Indexed in Cite Factor - Directory of International Research Journals in association with leading universities DEVELOPMENT AND VALIDATION OF UV SPECTROPHOTOMETRIC METHOD FOR THE SIMULTANEOUS ESTIMATION OF TENOFOVIR DISPROXIL FUMARATE AND EMTRICITABINE IN TABLET DOSAGE FORM BY DERIVATIVE SPECTROSCOPIC METHOD M. SASIKALA* 1, M. TEJA DEEPTHI 2, K. VINOD KUMAR 3, NAGA MALLIKARJUNA RAJA B. 4 ABSTRACT A simple, accurate, precise, economical spectroscopic method was developed and validated for the quantification of Tenofovir Disoproxil Fumarate and Emtricitabine in combined dosage form. The method obeys Beer s law in concentration ranges of 10-80 μg/ml with correlation coefficient of 0.998 for Tenofovir Disoproxil Fumarate and correlation coefficient of 0.997 for Emtricitabine respectively. The method was validated for linearity, accuracy, precision, LOD, LOQ and assay as per ICH guidelines. The zero crossing point for Tenofovir Disoproxil Fumarate and Emtricitabine was 240 and 280nm respectively in water. The LOD values were found to be 0.286 μg/ml and 0.392 μg/ml for Tenofovir Disoproxil Fumarate and Emtricitabine respectively. The LOQ values were found to be 0.869 μg/ml and 1.190 μg/ml for Tenofovir Disoproxil Fumarate and Emtricitabine respectively. The %RSD for intraday and interday precision were found to be less than 2%. Recovery by this method was found to be 99% for both the analytes. The assay results were found to be 98.4% for Tenofovir Disoproxil Fumarate and 97.5% for Emtricitabine respectively. The developed and validated method was successfully used for the quantitative analysis of commercially available dosage forms. KEYWORDS Tenofovir Disoproxil Fumarate, Emtricitabine, Derivative spectroscopy, zero crossing point, combined dosage form. *Address for correspondence: AFFILIATION 1. Division of Pharmaceutical Analysis and Quality Assurance, 2. Centre for Pharmaceutical Research (CPR), 3. Raghavendra Institute of Pharmaceutical Education and Research, K.R.Palli cross, Anantapur, Andhra Pradesh, India 515721. *Corresponding author mallikarjuna.sasikala753@gmail.com, +91-9059496441 20
OBJECTIVE The present study was aimed on development and validation of a method for the simultaneous UV-Spectrophotometric determination of Tenofovir Disoproxil Fumarate and Emtricitabine by derivative spectroscopic method. The present study was designed as the following part. Part 1: Method development Part 2: Validation Part 3: Assay of marketed dosage form. Combined Dosage Form Table 1: Various Brand Names of Combined Formulations. Composition Brand name Formulation Company FTC-200 mg + TDF-300 mg Truvada Tablet Gilead sciences Forstavir-EM Tablet Aurobindo Tenvir-EM Tablet Cipla Tenof-EM Tablet Hetero MATERIALS & METHODS Table 2: Materials Selected. S.No. Material Manufacturer/Made Purity 1. Tenofovir Disoproxil Fumarate Emtricitabine Heterolabs, Hyderabad (India) 99.9%(COA) 2. Distilled water In house INSTRUMENTATION Table 3: Description of the UV Instrument. Instrument UV-Visible double beam spectrophotometer Calibration Model Lab India 3000 + Complies Operating mode Single wavelength, multi wavelength, spectrum scan, time scan Complies 21
Wavelength range 200-800 nm Complies Wavelength accuracy 1 nm Complies Wavelength read out 0.1 nm interval Complies Wavelength band width 2 nm Complies Sample holders 8 (1 cm cuvette) Complies Display 4 line 20 character LCD Complies Detector Photo diode uv enhance wide range solid state photodiode Complies Method Development and Validation of Selected API s Tenofovir Disoproxil Fumarate and Emtricitabine: Development and validation of a UV spectrophotometric method for the determination of Emtricitabine and Tenofovir was carried by the absorption correction method UV spectrophotometric method for estimation of Emtricitabine and Tenofovir was carried by the derivative spectroscopic method. Method Development Determination of Solubility Emtricitabine and Tenofovir Disproxil Fumarate solubility were tested in different organic and aqueous solvents. Both are soluble in water. Selection of a Suitable Wavelength The working standard solutions were scanned from 200 to 400 nm to select the wavelengths for estimation. The zero crossing point for Tenofovir Disoproxil Fumarate and Emtricitabine was 294 nm and 280 nm respectively in water. From the overlain spectrum shown in figure the wavelength selected for estimation of Emtricitabine was 294 nm, where Tenofovir has no absorbance and for Tenofovir it was 280 nm, where Emtricitabine has no absorbance. Different binary mixture solutions of Emtricitabine and Tenofovir were then run in entire range from 200 to 400 nm. The drugs obey the Beer s law in the concentration range of 10 to 80 µg/ml. Standard Solutions and Calibration Graphs for UV Measurement Standard stock solution of Emtricitabine and Tenofovir Disoproxil Fumarate were prepared in water (1000µg/mL). From this solution 1 ml was taken and diluted to 10 ml with water (100µg/mL). Calibration standards at eight levels were prepared by approximately mixed and further diluted stock standard solutions in the concentration range of 10-80 µg/ml for Tenofovir Disoproxil Fumarate and Emtricitabine respectively. Similarly, quality control (QC) standard solutions were prepared daily by diluting the corresponding stock standard 22
solutions for the final QC concentrations of 20, 40, 60 µg/ml for Emtricitabine and Tenofovir Disoproxil Fumarate respectively. Samples in triplicates were made for each concentration and absorption was plotted against the corresponding concentrations to obtain the calibration graph. Method Validation of Emtricitabine and Tenofovir Method validation was performed in terms of sensitivity, specificity, linearity, LOQ, LOD, precision, accuracy, robustness and system suitability. Linearity The linearity of calibration curves in pure solution was checked over the concentration ranges of about 10-80 µg/ml for Emtricitabine and Tenofovir Disoproxil Fumarate. The regression line relating standard concentrations of drug using regression analysis, the calibration curves were linear in the studied range and equations of the regression analysis were obtained: Y=0.0007x - 0.0006; R 2 =0.9996 for Tenofovir Disoproxil Fumarate at 280 nm and Y=0.0011x + 0.0006; R 2 =0.9993 at 294 nm for Emtricitabine respectively. The mean and correlation coefficient of standard curves (n=3) were calculated. The represented data was shown in below Table 4. Precision The precision of the developed method was assessed in terms of repeatability and intermediate precision by analyzing three replicate QC standard samples 20, 40, 60 µg/ml for Tenofovir Disoproxil Fumarate and Emtricitabine respectively. The % R.S.D values of the results corresponding to the absorption values were expressed for intraday precision and on 3 days for intermediate (inter-day) precision. The intra and inter-day accuracy and precision were calculated and results were presented in the table. Precision of the analytical method was found to be reliable based on %R.S.D. Accuracy The accuracy of the method was determined by recovery experiments. The recovery studies were carried out at three levels of 80, 100 and 120%. For determining accuracy, pre analyzed solution µg/ml was spiked with µg/ml standard stock solutions. Results of assay and recovery were presented in the table. Specificity For determining Specificity of the method, a tablet dosage form was analysed. These results demonstrate that there was no interference from other materials in the tablet formulation therefore, confirm the specificity of the method. Limit of detection (LOD), Limit of Quantification (LOQ) Limit of detection was found to be 0.94 µg/ml for Tenofovir Disoproxil Fumarate at 280 nm and 0.60 µg/ml for Emtricitabine at 294 nm respectively and Limit of Quantification was found to be 2.85 µg/ml Tenofovir Disoproxil Fumarate at 280 nm and 1.81 µg/ml for Emtricitabine at 294 nm respectively. 23
Assay of Tablets (Combined Formulation of Tenofovir Disoproxil Fumarate and Emtricitabine) Ten tablets of FORSTAVIR-EM were weighed and finely powdered and extracted with water in a 10 ml volumetric flask. The flask was sonicated for 15 min and volume was made up to the mark with water. The above solution was filtered using Whatman No.1 filter, 1mL was transferred into a 10mL volumetric flask and the volume was made upto the mark with mobile phase to obtain 8µg/mL of Emtricitabine and 12 µg/ml of TDF. The absorbance of the solution was measured under UV spectrophotometer. The assay procedure was made triplicate and weight of sample taken for assay was calculated. The percentage of drug found in formulation, mean and standard deviation in formulation were calculated. Simultaneous Estimation is Made by Derivative Spectroscopic Method The zero crossing point for Tenofovir Disoproxil Fumarate and Emtricitabine was 294 nm and 280 nm respectively in water. From the overlain spectrum of Tenofovir Disoproxil Fumarate and Emtricitabine in water, it was observed that Tenofovir Disoproxil Fumarate was estimated at 280 nm and Emtricitabine at 294 nm. RESULTS AND DISCUSSIONS The results obtained in the studies are portrayed from Table 4 to Table 7. Table 4: Linearity of Emtricitabine and Tenofovir Emtricitabine Tenofovir Disoproxil Fumarate S.No Concentration Absorbance at 294 nm ± SD Concentration Absorbance at 280 nm ± SD 1 10 0.012 ± 0.0005 10 0.007 ±0.0005 2 20 0.022 ± 0.001 20 0.014 ± 0.002 3 30 0.033 ±0.0011 30 0.022 ± 0.001 4 40 0.045 ± 0.0017 40 0.029 ± 0.0011 5 50 0.056 ± 0.002 50 0,037 ±0.0015 6 60 0.066 ± 0.0020 60 0.044 ± 0.001 24
Fig. 3: Linearity Curve of Emtricitabine. S.No. Sample Fig. 4: Linearity Curve of Tenofovir. Table 5: Precision studies by UV Method. Intra-day (%RSD) Inter-day (% RSD) TDF at 280 nm EMC at 294 nm TDF at 280 nms EMC at 294 nm 1 LQC 0.66 0.83 0.71 0.90 2 MQC 0.68 0.85 1.29 1.13 3 HQC 0.51 1.46 1.42 1.64 25
Table 6: Assay of Formulation by Derivative Spectroscopic Method. Formulation Drug Lable Claim Amount Found ± SD % Recovery %RSD FORSTAVIR- EM Tenofovir Isoproxil Fumarate 300 mg 295.2 mg ± 1.52 98.4% 0.51 Emtricitabine 200mg 195mg ± 0.12 97.5% 0.06 Table 7: Recovery Studies. S.No. Name of the drug Amount of sample (µg/ml) Recovery level Amount of drug added (µg/ml) Total amount found (µg/ml) ± SD % Recovery % RSD Tenofovir 80% 9.6 21.52. ± 0.4 101.8 1.8 1. Disoproxil 12 100% 12.0 24.54 ± 0.3 102.0 1.2 Fumarate 120% 14.4 26.57 ± 0.1 100.6 0.3 2. Emtricitabine 8 80% 100% 120% 6.4 8.0 9.6 14.53 ± 0.2 15.86 ± 0.1 17.27 ± 0.2 100.6 98.7 98.1 1.3 0.6 1.1 DISCUSSION The selected drugs Tenofovir Disoproxil Fumarate and Emtricitabine were estimated by using simultaneous estimation by derivative spectroscopic method as per ICH guidelines. The method was validated for all validation parameters as per ICH guidelines. The linearity range for Tenofovir Disoproxil Fumarate and Emtricitabine was 10-80 µg/ml with R 2 value of 0.9996 for Tenofovir Disoproxil Fumarate and 0.9993 for Emtricitabine. The % RSD for intraday and inter-day precision was <2%. The method has been validated in assay of tablet dosage forms. The accuracy of the method was validated by recovery studies and was found to be significant and under specification limits, with % recovery 98-102 (i.e., within acceptable range 98-102%). The assay results were found to be 98% and 97% (i.e., within acceptable range 95-105%). SUMMARY The present work was aimed at developing new validated spectrophotometric method for the simultaneous determination of Tenofovir Disoproxil Fumarate and Emtricitabine by derivative spectroscopic method. The work was aimed comparatively to the earlier literature 26
report in connection to the priority of the present investigation with respect to the parameters like linearity, LOD, precision etc. The method was validated for system suitability, linearity, accuracy, precision, robustness. The linear range was 10-80 µg/ml for Tenofovir Disoproxil Fumarate and 10-80 µg/ml for Emtricitabine with R 2 value of 0.9996 for Tenofovir Disoproxil Fumarate and 0.9993 for Emtricitabine respectively. The % RSD for intraday and interday precision was <2%. The method has been used to analyse commercial solid dosage i.e., tablets containing 300 mg of Tenofovir Disoproxil Fumarate and 200 mg of Emtricitabine with % recovery of 98-102% (within acceptable range i.e., (98-102%). The assay results were found to be 98.4% and 97.5% (within limits 95-105%). Table 8: Summary of the Present Study. S.No. Parameter Tenofovirdisoproxil Fumarate Emtricitabine 1. λ max 260 nm 282 nm 2. Beer s limit (µg/ml) 10-80 10-80 Regression equation at 280 nm at 294 nm 3. a) Slope 0.0007 0.0011 b) Intercept 0.0006 0.0006 c) Co-relation coefficient 0.9996 0.9993 4. LOD (µg/ml) 0.94 0.60 5. LOQ (µg/ml) 2.85 1.81 6. Precision <2% <2% 7. Recovery 99% 99% 8. Zero crossing point 294 nm 280 nm 27
REFERENCES 1. A. H. Beckett, J. B. Stenlake, Practical Pharmaceutical Chemistry, Fourth Edition Part two, CBS Publications, p.286 288. 2. International Conference on Harmonisation (ICH) of Technical Requirements for the Registration of Pharmaceuticals for Human Use, Validation of analytical procedures: Methodology, adopted in 1996, Geneva. 3. Validation of Analytical Methods and Procedures.zip\Analytical Method Development for Pharmaceutical Formulations Pharmainfo_net.htm. 4. U. S. EPA, Guidance for methods development and methods validation for the Resource Conversation and recovery Act (RCRA) programme, Washington, D. C. (1995)., http://www.epa.gov/sw- 846/pdfs/methdev.pdf. 5. Patel Suhel, Baghel U.S., Rajesh P., Prabhakar D., Engla G., Nagar P.N.; Spectrophotometric Method Development and Validation for Simutaneous estimation Of Tenofovir Disoproxil Fumarate and Emtricitabine in Bulk drug and Tablet dosage form; International Journal of Pharmaceutical and Clinical Research 2009; 1(1): 28-30. 6. ShirkhedkarAtul A*, BhirudCharushila H and Surana Sanjay J; Application of UV- Spectrophotometric methods for estimation of TenofovirDisoproxilFumarate in Tablets; Pak. J. Pharm. Sci., Vol.22, No.1, January 2009, P no.27-29. 7. Prasanna A. Nevasel*, Hemalatha M. Nimjel,Rajesh J. Oswall, Rishikesh V. Antrel, Sandip S. Kshirsagar1; UV Spectrophotometric method for estimation of TenofovirDisoproxilFumarate Tablet dosage form ; International Standard serial number 0974-9446; NevaseEt Al., Ijprd, 2011; Vol 3(3):11; May 2011(73-75). 8. Carr GP, Wahlich JC. A Practical approach to method validation in pharmaceutical analysis; J.Pharm. Biomed. Anal, 86, 1990, 613-618. 9. U.S. FDA Guidance for Industry (draft) Analytical procedures and method validation: Chemistry, Manufacturing, Controls and Documentation, 2000. 10. P.B. Khedekha, S.M. Dholea, K.P. Bhusari, Application of Vierodt s and Derivative Spectrophotometric methods for estimation of Tenofovir Disoproxil Fumarate and Emtricitabine in tablets; Digest Journal of Nanomaterials and Bio structures Vol. 5, No. 1, March 2010, p.77-84. 11. General Chapter 1225, Validation of compendial methods, United states pharmacopeia 30, National Formulary 25 Rockville, Md., USA, The United States Pharmacopoeial convention, Inc.,(2007). 12. PS Tarte*, SP Wate, PB Khedikar And G Pawnikar ; Absorption Correction Method for estimation of Nebivolol and Hydrochlorothiazide in combined tablet dosage form; Asian J. Research Chem. 1(2): Oct-Dec 2008. 28