Pelagia Research Library. Pelagia Research Library

Transcription

1 Available online at Der Pharmacia Sinica, 2014, 5(5): A validated stability-indicating HPLC assay method for Linagliptin B. R. C. Sekhar Reddy 1*, Nallagatla Vijaya Bhaskar Rao 2 and K. Saraswathi 3 1 Department of Chemistry, Acharya Nagarjuna University, Andhra Pradesh, India 2 Govt. Degree College, Alair, Nalgonda Dist, Andhra Pradesh, India 3 Department of Chemistry, SV University (Retd), Andhra Pradesh, India ABSTRACT A stability-indicating reversed-phase liquid chromatographic method for the determination of Linagliptin was developed. Different chromatographic conditions were carefully studied to optimize the parameters for the evaluation of the studied drug. The chromatographic assay involved the use of a C18 Column (250 mm 4.6 mm I.D., 5µm) with a simple mobile phase composed of methanol: phosphate buffer 70:30 at a flow rate of 0.9ml/min and UV detection at 218nm.The method showed good linearity over the range of µg/ml. The proposed method was successfully applied for the analysis of atenolol in three commercial tablets with average percent recoveries of Several co-formulated and co-administered drugs did not interfere with the proposed method. The results were statistically compared with those obtained by the official method and were found to be in good agreement. The stability-indicating capability of the method was also tested after accelerated degradation of Linagliptin in acidic and basic media and after freezing and heating treatments. Hencee the method was accurate, stability indicating and can be applicable for the routine analysis of Linagliptin. Keywords: Linagliptin, HPLC method, Stress degradation, Assay. INTRODUCTION ISSN: CODEN (USA): PSHIBD Linagliptin is dipeptidyl peptidase-4 (DPP-4) enzyme inhibitor developed by Boehringer Ingelheim [1] for the treatment of type II diabetes. The drug was approved by the U.S. Food and Drug Administration (FDA) on May 2011 for treatment of improves blood glucose levels in patients with type 2 diabetes [2-3]. Figure 1: Chemical structure of Linagliptin Linagliptin reduces blood glucose levels by inhibiting DPP-4 and increasing the levels of GLP-1 and GIP. Glucagon-like Peptide-1 (GLP-1) and Glucose-dependent Insulinotropic Polypeptide (GIP) are released from the 131

2 intestine, and their levels increase in the blood after meal. GLP and GIP are incretin hormones that increase the production and release of insulin from pancreatic beta cells and decrease the release of glucagon from pancreatic alpha cells. This results in an overall decrease in glucose production in the liver and increase insulin in a glucosedependent manner [4]. The present work is carried out after reviewing the previous trails, so as to develop a best suitable method to analyze and quantify the Linagliptin in pure and pharmaceutical dosage form. The literature survey reveals that there are few HPLC [5-11], Spectrophotometry [12-14], HPTLC [15] methods were found for the estimation of Linagliptin. MATERIALS AND METHODS Instrumentation: Chromatographic separation was performed on a PEAK chromatographic system equipped with LC-P7000 isocratic pump; Rheodyne injector with 20µl fixed volume loop, variable wavelength programmable UV detector UV7000 and the output signal was monitored and integrated by PEAK Chromatographic Software version Teccomp UV-2301 double beam UV-Visible spectrophotometer was used to carry out spectral analysis and the data was recorded by Hitachi software. Sonicator (1.5L, Ultra-sonicator) was used to sonicating the mobile phase and samples. Standard and sample drugs were weighed by using Denver electronic analytical balance (SI-234) and ph of the mobile phase was adjusted by using Systronics digital ph meter. Chemicals and solvents: The solvents used for the analysis like methanol, acetonitrile and water were of HPLC grade and were purchased from Merck specialties. The salt buffers used were of analytical reagent grade and were purchased from fisher scientific company, Mumbai. 0.45µm nylon membrane sample and mobile phase filter papers were purchased from Pall Corporation, Bangalore. Preparation of Linagliptin stock solution: 10mg of the standard drug Linagliptin was weighed accurately and the drug was dissolved in 10ml of solvent. The stock solution of concentration 1000µg/ml was obtained. The solution was filtered through 0.45micron meter nylon membrane filter paper. The solution was preserved safely and required concentrations for the construction of calibration curve were prepared by proper dilution from the stock solution. Preparation of Linagliptin sample solution: 20 Tablets of Linagliptin (Tradjenta-5mg) were crushed and made into fine powder using mortar and piston. Accurately weighed 100mg of Linagliptin sample into a 100ml dry volumetric flask add about 70ml of diluent and sonicate to dissolve it completely and make volume up to the mark with the same solvent. Further pipette 0.25ml of Linagliptin of the above stock solution into a 10ml volumetric flask and dilute up to the mark with diluents. RESULTS AND DISCUSSION The development of HPLC methods for the determination of drugs has received considerable attention in recent years because of their importance in the quality control of drugs and drug products. The goal of this study was to develop and validate a RP-HPLC method for the estimation of Linagliptin in bulk and pharmaceutical commercial preparations. The main objective of method development was to determine the drug content present in the formulation and its % purity. The chromatographic conditions like mobile phase composition, flow rate was optimized and the method was developed, validated success fully. The selected mobile phase system gave a single sharp peak without interfering peaks. Initial development of the method various mobile phase phases were tried to get sharp peak, finally a mobile phase of methanol: phosphate buffer in the ratio of 70:30(v/v) on Chromicil C18 column (250mm 4.6mm, 5µ) with UV detection at 218nm was selected which gave a single sharp peak with retention of 7.07min, tailing factor 0.63 and theoretical plates The optimized chromatographic conditions are shown in Table

3 Table 1: Optimized chromatographic conditions for Linagliptin S.No Method Parameter Linagliptin Condition 1 Mobile phase Methanol: Phosphate buffer 70:30 (v/v) 2 Pump mode Isocratic 3 Mobile Phase P H Wavelength 218nm 5 Column Chromicil C18 (250mm 4.6mm, 5µ) 6 Column Temp Ambient 7 Injection Volume 20µl 8 Flow rate 0.9m/min 9 Retention Time 7.02min 10 Run time 14min 11 Peak Area Theoretical plates Tailing Factor Pump Pressure 9.5±5MPa Commercial marketed formulation of Linagliptin was analyzed for its contents and % of content was calculated. The % assay was found to be 99.03%. The proposed method was found to be simple, rapid, economic and accurate. The method was applicable to routine laboratory analysis. The standard chromatogram was given in Figure 2. Figure 2: Standard chromatogram for Linagliptin The method was validated statistically for various parameters like standard deviation, % relative standard deviation, slope and intercept. The linearity for the detection of Linagliptin was µg/ml with (R 2 =0.9977; y = 10703x ) the coefficient of variation based on mean peak area for six replicate injections were found to be less than 2. Statistical data of calibration curves are shown in Table

4 Table 2: Linearity Results for Linagliptin S.No Alogliptin Concentration in µg/ml Peak Area Linearity range µg/ml Slope (m) Intercept (b) r The intraday and interday variations of the method were determined using six replicate injections of three concentrations and analyzed on the same day and three different days over a period of two weeks. The result revealed the precision with %RSD of and 0.243, respectively for intraday and inter day. Results are shown in Table 3. Table 3: Precision results for the proposed method S.No Linagliptin at 60µg/ml Intraday Interday RSD To ensure the reliability and accuracy of the method, the recovery studies were carried out by adding a known quantity of drug with pre-analyzed sample and contents were reanalyzed by the proposed method. Accuracy was evaluated by injecting the solution about five times, at three different concentrations equivalent to 50, 100, and 150% of the active ingredient, by adding a known amount of Linagliptin standard to a sample of known concentration and calculating the recovery with RSD (%), and % recovery for each concentration. The mean % recoveries were in between % and are given in Table 4. Recovery 50% 100% 150% Table 4: Recovery results for Linagliptin Linagliptin Concentration in µg/ml Target Spiked Final Amount found % of Assay Robustness of the proposed method was estimated by changing mobile phase composition of mobile phase, ph of the mobile phase and changing the wave length and system suitability parameters were found to be within 134

5 acceptable limits and indicating that the test method was robust for all variable conditions. Hence the method was sufficiently robust for normally expected variations in chromatographic conditions. The ruggedness and robustness for the method was performed as per ICH guidelines. Limits of Detection (LOD) and Quantification (LOQ), the limits of detection and quantitation were calculated by the method based on the standard deviation (σ) and the slope (S) of the calibration plot, using the formulae LOD = 3.3σ/S and LOQ = 10σ/S. The specificity test of the proposed method demonstrated that the excipients from tablets do not interfere in the drug peak. Furthermore, well-shaped peaks indicate the specificity of the method. The standard drug solution was prepared and was applied to different stressed conditions like acidic, base, peroxide. The stressed solution was analyzed using the optimized method conditions after a period of 24hrs. Results of the forced degradation studies conforms that the molecules in the study were stable in all the stressed conditions under the study. This conformed by the retention time in all the stressed conditions was equal to the corresponding standard retention time of the drug. Few of the molecules degrade in to different degradation products and the degradation products are also observed with different retention times in the chromatogram. The developed methods can able to separate the degradation products also. The number of additional peaks observed for the drugs in different stressed conditions was shown in Table 5. Stressed chromatograms are given in Figure 3. Table 5: Number of peaks observed in stressed condition S.No Condition Linagliptin 1 3% Peroxide N Basic N Acidic 2 4 Sun light 1 5 UV light 3 6 Aqueous 1 7 Thermal 2 135

6 Figure 3: Degradation chromatograms for Linagliptin 136

7 CONCLUSION The proposed method for the determination of atenolol based on the use of liquid chromatography with spectrophotometric detection was shown to be reliable, simple, accurate, sensitive and precise. Moreover,the method is fast and feasible. It could be successfully applied for the determination of Linagliptin in pharmaceutical preparations without interference from co-formulated drugs. The good validation criteria of the proposed method allow its use in quality control laboratories as an alternative to the official methods. The results demonstrated the ability of the proposed method to be used as a stability-indicating HPLC method for the analysis of Linagliptin. Acknowledgements I take this opportunity to express my profound gratitude and deep regards to my guide Dr. Nallagatla Vijay Bhaskar Rao, Principal of Govt. Degree College, Alair, Nalgonda, INDIA., for his counsel and effective guidance during the course of the work, helpful discussions, preparation of this dissertation and constant inspiration throughout the period of research work. I also take this opportunity to express a deep sense of gratitude to Prof. K. Saraswathi, Department of Chemistry (retd), Sri Venkateswara University, Tirupati, INDIA., for the supported this work directly or indirectly. Lastly, I thank almighty, my wife (Mrs. Bhimireddy Deepti) and my friends for their encouragement and grateful cooperation during the period of this assignment. REFERENCES [1] Forst T and Pfutzner A, Expert Opin Pharmacother, 2012, 13(1): [2] "FDA Approves Type 2 Diabetes Drug from Boehringer Ingelheim and Lilly". 3 May [3] Genetic Engineering & Biotechnology News. 28 June [4] Praveen Kumar A, Aruna G, Rajasekar K and Jayachandra Reddy P, International Bulletin of Drug Research, 2013, 3(5): [5] Lakshmi B, Journal of Atoms and Molecules, 2012, 2(2); [6] Dilip Patil A, Inventi Rapid: Pharm Analysis & Quality Assurance, 2013, Vol.12, 598. [7] Archana M, IJMCA, 2013, 3(1), 1-5. [8] Kavitha K.Y, Journal of Chemical and Pharmaceutical Research, 2013, 5(1): [9] Sujatha K., Indo American Journal of Pharm Research., 2013, 3(10), [10] Lakshman Raju Badugu, Am. J. PharmTech Res., 2012, 2(4), [11] Rutvik H Pandya, Pharmacophore, 2014, Vol. 5 (2), [12] Ramzia El-Bagary I, Int. J Biomed Sci, 2013, 9(1), [13] Chandra Sekhar K, International Journal of Universal Pharmacy and Bio Sciences, 2013, 2(4), [14] Sujan Banik, Indian Journal of Novel Drug Delivery, 2013, 5(4), [15] Rajasekaran A, World Journal of Pharmaceutical Sciences, 2014, 2(4):