Development and Validation of Stability Indicating High-Performance Thin-Layer Chromatographic (HPTLC) Method for Quantification of Asiaticoside from Centella asiatica L. and its Marketed Formulation.

Background: Ayurvedic medicines help in healing disease with fewer undesirable effects in comparison with an allopathic system of medicine to treat central nervous system (CNS) disorders, as the latter is more expensive. Centella asiatica L. is often used in Ayurvedic formulations for the treatment of CNS disorders. Objective: A stability test using an HPTLC method for the estimation of an important marker asiaticoside (ASI) from C. asiatica powder and marketed formulation was developed. Methods: The marker compound ASI from plant powders and marketed formulations were resolved using toluene-ethyl acetate-methanol-glacial acetic acid (2+7+3+1, v/v/v/v) as the mobile phase and then was derivatized. The plant powder and marketed formulation were also subjected to stability studies. Results: The Rf value of ASI was found in range of 0.43-0.47 for the standard ASI, plant powder, and marketed formulation. It was found that the plant powder and formulation exhibited first-order degradation kinetics. Conclusions: The contents of ASI in the formulation (Churna) and its flow characters reduced at the end of the 6 months during an accelerated stability study. The developed method can be used to quantify ASI in the presence of its degradation products. Highlights: The developed method helps in determining batch to batch variation in the content of ASI in herbal formulations.

Comparing translational population-PBPK modelling of brain microdialysis with bottom-up prediction of brain-to-plasma distribution in rat and human.

The prediction of brain extracellular fluid (ECF) concentrations in human is a potentially valuable asset during drug development as it can provide the pharmacokinetic input for pharmacokinetic-pharmacodynamic models. This study aimed to compare two translational modelling approaches that can be applied at the preclinical stage of development in order to simulate human brain ECF concentrations. A population-PBPK model of the central nervous system was developed based on brain microdialysis data, and the model parameters were translated to their corresponding human values to simulate ECF and brain tissue concentration profiles. In parallel, the PBPK modelling software Simcyp was used to simulate human brain tissue concentrations, via the bottom-up prediction of brain tissue distribution using two different sets of mechanistic tissue composition-based equations. The population-PBPK and bottom-up approaches gave similar predictions of total brain concentrations in both rat and human, while only the population-PBPK model was capable of accurately simulating the rat ECF concentrations. The choice of PBPK model must therefore depend on the purpose of the modelling exercise, the in vitro and in vivo data available and knowledge of the mechanisms governing the membrane permeability and distribution of the drug.

Simultaneous determination of ginsenosides and lignans in Sheng-mai injection by ultra-performance liquid chromatography with diode array detection.

An ultra-performance liquid chromatography (UPLC) method with diode array detection was developed for simultaneous analysis of eight ginsenosides (ginsenosides Rg1, Re, Rf, Rb1, Rc, Rb2, Rb3, Rd) and one lignan (schizandrin) in Sheng-mai injection, a traditional Chinese medicine prescription widely used for the treatment of cardiovascular diseases. The chromatographic separation was performed on a Waters ACQUITY UPLC HSS T3 column (1.8 microm, 100 mm x 2.1 mm i.d.) using a linear gradient elution over 28 min with a mixture of water and acetonitrile as the mobile phase. All calibration curves showed good linearity (r2 > 0.9998) within the test ranges. Validation proved the repeatability of the method was good and recovery was satisfactory. The validated method was successfully applied to 12 batches of Sheng-mai injection. The results showed that there was a great variation among different samples. Principal component analysis (PCA) further proved considerable variations among the samples from different factories and suggested that schizandrin, ginsenosides Rb1 and Rg1 might have the greatest influence on the variation of 12 samples. In conclusion, these results demonstrated that the UPLC method proposed was very useful for the analysis and quality evaluation of Sheng-mai injection.

Anesthesiologist suicide with atracurium.

Atracurium is a nondepolarizing skeletal muscle relaxant used to facilitate endotracheal intubation and to induce skeletal muscle relaxation during surgery or mechanical ventilation. The drug undergoes a spontaneous non-enzymatic biotransformation, yielding laudanosine and an acrylate moiety. This report documents the case of a 45-year-old anesthesiologist who was found dead at the hospital where he worked. The victim was known to be depressed and undergoing treatment with venlafaxine. An empty syringe was found near the body. Toxicological analysis revealed the presence of laudanosine in the syringe, 0.6 mg/L of laudanosine in heart blood, 0.3 mg/L in urine, and 0.02 mg/L in vitreous humor. Meanwhile, concentrations of venlafaxine and O-desmethyl-venlafaxine, its active metabolite, were 0.7 and 1.1 mg/L in heart blood, 1.7 and 5.2 mg/L in urine, 0.5 and 0.7 mg/L in vitreous humor, and 400 and 20 mg in gastric content, respectively. All drugs and metabolites involved in the case were detected using gas chromatography with nitrogen-phosphorus detection (GC-NPD) and confirmed using GC-mass spectrometry in full scan mode after solid-phase extraction using Bond-Elut Certify columns. Additional high-performance liquid chromatography coupled to diode-array detection screening also obtained the same results. Quantitation of laudanosine and venlafaxine together with its metabolite was carried out using GC-NPD. No other drugs, including ethanol, were detected. Recoveries for laudanosine and venlafaxine were 89% and 86%, respectively, at 0.5 mg/L; intraday and interday precisions were 2% and 6%, and 3% and 7%, respectively; and limits of detection and quantitation were 6 and 20 ng/mL and 18 and 59 ng/mL, respectively. The linearity of the blood calibration curves was excellent for both drugs with r(2) values of > 0.999 (range 0.1-2.0 mg/L). Based on the autopsy findings, case history, and toxicology results, the forensic pathologists ruled that the cause of death was an overdose of atracurium, and the manner of death was suicide.

LC/MS fingerprinting of Shenmai injection: a novel approach to quality control of herbal medicines.

Chromatographic fingerprinting has been recommended as a potential and reliable strategy for the quality control of herbal medicines. Although varieties of chromatographic techniques, particularly HPLC, have been widely employed, hyphenated chromatographic approach has not been sufficiently exploited in chromatographic fingerprinting. In this work, LC/MS fingerprinting of Shenmai injection was developed. Thirty ginsenosides as well as seven ophioponins were selected to construct the LC/MS fingerprint using selective ion monitoring (SIM) mode, while previous HPLC fingerprint [H.J. Zhang, Y.J. Wu, Y.Y. Cheng, J. Pharm. Biomed. Anal. 31 (2003) 175-183] only represents the ginsenosides. Subsequently, the proposed LC/MS fingerprints were applied to identifying the product manufacturers. All the samples were accurately classified based on their LC/MS fingerprints in conjunction with principal components analysis (PCA). This study would be potentially helpful to improve the quality control ability of fingerprinting-based strategy for complex herbal medicines.

Determination of ginsenosides in plant extracts from Panax ginseng and Panax quinquefolius L. by LC/MS/MS.

An HPLC/MS/MS method has been developed for the characterization and quantification of ginsenosides contained in extracts of the root of Panax ginseng (Korean ginsengs) and Panax quinquefolius L. (American ginsengs). The [M + H]+ and [M + Na]+ ions were observed for ginsenoside standards (Rb1, Rb2, Rc, Rd, Re, Rf, Rg1) and four different ginseng extracts. The glycosidic linkages, the core, and the attached sugar(s) of the ginsenosides can be determined from the collision-induced dissociation spectra from the protonated molecules. The relative distribution of these ginsenosides in each extract of American or Korean ginseng was established.