Current Pharmaceutical Analysis - Volume 16, Issue 2, 2020

Background: TJAB1099 is a novel, highly active inhibitor of human enterovirus 71 (HEV71), which is a most commonly found virus leading to Hand-Foot-Mouth Disease (HFMD). However, the TJAB1099 could not be detected in the plasma using a regular HPLC-UV detection during the pharmacokinetic study due to the poor solubility, which in turn limited the release prior to be absorbed by the gastrointestinal tract. Objective: The objectives of the present study were to improve the solubility of TJAB1099 by preparing formulation and develop an Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) method applied to the pharmacokinetic study. Methods: The TJAB1099 was prepared as a phospholipid complex that intends to increase the watersolubility and subsequently improving TJAB1099 exposed in the circulation system. A highly sensitive UPLC-MS/MS method was developed for the pharmacokinetic study, in which the pharmacokinetic parameters were determined following oral and intravenous administration of 5 mg/kg and 1 mg/kg of TJAB1099 in rats, respectively. Results: The precisions for the method were less than 12.8%, while the accuracies were in the range of 90.8 - 98.0% and 96.1 - 99.6% for within-day and between-day, respectively. The mean recoveries for TJAB1099 and terfenadine (internal-standard, IS) were 85.0 ± 5.4% and 92.4 ± 4.1%, respectively. The pharmacokinetic study revealed that the Cmax of TJAB1099 after oral administration can reach 6.84 ± 2.43 ng/mL, while the Tmax is 0.70 ± 0.11 h. The AUC0-12 is 19.81 ± 11.07 μg/mL/h. However, the absorption was poor with an absolute oral bioavailability of 0.62. Conclusion: The UPLC-MS/MS method was successfully applied in the pharmacokinetic study of TJAB1099 in rats.

Purpose: A new multivariate chemometric approach was developed for fast and economic compatibility determinations of ranitidine hydrochloride (as model drug) with certain pharmaceutical; polymers (Alginate & Chitosan), excipient (Lactose) and intravenous fluids (Dextrose, Ringer & Dextrose/ Ringer). Binary mixtures of the drug and each item were prepared and investigated by chemometric- assisted UV- spectrophotometry as well as by HPLC reference method. Methods: Five drug concentration levels (0.004-0.025mg/ml) of test-mixtures were used and the average drug recovery percent after two and seven days of storage from initial concentration was determined. Physico-chemical techniques including DSC, XRD, & FTIR were also performed to investigate the nature of the observed drug-additive interactions. Results: UV-chemometric and HPLC results showed that ranitidine stability in mixture aqueous solutions appears to be concentration dependent. The ranitidine content remained greater than 90% in alginate & chitosan test mixtures at all used drug concentrations (0.004-0.025mg/ml), while in lactose, dextrose, ringer & dextrose/ringer test mixtures fell below 90% at low drug concentrations (0.004- 0.009mg/ml), which suggests more ranitidine compatibility with alginate & chitosan rather than the other additives. Conclusion: The developed chemometric method, employing UV absorbance data successfully used as simple, rapid, and economic alternative tool in drug-additive compatibility determinations.

Introduction: A selective, sensitive, precise and rapid analytical method using liquid chromatography- tandem mass spectrometry (LC/MS/MS) for simultaneous determination of oseltamivir and oseltamivir carboxylic acid in plasma has been developed and validated, using oseltamivir-D5 and oseltamivir acid-D3 as internal standards. Methods: The analytes were extracted from 300μL of human plasma using solid phase extraction technique. A mixture of methanol and 0.1% formic acid (60:40, v/v) was used as mobile phase at a flow rate of 0.7mL/min, to separate the analytes on Zorbax SB-C18 (50x4.6mm, 3.5μm) analytical column. Results: The calibration curves obtained were linear over the concentration ranges of 0.5-200ng/mL and 2.0-800ng/mL for oseltamivir and oseltamivir carboxylic acid respectively. A run time of 2.5min makes it possible to analyze more than 350 plasma samples in a day, thereby increasing the productivity. Conclusion: The present method was applied successfully to a clinical pharmacokinetic study in South Indian male subjects with 75mg oseltamivir phosphate capsule under fasting conditions and the results were authenticated by incurred sample reanalysis.

Context: Benzoic acid is a kind of extensively used preservative. It is of great significance to detect benzoic acid by a rapid method for quality assurance and protection in the fields of pharmaceutical, food and chemistry industry. Objective: The present research is aimed to prepare polyaniline/Al bismuthate composite nanorods by an in-situ polymerizing process for effective detection of benzoic acid. Methods: The polyaniline/Al bismuthate composite nanorods are prepared by an in-situ polymerizing process. The structure, morphology and electrochemical performance of the obtained polyaniline/Al bismuthate composite nanorods are analyzed by X-ray diffraction (XRD), transmission electron microscopy and electrochemical measurement. Results: XRD and transmission electron microscopy observations show that the amorphous nanoscale polyaniline particles attach to the surface of the crystalline nanorods. The electrochemical measurement of 2 mM benzoic acid using the composite nanorods modified glassy carbon electrode (GCE) shows that a pair of semi-reversible CV peaks is located at -0.11 V (cvp1) and -0.48 V (cvp1′), respectively. The electrochemical responses of 2 mM benzoic acid at the composite nanorods modified GCE are enhanced with increasing the scan rate and benzoic acid concentration. The polyaniline/Al bismuthate composite nanorods modified GCE shows a linear range of 0.001-2 mM with the limit of detection (LOD) of 0.18 μM. Conclusion: The composite nanorods may be used as the electrode materials with good reproducibility and stability for the detection of benzoic acid.

Background: Menbutone is widely used as a veterinary choleretic drug in many countries. There was no publicly available analysis method for the determination of menbutone residues in swine tissues. It is necessary to establish a method to control the maximum residue limit and ensure food safety of the public. Objective: The aim of this study is to establish an analytical method for the simultaneous determination of menbutone in muscle, fat, liver and kidney tissues from swine. Methods: MBT residue was extracted by acetonitrile from the tissues then purified by using a C18 solid phase extraction (SPE) cartridge and an alkaline alumina (ALA) SPE cartridge. MBT was detected by RP-HPLC and separation was achieved on a Shim-pack VP-ODS C18 HPLC column using phosphoric acid solution (0.5%, v/v) and acetonitrile (45/55, v/v) at a flow rate of 1.0 mL/min. The effluent was monitored at 235 nm, and the column temperature was set to 30°C. Results: MBT eluted at 6.3 min and no interfering peak nearby was observed. This linearity within the concentration range of 0.02 (LOQ) and 12 μg/mL (r2>0.9999, n=6). The accuracy ranged from 74.07 to 110.83% of the actual values. Intra and inter-day precision were within 15.11%. In the application study, MBT was detectable in continuously dosing MBT 10 μg/g/day to healthy swine for 7 days. Conclusion: The proposed method has specificity, accuracy, and sensitivity, with an excellent linear relationship that successfully applied to swine tissues.

Background: Cysteamine is used as an orphan drug in the treatment of cystinosis to prevent long-term cystine accumulation in lysosomes. Dosing in cysteamine treatment is extremely important and overdose may cause some side effects. Up to now, various analytical methods have been used for cysteamine determination. Many of these methods require sophisticated instruments, expert operators, time-consuming measurement procedures and manipulation steps, expensive supplies and long analysis time. Aims and Objective: The present study deals with the development of a potentiometric PVC-membrane cysteamine-selective electrode based on an ion-pair of cysteamine and its application in a pharmaceutical formulation. Methods: Cysteamine (Cys)-Phosphomolybdate (PM) ion-pair was synthesized by mixing the equal volumes of 10-2 M Cysteamine HCl and sodium phosphomolybdate aqueous solutions. The obtained precipitate was used as ionophore in the structure of PVC-membrane. Results and Discussion: The electrode exhibited a linear response in the concentration range of 1.0x10- 1-1.0x10-5 M cysteamine with a slope of 51,7 mV per decade and detection limit of 1.0x10-5 M. The potentiometric response of the electrode was very rapid (5 s), adequately repeatable, stable and selective. pH working range and life-time of the electrode were also determined as 3.0-7.0 and 25 days, respectively. Conclusion: A PVC-membrane cysteamine selective electrode was easily prepared. Cysteamine determination in a pharmaceutical formulation was performed. Analysis results indicated that it can be successfully used in drug quality control laboratories for routine analysis of cysteamine in pharmaceutical preparations alternative to more sophisticated, expensive and time-consuming analytical methods.

Background: Hydrochlorothiazide (HCTZ) is a thiazide diuretic which comprises two sulfonamide groups. The literature is not clear regarding the identification of the chromatographic peaks of its two major related substances: chlorothiazide and 4-amino-6-chloro-1,3-benzenedisulfonamide (DSA). Methods: In the present study, a simple, sensitive, and selective HPLC method was developed and validated for the assay of HCTZ, Chlorothiazide and DSA. The method was carried out on a C18 column, maintained at 40ºC. The mobile phase was composed of monobasic potassium phosphate buffer 0.02M pH 3.0/acetonitrile/methanol (82:9:9, v/v/v), run at a flow rate of 1.0 mL/min, and UV detection at 270 nm. Results: All related compounds including processing impurities and degradants from stressed samples were well separated from each other. The performance of this method was validated in accordance to the ICH guidelines and included specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. Conclusion: Based on the results, the HCTZ degradation pathway was proposed and the validated HPLC method was successfully applied to the quantitative analysis of HCTZ in pharmaceutical formulations, contributing to improve quality control, to assure therapeutic efficacy and to clarify the literature.

Background: In this work, a novel and extra sensitive blood sample determination method for on-line monitoring of Daptomycin is represented. Materials and Methods: This technique is in accordance with the electro-membrane extraction (EME) and stripping fast Fourier transform continuous cyclic voltammetry (SFFTCCV) coupling. Briefly, the potential waveform had become constantly utilized over a Gold Electrode and the electrode impulse was acquired by taking away the base current and developing the current in the particular potential area of oxidation of sample. Results: This method was performed by utilizing a DC potential and migration of Daptomycin from the analyte fluid to the layer of 4-methyl-2-pentanol as well as following migration to the acceptor fluid. Conclusion: A low and valuable detection limit of 3.5 ng ml-1 and quantification limit of 10.2 ng ml-1 are considered as a part of the sensible results of this experiment. Furthermore, efficient linearity in the range of 10.0-600 ng ml-1 was observed.

Background: Smart different stability-indicating spectrophotometric methods have been established for the assay of chlordiazepoxide and clidinium bromide without the intervention of alkaline degradate of clidinium via various and different manipulating pathways without previous separation steps. Objective: The specificity of the established methods was inspected by analysing mixtures of cited drugs in the existence of the alkali-induced degradation product. Methods: These methods were employed either on scanned zero-order absorption spectra using absorbance subtraction, dual wavelength and Q-absorbance ratio or the amplitudes of the ratio spectra of zero-order absorption spectra like amplitude modulation and by derivative techniques to the ratio spectra as a derivative ratio method. In addition, the absorbance of the recovered zero-order absorption spectra was applied by successive ratio subtraction coupled with constant multiplication. Finally, the pathway depends on the amplitudes of the derivative spectra, successive derivative subtraction coupled with constant multiplication. The ranges of linearity were (1-12μg/mL) for chlordiazepoxide and (3- 12μg/mL) for clidinium bromide. Results: The outcomes achieved by the prospective methods were in consent with those of the official and reported methods when statistically compared using student’s t test, F-test and one-way ANOVA where no significant difference was detected with suitable precision, proving the absence of any important difference in accuracy and precision between them. They were confirmed in accordance with International Conference on Harmonization guidelines. Conclusion: The established methods can be considered as alternative methods for the routine determination of this fixed dose combination with minimum sample preparation.

Background: A Vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME) method is presented for the determination of aspirin (acetylsalicylic acid) in human urine by spectrofluorimetry. Objective: To determine trace levels of aspirin in biologic samples by using green and low-cost method development. Methods: For the microextraction procedure, chloroform and acetonitrile were used as extraction and disperser solvent, respectively. The factors affecting the efficiency of extraction such as volume of chloroform, volumes of acetonitrile, ionic strength, sample pH, centrifuging time, and extraction time were investigated. Then significant variables were optimized by the response surface method using the Box- Behnken design. Results: Under the optimum extraction conditions, a linear calibration curve in the range of 0.1 to 130 ng mL-1 with a correlation coefficient of R2 = 0.998 was obtained. The limits of detection (LOD) and limits of quantification (LOQ) were 0.031 and 0.103 ng mL-1, respectively. The relative standard deviations (RSD) were less than 4%. Conclusion: Enrichment factor and recoveries were achieved for the extraction of aspirin in human urine. This method gives a rapid, simple, sensitive and environmentally friendly for the measurement of trace amount aspirin.

Background: Erlotinib hydrochloride is a novel drug for the treatment of lung cancer. Objective: The objective of the present study was to design an uncomplicated and precise reverse phase high-performance liquid chromatography (RP-HPLC) method and optimize the chromatographic parameters using response surface methodology derived from Box Behnken design. The optimized method was validated for estimating Erlotinib from bulk and nanostructured lipid carriers (NLCs) formulation. Methods: Independent variables such as flow rate, injection volume and strength of the buffer were optimized in order to decrease retention time and curtail asymmetry factor of Erlotinib. Forced degradation studies were done to determine the stability of the drug. The developed method was validated as per ICH guidelines. Results: The optimized strength of ortho-phosphoric acid buffer by blending with Acetonitrile (80:20 v/v), flow rate and injection volume were found to be 25mM, 1ml/min, 20μL respectively. Linearity was observed in the concentration range of 1-6 μg/mL. The retention time of Erlotinib was found to be 3.717 minutes. The limit of detection and limit of quantification for Erlotinib were found to be 0.01ng/ml and 1ng/ml, respectively. Conclusion: The proposed method was found to be a simple and the best method for analysing Erlotinib in nanostructured lipid carriers. Chemometric approach was employed as an effective tool for optimising the chromatographic conditions of the proposed method.

Background: The rationality of cilnidipine tablets and capsules with four different pharmaceutical packaging materials was evaluated, and the structure of photodegradation impurities was analyzed by LC-Q-TOF. Materials and Methods: The impurity profiling of commercial cilnidipine tablets and capsules was analyzed by LC-Q-TOF for the further improvement of official monograph in pharmacopoeias and the source of the impurities was investigated. The contents of photodegradation impurities were analyzed by HPLC, and remarkable difference in the formation of the photodegradation impurities in cilnidipine tablets and capsules with four different pharmaceutical packaging materials was observed. The shading effect of the four packaging materials was investigated by UV-Vis spectrophotometer and a remarkable difference was detected, which might be responsible for the difference in the formation of photodegradation products. The structures of photodegradation products were further characterized by LC-Q-TOF MS/MS. Five impurities in commercial cilnidipine tablets and capsules were separated and identified based on the high resolution MS/MS data. Results: The obtained results revealed that the impurity III was derived from the ethanol solution of cilnidipine when it was exposed to light, and the impurity II was produced when the cilnidipine powder was exposed to light directly. The concentrations for 50% reduction of impurity II and impurity III on the Chinese hamster lung cells (CHL) with CellTiter-Glo method were studied and the results indicated that the cytotoxicity of impurity II and impurity III on CHL cells was larger than cytotoxicity of cilnidipine. Conclusion: On the basis of our study, we suggested that the pharmaceutical packaging materials of cilnidipine tablets should be modified.