Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan in their Pharmaceutical Dosage Form

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1 4208 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 International Journal of Pharmaceutical Sciences and Nanotechnology Research Paper Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan in their Pharmaceutical Dosage Form Gopi Patel 1 *, Arshad Vohra 2 and Dr. Samir Shah 3 1,2 Department of Pharmaceutical Chemistry, and 3 Department of Pharmacology, Sardar Patel College of Pharmacy, Bakrol, Gujarat, India. Received April 10, 2018; accepted May 10, 2018 Volume 11 Issue 4 July August 2018 MS ID: IJPSN GOPI-PATEL ABSTRACT A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and completely validated for the estimation of Valsartan and Sacubitril in pharmaceutical dosage forms. Quantification of Valsartan and Sacubitril were carried out with precoated silica gel aluminum Plate 60 F254, (20 cm 10 cm) 100 μm thickness as stationary phase. Toluene: Methanol: Ethyl Acetate: Glacial Acetic acid (8:2:1:1 % v/v/v). The optimized chamber saturation time before chromatographic development was 20 min at room temperature (25ºC ± 2). The length of chromatographic run was 8 cm which took average 15 min to develop. Densitometry scanning was performed using Camag TLC scanner IV with Win CATS software (V , Camag). Optimized chromatogram of Valsartan and Sacubitril having of 0.43 and 0.33, respectively. Linear relationship Rf between peak area and concentration of standard was evaluated over the concentration range expressed in ng/band by making five replicate measurements in the concentrations range of ng/band and ,000 ng/band, respectively for Valsartan and Sacubitril. Literature reveals that there was no any method developed using HPTLC in simultaneous estimation of Valsartan and Sacubitril in their pharmaceutical dosage form. The proposed method can be successfully applied for the estimation of drug content of different marketed formulations. KEYWORDS: HPTLC; Stability Indicating Method; Sacubitril; Valsartan. Introduction Valsartan is (2S)-3-methyl-2-[N-({4-[2-(2-H-1,2,3,4- tetrazol-5-yl) phenyl] phenyl} methyl) pentanamide] butanoic acid (fig. 1). It is an angiotensin receptor blocker (ARB) that may be used to treat a variety of cardiac conditions including hypertension, diabetic nephropathy and heart failure. Valsartan is an ARB that selectively inhibits the binding of angiotensin II to AT1, which is found in many tissues such as vascular smooth muscle and the adrenal glands (Tripathi et al. 2008). Sacubitril is 3{-[(2S,4R)-1-{[1,1-'biphenyl]-4-yl}-5-ethoxy 4methyl-5-oxopentan-2-yl] carbamoyl} propanoic acid (fig. 2). It is a prodrug neprilysin inhibitor used in combination with valsartan to reduce the risk of cardiovascular events in patients with chronic heart failure. Under normal conditions, neprilysin breaks down other vasodilating peptides and vasoconstrictors such as angiotensin I and II, endothelin1 and peptide amyloid beta protein. Therefore, the inhibition of neprilysin leads to reduced breakdown and increased concentration of endogenous natriuretic peptides in addition to increased levels of vasoconstriction hormones such as angiotensin II. (However, when combined with valsartan, would result in blocking of angiotensin II to its receptor, preventing the vasoconstrictive effects and resulting in a decrease in vascular resistance and blood pressure). Cardiovascular and renal effects of Sacubitril are a result of the increased levels of peptides that are normally degraded by neprilysin. Several analytical methods were developed by RP- HPLC with different combination (Bhatia et al., 2009, Parambi et al., 2011). But no any stability indicating method was developed by HPTLC. Literature survey reveals that many analytical methods have been reported for determination of Sacubitril and Valsartan individually and combination with other drugs. (Imam et al., 2013, Kumar et al., 2011). One method reported was simultaneous estimation of Valsartan and Sacubitril by RP HPLC method. (Patel et al., 2016). The present work describes the development of stability indicating HPTLC method, which can quantify these components simultaneously from a combined dosage form and also separate this component from its degradation products. ABBREVIATIONS: HPTLC, High Performance Thin Layer Chromatography; HPLC, High Performance Liquid Chromatography; TLC, Thin Layer Chromatography; ICH, International Conference on Harmonisation; RSD, Relative Standard Deviation; SD, Standard Deviation; Rf, Retention Factor 4208

2 Patel et al: Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan 4209 Fig. 1. Structure of Valsartan. Fig. 2. Structure of Sacubitril. Materials and Methods Reagent and Materials Methanol, Toluene, Glacial acetic acid and Ethyl acetate. All chemicals were of HPLC grade. Instruments: Hamilton microlitre syringe (Linomat syringe , Hamilton-Bonaduz Schweiz, Camag, Switzerland), precoated silica gel aluminium plate 60 F254, (20 20 cm, 1000 μm thickness; E. Merck, Darmstadt, Germany), UV chamber (Camag, Switzerland), Twin trough chamber (20 10 cm; Camag, Switzerland), Linomat 5 sample applicator (Camag, Switzerland) and TLC scanner 4 (Camag, Switzerland) operated by win CATS version software (Camag, Switzerland) were used in the study. All drugs and chemicals were weighed on an electronic balance (AUW 220, Shimadzu Corp., and Japan). Preparation of standard d stock solutionon of standard: 10 mg of standard Valsartan was accurately weighed and was transferred into 10 ml volumetric flasks, dissolved in a 5 ml of methanol and then volumes was made up to the mark with methanol, to obtain solution containing 1000 μg/ml. Aliquots of the stock solution was appropriately diluted with methanol to obtain working standard of 100 μg/ml. 10 mg of standard Sacubitril was accurately weighed and was transferred into 10 ml volumetric flasks, dissolved in a 5 ml of methanol and then volumes was made up to the mark with methanol, to obtain solution containing 1000 μg/ml which was used as working standard. Detection wavelength: The sensitivity of an HPTLC method with ultraviolet detection depends on an appropriate wavelength. Detection of standard was performed at 228 nm, whichh was found to be the isobestic point. (Fig. 3) Fig. 3. Detection of wavelength.

4210 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 Optimized chromatographic conditions were as shown below: TABLE 1 Optimized chromatographic conditions Parameters Band width 6 mm

3 4210 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 Optimized chromatographic conditions were as shown below: TABLE 1 Optimized chromatographic conditions Parameters Band width 6 mm Conditions Micro-syringe 100 μl Pre-coated silica gel 250 μm thickness Plate dimension 20 cm x 10 cm Development Linear ascending Chamber Twin trough glass chamber Saturation time 20 min Length of 8 cm chromatographic run Wavelength 228 nm Slit dimension 6.00 x 0.30 nm, micro Mobile phase composition Toluene: Methanol: Ethyl Acetate: Glacial Acetic acid (8:2:1:1 % v/v) Optimized chromatogram of valsartan and sacubitril having R f of 0.43 and 0.33, respectively. (Fig. 4) Method Validation The HPTLC method was validated for linearity, accuracy, and precision, limit of detection (LOD), limit of quantification (LOQ), specificity and robustness, in accordance with ICH Q2 (R1) guideline. Linearity Linear relationship between peak area and concentration of standard was evaluated over the concentration range expressed in ng/band by making five replicate measurements in the concentrations range of ng/band and ,000 ng/band, respectively for Valsartan and Sacubitril, by applying different volumes (4 to 12 μl) of working standard solution (1000 μg/ml for Sacubitril and 100 μg/ml for Valsartan) on the HPTLC plate. Calibration plots were constructed by plotting the area of the peak of band versus the concentration of the standards and were further treated using the method of ordinary linear regression analysis. Precision The experiment was repeated three times in a day (Intra-day precision) and the average % RSD values of the results were calculated. Similarly, the experiment was repeated on three different days (Inter-day precision) and the average % RSD values for peak area of standard were calculated. Results of intra-day and interday precision expressed in terms of % RSD was found to be less than 2 demonstrating good repeatability and reproducibility of method. The low value of % RSD depicts the high precision of the method. Fig. 4. Optimized chromatogram of valsartan and sacubitril.

Patel et al: Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan 4211 Fig. 5. 3D Chromatogram showing linearity of standard.

with 150, 300 and 450 ng/band of standard Valsartan working solution (100 μg/ml), similarly Sacubitril 3000 ng/band sample was spotted and was spiked with 1500, 3000 and 4500 ng/band of standard

The retardation factor of the standard and sample for both Valsartan and Sacubitril was found to be same, so the method was found to be specific.

4 Patel et al: Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan 4211 Fig. 5. 3D Chromatogram showing linearity of standard. Accuracy The proposed method when used for evaluation of recovery at three concentrations levels, 50%, 100% and 150%, where for Valsartan 300 ng/band sample (formulation) was spotted and was spotted with 150, 300 and 450 ng/band of standard Valsartan working solution (100 μg/ml), similarly Sacubitril 3000 ng/band sample was spotted and was spiked with 1500, 3000 and 4500 ng/band of standard Sacubitril working solution (1000 μg/ml). Specificity Specificity of the method was ascertained by comparing retardation factor of standard and sample in chromatogram. The retardation factor of the standard and sample for both Valsartan and Sacubitril was found to be same, so the method was found to be specific. Moreover, there was no interference from other active ingredients at the peaks observed for standard from the prepared isolated standard and also the base line did not show any significant noise. Formulation Analysis Each tablet contained 97 mg Sacubitril and 103 mg Valsartan, average weight of 1 tablet was found to be mg (97 mg Sac and 103 mg Val) and hence mg of the crushed powder was weighed accurately containing 10 mg of Sacubitril and 10.2 mg of Valsartan and was diluted with methanol and volume was made up to the mark by 10 ml by methanol. This solution containing 1000 μg/ml Sacubitril was used for sample analysis and this solution was further diluted with methanol to give solution of 100 μg/ml which was used for sample analysis of Valsartan, for the both the sample analysis 8 μl sample was spotted. Stability Studies Acid degradation: Forced degradation in acidic media was performed by keeping the 5 ml standard solution of Valsartan (1000 μg/ml) and Sacubitril ( μg/ml) in contact with 5 ml 0.1 N HCl for 1 hr. at room temperature. After 1 hr. the solution was neutralized with 0.1 N NaOH and solution was diluted up to 10 ml with methanol. Dilution was done to achieve the appropriate concentration μg/ml of Sacubitril and 1200 μg/ml of Valsartan. Alkaline degradation: Forced degradation in basic media was performed by keeping the 5 ml standard solution of Valsartan (1000 μg/ml) and Sacubitril (10000 μg/ml) in contact with 5 ml 0.1 N NaOH for 1 hr. at room temperature. After 1 hr. the solution was neutralized with 0.1 N HCl and solution was dilutedd up to 10 ml with methanol. Dilution was done to achieve the appropriate concentration μg/ml of Sacubitril and 1200 μg/ml of Valsartan. Oxidation degradation: Forced degradation in oxidising media, was performed by keeping the 5 ml standard solution of Valsartan (1000 μg/ml) and Sacubitril (10000 μg/ml) in contact with 5 ml 3% H 2 O 2 for 1 hr. at room temperature. After 1 hr. the solution was diluted up to 10 ml with methanol. Dilution was done to achieve the appropriate concentration μg/ml of Sacubitril and 1200 μg/ml of Valsartan. Thermal degradation: Standard solution of Valsartan (1000 μg/ml) and Sacubitril (10000 μg/ml) was exposed to temperature of 105 C for half an hour in an oven. After half an hour, the solution was diluted up to 10 ml with methanol. Dilution was done to achieve the

5 4212 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 appropriate concentration μg/ml of Sacubitril and 1200 μg/ml of Valsartan. Photolytic degradation: Standard solution of Valsartan (1000 μg/ml) and Sacubitril (10000 μg/ml) was exposed in the sunlight for 2 hrs. After 2 hrs, the solution was diluted up to 10 ml with methanol. Dilution was done to achieve the appropriate concentration μg/ml of Sacubitril and 1200 μg/ml of Valsartan. Results and Discussion Linearity The calibration curve for Sacubitril and Valsartan were found to be linear over the range of ng/band and ,000 ng/band, respectively for valsartan and Sacubitril. The % RSD was less than 2 (Table 2). The R 2 Values of Valsartan and Sacubitril were and respectively. (Figure 6 & 7). TABLE 2 Linearity Data of Valsartan and Sacubitril. Concentration of Valsartan Peak Area Average SD % RSD ng/band LOD (ng/band) LOQ (ng/band) Concentration for Sacubitril Peak Area Average SD %RSD ng/band LOD (ng/band) LOQ (ng/band) Fig. 6. Calibration curve of Sacubitril. Fig. 7. Calibration curve of Valsartan.

6 Patel et al: Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan 4213 Precision The data for intra-day and inter day precision for Valsartan and Sacubitril were shown in Table 3 and 4 respectively. The % RSD value for inter day and intra day precision was found to be less than 2, which indicated that the method was precise. (Tables 3 & 4) Intra-day Precision Inter-day Precision The experiment was repeated on three different days (Inter-day precision) and the average % RSD values for peak area of standard were calculated. Accuracy The proposed method when used for evaluation of recovery at three concentrations levels, 50%, 100% and 150%. (Table 5) Specificity Specificity of the method was ascertained by comparing retardation factor of standard and sample in chromatogram. There was no interference of excipient at the retention time of standard Valsartan and Sacubitril. So, both drugs can be separated without any interference in sample. (Figure 8). Formulation Analysis Percentage Purity of Valsartan and Sacubitril were found to be % and % respectively. (Table 6) Stability Studies The % degradation was calculated in each degradation condition with the corresponding of both the drugs under non-degradation condition. Summary of degradation studies of Valsartan and Sacubitril were given in Table 7. Both drugs show highest degradation in acidic condition. TABLE 3 Precision Data of Valsartan and Sacubitril (Intra-day). Conc. Peak Area Average Conc. % Recovery SD %RSD ng/band ng/band Valsartan Sacubitril TABLE 4 Precision Data of Valsartan and Sacubitril ( Inter-day). Conc. Peak Area Average Conc. % Recovery SD % RSD ng/band ng/band Valsartan Sacubitril TABLE 5 Accuracy Data of Valsartan and Sacubitril. Level Conc. sample Conc. Std. Conc. (ng/band) % Recovery Avg. ng/band ng/band

4214 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 Fig. 8. Specificity chromatogram. TABLE 6 Fomulation data of Valsartan and Sacubitril.

7 4214 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 Fig. 8. Specificity chromatogram. TABLE 6 Fomulation data of Valsartan and Sacubitril. Concentration recovered % Recovered Sample ng/band Average SD % RSD Valsartan Sacubitril TABLE 7 Data for stability studies. S. No Degradation % Recovery Average % RSD % Degradation Valsartan 1. Acid Base Oxidation Thermal Photolytic Sacubitril 1. Acid Base Oxidation Thermal Photolytic Acid degradation: Forced degradation in acidic media was performed and % degradation was within the limit (Table 7). Chromatogram of acid degradation shown in Fig. 9. Base degradation: Forced degradation in alkaline media was performed and % degradation was within the limit. Chromatogram of base degradation shown in Fig. 10. Oxidation degradation: Forced degradation in oxidizing media was performed and % degradation was within the limit (Table 7). Chromatogram of Oxidation degradation shown in Fig. 11. Thermal degradation: Forced degradation in thermal condition was performed and % degradation was within the limit (Table 7). Chromatogram of thermal degradation shown in Fig. 12. Photolytic degradation: Forced degradation in photolytic condition was performed and % degradation was within the limit. (Table 7). Chromatogram of photolytic degradation shown in Fig. 13.

8 Patel et al: Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan 4215 Fig. 9. Acid Degradation. Fig. 10. Alkaline Degradation.

9 4216 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 Fig. 11. Oxidation Degradation. Fig. 12. Thermal Degradation.

10 Patel et al: Stability Indicating HPTLC Method for Simultaneous Estimation of Sacubitril and Valsartan 4217 Fig. 13. Photolytic Degradation. Conclusions A specific, accurate stability indicating method was developed for the estimation of Valsartan and Sacubitril in pharmaceutical dosage form using HPTLC. The method was validated by using various validation parameters and the method was found to be linear, precise, accurate and specific. From the degradation studies conducted it is concluded that Sacubitril and Valsartan were highest degradation in acidic media. This method was enable rapid quantitation of many samples in routine and quality control analysis of formulations. Acknowledgements The authors are thankful to Gitar Laboratories for providing gift sample of pure Valsartan and Sacubitril. The authors extended gratitude to institute (Sardar Patel College of Pharmacy, Bakrol, Anand). References Bhatia MS and Kokil SU (2009). Determination and validation of Valsartan and its degradation products by isocratic HPLC. J. chem. Met 3(1): Celebier M, Kaynak MS, Altinoz S, and Sahin S (2010). HPLC method development for the simultaneous analysis of amlodipine and valsartan in combined dosage forms and in vitro dissolution studies. Braz. J. pharm. Sci 46(4): Ghanty S, Das R, Maity S, and Sen KK (2014). RP-HPLC Method for Estimation of Valsartan in Solid Oral Dosage Forms. J. pharm. Sci. tech., 3(2); Goyal. R.K. (2009). Element of Human Anatomy and Health Education, 21 st, B.S Shah Prakashan, Ahmedabad. Haque MA, Amrohi SH, Kumar PK, Dibyalochan P, and Diwan PV (2012). Stability indicating RP-HPLC method for the estimation of Valsartan in pharmaceutical dosage form. Int. J. Pharm 2(4): ICH Harmonized Tripartite Guideline: Validation of Analytical Procedures: Text and Methodology, Q2 (R1), Geneva, Switzerland, ICH, Validation of Analytical Procedures; Methodology, Q2 (R1), International Conference on Harmonization, IFPMA, Geneva Imam SS, Ahad A, Aqil M, Ali A, and Sultana Y (2013). A validated RP-HPLC method for simultaneous determination of propranolol and valsartan in bulk drug and gel formulation. J. Pharm. Bio. Allied Sci 5(1): Kendre MD and Banerji SK (2012). Precise and Accurate RP-HPLC Method Development for Quantification of Valsartan in Tablet Dosage Form, Int. J. Pharm. Sci. and Drug Res., 4(2): Kokil SU and Bhatia MS (2009). Simultaneous Estimation of Nebivolol Hydrochloride and Valsartan using RP-HPLC. Ind. J. Pharm. Sci 71(2): Kumaraswamy G, Kumar JM, Rao SJ, and Laxmi SM (2012). Validated RP-HPLC Method For Simultaneous Estimation of Aliskiren and Valsartan in Tablet Dosage Form. J. drug del. And thera 2(5): Kumar PS, Sahu M, Prasad KD, and Shekhar MC (2011). Development and Validation of Analytical Method for the Estimation of Valsartan In Pure And Tablet Dosage Form By RP-HPLC Method, Int. J. Res in Phar. And Chem 1(4): Manoranjani M and Bhagykumar T (2011). RP-HPLC Method for the Estimation of Valsartan in Pharmaceutical Dosage Forms. Int. J. Sci. Inn. Disc 1(2):

11 4218 Int J Pharm Sci Nanotech Vol 11; Issue 4 July August 2018 Nissan Kararao S, Kumar A, Sravanthi A, and Naga SJ (2013). Method development and validation for the estimation of valsartan in bulk and tablet dosage forms by RP-HPLC Der Pharm. Chem 5(2): Parambi DT, Mathew M, and Ganesan V (2011). A validated stability indicating HPLC method for the determination of Valsartan in tablet dosage forms. J. App Pharm. Sci 1(4): Patel NR and Patel SK (2012). First derivative Spectrophotometric method for the simultaneous estimation of Valsartan and Hydrochlorthiazide in their combined dosage form. Int. J. Pharm. And Life sci 3(7): Patel KH, Luhar SV, and Narkhede SB (2016). Simultaneous Estimation of Sacubitril and Valsartan in Synthetic Mixture by RP-HPLC Method. J. Pharm. Sci. and Bio. Sci 6(3): The Merk Index, An Encyclopedia of chemical, Drugs and Biological, 14 th ed. pp Tripathi K D. (2008). Essential of medical pharmacology, 6 th ed. Jaypee Brothers Medical Publishers (p) Ltd, New Delhi. Vizuda DU, Sailor GU, and Sheth NR (2010). RP-HPLC Method for Determination of Valsartan in Tablet Dosage Form. Int. J. Chem. Tech. Res. 2(3): Address correspondefnce to: Gopi Patel, Department of Pharmaceutical, Chemistry, Sardar Patel College of Pharmacy, Bakrol, Anand, Gujarat, India. Ph: gopiptl@gmail.com

Development and Validation of Stability Indicating HPTLC Method for Estimation of Seratrodast

ARC Journal of Pharmaceutical Sciences (AJPS) Volume 2, Issue 3, 2016, PP 15-20 ISSN 2455-1538 DOI: http://dx.doi.org/10.20431/2455-1538.0203004 www.arcjournals.org Development and Validation of Stability