Felodipine (FLD), a calcium channel antagonist, is commonly prescribed for the treatment of hypertension either with Metoprolol (MET) or Ramipril (RAM) in two different drug combinations. FLD has high plasma protein binding ability affecting its extraction recoveries from plasma samples. Hence, a specific ultrasound assisted dispersive liquid-liquid microextraction (UA-DLLME) method coupled with HPLC using photodiode array detector was developed and validated for the simultaneous determination of FLD, MET and RAM in rat plasma after oral administration of these combinations. The factors affecting UA-DLLME were carefully optimized. In this study, UA-DLLME method could provide simple and efficient plasma extraction procedures with superior recovery results. Under optimum condition, all target drugs were separated within 13 min. The validation procedures was carried out in agreement with US-FDA guidelines and shown to be suitable for anticipated purposes. Linear calibration ranges were obtained in the range 0.05–2.0mgmL−1 for FLD and MET and 0.1–2.0mgmL−1 for RAM with detection limits of 0.013–0.031mgmL−1 for all the studied drug combinations. The%RSD for inter-day and intra-day precisions was in range of 0.63–3.85% and the accuracy results were in the range of 92.13–100.5%. The validated UA-DLLME-HPLC method was successfully applied for the bioavailability studies of FLD, MET and RAM. The pharmacokinetic parameters were calculated for all the investigated drugs in rats after single-dose administrations of two different drug combinations. Although FLD was bioequivalent in the two formulations, a small increase in plasma levels of MET and RAM was found in the presence of FLD.

Felodipine (FLD), a calcium channel antagonist, is commonly prescribed for the treatment of hypertension either with Metoprolol (MET) or Ramipril (RAM) in two different drug combinations. FLD has high plasma protein binding ability affecting its extraction recoveries from plasma samples. Hence, a specific ultrasound assisted dispersive liquid-liquid microextraction (UA-DLLME) method coupled with HPLC using photodiode array detector was developed and validated for the simultaneous determination of FLD, MET and RAM in rat plasma after oral administration of these combinations. The factors affecting UA-DLLME were carefully optimized. In this study, UA-DLLME method could provide simple and efficient plasma extraction procedures with superior recovery results. Under optimum condition, all target drugs were separated within 13 min. The validation procedures was carried out in agreement with US-FDA guidelines and shown to be suitable for anticipated purposes. Linear calibration ranges were obtained in the range 0.05–2.0mgmL−1 for FLD and MET and 0.1–2.0mgmL−1 for RAM with detection limits of 0.013–0.031mgmL−1 for all the studied drug combinations. The%RSD for inter-day and intra-day precisions was in range of 0.63–3.85% and the accuracy results were in the range of 92.13–100.5%. The validated UA-DLLME-HPLC method was successfully applied for the bioavailability studies of FLD, MET and RAM. The pharmacokinetic parameters were calculated for all the investigated drugs in rats after single-dose administrations of two different drug combinations. Although FLD was bioequivalent in the two formulations, a small increase in plasma levels of MET and RAM was found in the presence of FLD.

A simple, sensitive, novel and eco-friendly electrochemical sensor was fabricated using naturally occurring dye and glassy carbon microparticles as an electro-conducting modifier. The modified electrode was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and scanning electron microscopy (SEM) techniques. This novel electrochemical sensor gave potent electrocatalytic activity and lowest detection limit toward oxidation of dacarbazine (DAC). The proposed method showed good linearity in the range of 7×10−8 to 5×10−6 M with low detection limit of 1.28×10−8 M. Furthermore, different chemical and instrumental variables were studied by factorial design approach and the optimum analytical conditions for determination of DAC were established. The proposed method was successfully applied to study photolytic degradation of DAC in 5% dextrose and 0.9% sodium chloride infusions after exposure to daylight and UV light. The presented work suggested different photo-degradation pathways of DAC indicating its importance for future development of a stable formulation for a long-term infusion therapy.

A simple, sensitive, novel and eco-friendly electrochemical sensor was fabricated using naturally occurring dye and glassy carbon microparticles as an electro-conducting modifier. The modified electrode was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and scanning electron microscopy (SEM) techniques. This novel electrochemical sensor gave potent electrocatalytic activity and lowest detection limit toward oxidation of dacarbazine (DAC). The proposed method showed good linearity in the range of 7×10−8 to 5×10−6 M with low detection limit of 1.28×10−8 M. Furthermore, different chemical and instrumental variables were studied by factorial design approach and the optimum analytical conditions for determination of DAC were established. The proposed method was successfully applied to study photolytic degradation of DAC in 5% dextrose and 0.9% sodium chloride infusions after exposure to daylight and UV light. The presented work suggested different photo-degradation pathways of DAC indicating its importance for future development of a stable formulation for a long-term infusion therapy.

YANG XIN is a traditional Chinese medicine formulation used for nervous fatigue and consists of a proprietary blend of concentrated extracts from 18 plant ingredients. The 18 constituent plant ingredients, YANG XIN capsules, and formulations 2014–005_1 A and 1B were extracted by consecutive 24-hour macerations with dichloromethane followed by methanol. Metabolite separation was carried out through LC‑MS in 40 minutes. Data acquisitions for qualitative and quantitative analyses of the samples were collected under (±) ESI modes and (+) APCI mode using full spectrum scan analysis. A total of 18 analytical markers were identified by LC‑MS for YANG XIN formulations based on accurate mass measurements, molecular formula, double bond equivalent, MFG score, and error (ppm) of the measurement. Aditionally, a comparison of the data with previously reported results for the compounds, followed by identity confirmationwith standard compounds, was performed. Seventeen analytical markers representing 17 plant ingredients in the different YANG XIN formulations were quantified for the first time. The YANG XIN capsules and the 2014– 005_1B formulation were similar to each other and different from the 2014–005_1 A formulation based on the fact that both YANG XIN capsules and the 2014–005_1B formulation contain the same analytical markers. This method provides good linearity (r2 > 0.9945), intraday precision (R.S.D. 3.9%), interday precision (R. S. D. 5.6 %), accuracy (99.2–101%), recovery (145.7%), limit of detection (0.0011–0.0732 μg/mL), and limit of quantitation (0.0038–0.2441 μg/mL).

A simple and non-destructive FTIRmethodwas used to determine certain proton pumpinhibitors (PPIs) in binary and ternary mixtures. Proton pump inhibitors (PPIs); omeprazole (OMZ), esomeprazole (EZM), lansoprazole (LAN), pantoprazole sodium (PAN sodium) and rabeprazole sodium (RAB sodium) in binary mixture with domperidone (DOM) and ternary mixture of OMZ, clarithromycin (CLM) and tinidazole (TNZ) were determined in the solid-state by FTIR spectroscopy for the first time. The method was validated according to ICH-guidelines where linearitywas ranged from20 to 850 μg/g and 20–360 μg/g for PPIs and DOM, respectively in binarymixtures and 10–400, 100–8000 and 150–14,000 μg/g forOMZ, CLMand TNZ, respectively. Limits of detectionwere found to be 6–100 and 9–100 μg/g for PPIs and DOM, respectively and 4, 40 and 50 μg/g forOMZ, CLMand TNZ, respectively. The method was applied successfully for determination of the cited drugs in their respective pharmaceutical dosage forms.

A simple and non-destructive FTIRmethodwas used to determine certain proton pumpinhibitors (PPIs) in binary and ternary mixtures. Proton pump inhibitors (PPIs); omeprazole (OMZ), esomeprazole (EZM), lansoprazole (LAN), pantoprazole sodium (PAN sodium) and rabeprazole sodium (RAB sodium) in binary mixture with domperidone (DOM) and ternary mixture of OMZ, clarithromycin (CLM) and tinidazole (TNZ) were determined in the solid-state by FTIR spectroscopy for the first time. The method was validated according to ICH-guidelines where linearitywas ranged from20 to 850 μg/g and 20–360 μg/g for PPIs and DOM, respectively in binarymixtures and 10–400, 100–8000 and 150–14,000 μg/g forOMZ, CLMand TNZ, respectively. Limits of detectionwere found to be 6–100 and 9–100 μg/g for PPIs and DOM, respectively and 4, 40 and 50 μg/g forOMZ, CLMand TNZ, respectively. The method was applied successfully for determination of the cited drugs in their respective pharmaceutical dosage forms.

A simple and non-destructive FTIRmethodwas used to determine certain proton pumpinhibitors (PPIs) in binary and ternary mixtures. Proton pump inhibitors (PPIs); omeprazole (OMZ), esomeprazole (EZM), lansoprazole (LAN), pantoprazole sodium (PAN sodium) and rabeprazole sodium (RAB sodium) in binary mixture with domperidone (DOM) and ternary mixture of OMZ, clarithromycin (CLM) and tinidazole (TNZ) were determined in the solid-state by FTIR spectroscopy for the first time. The method was validated according to ICH-guidelines where linearitywas ranged from20 to 850 μg/g and 20–360 μg/g for PPIs and DOM, respectively in binarymixtures and 10–400, 100–8000 and 150–14,000 μg/g forOMZ, CLMand TNZ, respectively. Limits of detectionwere found to be 6–100 and 9–100 μg/g for PPIs and DOM, respectively and 4, 40 and 50 μg/g forOMZ, CLMand TNZ, respectively. The method was applied successfully for determination of the cited drugs in their respective pharmaceutical dosage forms.

+is contribution describes a simple, fast, and sensitive application of localized surface plasmon resonance e0ect of silver nanoparticles for simultaneous determination of antihypertensive drugs’ mixture atenolol and amiloride in both pharmaceutical dosage forms and in biological samples (urine). Silver nanoparticles were prepared by chemical reduction of silver nitrate using hydroxylamine HCL in an alkaline medium. Application of silver-hydroxylamine nanoparticles (SH NPs) provides many advantages including reproducibility, sensitivity, and cost e0ective way of analyte determination. Amiloride has four amino groups which act as attachment points on the surface of silver nanoparticles resulting in a synergistic e0ect on the absorption intensity of atenolol, leading to increase the sensitivity of the determination of both compounds. +is method shows excellent advantages comparing with the previously reported methods, including accuracy, precision, and selectivity. +e linear range of atenolol is 1 ×10−5–1 ×10−4 mol·L−1 and of amiloride is 1 ×10−6–1 ×10−5 mol·L−1. +e limit of detection (LOD) values of atenolol and amiloride are 0.89 ×10−5 and 0.42 ×10−6 mol·L−1, respectively.

Nifedipine and atenolol dugs are conjugated in several anti-hypertensive pharmaceutical formulations. Herein, a reproducible and sensitive voltammetric procedure has been developed for the simultaneous analysis of nifedipine and atenolol for the first time using MgO - nanoplatelets modified screen-printed electrodes (MgO - SPEs) via differential pulse voltammetry (DPV). Two very well-resolved and reproducible signals/oxidation peaks with a voltammetric separation of 0.35 V were obtained in Britton–Robinson (BR) buffer (pH 9). The MgO NPLs are found to exhibit a high electrocatalytic activity and improved voltammetric response compared to unmodified (bare) SPEs. Under optimum pH conditions (pH 9), the DPV curves exhibit linear responses to nifedipine and atenolol over the concentration ranges of 0.2–104.41 µM and 6.66–909.09 µM with detection limits of 0.032 µM and 1.76 µM, respectively. The applicability of the MgO-SPEs is successfully utilized for simultaneous determination of nifedipine and atenolol in pharmaceutical tablets and human urine samples with good accuracy and precision, these results agreeing with independent high-performance liquid chromatography (HPLC).