity and Range Six samples of each calibration standard were analysed. The spiked concentration and their respective peak area ratios with respective to internal standards were subjected to least squares regression. After examining the percent deviation, a proper model was chosen. The slope, Y-intercept, and coefficient of determination (r 2 ) were obtained from linear regression equation. Limit of Detection (LOD) and Limit of Quantitation (LOQ) The limit of quantitation refers to the lowest amount of an analyte in a sample that can be quantitatively determined with suitable precision and accuracy. There are different approaches to determine the LOD and LOQ. Typically the concentration level that generates a signal-to-noise (S/N) of 3.3 is regarded as the LOD and the concentration level that generates S/N = 3 is regarded as the LOQ. 108

9 Here LOD is calculated using the formula 3.3 times σ/s, similarly LOQ was calculated using the formula 10 times σ/s where σ is the standard deviation of the intercept obtained for calibration curve and s is the slope of the calibration curve. Accuracy and precision Intraday precision and accuracy was determined by analyzing quality control standards (2.0, 40.0 and 80.0µg/ml) and LLOQC standards (0.78µg/ml) five times a day randomly, interday precision and accuracy were determined from the analysis of each quality control standards (2.0, 40.0 and 80.0µg/ml) and LLOQC standards (0.78µg/ml) once on each of five different days. Ruggedness The ruggedness of the method was determined by analyzing spiked control samples (n=6) of medium concentration, i.e. 40.0µg/ml using two different columns. Recovery studies The percent mean recoveries were determined by measuring the responses of the extracted plasma Quality control samples at HQC, MQC and LQC against unextracted Quality control samples at HQC, MQC and LQC. For calculation of recovery of the compound, spiked control samples were prepared at low, medium and high concentrations i.e. 2.0, 40.0 and 80.0µg/ml concentrations. The samples were processed as mentioned above and the concentration of the compound was determined from the regression of the analytical standard calibration curve. Recovery was calculated by comparing the observed concentrations in spiked samples to that of respective unextracted samples. 109

10 Stability studies The stability of Oxaprozin was determined by measuring concentration change in control samples overtime under set conditions. Freeze-thaw stability study of Oxaprozin was carried out by subjecting samples to three freeze and thaw cycles. Samples before study and after study were analysed by developed method. Similarly Stock solution stability study of Oxaprozin (Stability at 0 hrs), Stock solution stability study (Stability after 8 hrs), Bench top stability study of Oxaprozin (Stability after 10 hrs) and Inter injection stability study of Oxaprozin were carried out by subjecting samples to study conditions DATA ANALYSIS 13 Data analysis was done using MS-Excel package for calculating mean, standard deviation and % relative standard deviation. 110

11 4.5. RESULTS AND DISCUSSION Under the chromatographic conditions employed, the sample showed sharp peaks for drug and internal standard with good resolution. The retention time for the drug was found to be 7.7±0.05 minutes and the retention time for internal standard was 3.4±0.03 minutes (Figure 17). The method developed was validated for specificity, accuracy, precision, linearity, range and stability as per USFDA guidelines. The results of validation parameters are given below. Specificity of the method was proven by the absence of peaks near the retention time of the drug as well as the internal standard (Figure 18). The calibration function was developed for Peak area ratio Vs Concentration (in µg/ml) and it was linear over concentration range of 0.78 to 100.0µg/ml. The regression line equation for the analysis was y= 0.061x with a coefficient of correlation (r 2 ) = The chromatograms of calibration standard and calibration curve were shown in Figures 19 to 27. The calculated LOD and LOQ results were shown in Table 23. A system suitability test was carried out and the following parameters were observed for repeated injections (n=6) of both Oxaprozin and Nevirapine (IS) (Table 29). The intraday and interday precision and accuracy of the method was found to be 0.90 to 3.10% and to % respectively for the quality control samples. This is within the acceptance limits of precision is 15% and accuracy is 85 to 115% (Tables 30 to 31). The limit of Quantitation was found to be 0.78µg/ml at 111

12 such concentration the inter day precision was 0.82 and the accuracy was %, which are within the acceptance limits of precision is 20% and accuracy is 80 to 120% (Table-32). The result for ruggedness on different columns was shown in Table 33. The percent mean recovery of Oxaprozin for LQC, MQC and HQC was 63.06%, 66.92% and 62.52% respectively (Tables 34 to 36). Stability was assessed by comparing against the freshly thawed quality control samples. The percent mean stability for HQC and LQC were % and % respectively, which is within the acceptance limits of 85 to 115%. Plasma Quality control samples of Oxaprozin were found to be stable for at least one month (Table 37). Results for Stock solution stability study (Stability after 0 hrs), Stock solution stability study (Stability after 8 hrs), Bench top stability (Stability after 10 hrs) and Inter injection stability study were shown in Tables 38 to

13 Table 22: Preparation of Oxaprozin calibration standards in Plasma Oxaprozin Concentration Drug stock (µg/ml) solution (µl)* Blank plasma (µl) OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS Δ 900 OXP CS Δ 800 * indicates drug stock solution from 25 µg/ml Δ indicates drug stock solution from 500 µg/ml Concentration (µg/ml) Table 23: Calibration data of Oxaprozin Peak Area Ratio of Peak Oxaprozin Internal Standard Area

14 Table 24: Calculated concentrations of Oxaprozin calibration standards Oxaprozin Concentration (µg/ml) Calculated concentrations OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS Table 25: Mean Concentrations of Oxaprozin calibration standards Sample ID Concentration (µg/ml) Mean calculated concentration SD % RSD OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS OXP CS EPR CS

15 Table 26: Preparation of Oxaprozin quality control standards in Plasma Oxaprozin Concentration Drug stock solution Blank plasma (µg/ml) (µl) (µl) OXP LQC * 920 OXP MQC Δ 920 OXP HQC Δ 840 * indicates drug stock solution from 25 µg/ml Δ indicates drug stock solution from 500 µg/ml Table 27: Calibration curve parameters for Oxaprozin Mean SD Slope Intercept r Table 28: Limit of detection (LOD) and Limit of quantitation (LOQ) for Oxaprozin in human plasma using HPLC system LOD LOQ µg/ml µg/ml 115

16 Table 29: HPLC System suitability parameter (Precision) for Oxaprozin and Nevirapine (IS) Name Replicates RT Peak area Oxaprozin (n=6) Internal Standard (n=6) Mean SD % RSD Mean SD % RSD

17 Table 30: Intra-day accuracy and precision for Oxaprozin Oxaprozin QC ID LQC MQC HQC Actual conc.(µg/ml) Intraday Mean ± SD % RSD % Accuracy Table 31: Inter-day accuracy and precision for Oxaprozin Oxaprozin QC ID LQC MQC HQC Actual conc.(µg/ml) Interday Mean ± SD % RSD % Accuracy

18 Table 32: Precision & Accuracy of LLOQC Standard QC ID LLOQC Actual conc.(µg/ml) Mean ±SD %RSD % Accuracy Table 33: Ruggedness of the method developed for Oxaprozin (on different columns) MQC Peak area ratio 40.0 µg/ml Column 1 Column Mean ± SD % RSD %Accuracy

19 Table 34: Recovery study for Oxaprozin from human plasma - LQC LQC Replicates Unextracted Extracted %Recovery (area ratio) (area ratio) Mean ±SD %RSD Table 35: Recovery study for Oxaprozin from human plasma - MQC MQC Replicates Unextracted Extracted %Recovery (area ratio) (area ratio) Mean ±SD %RSD

20 Table 36: Recovery study for Oxaprozin from human plasma - HQC HQC Replicates Un-extracted Extracted %Recovery (area ratio) (area ratio) Mean ±SD %RSD Table 37: Freeze-thaw Stability of Quality Control Standards Stability after 3 freeze thaw cycles Oxaprozin LQC HQC Actual conc.(µg/ml) Mean ± SD % RSD % Accuracy

21 Table 38: Stock solution stability study of Oxaprozin (Stability at 0 hrs) Replicates SSS (0hrs) LQC SSS(0hrs) HQC Mean ± SD % RSD Table 39: Stock solution stability study of Oxaprozin (Stability after 8 hrs) Replicates SSS(8hrs) LQC SSS(8hrs) HQC Mean ± SD % RSD % Accuracy

22 Table 40: Bench top stability study of Oxaprozin (Stability after 10 Hours) Time (h) 10.00(h) BTS QC ID LQC HQC Actual conc.(µg/ml) Mean ± SD % RSD % Accuracy Table 41: Inter injection stability study of Oxaprozin Oxaprozin LQC HQC Actual conc.(µg/ml) Mean ± SD % RSD % Accuracy

23 CHROMATOGRAMS OF DEVELOPED METHOD Figure 17: Chromatogram showing Retention times of Aqueous Mixture consists of Oxaprozin (5µg/ml) and Nevirapine (5µg/ml) Figure 18: Chromatogram of Blank plasma sample showing no interference at the RT of Oxaprozin and Nevirapine. 123

24 Figure 19: Chromatogram of Oxaprozin calibration standard-1(oxp CS1 ) Figure 20: Chromatogram of Oxaprozin calibration standard-2(oxp CS2 ) 124

25 Figure 21: Chromatogram of Oxaprozin calibration standard-3(oxp CS3 ) Figure 22: Chromatogram of Oxaprozin calibration standard-4(oxp CS4 ) 125

26 Figure 23: Chromatogram of Oxaprozin calibration standard-5(oxp CS5 ) Figure 24: Chromatogram of Oxaprozin calibration standard-6(oxp CS6 ) 126

27 Figure 25: Chromatogram of Oxaprozin calibration standard-7(oxp CS7 ) Figure 26: Chromatogram of Oxaprozin calibration standard-8(oxp CS8 ) 127

28 Figure 27: Calibration curve of spiked concentrations (OXP CS1-CS8 ) Figure 28: Chromatogram of Oxaprozin Low Quality Control (OXP LQC ) 128

29 Figure 29: Chromatogram of Oxaprozin Middle Quality Control (OXP MQC ) Figure 30: Chromatogram of Oxaprozin High Quality Control (OXP HQC ) 129

30 4.6. SUMMARY A Simple, rapid, selective and sensitive HPLC method was developed and validated for the determination of Oxaprozin from human plasma. The drug was extracted with ethyl tertiary butyl methyl ether. Oxaprozin was measured in plasma using a validated a HPLC method with UV detector at 240nm chromatographic peaks were separated on 5µm Inertsil, C 18 column (4.6x250mmx5µm) using 40:60 v/v Phosphate buffer ph-3.0 and Acetonitrile as mobile phase at a flow rate of 1.0 ml/min. The chromatograms showed good resolution and no interference from plasma. The retention time of Oxaprozin and Nevirapine (IS) were approximately 7.7±0.05 min and 3.4±0.03 min respectively. The mean recovery from human plasma was found to be above 50%. The method was linear over the concentration range of 0.78 to 100µg/ml with coefficient of correlation (r 2 ) Both intraday and interday accuracy and precision data showed good reproducibility CONCLUSION Various methods reported in literature were studied. In the present study a simple, rapid, specific, rugged, accurate, precise and stable method was developed for estimation of Oxaprozin in human plasma. The calibration curve developed is y= 0.061x µg/ml with r 2 = The percent mean recovery for Oxaprozin in LQC, MQC and HQC was 63.06%, % and 62.52% respectively. The method is accurate, precise and rugged with % RSD < 15% and 20% when tested at MQC, HQC and LQC levels respectively. The stability was assessed at different levels. The results of the Freeze-thaw stability, Bench top stability, Inter injection stability studies showed that the compound under analysis was stable under test conditions. 130

31 Hence the method developed can be used for estimation of Oxaprozin present in human plasma. 131

32 4.8. BIBLIOGRAPHY 1. Maryadele JO.Merck Index., 2006; 14: /august/2011, /august/2011, /august/2011, 5. YU Li, Hai-Long WU, Hai-Yan FU, Yong-Jie YU, Ya-Juan LIU, Xiang-Dong, QING, Ru-Qin YU.Rapid determination of oxaprozin contents in urine and combined pharmacotherapy samples using three-dimensional fluorescence coupled with second-order calibration methods. Chinese. J. Pharm. Anal 2011; 5: Małgorzata S, Jan K, Monika T.TLC-densitometric method for quantitation of oxaprozin and its degradation products in pharmaceutical preparations. J. Planar. Chrom 2010; 4: Marland A, Sarkar P, Leavitt R, Lee-Ruff E, Ramnauth J.The elimination profiles of oxaprozin in equine urine and serum after a 4.8g dose. J. Anal. Toxicol 2009; 4: Ganesh M, Rahul B, Siva T.Simple extractive colorimetric determination of oxaprozin by acid-dye complexation methods in solid dosage form. E. J. Chem 2008:5: Ganesh M. Rahul B, Siva T. Validated HPLC method for analysis of oxaprozin in a formulation. Acta. Chrom 2008; 2: Sun S, Xiang G.Molecular spectroscopic studies on the interaction between oxaprozin-p and bovine serum albumin. chemistrymag.org., 2007; 9:

33 11. Reddy KV, Rao DS, Vyas K, Reddy GO.LC method for the quantitative determination of oxaprozin and its impurities in the bulk drug. J. Pharm. Biomed. Anal.2000; 4: Yang G, Xiang Yi, Zhen H, Studies on the quantitative determination of oxaprozin by HPLC, UV Spectrophotometry and Potentiometry. Chinese J. Pharm. Anal 1994; 3: Bolton S.Pharmaceutical Statistics: practical and clinical application. Marcel Dekker 1994; 3: