다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

비만아 부모의 돌봄 경험: q 방법론

Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one drawback of using this natural polysaccharide in modified release dosage forms for oral administration is its fast dissolution rate in the stomach. Since chitosan is positively charged at low pH values (below its pK(a) value), it spontaneously associates with negatively charged polyions in solution to form polyelectrolyte complexes. These chitosan based polyelectrolyte complexes exhibit favourable physicochemical properties with preservation of chitosan's biocompatible characteristics. These complexes are therefore good candidate excipient materials for the design of different types of dosage forms. It is the aim of this review to describe complexation of chitosan with selected natural and synthetic polyanions and to indicate some of the factors that influence the formation and stability of these polyelectrolyte complexes. Furthermore, recent investigations into the use of these complexes as excipients in drug delivery systems such as nano- and microparticles, beads, fibers, sponges and matrix type tablets are briefly described.

https://www.mdpi.com/1660-3397/8/4/1305/pdf

Chitosan based polyelectrolyte complexes as potential carrier materials in drug delivery systems.

Emodin is a natural anthraquinone derivative that occurs in many widely used Chinese medicinal herbs, such as Rheum palmatum, Polygonum cuspidatum and Polygonum multiflorum Emodin has been used as a traditional Chinese medicine for over 2000 years and is still present in various herbal preparations Emerging evidence indicates that emodin possesses a wide spectrum of pharmacological properties, including anticancer, hepatoprotective, antiinflammatory, antioxidant and antimicrobial activities However, emodin could also lead to hepatotoxicity, kidney toxicity and reproductive toxicity, particularly in high doses and with long-term use Pharmacokinetic studies have demonstrated that emodin has poor oral bioavailability in rats because of its extensive glucuronidation This review aims to comprehensively summarize the pharmacology, toxicity and pharmacokinetics of emodin reported to date with an emphasis on its biological properties and mechanisms of action Copyright © 2016 John Wiley & Sons, Ltd

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ptr.5631

Aloe‐emodin: A review of its pharmacology, toxicity, and pharmacokinetics

3,6′-Disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C are the major pharmacologically active ingredients in Radix Polygalae. The hydrolytic kinetics and degradation mechanism of these compounds were studied using high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). The influence of temperature and pH on the stability of these compounds was investigated. The activation energy of 3,6′-disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C in neutral aqueous solution (pH 6.8) was calculated to be 52.00, 42.25, 39.64, and 45.50 kJ mol−1, respectively. These four oligosaccharide esters were more susceptible to degradation under alkaline conditions. The minimum stability of 3,6′-disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C were found at pH 10.8, and t1/2 was 0.21, 0.02, 0.17 and 0.03, respectively. The degradation products of these compounds were identified by UHPLC-Q-TOF/MS, and the degradation mechanisms were thought to be hydrolysis and isomerization, such as cis-trans isomerism, keto–enol tautomerism and optical isomerism.

Kinetics and mechanism of 3,6′-disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C degradation in aqueous solutions

Ginsenoside Rd was shown to have protective effects against several injuries and efficient for the treatment of acute ischemic stroke. Some research studies of ginsenoside Rd in the past mainly focused on the pharmacokinetics after intravenous and oral administration. However, we still lack some basic knowledge about the plasma pharmacokinetics and brain distribution of ginsenoside Rd by any other route, such as intranasal administration. It was found that intranasal administration exhibited good brain-targeting. In this study, a sensitive LC-MS/MS method was developed and validated for the determination of ginsenoside Rd in rat plasma and brain tissue. Detection was performed on an ACQUITY UPLC™ BEH C18 column using gradient elution with a flow rate of 0.2 mL min−1. Mass spectrometry was operated in selected reaction monitoring mode using a negative electrospray ionization interface. The method was linear over the concentration range of 1.0–1000 ng mL−1, and the lower limit of quantification was 1.0 ng mL−1 for ginsenoside Rd. The method was validated in terms of specificity, linearity, intra- and inter-day precision (<12.39%), accuracy (within ±10.1%), dilution integrity, recovery, matrix effects and stability, and has been successfully applied to the pharmacokinetic study of ginsenoside Rd in rats after intranasal administration and evaluation of the brain targeting of ginsenoside Rd.

Pharmacokinetics and brain distribution studies of ginsenoside Rd in rats via intranasal administration by LC-MS/MS

Isoimperatorin is a naturally occurring furocoumarin and is being considered as a potential chemoprevention. Only one crystal form of isoimperatorin (Form I) was reported during previous research so that an investigation of polymorphism of isoimperatorin was successfully undertaken. A new polymorph of isoimperatorin was discovered through comprehensive polymorph screening experiments. Their structures were elucidated by single-crystal structure analysis and extensively characterized by XRPD, DSC, FT-IR, and SEM. The results showed that the crystal structure and thermal properties of the new polymorph (Form II) were significantly different from those of Form I. Thermodynamic stability and phase transformation were also discussed in detail.

A new polymorph of isoimperatorin.

https://www.tiprpress.com/chmen/ch/reader/create_pdf.aspx?file_no=CHM20150102&year_id=2015&quarter_id=3&falg=1

Concentration Prediction of Total Flavonoids in Aurantii Fructus Extraction Process: Locally Weighted Regression versus Kinetic Model Equation Based on Fick's Law

OBJECTIVE To research the absorbed character of piperine in Erxiekang plaster, and piperine by transdermal absorption was determined. METHOD The percutaneous absorption of piperine in vitro at different times was conducted by Franz osmosis and diffusion apparatus as well as high-performance liquid chromatography. RESULT It showed that the piperine through skins of mice gradually increased within the experiment time. After 52 h, the penetration of piperine was 78.51%, and remained basically unchanged. CONCLUSION The method is reliable, and can be used for Erxiekang plaster of determination of transdermal absorption.

Jian Ni

Papers

Kinetics and mechanism of 3,6′-disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C degradation in aqueous solutions

Pharmacokinetics and brain distribution studies of ginsenoside Rd in rats via intranasal administration by LC-MS/MS

A new polymorph of isoimperatorin.

Concentration Prediction of Total Flavonoids in Aurantii Fructus Extraction Process: Locally Weighted Regression versus Kinetic Model Equation Based on Fick's Law

Study on transdermal absorption of piperine in Erxiekang plaster