Journal of Pharmaceutical Analysis

Charge-transfer interaction of drug quinidine with quinol, picric acid and DDQ:Spectroscopic characterization and biological activity studies towards understanding the drug-receptor mechanism

Hala H. Eldaroti, Suad A. Gadir, Moamen S. Refat, Abdel Majid A. Adam

2014, (2): 81-95.

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Abstract:
Investigation of charge-transfer (CT) complexes of drugs has been recognized as an important phenomenon in understanding of the drug-receptor binding mechanism. Structural, thermal, morpholo-gical and biological behavior of CT complexes formed between drug quinidine (Qui) as a donor and quinol (QL), picric acid (PA) or dichlorodicyanobenzoquinone (DDQ) as acceptors were reported. The newly synthesized CT complexes have been spectroscopically characterized via elemental analysis;infrared (IR), Raman, 1H NMR and electronic absorption spectroscopy; powder X-ray diffraction (PXRD);thermogravimetric (TG) analysis and scanning electron microscopy (SEM). It was found that the obtained complexes are nanoscale, semi-crystalline particles, thermally stable and spontaneous. The molecular composition of the obtained complexes was determined using spectrophotometric titration method and was found to be 1:1 ratios (donor:acceptor). Finally, the biological activities of the obtained CT complexes were tested for their antibacterial activities. The results obtained herein are satisfactory for estimation of drug Qui in the pharmaceutical form.

Quantitative and qualitative analysis of common peaks in chemical fingerprint of Yuanhu Zhitong tablet by HPLC-DAD-MS/MS

Dao-Quan Tang, Xiao-Xiao Zheng, Xu Chen, Dong-Zhi Yang, Qian Du

2014, (2): 96-106.

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Abstract:
A quality control (QC) strategy for quantitative and qualitative analysis of “common peaks” in chemical fingerprint was proposed to analyze Yuanhu Zhitong tablet (YZT), using high performance liquid chromatography with diode array detector and tandem mass spectrometry (HPLC-DAD-MS/MS). The chromatographic separation was achieved on an Agilent Eclipse plus C18 column with a gradient elution using a mixture of 0.4‰ ammonium acetate aqueous (pH 6.0 adjusted with glacial acetic acid) and acetonitrile. In chemical fingerprint, 40 peaks were assigned as the “common peaks”. For quantification of “common peaks”, the detection wavelength was set at 254 nm, 270 nm, 280 nm and 345 nm, respectively. The method was validated and good results were obtained to simultaneously determine 10 analytes (protopine, jatrorrhizine, coptisine, palmatine, berberine, xanthotoxin, bergapten, tetrahydropalmatine, imperatorin and isoimperatorin). For qualification of “common peaks”, 33 compounds including 10 quantitative analytes were identified or tentatively characterized using LC-MS/MS. These results demonstrated that the present approach may be a powerful and useful tool to tackle the complex quality issue of YZT.

Selective separation, detection of zotepine and mass spectral characterization of degradants by LC-MS/MS/QTOF

M.V.N. Kumar Talluri, Naveen Reddy Kandimalla, Raju Bandu, Divya Chundi, Ramesh Marupaka, Ragampeta Srinivas

2014, (2): 107-116.

Abstract(80) PDF(2)

Abstract:
A simple, precise, accurate stability-indicating gradient reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the quantitative determination of zotepine (ZTP) in bulk and pharmaceutical dosage forms in the presence of its degradation products (DPs). The method was developed using Phenomenex C18 column (250 mm ~ 4.6 mm i.d., 5 mm) with a mobile phase containing a gradient mixture of solvents, A (0.05%trifluoroacetic acid (TFA), pH ? 3.0) and B (acetonitrile). The eluted compounds were monitored at 254 nm;the run time was within 20.0 min, in which ZTP and its DPs were well separated, with a resolution of 41.5. The stress testing of ZTP was carried out under acidic, alkaline, neutral hydrolysis, oxidative, photolytic and thermal stress conditions. ZTP was found to degrade significantly in acidic, photolytic, thermal and oxidative stress conditions and remain stable in basic and neutral conditions. The developed method was validated with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness as per ICH guidelines. This method was also suitable for the assay determination of ZTP in pharmaceutical dosage forms. The DPs were characterized by LC-MS/MS and their fragmentation pathways were proposed.

A solid-phase extraction approach for the identification of pharmaceutical-sludge adsorption mechanisms

Laurence Berthod, Gary Roberts, Graham A. Mills

2014, (2): 117-124.

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Abstract:
It is important to understand the adsorption mechanism of chemicals and active pharmaceu-tical ingredients (API) on sewage sludge since wastewater treatment plants are the last barrier before the release of these compounds to the environment. Adsorption models were developed considering mostly hydrophobic API-sludge interaction. They have poor predictive ability, especially with ionisable compounds. This work proposes a solid-phase extraction (SPE) approach to estimate rapidly the API-sludge interaction. Sludge-filled SPE cartridges could not be percolated with API spiked mobile phases so different powders were tested as SPE sludge supports. Polytetrafluoroethylene (PTFE) was selected and tested at different PTFE/sludge ratios under eight different adsorption conditions with three API ionisable compounds. The PTFE/sludge mixtures with 50% or less sludge could be used in SPE mode for API sorption studies with methanol/water liquid phases. The results gave insights into API-sludge interactions. It was found that π-π, hydrogen-bonding and charge-charge interactions were as important as hydrophobicity in the adsorption mechanism of charged APIs on sludge.

Reagent-free determination of amikacin content in amikacin sulfate injections by FTIR derivative spectroscopy in a continuous flow system

José F. Ovalles, Máximo Gallignani, María R. Brunetto, Rebeca A. Rondón, Carlos Ayala

2014, (2): 125-131.

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Abstract:
The quantitative estimation of amikacin (AMK) in AMK sulfate injection samples is reported using FTIR-derivative spectrometric method in a continuous flow system. Fourier transform of mid-IR spectra were recorded without any sample pretreatment. A good linear calibration (r40.999, %RSDo 2.0) in the range of 7.7-77.0 mg/mL was found. The results showed a good correlation with the manufacturer's and overall they all fell within acceptable limits of most pharmacopoeial monographs on AMK sulfate.

Determination of a novel ACE inhibitor in the presence of alkaline and oxidative degradation products using smart spectrophotometric and chemometric methods

Maha Abdel-Monem Hegazy, Maya Shaaban Eissa, Osama Ibrahim Abd El-Sattar, Mohamed Mohamed Abd El-Kawy

2014, (2): 132-143.

Abstract(90) PDF(0)

Abstract:
Simple, accurate, sensitive and validated UV spectrophotometric and chemometric methods were developed for the determination of imidapril hydrochloride (IMD) in the presence of both its alkaline (AKN) and oxidative (OXI) degradation products and in its pharmaceutical formulation. Method A is the fourth derivative spectra (D4) which allows the determination of IMD in the presence of both AKN and OXD, in pure form and in tablets by measuring the peak amplitude at 243.0 nm. Methods B, C and D, manipulating ratio spectra, were also developed. Method B is the double divisor-ratio difference spectrophotometric one (DD-RD) by computing the difference between the amplitudes of IMD ratio spectra at 232 and 256.3 nm. Method C is the double divisor-first derivative of ratio spectra method (DD-DR1) at 243.2 nm, while method D is the mean centering of ratio spectra (MCR) at 288.0 nm. Methods A, B, C and D could successfully determine IMD in a concentration range of 4.0-32.0 mg/mL. Methods E and F are principal component regression (PCR) and partial least-squares (PLS), respectively, for the simultaneous determination of IMD in the presence of both AKN and OXI, in pure form and in its tablets. The developed methods have the advantage of simultaneous determination of the cited components without any pre-treatment. The accuracy, precision and linearity ranges of the developed methods were determined. The results obtained were statistically compared with those of a reported HPLC method, and there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision.

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC-MS/MS and its application in bioequivalence studies

Bhupinder Singh, Rama S. Lokhandae, Ashish Dwivedi, Sandeep Sharma, Naveen Dubey

2014, (2): 144-152.

Abstract(73) PDF(1)

Abstract:
A validated ultra-performance liquid chromatography mass spectrometric method (UPLC-MS/MS) was used for the simultaneous quantitation of candesartan (CN) and hydrochlorothiazide (HCT) in human plasma. The analysis was performed on UPLC-MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring (MRM) mode. The analytes were extracted using a liquid-liquid extraction (LLE) method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d4 and HCT-13Cd2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Pheno-menex, Gemini NX (100 mm ~ 4.6 mm, 5 mm) column with organic mixture:buffer solution (80:20, v/v) at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil (CNC) and HCT immediate release tablets with reference product in human subjects.

Determination of gouty arthritis' biomarkers in human urine using reversed-phase high-performance liquid chromatography

Lei-Wen Xiang, Jing Li, Jin-Ming Lin, Hai-Fang Li

2014, (2): 153-158.

Abstract(113) PDF(0)

Abstract:
Creatinine, uric acid, hypoxanthine and xanthine are important diagnostic biomarkers in human urine for gouty arthritis or renal disease diacrisis. A simple method for simultaneous determination of these biomarkers in urine based on reversed-phase high-performance liquid chromatography (RP-HPLC) with ultraviolet (UV) detector was proposed. After pretreatment by dilution, centrifugation and filtration, the biomarkers in urine samples were separated by ODS-BP column by elution with methanol/50 mM NaH2PO4 buffer solution at pH 5.26 (5:95). Good linearity between peak areas and concentrations of standards was obtained for the biomarkers with correlation coefficients in the range of 0.9957-0.9993. The proposed analytical method has satisfactory repeatability (the recovery of data in a range of creatinine, uric acid, hypoxanthine and xanthine was 93.49-97.90%, 95.38-96.45%, 112.46-115.78%and 90.82-97.13%with standard deviation of o5%, respectively) and the limits of detection (LODs, S/N Z 3) for creatinine, uric acid, hypoxanthine, and xanthine were 0.010, 0.025, 0.050 and 0.025 mg/L, respectively. The established method was proved to be simple, accurate, sensitive and reliable for the quantitation of gouty arthritis' biomarkers in human urine samples. The ratio of creatinine to uric acid was found to be a possible factor for assessment of gouty arthritis.

Application of analytical instruments in pharmaceutical analysis

2014, (2): 159-162.

Abstract(84) PDF(0)

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2014 Vol. 4, No. 2