Development and validation of a reliable and rapid LC-MS/MS method for simultaneous quantification of sacubitril and valsartan in rat plasma and its application to a pharmacokinetic study: Simultaneous quantification of sacubitril and valsartan in rat plasma

Bioanalytical HPLC method with fluorescence detector for determination of Entresto™ when co-administered with ibuprofen and fexofenadine: a pharmacokinetic study

Entresto™ (LCZ696) has been approved globally for heart failure management. However, its lifelong use alongside over-the-counter (OTC) drugs like ibuprofen (IBU) and fexofenadine (FEX) necessitates an in-depth investigation of potential pharmacokinetic interactions, as they share the same metabolic and elimination pathways. This study aimed to develop a bioanalytical HPLC method with a fluorescence detector (FLD) to quantify LCZ696 analytes (valsartan, VAL; sacubitril, SAC; and sacubitril active metabolite, LBQ657) in rat plasma. Additionally, an in vivo study was performed to investigate the pharmacokinetic interactions of LCZ696 with IBU and FEX. Utilizing HPLC with a gradient-mode mobile phase of acetonitrile and 0.025 M phosphate buffer (pH 3), the study demonstrated a significant increase in the bioavailability of LCZ696 analytes (VAL and LBQ657) when co-administered with IBU (C max 0.23 ± 0.07 and 0.53 ± 0.21 μg mL-1, respectively) compared to the control (0.17 ± 0.03 and 0.33 ± 0.14 μg mL-1). A more significant increase in C max was noticed with FEX (0.38 ± 0.01 and 0.77 ± 0.18 μg mL-1, respectively). Moreover, a decrease in the clearance (Cl/F) of VAL and LBQ657 was observed (18.05 ± 1.94 and 12.42 ± 2.97 L h-1 kg, respectively) with a more pronounced effect in the case of FEX (30.87 ± 4.29 and 33.14 ± 9.57 L h-1 kg, respectively) compared to the control (49.99 ± 7.31 and 51.19 ± 9.12 L h-1 kg, respectively). In conclusion, our study underscores the importance of cautious administration and appropriate dose spacing of IBU and FEX in patients treated with LCZ696 to prevent elevated serum concentrations and potential toxicity. The novelty of this work lies in its dual contribution: developing a highly sensitive HPLC-FLD method and comprehensively elucidating significant pharmacokinetic interactions between LCZ696 and common OTC drugs.

Development and validation of a sensitive and simple LC-MS/MS method for simultaneous quantitation of valsartan, sacubitril and sacubitrilat in pediatric population

Pediatric heart failure (HF) is an important clinical disease with high hospitalization rates, morbidity, mortality and medical costs. Sacubitril/valsartan (also known as Entresto), was approved for the treatment of adult HF and is recently used in pediatrics. However, clinical therapy on children is more challenging than adults, and the pharmacokinetics of Entresto in children are still largely unknown and urgently needed. Herein, we aim to develop a simple and sensitive analytic method to monitor Entresto in pediatric patients, which is of great importance for individualized safe medication in children. Specifically, a liquid chromatography tandem mass spectrometry method for simultaneously quantification of valsartan, sacubitril and its bio-active metabolite sacubitrilat in human plasma has been developed and validated in pediatric patients. Plasma samples were pretreated with acetonitrile for protein precipitation. Elution was performed on X Select HSS T3 column (2.1 × 100 mm, 5 µm; Waters) column using an isocratic mobile phase process consisting of 0.1% formic acid aqueous solution and 0.1% formic acid acetonit rile with a total run time of 3.0 min. Valsartan-d3, sacubitrilin-d4 and sacubitrilat-d4 were used as the corresponding deuterium internal standards. According to the Bioanalytical Method Validation Guidance for Industry, the method was validated in the range of 0.5-5000 ng/mL. Intra- and inter-day accuracy of sacubitril,valsartan and sacubitrilat ranged from 93%- 108%, 98%- 109%, 91%- 102%, respectively, with relative standard deviation of precision ranging from 2.0% to 5.1%, 2.4%- 7.5%, 1,3%- 7.4%. The proposed method demonstrated good accuracy, precision and linearity. The matrix factors normalized by internal standard meet the acceptance criteria. The method was fully validated and applied in 39 children. Trough concentration of the three substances to be measured were: valsartan (11.3-938.0 ng/mL), sacubitril (0.5-395.5 ng/mL) and sacubitrilat (522.1-4890.0 ng/mL). Overall, this is the first study to simultaneously determined the plasma valsartan, sacubitril and sacubitrilat concentrations in children, which is believed to facilitate the clinical management of pediatric HF.

Comparison of the Determination of Some Antihypertensive Drugs in Clinical Human Plasma Samples by Solvent Front Position Extraction and Precipitation Modes

The determination of the selected antihypertensive drugs in human plasma samples with the novel solvent front position extraction (SFPE) technique is presented. The SFPE procedure combined with LC-MS/MS analysis was used for the first time to prepare a clinical sample containing the drugs mentioned above from different therapeutic groups. The effectiveness of our approach was compared with the precipitation method. The latter technique is usually used to prepare biological samples in routine laboratories. During the experiments, the substances of interest and the internal standard were separated from other matrix components using a prototype horizontal chamber for thin-layer chromatography/high-performance thin-layer chromatography (TLC/HPTLC) with a moving pipette powered by a 3D mechanism, which distributed the solvent on the adsorbent layer. Detection of the six antihypertensive drugs was performed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring (MRM) mode. Results obtained by SFPE were very satisfactory (linearity R² ≥ 0.981; %RSD ≤ 6%; LOD and LOQ were in the range of 0.06-9.78 ng/mL and 0.17-29.64 ng/mL, respectively). The recovery was in the range of 79.88-120.36%. Intra-day and inter-day precision had a percentage coefficient of variation (CV) in the range of 1.10-9.74%. The procedure is simple and highly effective. It includes the automation of TLC chromatogram development, which significantly reduced the number of manual operations performed, the time of sample preparation and solvent consumption.

Development and validation of a stability-indicating, single HPLC method for sacubitril-valsartan and their stereoisomers and identification of forced degradation products using LC-MS/MS

The aim of this research work was to develop and validate a stability-indicating, single reversed-phase HPLC method for the separation of five impurities, including enantiomers, diastereomers, and degradation products in sacubitril-valsartan tablets. The method was developed using a Chiralcel OJ-RH column (150 × 4.6 mm, 5 μm) at 45°C with a gradient program of (T/%B) 0.01/25, 10.0/25, 25/38, 37.0/45, 39.0/25, and 45.0/25 at a flow rate of 0.8 ml/min. Mobile phase A consisted of 1 ml of trifluoroacetic acid in 1000 ml of Milli-Q water. Mobile phase B consisted of 1 ml of trifluoroacetic acid in a mixture of acetonitrile and methanol in the ratio of 950:50 (v/v). Sacubitril, valsartan, and their five impurities were monitored at 254 nm. Degradation was not observed when sacubitril-valsartan was subjected to heat, light, hydrolytic, and oxidation conditions. In acid degradation study (1 N HCl/60°C/2 h) impurity 1 (m/z 383.44) was formed, and in base degradation study (0.1 N NaOH/40°C/1 h) impurities 1 and 5 (m/z 265.35) were formed; both impurities were confirmed using LC-MS. The degradation products, enantiomers, and diastereomers were well separated from sacubitril and valsartan, proving the stability-indicating power of the method. The developed method was validated per the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines. The inter- and intra-day percentage relative standard deviation for sacubitril, valsartan, and their five impurities was less than 5.2%, recovery of the five impurities was between 93 and 105%, and linearity was ≥0.999. The limit of detection was 0.030-0.048 μg/ml, and the limit of quantification was 0.100-0.160 μg/ml.

Development and validation of a novel stability-indicating reverse phase HPLC method for the determination of sacubitril-valsartan premix stereoisomers: Cellulose tris(4-methyl benzoate) stationary phase

A new stability indicating reverse phase HPLC method has been developed, optimized and validated as per International Conference on Harmonization guidelines for the determination of stereoisomers namely (2R)-valsartan, (2S,4S)-sacubitril, (2R,4S)-sacubitril and (2R,4R)-sacubitril in sacubitril-valsartan premix. Primarily, stability indicating separation study was done on reverse phase LC conditions; it was described by peak homogeneity of sacubitril-valsartan and its stereoisomers. Separation achieved on cellulose tris(4-methylbenzoate) packing column Chiralcel OJ-RH(150 mm x 4.6 mm), 5 μm than those of amylose based stationary phase's. Resolution between two arbitrary adjacent analyte was found to be more than 2.0 with 0.1% trifluoroacetic acid in water as mobile phase-A and mobile phase-B consisting of acetonitrile, methanol and trifluoroacetic acid (90:10:0.1 v/v/v). Gradient elution was performed at a flow rate of 1.0 mL/min, column temperature 20°C, injection volume 10 μL, UV detection at 254 nm and run time was 52 mins. The detector response found to be linear (R²  ≥ 0.9998), limit of detection (0.290 μg/mL, 0.122 μg/mL, 0.123 μg/mL and 0.124 μg/mL) and limit of quantification (0.878 μg/mL, 0.370 μg/mL, 0.373 μg/mL and 0.375 μg/mL), respectively. Percentage recovery found to be 98-105. Finally, the proposed method is user-friendly and can be used in bulk drugs analysis. This article is protected by copyright. All rights reserved.

Synchronized determination of sacubitril and valsartan with some co-administered drugs in human plasma via UPLC-MS/MS method using solid-phase extraction

An accurate and sensitive UPLC-MS/MS method was developed and validated for the simultaneous estimation of the newly developed combination of sacubitril and valsartan and the co-administered drugs nebivolol, chlorthalidone and esomeprazole in human plasma. Solid-phase extraction was conducted for the purification and extraction of the drugs from human plasma. Chromatographic separation was carried out on an Agilent SB-C₁₈ (1.8 μm, 2.1 × 50 mm) column using losartan as internal standard. Isocratic elution was applied using acetonitrile-0.1% formic acid in water (85: 15, v/v) as mobile phase. Detection was carried out using a triple-quadrupole tandem mass spectrometer using multiple reaction monitoring, at positive mode at m/z 412.23 → 266.19 for sacubitril, m/z 436.29 → 235.19 for valsartan, m/z 405.8 → 150.98 for nebivolol, m/z 346.09 → 198 for esomeprazole and a selected combination of two fragments m/z 423.19 → 207.14 and 423.19 → 192.2 for losartan (internal standard), and in negative ionization mode at m/z 337.02 → 190.12 for chlorthalidone. The method was linear over the concentration ranges 30-2,000 ng/ml for sacubitril, 70-2,000 ng/ml for valsartan, esomeprazole and chlorthalidone and 70-5,000 pg/ml for nebivolol. The developed method is sensitive and selective and could be applied for dose adjustment, bioavailability and drug-drug interaction studies.

Synchronized determination of the novel heart failure combination therapy containing sacubitril calcium and valsartan by a validated spectrofluorimetric method

A sensitive and accurate spectrofluorimetric method was proposed for the determination of Sacubitril calcium and Valsartan simultaneously in binary mixture. The method was established on measuring the native fluorescence of Sacubitril calcium and Valsartan upon excitation at 240 nm in acetonitrile. The emission of Sacubitril calcium was measured at 615 nm. For the determination Valsartan a first derivative ratio method was employed to eliminate any spectral interference. The ratio emission spectra were achieved by dividing the emission spectra of various concentrations of Valsartan by the emission spectrum of Sacubitril calcium (100 ng/ml) then the first derivative of the obtained ratio emission spectra was recorded using the proper smoothing factor. The amplitude at 354.9 nm on the first derivative ratio emission spectrum was used to calculate the concentrations of Valsartan in presence of Sacubitril calcium. The method was linear over the concentration range 100-1000 ng/ml for both Sacubitril calcium and Valsartan. The mean accuracy values were found to be 99.32 ± 0.62 and 99.30 ± 0.70 for Sacubitril calcium and Valsartan, respectively. Statistical comparison between results obtained by the proposed method and a reported method for this drugs showed no significant difference. This developed method was used for the quantitative determination of Sacubitril calcium and Valsartan in both pure and pharmaceutical dosage form.

Quality by Design Approach to Develop Stability Indicating Method to Quantify Related Substances and Degradation Products of Sacubitril by High Performance Liquid Chromatography

Sacubitril (SBT) is a neprilysin inhibitor, approved by food and drug administration (FDA) in 2015, under the FDA's priority review process. In this work, we report the validated stability indicating method of SBT by employing quality by design (QbD) principles related to analytical method development, capable in separation of 11 impurities. Chromatographic separation was performed on an ascentis phenyl hexyl column using 10 mM KH2PO4 as a mobile phase-A and the pH adjusted to 2.1. Methanol: acetonitrile (70:30 v/v) solvent mixture was employed as the mobile phase-B in a gradient mode of elution at a flow rate 0.8 mL/min at 30°C. The column effluents were monitored by a photo diode array detector set at a wavelength of maximum absorption 254 nm noted for all the impurities and furthermore for SBT. This method was remarked to be accurate in the range from 92 to 116%, precise with relative standard deviation 0.9% for SBT (0.8 mg/mL) and 1.0 to 2.1% for its related impurities (0.0005 mg/mL) also linear with correlation coefficient r ≥ 0.9989. The limits of quantification for all impurities were 0.05% with respect to sample concentration 0.8 mg/mL. The developed method revealed a good method operable design range for the experimental chromatographic conditions. Forced degradation of SBT carried under acidic, basic and oxidative stressed conditions manifested that the method is stability indicating.

A validated RP-HPLC method for the evaluation of the influence of grapefruit juice on liver S9 activation of sacubitril

Grapefruit juice inhibits esterase enzyme. Therefore, a possible interaction with ester prodrugs should be taken into consideration. In this study, the influence of grapefruit juice on sacubitril (SAC) rat liver S9 activation by esterase enzyme was evaluated. An RP-HPLC method was developed and validated for estimation of SAC in rat liver S9 fraction using a C₁₈ Cyano column as stationary phase and acetonitrile-sodium di-hydrogen phosphate buffer (0.02 m, pH 4 adjusted by o-phosphoric acid, 40:60, v/v), as mobile phase at a flow rate of 1 mL/min and UV detection at 254 nm. The method was successfully applied to an in vitro study in which SAC was incubated with rat liver S9 fraction prepared from rats that had previously ingested grapefruit juice for a week. The calculated SAC concentration after incubation was compared with that of SAC incubated with rat liver S9 fraction from the rat control group. The statistical significance between the results of test and control incubation sets was assessed. In conclusion, the current study demonstrated that grapefruit juice decreased SAC hydrolysis, hence delaying its activation to sacubitrilat (active form) in gut lumen. Based on this food-drug interaction, it may be required that grapefruit juice should be consumed with caution in patients receiving SAC.

High performance thin-layer and high performance liquid chromatography coupled with photodiode array and fluorescence detectors for analysis of valsartan and sacubitril in their supramolecular complex with quantitation of sacubitril-related substance in raw material and tablets

Valsartan (VAL) and sacubitril (SAC) are combined in a supramolecular complex, LCZ696, which is a newly approved remedy for heart failure. SAC-related substance (biphenyl methyl pyrrolidinone [BMP]) which also appears as an intermediate during SAC synthesis is considered to be a suspected impurity for SAC and/or LCZ696 tablets. The study investigates the analysis of VAL and SAC in their supramolecular complex along with SAC-related substance, BMP, using high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) with two different detectors; fluorescence detector (FLD) and diode array detector (DAD). The work aimed at analyzing BMP at low levels in the presence of its parent drug, SAC. BMP was successfully analyzed at a level of 0.167, 1 and 3% of its parent drug, SAC upon using HPLC-FLD, HPLC-DAD and HPTLC, respectively. For HPLC-FLD, the detector was set at λex/λem (nm/nm): 0-4.5 min at 255/374; 4.5-6 min at 255/314, for achieving an adequate sensitivity of the method to monitor and quantify VAL and SAC in the presence of BMP. Low limits of detection (8.3, 3.3 and 1.7 ng mL-1) and limits of quantitation (25, 10 and 5 ng mL-1) values obtained for VAL, SAC and BMP, respectively, upon using FLD suggest that low level of baseline noise enables the detection and quantitation of low BMP concentration.

Innovative spectrophotometric methods for simultaneous estimation of the novel two-drug combination: Sacubitril/Valsartan through two manipulation approaches and a comparative statistical study

Different innovative spectrophotometric methods were introduced for the first time for simultaneous quantification of sacubitril/valsartan in their binary mixture and in their combined dosage form without prior separation through two manipulation approaches. These approaches were developed and based either on two wavelength selection in zero-order absorption spectra namely; dual wavelength method (DWL) at 226nm and 275nm for valsartan, induced dual wavelength method (IDW) at 226nm and 254nm for sacubitril and advanced absorbance subtraction (AAS) based on their iso-absorptive point at 246nm (λ_iso) and 261nm (sacubitril shows equal absorbance values at the two selected wavelengths) or on ratio spectra using their normalized spectra namely; ratio difference spectrophotometric method (RD) at 225nm and 264nm for both of them in their ratio spectra, first derivative of ratio spectra (DR¹) at 232nm for valsartan and 239nm for sacubitril and mean centering of ratio spectra (MCR) at 260nm for both of them. Both sacubitril and valsartan showed linearity upon application of these methods in the range of 2.5-25.0μg/mL. The developed spectrophotmetric methods were successfully applied to the analysis of their combined tablet dosage form ENTRESTO™. The adopted spectrophotometric methods were also validated according to ICH guidelines. The results obtained from the proposed methods were statistically compared to a reported HPLC method using Student t-test, F-test and a comparative study was also developed with one-way ANOVA, showing no statistical difference in accordance to precision and accuracy.