HPLC-DAD method for the simultaneous determination of zofenopril and hydrochlorothiazide in oral pharmaceutical formulations

An LC-MS/MS Method for Determination of Triple Drugs Combination of Valsartan, Amlodipine and Hydrochlorothiazide in Human Plasma for Bioequivalence Study

Background:

Current guidelines for the treatment of hypertension recommend combination therapy, which intends to control blood pressure and enhance cardiovascular protection.

Materials and Methods:

A sensitive, reliable and selective tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous quantification of amlodipine (AML), valsartan (VAL) and hydrochlorothiazide (HCTZ) in human plasma. The chromatographic system was equipped with ACE 5 C8 (50 X 2.1 mm) column and utilized a mobile phase composition of 0.5 mM Ammonium Chloride & 0.04% FA-Methanol (45:55% v/v). The method used three internal standards; AML-D4, HCTZ-D2 C13 and VAL-D3 with 10% intra- and inter-day precision, and 6% bias for all the analytes.

Results:

The assay was found to be linear with R-2 > 0.998, and the limits of quantification for AML, VAL and HCTZ were 0.2, 50.0 and 2.0 ng/mL, respectively. The analytes were found to be stable in plasma samples over short and long term storage.

:

The developed method is rapid with a run time of 3.5 min and cost-effective since the simple sample preparation method is adopted. This method was successfully applied for the bioequivalence study of AML, VAL, and HCTZ in human plasma after administration of the fixed-dose combination tablet of (10/160/25 mg). Pharmacokinetic parameters (Cmax and AUC0-72) for AML and (Cmax, AUC0-t, AUC0-∞) for VAL and HCTZ were used for bioequivalence assessment. These were determined by noncompartmental analysis of concentration data.

Conclusion:

The result showed 90% confidence intervals (obtained by ANOVA) which were within the predefined ranges. As a consequence, this method can be successfully applied for measuring and quantifying a large number of samples.

Novel feature extraction approach for achieving potential spectral resolution: Green analytical application on zofenopril calcium and hydrochlorothiazide in their spectrally overlapping binary mixture

A novel and green spectrophotometric method, namely constant extraction, based on extracting a spectral feature value (constant ratio) has been developed and validated for simultaneous estimation of a binary mixture of zofenopril calcium (ZOF) and hydrochlorothiazide (HCT) in their bulk and marketable formulation. A comparative study between this newly developed method and four long-established ones; ratio difference, ratio subtraction coupled with constant multiplication, advanced amplitude modulation and absorbance subtraction has been carried out giving very promising results. Various analytical performance parameters like linearity, accuracy, precision, and robustness were investigated in accordance with ICH (Q2B). Satisfying optimized instrumental parameters; absorbance of ZOF and HCT were linearly increased for the previously mentioned methods in a concentration range 5.0-35.0 and 3.0-20.0 μg/mL, respectively showing correlation coefficients ≥0.9990. Moreover, specificity has been checked through analyzing synthetic mixtures of the studied analytes. Feasibility has been successfully assessed by simultaneous quantification of both analytes in the commercially available formulation. As well, validity was examined and no interference from common excipients was noticed. Observed data has been statistically compared with those of the published one concluding that no significant variations between both results have been indicated. Furthermore, greenness profile of these methods was assessed by analytical Eco-Scale and found superior to that of the reported HPLC method as an even greener approach for the simultaneous analysis of ZOF and HCT.

Conductomeric Evaluation of the Release Kinetics of Active Substances from Pharmaceutical Preparations Containing Iron Ions

The aim of this study was to verify the effect of the formulation on the release kinetics of active substances from preparations containing iron ions using in-line conductivity measurements. A simple, fast method was developed and may be applied for detailed evaluation of some kinetics factors obtained from the release data. Four different equations were used: zero-order equation, first-order equation, models: Korsmeyer–Peppas and Hixson–Crowell. Values of the determined half-time release for zero and first-order kinetic models ranged from 11.56 to 89.97 min. In the case of analysis according to these typical models, the values of the square root of the correlation coefficients were included between 0.9916 and 0.9995. The results transformed for the Hixson–Crowell model as constant release Ks, ranged between 0.0160 and 0.0437. The values of the respective calculated squares of the correlation coefficient ranged from 0.9933 to 0.9959. The determined release rate constants according to the Korsmeyer–Peppas model were between 0.0023 and 0.1630. The coefficients ‘n’ of the Korsmeyer–Peppas equation did not exceed 1.2 with the corresponding r² values 0.9408–0.9960. Obtained results confirmed that the method is applicable for evaluation of selected drug compositions containing iron ions.

Simultaneous determination of four sesquiterpenoids in Atractylodes Macrocephala Rhizoma by GC-FID: optimisation of an ultrasound-assisted extraction by central composite design

INTRODUCTION

Atractylodes Macrocephala Rhizoma (AMR) is a traditional Chinese medicine containing several sesquiterpenoids with a series of effects. These bioactive compounds may be used as chemical markers for the quality control of AMR. It is necessary to optimise the extraction method and conditions in order to improve extraction productivity.

OBJECTIVE

To develop a simple and effective method for the extraction of sesquiterpenoids from AMR and then to simultaneously determine four sesquiterpenoids, selina-4 (14), 7(11)-dien-8-one (SA), atractylenolide II (AII), atractylenolide III (AIII) and atractylenolide VII (AVII), in AMR.

METHODOLOGY

Ultrasound-assisted extraction (UAE) was optimised by central composite design (CCD) to obtain the maximum efficiency. The gas chromatography method was validated and applied for the quantification of four sesquiterpenoids.

RESULTS

The optimum values of factors were: particle size (120 mesh), extraction time (26 min), extraction temperature (39°C) and 31 mL of chloroform. The selectivity, linear range, limits of detection (LOD) and quantification (LOQ), accuracy, precision and repeatability of the method developed indicated its validity. The application of the method showed that the contents of four sesquiterpenoids in AMR were rather variable.

CONCLUSION

The results indicated that the described GC method could be used for the quality control of AMR and its related preparations. Meanwhile, this research revealed that UAE under optimum conditions could be considered as a powerful tool for the extraction of phytochemicals from plants.