Population pharmacokinetics and clinical outcomes of polymyxin B in paediatric patients with multidrug-resistant Gram-negative bacterial infections.

BACKGROUND: Current polymyxin B dosing in children relies on scant data. OBJECTIVES: To build a population pharmacokinetic (PK) model for polymyxin B in paediatric patients and assess the likely appropriateness of different dosages. METHODS: A total of 19 paediatric patients were enrolled to receive intravenous polymyxin B (1.33-2.53 mg/kg/day), and the median age was 12.5 (range 3.2-17.8) years. Serial plasma samples were collected at steady-state and modelled by population PK analysis. Clinical efficacy and nephrotoxicity of polymyxin B treatment were also assessed. RESULTS: PK data were adequately described by a two-compartment model with first-order elimination, and weight was a significant covariate of polymyxin B clearance. Clinical success occurred in 14 of 19 patients (73.7%) and only one patient developed acute kidney injury. The 28 day mortality was 10.5% (2/19). The steady-state polymyxin B exposure was 36.97 ±â€Š9.84 mg·h/L, lower than the therapeutic exposure of 50-100 mg·h/L. With the AUC24h/MIC target of 50, the dosage of 1.5-3.0 mg/kg/day had a probability of target attainments over 90% when MICs were <0.5 mg/L. CONCLUSIONS: Dose adjustment of polymyxin B needs to consider the MIC of infecting pathogens. Current polymyxin B dosing for paediatric patients may be acceptable when MICs are <0.5 mg/L.

[Study on metabolic dynamics,metabolic enzyme phenotype and species difference of hepatic and intestinal microsome of psoralidin].

This study aims to investigate metabolic activities of psoralidin in human liver microsomes( HLM) and intestinal microsomes( HIM),and to identify cytochrome P450 enzymes( CYPs) and UDP-glucuronosyl transferases( UGTs) involved in psoralidin metabolism as well as species differences in the in vitro metabolism of psoralen. First,after incubation serial of psoralidin solutions with nicotinamide adenine dinucleotide phosphate( NADPH) or uridine 5'-diphosphate-glucuronic acid( UDPGA)-supplemented HLM or HIM,two oxidic products( M1 and M2) and two conjugated glucuronides( G1 and G2) were produced in HLM-mediated incubation system,while only M1 and G1 were detected in HIM-supplemented system. The CLintfor M1 in HLM and HIM were 104. 3,and57. 6 µL·min~(-1)·mg~(-1),respectively,while those for G1 were 543. 3,and 75. 9 µL·min~(-1)·mg~(-1),respectively. Furthermore,reaction phenotyping was performed to identify the main contributors to psoralidin metabolism after incubation of psoralidin with NADPH-supplemented twelve CYP isozymes( or UDPGA-supplemented twelve UGT enzymes),respectively. The results showed that CYP1 A1( 39. 5 µL·min~(-1)·mg~(-1)),CYP2 C8( 88. 0 µL·min~(-1)·mg~(-1)),CYP2 C19( 166. 7 µL·min~(-1)·mg~(-1)),and CYP2 D6( 9. 1 µL·min~(-1)·mg~(-1)) were identified as the main CYP isoforms for M1,whereas CYP2 C19( 42. 0 µL·min~(-1)·mg~(-1)) participated more in producing M2. In addition,UGT1 A1( 1 184. 4 µL·min~(-1)·mg~(-1)),UGT1 A7( 922. 8 µL·min~(-1)·mg~(-1)),UGT1 A8( 133. 0 µL·min~(-1)·mg~(-1)),UGT1 A9( 348. 6 µL·min~(-1)·mg~(-1)) and UGT2 B7( 118. 7 µL·min~(-1)·mg~(-1)) played important roles in the generation of G1,while UGT1 A9( 111. 3 µL·min~(-1)·mg~(-1)) was regarded as the key UGT isozyme for G2. Moreover,different concentrations of psoralidin were incubated with monkey liver microsomes( MkLM),rat liver microsomes( RLM),mice liver microsomes( MLM),dog liver microsomes( DLM) and mini-pig liver microsomes( MpLM),respectively. The obtained CLintwere used to evaluate the species differences.Phase Ⅰ metabolism and glucuronidation of psoralidinby liver microsomes showed significant species differences. In general,psoralidin underwent efficient hepatic and intestinal metabolisms. CYP1 A1,CYP2 C8,CYP2 C19,CYP2 D6 and UGT1 A1,UGT1 A7,UGT1 A8,UGT1 A9,UGT2 B7 were identified as the main contributors responsible for phase Ⅰ metabolism and glucuronidation,respectively. Rat and mini-pig were considered as the appropriate model animals to investigate phase Ⅰ metabolism and glucuronidation,respectively.

[A new 3, 4-seco-lanostane triterpenoid from a marine-derived fungus Ascotricha sp. ZJ-M-5].

To study the secondary metabolites of a marine-derived fungus Ascotricha sp. ZJ-M-5, several chromatographic methods including macroporous resin, silica gel, ODS and Sephadex LH-20 were used to isolate the compounds, and their structures were elucidated on the basis of physicochemical properties and spectroscopic methods. Ten compounds were obtained and identified as ascotrichic acid B (1), (3R)-6-hydroxymellein (2), beta-carboline (3), (22E, 24R)-ergosta-7, 22-diene-3beta, 5alpha, 6beta-triol (4), (22E, 24R)-ergosta-7, 22-diene-3beta, 5alpha, 6beta, 9alpha-tetraol (5), cyclo (Leu-Pro) (6), cyclo (Ile-Leu) (7), cyclo (Pro-Val) (8), cyclo (Pro-Gly) (9), and cyclo (Hpro-Ala) (10). Among them, compound 1 is a new 3, 4-seco-lanostane triterpenoid which has been isolated from the filamentous fungi for the first time, and compounds 2-10 are firstly isolated from Ascotricha genus.

A homologues prediction strategy for comprehensive screening and characterization of C21 steroids from Xiao-ai-ping injection by using ultra high performance liquid chromatography coupled with high resolution hybrid quadrupole-orbitrap mass spectrometry.

Because of the complicated chemical composition of Traditional Chinese Medicines, their chemical profile study has been a great challenge. In the present work, a homologues prediction strategy for rapid screening and identification of C21 steroids in Xiao-ai-ping injection was developed by using an ultra high performance liquid chromatography coupled with high resolution hybrid quadrupole-orbitrap mass spectrometry. This strategy was characterized by the design of C21 steroidal skeleton, substituent group and glycan chain in an orderly way, which could quickly and efficiently screen the interested precursor ions. As a result, a total of 95C21 steroids including 47 potential new ones were identified or tentatively identified, which greatly expanded our knowledge of C21 steroids in Xiao-ai-ping injection. The results indicated that the homologues prediction strategy not only provided an efficient technique to screen and identify target constituents, but also offered a new perspective for discovery new components in Traditional Chinese Medicines.

Chemical profiling and quantification of Dan-Deng-Tong-Nao-capsule using ultra high performance liquid chromatography coupled with high resolution hybrid quadruple-orbitrap mass spectrometry.

Dan-Deng-Tong-Nao capsule (DDTN) was a traditional Chinese medicine (TCM) formula, and has been widely used for the treatment of stroke clinically which caused by blood stasis. However, the bioactive substances and mechanism are unclear because of the complex compositions in DDTN. In this research, An ultra high-performance liquid chromatography (UHPLC) coupled with hybrid quadruple-orbitrap mass spectrometry (Q-Orbitrap MS) method was utilized to identify the chemical constituents of DDTN. In total, 102 compounds including diterpenes, lactones, flavonoids, and phenolic acids were identified by the accurate masses and fragmentation pathways, and 18 of them were unambiguously determined by comparison of reference standards. Besides, 12 representative compounds were simultaneously quantification analyzed and successfully applified for detecting in 9 batches of DDTN samples by UHPLC-Q-Orbitrap MS in parallel reaction monitoring (PRM) mode. The proposed approach was validated to be satisfied in terms of linearity (0.9954-0.9999), LOD (0.771ng/mL), LOQ (2.568ng/mL), intra-day precision ( <2.68%), inter-day precision ( <4.52%), repeatability ( <2.96%), stability ( <3.21%), and recovery (94.6-105.5%). The results indicate that the method of combining UHPLC with Q-Orbitrap MS is practical and efficient for the chemical clarification in DDTN, and has great potential for the integrating quality control of other traditional Chinese medicines.

Isolation and identification of metabolites of bakuchiol in rats.

Bakuchiol, the main active component of Psoralea corylifolia, showed a range of significant pharmacological activities, including antimicrobial, antiinflammatory, reduction of bone loss and estrogenic activities. In this research, 12 metabolites, including 11 new compounds, were isolated from the urine and feces of rats after oral administration of bakuchiol, and their structures were elucidated by extensive spectroscopic analysis. The possible metabolic pathways of bakuchiol in rats were proposed, and a rare bile acid conjugation reaction was found. In addition, bakuchiol and its metabolites M1-M3 were studied for their alkaline phosphatase (ALP) activities on MC3T3-E1 cells and cytotoxicity on HKC-8 cells. The data showed that bakuchiol exerted significant effects on ALP activity of MC3T3-E1 cells and cytotoxicity on HKC-8 cells, while M1-M3 only showed ALP activities at 10(-5)M on MC3T3-E1 cells and no cytotoxicity on HKC-8 cells.

Identification of metabolites of PSORALEAE FRUCTUS in rats by ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry analysis.

The fruit of Psoralea corylifolia (Psoraleae Fructus) is a traditional Chinese medicine (TCM), which has been used to prevent and treat vitiligo, psoriasis, and osteoporosis in China for thousands of years. Phytochemical investigation on Psoraleae Fructus, as well as some metabolism research focused on pharmacokinetics of several single compounds from this plant, has been reported. However, the effective material of Psoraleae Fructus is still unknown. In the present study, the metabolic fate of multiple components of Psoraleae Fructus in rats was investigated by ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). Based on a three-step strategy, a total of 142 Psoraleae Fructus-related xenobiotics were identified or tentatively characterized in rat biofluids after oral administration of six representative single compounds and Psoraleae Fructus extract. All six different types of constituents of Psoraleae Fructus, including furocoumarin, coumestan, isoflavone, flavanone, chalcone and monoterpene phenol, could be absorbed into the circulation system. In addition, compared with the metabolism of six representative single compounds, different metabolic fate was observed after oral administration of Psoraleae Fructus extract, which indicated that the drug-drug interactions occurred when fed by multi-component herbal extract, and the investigations only focused on several main components were not sufficient to represent and reflect the overall efficacy of plants. The present study will be conducive to further pharmacological mechanism research on Psoraleae Fructus.

Two new compounds from a marine-derived fungus Penicillium oxalicum.

Two new anthraquinones, emodin-3-O-sulphate (1) and citreorosein-3-O-sulphate (2), as well as five known anthraquinones, were isolated from a marine-derived fungus Penicillium oxalicum. The structures of these compounds were determined by spectroscopic methods (1D and 2D NMR, HR-ESI-MS).

Novel decaturin alkaloids from the marine-derived fungus Penicillium oxalicum.

From the mycelia of Penicillium oxalicum two new compounds, decaturins E (1) and F (2), have been isolated, along with four known analogues, decaturin A (3), decaturin C (4), decaturin D (5), and oxalicine B (6). The structures were determined by HR-ESI-MS and 1D and 2D NMR analysis.

A new cyclonerol derivative from a marine-derived fungus Ascotricha sp. ZJ-M-5.

A new sesquiterpene, ascotrichic acid (1), was isolated from a marine-derived fungus Ascotricha sp., together with the other two known analogues, cyclonerodiol (2) and 10(Z)-cyclonerotriol (3). Its structure was established by spectroscopic methods (1D and 2D NMR, HR-ESI-MS).