Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation

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1 3794 Int J Pharm Sci Nanotech Vol 10; Issue 4 July August 2017 International Journal of Pharmaceutical Sciences and Nanotechnology Research Paper Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation Jinal N. Tandel 1 *, Jimi N. Patel 1 and Samir K. Shah 2 1 Department of Quality Assurance, Sardar Patel College of Pharmacy, Vidyanagar-Vadtal Road, Bakrol, (388315) Gujarat, India; and 2 Department of Pharmacology, Sardar Patel College of Pharmacy, Vidyanagar- Vadtal Road, Bakrol,(388315) Gujarat, India. Received May 11, 2017; accepted June 11, 2017 Volume 10 Issue 4 July August 2017 MS ID: IJPSN TANDEL ABSTRACT A simple, accurate and precise stability-indicating RP- HPLC method was developed for estimation of clofarabine in parenteral formulation. Some known impurities like, alpha-anomer, 2-chloroadenine and monobenzoate are used which are related substances of clofarabine, for the analysis of the marketed formulation. Inertsil C 18 (150 mm 4.6 mm) 5μ (particle size) was used as stationary phase and Buffer: Acetonitrile 90:10 v/v was used as mobile phase with flow rate 1 ml/min at 263 nm UV detection. The retention time of clofarabine was found to be 3.07 minutes. Linearity was observed over the concentration range of 5-25 μg/ml for clofarabine in which correlation coefficient value was found to be Force degradation study was perform and maximum degradation of Standard and Test of Clofarabine was found to be 18.8% and 17.5% respectively in Acidic condition. The LOD and LOQ was found to be μg/ml and 0.21 μg/ml, respectively for clofarabine. Moreover, the % RSD for repeatability, inter and intra day precision was found to be within the range, which reveals that the method is precise. Accuracy study of the drug in marketed preparation also reported within the limits. In conclusion, the assay is useful for estimation of clofarabine in parenteral formulations. KEYWORDS: Clofarabine; alpha-anomer; 2-chloroadenine; monobenzoate; RP-HPLC. Introduction Cloferabine is chemically (2R,3R,4S,5R)-5-(6-amino-2- chloropurin-9-yl)-4 fluro-2-(hydroxymethyl)oxolan-3-ol. (Fig. 1). It is an antineoplastic agent (Merck et al., 1996). Clofarabine is a purine analogue and antineoplastic agent used in therapy acute lymphoblastic Leukemia (ALL) in child. It works by blocking cancer cell growth, which results in death of the cancer cell. (Tripathi 2008) Clofarabine inhibits DNA synthesis by decreasing cellular deoxynucleotide triphosphate pools through an inhibitory action on ribonucleotide reductase, and by terminating DNA chain elongation and inhibiting repair through incorporation into the DNA chain by competitive inhibition of DNA polymerases (Goodman et al., 2003) (Fig. 2) (Buddhini et al., 2013). Fig. 1. Chemical structure of clofarabine. Fig. 2. Mechanism of clofarabine. Literature review showed that there is no official method for cloferabine. Several analytical methods have been reported for estimation of clofarabine alone and with combination of other drugs which include HPLC (Takahiro et al., 2011, Wang et al., 2009, Hseieh et al., 2007), HPTLC (Venkata et al., 2013), LC-MS/MS (Liusheng et al.,2014, Tu X et al., 2014). In the present work, a successful attempt has been made to estimate the drug simultaneously using RP- HPLC method with different mobile phase composition than the published one. Also developed the stress degradation study of the drug. Some known related substances like alpha anomer, 2-chloradenine and monobenzoate are added. So, aim of present work was to develop stability indicating RP- 3794

2 Tandel et al: Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation 3795 HPLC method for the estimation of clofarabine in parenteral formulation with related substances. This study attempts to develop a simple, accurate and precise analytical chromatographic method, which can quantify drug simultaneously from a parenteral dosage form. Also perform the stability indicating HPLC method for the simultaneous estimation. (ICH et al., 1996) The developed method was validated as per ICH guidelines and found to comply with the acceptance criteria (ICH et al., 1995). Materials and Methods Method Development Materials and reagents: Methanol, Acetonitrile, glacial acetic acid and Distilled water, all reagents of HPLC grade and Hydrochloric acid, Sodium hydroxide of AR grade were procured from Merck (India). Reference standards of cloferabine was obtained as a gift sample from Intas pharma, Ahmadabad(India). Marketed dosage form Clolar injection (20mg/20ml) was procured from local market. Apparatus and chromatographic conditions: Chromatographic separation was performed on a model of Agilent 1100/1200 series containing uv detector and LC solution software. A Inertsil C 18 (150 mm 4.6 mm) 5 was used for the separation, mobile phase of a mixture of Buffer: Acetonitrile (850:150)V/V was delivered at a flow rate of 1.0 ml/min with detection at 263 nm. The mobile phase was filtered through a 0.45μm membrane filter and degassed. The injection volume was 10 ml; analysis was performed at ambient temperature. Preparation of standard solutions: Standard stock solution of Clofarabine (100 μg/ml) was prepared. From the standard stock solution, take 1.5 ml of that solution and dilute to 10 ml with mobile phase. This gave concentration of 15 μg/ml Clofarabine. Preparation of sample solution: Clofarabine (10 ml) were transferred into 100 ml volumetric flask and dissolved in mobile phase to give a stock solution 100 μg/ml of Clofarabine. Stock solution (1.5 ml) was transferred in 10 ml volumetric flask and diluted up to mark with mobile phase to obtain working standard solution 15 μg/ml of Clofarabine and this solution was used to prepare standard solution for linearity. Selection of mobile phase: Buffer: 1 ml Glacial acetic acid 1000 ml water Mobile phase: Prepare a mixture of 90 volume of Buffer and 10 volumes of Acetonitrile. Filter through 0.45 μm filter and degas before use. Calibration curve of clofarabine: Calibration curves were prepared by taking appropriate aliquots 0.5, 1, 1.5, 2, 2.5mL of working standard solution of Clofarabine in 10 ml volumetric flask and dilute up to the mark with mobile phase of to give 5-25μg/ ml of concentration range. The standard solution was run for 10 minutes using mobile phase at a flow rate of 1mL/min. The graph of peak area vs concentration was plotted, regression equation and correlation co- efficient for both drugs were obtained. System suitability test: It is an integral part of chromatographic method. These tests are used to verify that the resolution and reproducibility of the system are adequate for the analysis to be performed. System suitability tests are based on the concept that the equipment, electronics, analytical operations and samples constitute an integral system that can be evaluated as a whole. System suitability testing provides assurance that the method will provide accurate and precise data for its intended use. Degradation Test Solution Preparation of solution for acid degradation: 1.5 ml of sample was taken in volumetric flask, 2 ml of 0.1N HCl was added, the sample was heated at 70 o C for 6 hours. Cool the sample and neutralised with 2 ml of 0.1N NaOH and diluted to req volume with mobile phase. Preparation of solution for basic degradation: 1.5 ml of sample was taken in volumetric flask, 2 ml of 0.1N NaOH was added the sample was heated at 80 o C for 3 hours. The sample was cooled and neutralised with 2 ml of 0.1N HCl and diluted to req volume with mobile phase. Preparation of solution for oxidative degradation: 1.5 ml of sample was taken in volumetric flask, 2 ml of 3% H 2 O 2 was added the sample was heated at 60 o C for 3 hour. Cool the sample and diluted to req volume with mobile phase. Preparation of solution for heat degradation: 1.5 ml of sample was taken in volumetric flask, The sample was heated at 105 o C for 30 min. Cool the sample and diluted to req volume with mobile phase. Preparation of solution for Photolytic degradation: 1.5 ml of sample was taken in volumetric flask, Place the solution in Sunlight for 5 hours. Cool the sample and diluted to req volume with mobile phase. Impurities Stock Solution (a) Alpha anomer: 0.40 mg of Alpha anomer impurity in 20 ml volumetric flask was taken, added about 10 ml methanol and sonicated to dissolve and diluted to volume with mobile phase. (b) 2-Chloradenine: 0.51 mg of 2-Chloradenine impurity in 20 ml volumetric flask was taken, added about 10 ml methanol and sonicated to dissolve and diluted to volume with mobile phase. (c) Monobenzoate: 0.50 mg of Monobenzoate impurity in 20 ml volumetric flask was taken, added about 10 ml methanol and sonicate to dissolved and diluted to volume with mobile phase. Impurities spike stock solution: 3.0 ml of each impurities stock solution in 25 ml with mobile phase. Method Validation As per ICH guidelines Q2R1, the method of validation parameters studied were linearity, range, accuracy, precision, limit of detection and limit of quantification, Robustness. Specificity: Specificity is a procedure to detect quantitatively the analyte in the presence of components that may be expected to be present in the sample matrix. While selectivity is the procedure to detect qualitatively the analyte in presence of components that may be expected to be present in the sample matrix. Specificity

3 3796 Int J Pharm Sci Nanotech Vol 10; Issue 4 July August 2017 of developed method was established by spiking of Clofarabine in hypothetical placebo (i.e. might be present) and expressing that analytes peak were not interfered from excipients. Linearity: Aliquots of standard solutions of Clofarabine in range 5-25 g/ml were prepared from working standard solution and injected to system with stated chromatographic conditions and analyzed. The graph of peak area obtained versus respective concentration was plotted. The mean area with its standard deviation and % relative standard deviation of peak were calculated. Precision: Precision of the methods was determined by performing interday variation, intraday variation and method repeatability studies. In interday variation, the peak area of standard solutions of Clofarabine (5, 15, and 25 g/ml) was measured on three consecutive days. In intraday variation the peak area were measured three times in a day. In repeatability study, six concentrations of drug Clofarabine (15 g/ml) was analysed. Recovery studies: To study the accuracy of the proposed method, recovery studies were carried out by standard addition method at three different levels. Known amount of the two drugs was added to pre analyzed tablet powder and percentage recoveries were calculated. Limits of detection and quantification: According to ICH, limit of detection (LOD) is the lowest concentration of the analyte that can be detected and limit of quantification (LOQ) is the lowest concentration of analyte that can be detected with acceptable accuracy and precision. LOD and LOQ are calculated from the formulae 3.3σ/s and 10σ/s respectively. Where σ is the standard deviation of y-intercepts of the regression line and s is the slope of the calibration curve. Robustness: It should show the reliability of an analysis with respect to deliberate variations in method parameters. In case of liquid chromatography, examples of typical variations are Influence of variations of ph(±0.2) in a mobile phase, Flow rate. (±0.2) Wavelength (±2%) Assay of the Marketed Formulation The developed method was applied to the simultaneous determination of Clofarabine in pharmaceutical formulations. Sample was analyzed by performing six independent determinations and each series was injected in triplicate Results and Discussion Selection of Elution Mode Reverse phase chromatography was chosen because of its recommended use for ionic and moderate to non-polar compounds. Reverse phase chromatography is not only simple, convenient but also better performing in terms of efficiency, stability and reproducibility. Hence C18, mm column of 5μm particle packing was selected for estimation of Clofarabine. Isocratic mode was chosen due to simplicity in application and robustness with respect to longer column stability. Selection of Wavelength Scan the standard solution and test solution on UV/Visible spectrophotometer, over the spectral range 200 to 400 nm. Use diluent as blank. The UV spectrum of the test solution should exhibit maxima at the same wavelength (±2 nm) as that of a standard solution. Clofarabine show reasonably good response at 263 nm. Mobile Phase Optimization Chromatographic parameters were optimized to develop a HPLC method for simultaneous determination of Clofarabine with short analysis time (< 10 min), and acceptable resolution (RS > 2). Various compositions of mobile phases like methanol: water and ACN: buffer in different ratios were tried. But Buffer: ACN (90:10 v/v) at a flow rate of 1mL/min, symmetrical peak was obtained. The optimum wavelength for detection was set at 263 nm at which better response for drug was obtained. The retention times was (Fig. 4). Force Degradation Various stress condition like acidic, basic, oxidative, thermal and photolytic are applied to the standard and test solution of the Clofarabine and observed the degradation in it. The different chromatogram of the different condition are shown in the below figure. (a) Acid Degradation (b) Basic Degradation (c) Oxidative Degradation (d) Thermal Degradation (e) Photolytic Degradation Fig. 3. UV Spectrum of Clofarabine Standard solution showing selection of wavelength detection.

4 Tandel et al: Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation 3797 Fig. 4. Trial in mobile phase Buffer: Acetonitrile (90:10) %v/v. Fig. 5. Standard Chromatogram of Clofarabine (15 μg/ml) for Acid Degradation. Fig. 6. Test Chromatogram of Clofarabine (15 μg/ml) for Acid Degradation. Fig. 7. Standard Chromatogram of Clofarabine (15 μg/ml) for Basic Degradation.

5 3798 Int J Pharm Sci Nanotech Vol 10; Issue 4 July August 2017 Fig. 8. Test Chromatogram of Clofarabine (15 μg/ml) for Basic Degradation. Fig. 9. Standard Chromatogram of Clofarabine (15 μg/ml) for Oxidative Degradation. Fig. 10. Test Chromatogram of Clofarabine (15 μg/ml) for Oxidative Degradation. Fig. 11. Standard Chromatogram of Clofarabine (15 μg/ml) for Heat Degradation.

6 Tandel et al: Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation 3799 Fig. 12. Test solution Chromatogram of Clofarabine (15 μg/ml) for Heat Degradation. Fig. 13. Standard solution Chromatogram of Clofarabine (15 μg/ml) for Photolytic Degradation. Fig. 14. Test solution Chromatogram of Clofarabine (15 μg/ml) for Photolytic Degradation Observation Table Summary report of the total degradation occurs in the various condition by standard and test are show in Table 1 Validation Specificity: The Chromatogram of Standard and sample solution showed in Fig. 15 and Fig. 16 respectively that there were no any interference by excipient peak. So, developed method was found to be specific. Calibration graphs were constructed by plotting the peak area versus their corresponding concentrations. (Fig. 17) Good linearity was obtained in the range of 5-25 μg/ml for Clofarabine. Graph of linearity was shown in Fig. 18. The results are shown in Table 2. Limit of detection (LOD) and limit of quantification (LOQ) were calculated from the slope and standard deviation of y- intercepts of the regression line of the calibration curve. The results are shown in Table 2. The precision of the method and instrument precision was evaluated and relative standard deviation (RSD) values were calculated. The RSD values for Clofarabine was showed that the precision of the method was satisfactory.the results are shown in Table 3. The accuracy of the method was determined by recovery studies. The recoveries were close to 100% for drug. The results are shown in Table 4. Developed method was found to be robust when the mobile phase ratio, flow rate and ph was changed. The results are shown in Table 5.

7 3800 Int J Pharm Sci Nanotech Vol 10; Issue 4 July August 2017 TABLE 1 Data of Force degradation study of Standard and Test Solution. Condition Aciddegradation Alkali degradation Oxidative degradation Heat degradation Photolytic degradation Stress Condition 2 ml of 0.1N HCl, 6 hours at 70º ºC 2 ml of 0.1N NaOH, 3 hours at 80 ºC 2 ml of 3% H 2 O 2 2, 3 hours at 60ºC Heat the sample at 105ºC for 30 min Place the solution at Sunlight for 5 hour % Degradation of standard % Degradation of test 18.8% 17.5% 15.1% 15.04% 17.1% 16.21% 11.2% 10.1% 15.4% 16.6% Fig. 15. Chromatogram of Standard preparation. Fig. 16. Chromatogram of Assay Preparation system suitability Parameters. Fig. 17. Overlay graph of Clofarabine range (5-25 μg/ml).

8 Tandel et al: Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation 3801 Fig. 18. Linearity curve of clofarabine. TABLE 2 Data system suitability Parameters. Parameters Results Acceptance Criteria In the chromatograms obtained with standard preparation: Theoretical plates per column 8910 ± 21 NLT 2000 Tailing factor 1.10 ± NMT 2.0 Resolution 5.6 ± Rs > 2 Retention time TABLE 3 Statistical data of Clofarabine. S. No. Parameter Clofarabine 1. Linearity range (μg/ml) Correlation co-efficients Regression line equations 37.84x Slope Intercept Limit of Detection (μg/ml) Limit of Quatificatiion (μg/ml) 0.21 TABLE 4 Precision parameters for Clofarabine Parameter Clofarabine Repeatability n=6 %RSD 0.15 Interday precision (n=3) %RSD Intraday precision (n=3) %RSD TABLE 5 Accuracy data of Clofarabine Level Amount of sample taken (μg/ml) Amount of standard spiked (μg/ml) Total Conc. Found (μg/ml) % Recovery ± S.D. (n=3) 80% ± % ± % ± 0.60 Assay of Marketed Formulation This method was applied to determine Clofarabine in parentral dosage form. The ml equivalent to 1 mg of drug was taken in 100 ml volumetric flask; mobile phase was added and the flask was kept in an ultrasonic bath for 10 min. The volume was made up to mark and the solution was filtered through 0.45 micro membrane filter. The diluted solution was analyzed under optimized chromatographic conditions. The areas of resulting peak were measured at 263 nm. Shown in Table 6. TABLE 6 Robustness study data Parameter Condition Mean area ± SD % RSD Flow rate(1ml/min) ± ± Mobile phase ratio 88 : ± (Buffer: Acetonitrile) (90:10%v/v) 92 : ± Wavelength(263nm) ± ± TABLE 7 Analysis of marketed formulation Clofarabine S. No. LableClaim Area of sample % Assay 1 1mg/ml mg/ml mg/ml Avg. Assay SD %RSD of Assay 1.25 Area of standard Impurities Study Alpha anomer: 0.40 mg of Alpha anomer impurity in 20 ml volumetric flask, Add about 10 ml methanol and sonicate to dissolved and diluted to volume with mobile phase. 2-Chloradenine: 0.51 mg of 2-Chloradenine impurity in 20 ml volumetric flask, Add about 10 ml methanol and sonicate to dissolved and diluted to volume with mobile phase. Monobenzoate: 0.50 mg of Monobenzoate impurity in 20 ml volumetric flask, Add about 10 ml methanol and sonicate to dissolved and diluted to volume with mobile phase. Impurities Spike stock solution: 3.0 ml of each impurities stock solution in 25 ml with mobile phase. Fig. 19. Chromatogram of Clofarabine alpha-anomer solution.

9 3802 Int J Pharm Sci Nanotech Vol 10; Issue 4 July August 2017 Fig. 20. Chromatogram of 2-Chloroadenine solution. Fig. 21. Chromatogram of Clofarabimenmonobenzoate solution. Fig. 22. Chromatogram of Impurity Mixture for identification. Fig. 23. Chromatogram of Assay preparation.

10 Tandel et al: Quantification of Clofarabine and its Impurity Substances by RP-HPLC Method in Parenteral Formulation 3803 Fig. 24. Chromatogram of Assay Preparation spiked with known impurities. TABLE 8 Summary of Impurity Studies Sample Name Clofarabine alpha anomer solution for identification 2-Chloroadenine solution for identification Clofarabine monobenzoate solution for identification Assay preparation Assay preparation spiked with known impurities Results Peak obtained due to Clofarabine alpha anomer at the retention time of minutes. Peak obtained due to 2- Chloroadenine at the retention time of minutes. No peak obtained due to Clofarabine monobenzoate. Peak obtained due Clofarabine at retention time of minutes. Peak obtained due to 2- Chlorodenine, Clofarabine and Clofarabine alpha anomer at the retention time of minutes, minutes and minutes respectively. Conclusions The proposed sensitive RP-HPLC method gives accurate and precise results for determination of lofarabine in marketed formulation and is easily applied for routine analysis. The most striking feature of the method is its simplicity and rapidity. Method validation has been demonstrated by variety of tests for linearity, accuracy, precision, LOD & LOQ., robustness. The proposed method was successfully applied to determination of these drugs in commercial injection. Acknowledgements The author is grateful to Sardar Patel College of Pharmacy, Bakrol for providing research facilities. Author is also thankful to Intas pharma, Ahmadabad (India) for providing drug sample as gift sample. References Buddhini Samarasinghe (2013). The Hallmarks of Cancer tissue Invasion and Metastasis Goodman & Gilman s (2003) the pharmacological basis of therapeutics: Mcgraw-Hill Medical. NK. Hsieh Y, Duncan CJ, Lee S and Liu M. (2007). Comparison of fast liquid chromatography/tandem mass spectrometric methods for simultaneous determination of cladribine and clofarabine in mouse plasma. J Pharm Biomed Anal. 44(2): ICH, Validation of Analytical Procedures; Methodology, Q2 (R1), International Conference on Harmonization, IFPMA, Geneva (1996). International Conference on Harmonization, Quality of Biotechnological Products: Stability Testing of Biotechnological/ Biological Products, International Conference on Harmonisation, IFPMA, Geneva. (1995). Liusheng H, Patricia L, Christopher C, Francesca A, and Janel L (2014). Simultaneous determination of fludarabine and clofarabine in human plasma by LC-MS/MS. J Chrom B Ana Tech Bio Life Sci Takahiro Y, Rie N and Takanori U (2011). Determination of Clofarabine Triphosphate Concentrations in Leukemia Cells Using Sensitive, Isocratic High performance Liquid Chromatography. Anticancer Res. 31(9): The Merck Index (1996). An Encyclopedia of chemicals, Drugs and Biologics: 12 th Edn. Published by Merck Research Laboratories, division of Merck &Co. inc.white house Station, NJ. Tripathi KD (2008). Essential of Medical Pharmacology: New Delhi, Jaypee brothers medical publishers (p) Ltd Tu X, Lu Y,, Zhong D, Zhang Y and Chen X. (2014). A sensitive LC- MS/MS method for quantifying Clofarabine triphosphate concentrations in human peripheral blood mononuclear cells. J Chrom B Ana Tech Bio Life Sci Venkata N, Jalandhar D, Gnana G, Rajendar B, Manoj P, Dhananiay D and Venkata N (2013). Development of supercritical fluid (carbon dioxide) based ultra performance convergence chromatographic stability indicating assay method for the determination of clofarabine in injection. Mylan Laboratories Ltd Wang Juan, Zhang Rong, ZHAO Yan-yan and Lu Lai-chun (2009). High performance liquid chromatography Clofarabine Injection Content. Med PapPharm. Address correspondence to: Jinal N. Tandel, Department of Quality Assurance, Sardar Patel College of Pharmacy, Vidyanagar-Vadtal Road, Bakrol,(388315) Anand, Gujarat, India. Mob: ; jinaltandel1202@gmail.com