Journal of Pharmaceutical Analysis

2017, 7(3): 封3-封4.

Abstract(72) PDF(0)

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Electromembrane extraction–Recent trends and where to go

Stig Pedersen-Bjergaard, Chuixiu Huang, Astrid Gjelstad

2017, 7(3): 141-147.

Abstract(102) PDF(0)

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Electromembrane extraction (EME) is an analytical microextraction technique, where charged analytes (such as drug substances) are extracted from an aqueous sample (such as a biological fluid), through a supported liquid membrane (SLM) comprising a water immiscible organic solvent, and into an aqueous acceptor solution. The driving force for the extraction is an electrical potential (dc) applied across the SLM. In this paper, EME is reviewed. First, the principle for EME is explained with focus on extraction of cationic and anionic analytes, and typical performance data are presented. Second, papers published in 2016 are reviewed and discussed with focus on (a) new SLMs, (b) new support materials for the SLM, (c) new sample additives improving extraction,(d) new technical configurations, (e) improved theoretical understanding, and (f) pharmaceutical new applications. Finally, important future research objectives and directions are defined for further development of EME, with the aim of establishing EME in the toolbox of future analytical laboratories.

Multi-spectroscopic characterization of bovine serum albumin upon interaction with atomoxetine

Arunkumar T. Buddanavar, Sharanappa T. Nandibewoor

2017, 7(3): 148-155.

Abstract(178) PDF(1)

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The quenching interaction of atomoxetine (ATX) with bovine serum albumin (BSA) was studied in vitro under optimal physiological condition (pH=7.4) by multi-spectroscopic techniques. The mechanism of ATX-BSA system was a dynamic quenching process and was confirmed by the fluorescence spectra and lifetime measurements. The number of binding sites, binding constants and other binding characteristics were computed. Thermodynamic parameters ΔH0 and ΔS0 indicated that intermolecular hydrophobic forces predominantly stabilized the drug-protein system. The average binding distance between BSA and ATX was studied by F?rsters theory. UV-absorption, Fourier transform infrared spectroscopy (FT-IR), circular dichroism (CD), synchronous spectra and three-dimensional (3D) fluorescence spectral results revealed the changes in micro-environment of secondary structure of protein upon the interaction with ATX. Displacement of site probes and the effects of some common metal ions on the binding of ATX with BSA interaction were also studied.

Separation of atropisomers by chiral liquid chromatography and thermodynamic analysis of separation mechanism

Ling Zhang, Yue Hu, Elizabeth Galella, Frank P. Tomasella, William P.Fish

2017, 7(3): 156-162.

Abstract(94) PDF(1)

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In the pharmaceutical industry, the analysis of atropisomers is of considerable interest from both scientific and regulatory perspectives. The compound of interest contains two stereogenic axes due to the hindered rotation around the single bonds connecting the aryl groups, which results in four potential configurational isomers (atropisomers). The separation of the four atropisomers was achieved on a derivatized β-cyclodextrin bonded stationary phase. Further investigation showed that low temperature conditions, including sample preparation (?70 °C), sample storage (?70 °C), and chromatographic separation (6 °C), were critical to preventing interconversion. LC-UV-laser polarimetric analysis identified peaks 1 and 2 as a pair of enantiomers and peaks 3 and 4 as another. Thermodynamic analysis of the retention data indicated that the separation of the pairs of enantiomers is primarily enthalpy controlled as indicated by the positive slope of the van't Huff plot. The difference in absolute Δ (Δ H), ranged from 2.20 kJ/mol to 2.42 kJ/mol.

Fast and sensitive LC–MS/MS method for the simultaneous determination of lisinopril and hydrochlorothiazide in human plasma

Jaivik V. Shah, Priyanka A. Shah, Priya V. Shah, Mallika Sanyal, Pranav S. Shrivastav

2017, 7(3): 163-169.

Abstract(165) PDF(10)

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A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC– MS/MS) method has been developed for the simultaneous determination of lisinopril (LIS) and hydrochlorothiazide (HCTZ) in human plasma using their labeled internal standards (ISs). Sample pre-treatment involved solid phase extraction on Waters Oasis HLB cartridges using 100 μL of plasma, followed by liquid chromatography on Hypersil Gold C18 (50 mm×3.0 mm, 5 μm) column. The analytes were eluted within 2.0 min using acetonitrile-5.0 mM ammonium formate, pH 4.5 (85:15, v/v) as the mobile phase. The analytes and ISs were analyzed in the negative ionization mode and quantified using multiple reaction monitoring. The method showed excellent linearity over the concentration range of 0.50–250.0 ng/mL for both the analytes. The intra-batch and inter-batch precision (% CV) was ≤5.26% and their extraction recoveries were in the range of 96.6% –103.1%. Matrix effect evaluated in terms of IS-normalized matrix factors ranged from 0.97 to 1.03 for both the analytes. The validated method was successfully applied to determine the plasma concentration of the drugs using 10 mg lisinopril and 12.5 mg hydrochlorothiazide fixed dose formulation in 18 healthy Indian volunteers.

Effect of processing on the alkaloids in Aconitum tubers by HPLC-TOF/MS

Min Liu, Yan Cao, Diya Lv, Wen Zhang, Zhenyu Zhu, Hai Zhang, Yifeng Chai

2017, 7(3): 170-175.

Abstract(179) PDF(2)

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According to the Chinese Pharmacopoeia 2015, only processed Aconitum tubers can be clinically applied, and the effect of processing is unclear. This research aimed to explore the effect of processing on cardiac efficacy of alkaloids in Aconitum tubers. First, the chemical ingredients in unprocessed and processed Aconitum tubers were identified and compared by using high performance liquid chromatography time-of-flight mass spectrometry (HPLC-TOF/MS) and multivariate pattern recognition methods. Then the representative alkaloids in Aconitum tubers, aconitine, benzoylaconine, and aconine, which belong to diester-diterpenoid alkaloids, monoester-diterpenoid alkaloids, and amine-diterpenoid alkaloids, respectively, were selected for further validation of attenuated mechanism. Subsequent pharmacological experiments with aconitine, benzoylaconine, and aconine in SD rats were used to validate the effect of processing on cardiac functions. After processing the Aconitum tubers, it was found that the contents of diester-diterpenoid alkaloids were reduced, and those of monoester-diterpenoid alkaloids and amine-diterpenoid alkaloids were increased, suggesting that diesterditerpenoid alkaloids were transformed into monoester-diterpenoid alkaloids and amine-diterpenoid alkaloids. Through further decocting the aconitine in boiling water, it was confirmed that the three alkaloids could be progressively transformed. Pharmacological experiments with aconitine, benzoylaconine, and aconine in SD rats showed that aconitine at a dose of 0.01 mg/kg and aconine at a dose of 10 mg/kg enhanced the cardiac function, while benzoylaconine at a dose of 2 mg/kg weakened the cardiac function. The effect of processing is attributed to the transformation of the most toxic diester-diterpenoid alkaloids into less toxic monoesterditerpenoid alkaloids and amine-diterpenoid alkaloids.

DNA-binding studies of valrubicin as a chemotherapy drug using spectroscopy and electrochemical techniques

Reza Hajian, Parvin Hossaini, Zahra Mehrayin, Pei Meng Woi, Nafiseh Shams

2017, 7(3): 176-180.

Abstract(138) PDF(0)

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In this study, the molecular interactions between valrubicin, an anticancer drug, and fish sperm DNA have been studied in phosphate buffer solution (pH 7.4) using UV–Vis spectrophotometry and cyclic voltammetry techniques. Valrubicin intercalated into double stranded DNA under a weak displacement reaction with methylene blue (MB) molecule in a competitive reaction. The binding constant (kb) of valrubicin-DNA was determined as 1.75×103 L/mol by spectrophotometric titration. The value of non-electrostatic binding constant (kt0) was almost constant at different ionic strengths while the ratio of kt0/kb increased from 4.51% to 23.77%. These results indicate that valrubicin binds to ds-DNA via electrostatic and intercalation modes. Thermodynamic parameters including ΔH0, ΔS0 and ΔG0 for valrubicin-DNA interaction were determined as ?25.21×103 kJ/mol, 1.55×102 kJ/mol K and ?22.03 kJ/mol, respectively. Cyclic voltammetry study shows a pair of redox peaks for valrubicin at 0.45 V and 0.36 V (vs. Ag/AgCl). The peak currents decreased and peak positions shifted to positive direction in the presence of DNA, showing intercalation mechanism due to the variation in formal potential.

Hepatoprotective activity of Macrothelypteris torresiana (Gaudich.) aerial parts against CCl4-induced hepatotoxicity in rodents and analysis of polyphenolic compounds by HPTLC

Sumanta Mondal, Debjit Ghosh, Seru Ganapaty, Surya Vamsi Gokul Chekuboyina, Manisha Samal

2017, 7(3): 181-189.

Abstract(99) PDF(0)

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Macrothelypteris torresiana is a fern species belonging to the family Thelypteridaceae. The present study was conducted to evaluate hepatoprotective potential of ethanol extract from M. torresiana aerial parts (EEMTAP) and detect the polyphenolic compounds present in the extract using high performance thin layer chromatography (HPTLC). Hepatoprotective potential of EEMTAP were tested at doses of 300 and 600 mg/kg, per os (p.o.), on Wistar albino rats. The extract and silymarin treated animal groups showed significant decrease in activities of different biochemical parameters like serum glutamic oxaloacetic transaminase (SGOT), serum glutamate-pyruvate transaminase (SGPT), and alkaline phosphatase (ALP), which were elevated by carbon tetrachloride (CCl4) intoxication. The levels of total bilirubin and total protein along with the liver weight were also restored to normalcy by EEMTAP and silymarin treatment. After CCl4 administration, the levels of hepatic antioxidant enzymes such as glutathione (GSH) and catalase (CAT) were decreased whereas the level of hepatic lipid peroxidation (LPO) was elevated. The levels of these hepatic antioxidant enzymes were also brought to normalcy by EEMTAP and silymarin treatment. Histological studies supported the biochemical findings, and treatment with EEMTAP at doses of 300 and 600 mg/kg, p.o. was found to be effective in restoring CCl4-induced hepatotoxicity in rats. A simple HPTLC analysis was conducted for the detection of polyphenolic compounds in EEMTAP, and the result revealed the presence of caffeic acid as phenolic acid and quercetin as flavonoid. The proposed HPTLC method is simple and concise and provides a good resolution of caffeic acid and quercetin from other constituents present in EEMTAP.

Preparation of monoclonal antibody against human KIAA0100 protein and Northern blot analysis of human KIAA0100 gene

He Cui, Xi Lan, Shemin Lu, Fujun Zhang, Wanggang Zhang

2017, 7(3): 190-195.

Abstract(112) PDF(0)

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Monoclonal antibodies (MAbs) are important tools for the study of proteins′ function and structure. But there has been no report on the preparation of MAbs against human KIAA0100 protein up to date. Here, first, we generated the mouse MAb against human KIAA0100 protein using purified recombinant 6×Histidinc (6×His)- tagged human KIAA0100 protein segment (1557–2234) as an antigen; then, the mRNA expression of human KIAA0100 gene was detected in U937 cells using Northern blot analysis. The results showed that the mouse MAb against human KIAA0100 protein could sensitively recognize the human KIAA0100 protein using Western blot analysis and immunocytochemistry analysis. Besides, Western blot analysis revealed that human KIAA0100 gene possibly encoded two different protein products (254 kDa and < 250 kDa) in U937 cells. Moreover, Northern blot analysis confirmed that human KIAA0100 gene might produced two different mRNA products (6000–10000 bp and 5000–6000 bp) in U937 cells. The results provide a basis for large-scale production of the MAb against human KIAA0100 protein, which will be useful for the study of human KIAA0100 protein′s function/structure and MAb-targeted drugs in the future.

Highly sensitive assay for the determination of therapeutic peptide desmopressin in human plasma by UPLC–MS/MS

Shiva Kumar Gudlawar, Nageswara Rao Pilli, Sridhar Siddiraju, Jaya Dwivedi

2017, 7(3): 196-202.

Abstract(152) PDF(1)

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An analytical method based on ultra-performance liquid chromatography with positive ion electrospray ionization (ESI) coupled with tandem mass spectrometry (UPLC–MS/MS) was developed and validated for the determination of therapeutic peptide desmopressin in human plasma. A desmopressin stable labeled isotope (desmopressin d8) was used as an internal standard. Analyte and the internal standard were extracted from 200 μL of human plasma via solid-phase extraction technique using Oasis WCX cartridges. The chromatographic separation was achieved on an Aquity UPLC HSS T3 column by using a gradient mixture of methanol and 1 mM ammonium formate buffer as the mobile phase. The calibration curve obtained was linear (r2≥0.99) over the concentration range of 1.01–200 pg/mL. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. The proposed method was successfully applied to pharmacokinetic studies in humans.

2017 Vol. 7, No. 3