Current Pharmaceutical Analysis - Volume 14, Issue 2, 2018

Background: Docetaxel is a potent anticancer agent used in various cancer types. Attempts are being made to improve docetaxel's pharmacokinetics because desirable modifications in disposition and biodistribution characteristics could enhance the therapeutic outcomes of the drug. Quantitative analysis of docetaxel in the body is important to understand modifications necessary to improve the drug's biodistribution and pharmacokinetics. Majority of studies have applied HPLC coupled with mass spectrometry (LC-MS) or HPLC alone to quantitatively analyse docetaxel in various matrices. Long separation times, many resources, and additional techniques are usually required to establish a proper liquid chromatographic (LC) method. Objective: Development and validation of a simple and rapid mass spectrometric method (ESIMS/ MS) for quantification of docetaxel in mouse biological matrices were the objective of the study. Methods: Docetaxel was extracted from mouse serum and liver using a liquid-liquid extraction with tert-butyl methyl ether. Samples were direct-injected to the instrument using 0.1% formic acid in methanol as the mobile phase (isocratic elution). Method development and validation were performed according to FDA guidelines. Detection was done by a Hybrid Triple Quadrupole/Linear Ion trap instrument through positive ESI source and MRM mode. Result: Docetaxel retention-time was about 0.6 min while the total run-time was 2 min. The method was linear, sensitive, and specific with an acceptable level of precision and accuracy and was successfully applied for rapid quantitative analysis of docetaxel in mouse biological matrices. Conclusion: The validated method allows simple and fast analysis of docetaxel in biological samples for pharmacokinetic and biodistribution studies.

Objective: Simple and sensitive UV method was developed and validated for the determination of meclizine hydrochloride in formulation, based on binary complex formation with eosin Y. Method: The absorbance of the formed complex was measured at 540 nm. Beer's law was obeyed in the range of 5-25 μgmL-1 with r2 value 0.9960. Results: The method showed good value of accuracy and precision (%RSD=1.096), and the limits of detection and quantification of the method were 0.76 and 2.29 μgmL-1, respectively. The analytical performance of the method was fully validated, and the results were satisfactory. The method can be applied successfully for the assay of meclizine hydrochloride in commercial tablets containing the drug alone or in combination. Conclusion: This method provides a valid alternative of reported methods for the determination of meclizine in formulations as it's a simple, less time and cost consuming and can be applied for pharmaceutical analysis in pharmaceutical industries.

Background: Icariin (ICN) is the main bioactive natural flavonoid in plants of the Epimedium genus and is valued in traditional Chinese medicine owing to its beneficial effects, including enhancement of cardiovascular function and antitumorigenic activity. Current methods for detecting ICN employ expensive instruments that require a high level of skill for operation. As such, a more simple and rapid assay is desired. Methods: A colloidal gold-conjugated anti-ICN monoclonal antibody was prepared and an Immunochromatographic Strip (ICS) test was developed for detecting ICN in plant preparations. Results: The prepared anti-ICN MAbs show weak reactivity with compounds that are structurally related to ICN. Using anti-ICN MAbs, a specific and reliable ELISA was developed to detect ICN. The system shows a full measurement range from 10 ng/mL to 1280 ng/ml with regression equation is y = -0.158ln(x) + 1.3336 (R2 = 0.9924). Moreover, the usefulness of the ICS assay using anti-ICN mAb as a qualitative method was confirmed for the analysis of ICN in different samples by comparing to indirect competitive enzyme-linked immunosorbent assay. This ICS assay based on the competitive immunoassay system showed high specificity for ICN and had a detection limit of 500 ng/ml. Conclusion: Our results indicate that the ICS assay can be a powerful tool for rapid screening of plant materials used in traditional Chinese medicine owing to its ease of manipulation and low cost. In addition, it can potentially be used for the detection of ICN in other types of biological sample.

Background: Rifaximin is an oral antimicrobial, which, until now, does not have standardized analytical methods in most official compendia. The literature shows few methods for the detection of drug, but has no analytical method for the determination of rifaximin in the pharmaceutical product. The lack of environmentally friendly methods with the use and minimal generation of toxic waste is also a gap. Methods: This work proposed the development and validation of an infrared spectrophotometry method for the determination of rifaximin in tablets. Results: The method was linear over the concentration range of 1.0-3.5 mg with correlation coefficient 0.9997 and the limits of detection and quantification of 0.20 and 0.61 mg, respectively. Conclusion: The validated method was adequate, reliable, fast, economical and eco-friendly for the routine quality control of rifaximin in tablets. In the current fight against climate change, we can and must do our role , even if the role part is to develop and validate environmentally friendly method for routine use in the quality control of drugs and medicines in laboratories and pharmaceutical industries.

Background: X22 is one of the imidazopyridine derivatives designed and synthesized in our laboratory. This compound showed excellent anti-inflammatory activity in LPS-stimulated macrophages. We previously investigated the biological activities of X22, including treatment of obesityrelated complications and retinal ischemia/reperfusion injury. Methods: In the present study, a reliable, rapid, and simple UPLC method was first established and validated for quantitative analysis of X22 in rat plasma. Plasma samples were prepared by protein precipitation and separated on an ACQUITY HSS T3 column with a gradient mobile phase consisting of acetonitrile and water containing 0.1% TFA at a flow rate of 0.3 mL/min. Results: Good linearity (R2>0.997) was achieved using weighted (1/x2) least-squares linear regression over a concentration range of 10 ng/mL to 1000 ng/mL with a lower limit of quantification of 10 ng/mL for X22. The average extraction recoveries were > 91.3 % for X22 and > 92.4 % for neohesperidin dihydrochalcone. The intra- and inter-precision values of the assay were both < 4.0 %. Conclusion: This method was successfully applied to a pharmacokinetic study on rats after administration of single intravenous and oral doses of 20 and 80 mg/kg, respectively.

Background: Dendrobium officinale (D. officinale) has been traditionally used as an herbal medicine in Eastern Asia. Because of its ambiguous chemical characteristics, an authentic quality evaluation system is urgently needed. The aim of this work is to establish a comprehensive method for the evaluation of D. officinale based on volatile constituents, methanol extracts and polysaccharide analysis. Methods: We identify the volatile constituents via headspace solid-phase micro-extraction and gas chromatography–mass spectrometry. We establish a standard fingerprint for the methanol extracts of D. officinale leaves by high performance liquid chromatography analysis. This work also compares the content of polysaccharide using the phenol-sulfuric acid method. Results: We identify 37 volatile constituents in D. officinale. Thirty compounds obtained in flowers, 18 in leaves, and 11 in stems. We then assess the quality of D. officinale leaves collected from four different regions by comparing volatile constituents. We further identify 22 volatile components from the sample from Anhui Huoshan, which contains more volatile components than the others. Besides, we establish a standard fingerprint for the methanol extracts of D. officinale leaves, which confirms 21 common peaks in six different regions. The results of hierarchical cluster analysis show that the samples from these six regions are classified into two main groups. The three samples from Zhejiang province are clustered into one subgroup. The sample from Zhejiang Deqing contains the most abundant polysaccharides both in stems and leaves. As the years of growth increase, the content of polysaccharide is also improved. Conclusion: This study provides a comprehensive method for quality evaluation of D. officinale. This study also explores the possible reasons for the discrepancies in the flavor of D. officinale in production.

Objective: A simple, reliable and specific method of HPLC which was performed on a reversed- phase Agilent SB column was developed for the determination of imatinib and CGP74588. Method: The mobile phase comprised water-acetonitrile-0.1% trifluoroacetic acid (59:21:20, v/v/v) flowed at the rate of 1 mL/min at 40°C. The detection wavelength was 278nm. Results: Sensitivity has been illustrated in this method, and a good linear relationship was observed between 0.1-20.00 μg/mL for imatinib with r2=0.9994 and 0.01-2.00 μg/mL for CGP74588 with r2=0.9998 in rat plasma. The relative recoveries of imatinib and CGP74588 were all more than 93%, whilst the absolute recoveries of imatinib and CGP74588 were all more than 75%. Both intra- and inter-day precisions were all less than 4.5% for imatinib and 4.74% for GCP74588. The limits of quantification of these analytic methods were 0.1 μg/mL for imatinib and 0.01 μg/mL for CGP74588. Conclusion: The method was suitable for studying the pharmacokinetic parameters of imatinib and GCP74588 and routine analysis.

Background: Carvedilol (CD) is a β-blocker drug that is used in the treatment of hypertension, coronary diseases, etc. The official methods for the assay of CD in British Pharmacopoeia (BP) and United States Pharmacopeia (USP) include potentiometric titration and HPLC analysis, respectively. There are two different methods reported in the USP; one is for the pure CD and the other is for its tablet dosage forms. Both methods are time consuming, require stringent preparation and have specific requirements such as temperature. Objective: The present study involves the development and validation of a simple, rapid and economical, stability-indicating RP-HPLC method for the assay of CD in pure and tablet dosage forms. Method: A mobile phase of acetonitrile and water in a ratio of 60:40, v/v, has been used for the assay of CD at pH 2.5 giving the retention time (tR) of around 3 min. The method has been validated according to the guidelines of International Council for Harmonization (ICH) for parameters such as linearity, range, accuracy, precision, sensitivity, robustness and specificity. Results: The results indicate that the method is linear in the range of 25-150% (6.25-37.50 μg/ml), highly accurate (100.1%), precise (<1%), robust (<1.5%) and statistically comparable to the official USP methods. Conclusion: The stress degradation studies yielded a number of degradation products with varying tR values, all different from the principle peak of CD thus indicating that the method is highly specific and reliable for the assay of CD.

Background: A precise, accurate, rapid and sensitive reverse phase liquid chromatographic (RP-HPLC) method has been developed in rabbit plasma spiked with Diltiazem hydrochloride (DTZ). Methods: The chromatographic method was standardized using an Agilent 5 TC- C18 column (2) 250 mm x 4.6 mm with UV detection at 237 nm and flow rate of 1 ml/min. The mobile phase consisted of methanol: water (90:10: v/v). The retention time for the Diltiazem hydrochloride was found to be 4.2 min. In spiked rabbit plasma, drug was extracted by using acetonitrile as disperser solvent for protein precipitation and the supernatant was mixed with100 mL dichloromethane as an extraction solvent. After centrifugation, this demented phase containing drug was collected and evaporated to dryness. The residue was re-dissolved in50 uL of mobile phase and injected into the HPLC system for analysis. Good linearity was obtained for the calibration curve of Diltiazem hydrochloride was found to be R2= 0.9999. Results: The intra- and inter-days precision and accuracy of three selected concentrations (25, 50, 100ng ml-1) showed % RSD within the range and excellent % recovery. The limit of detection (LOD) and limit of Quantification (LOQ) values were 1.325ng ml-1 and 4.02ng ml-1, respectively. Conclusion: The developed HPLC method for the estimation of Diltiazem HCL in rabbit plasma would be more accurate, precise, sensitive and selective.

Introduction: A simple, isocratic High Performance Liquid Chromatography (HPLC) method has been modified for the qualitative and quantitative analyses of amisulpride related substances. This method is based on using of RP-C8 (250 4.6 mm) column and a mixture of phosphate buffer and methanol as mobile phase. Materials and Methods: Various forced degradation studies were conducted to establish an impurity profile for amisulpride raw material and in the tablet formula. Four degradation products were produced upon exposing amisulpride to different degradation conditions (acidic, basic, oxidative, photolytic, aqueous and thermal); three of them were already identified by British Pharmacopeia (BP). Conclusion: The fourth new significant degradant was observed only under acidic degradation of amisulpride (4 ml of 4 M hydrochloric acid solution at 70 °C for 5 hrs). Its structure was characterized using LC-MS and NMR (1H NMR, 13C NMR and DEPT) techniques. Excipient components, examined in this study, have no effect towards producing any extra new degradation products.