Gadolinium Deposition in the Brain: Current Updates

Gadolinium-based contrast agents (GBCAs) are commonly used for enhancement in MR imaging and have long been considered safe when administered at recommended doses. However, since the report that nephrogenic systemic fibrosis is linked to the use of GBCAs in subjects with severe renal diseases, accumulating evidence has suggested that GBCAs are not cleared entirely from our bodies; some GBCAs are deposited in our tissues, including the brain. GBCA deposition in the brain is mostly linked to the specific chelate structure of the GBCA: linear GBCAs were responsible for brain deposition in almost all reported studies. This review aimed to summarize the current knowledge about GBCA brain deposition and discuss its clinical implications.

Development of self-nanoemulsifying tablet (SNET) for bioavailability enhancement of sertraline

The purpose of the study was to combine the advantages of self-nanoemulsifying drug delivery systems and tablets as a conventional dosage form. Self-nanoemulsifying drug delivery system (SNEDDS) was prepared to enhance the solubility and thus oral bioavailability of sertraline. Aqueous titration method was used to prepare the liquid SNEDDS; ternary phase diagrams were constructed and based on smaller droplet size (24.8 nm), minimum viscosity (153.63 cP) and polydispersity index (0.182), higher percentage transmittance (95%) and in vitro drug release (97%), an optimum system was designated. Liquid SNEDDS was transformed into free-flowing powder by solid adsorption technique followed by compression into tablets. In vitro release of sertraline from liquid and solid SNEDDS was found to be highly significant compared to plain sertraline (p<0.01). Pharmacokinetic studies after oral administration of liquid and solid SNEDDS in rats showed about 6-and 5-fold increased absorption of sertraline compared to the aqueous suspension of sertraline. These studies demonstrate that the solid SNEDDS are promising strategies for successful delivery of poorly water-soluble drug like sertraline

miRNA library and thermodynamic stability of Astragali Radix decoction pieces / 中草药

Objective: To establish a small RNA library of Astragalus membranaceus, in order to understand the intake and absorption of miRNAs in human body, and to lay the foundation for pharmacological research of Astragali Radix decoction pieces (ARP). Methods: The decoction of A. membranaceus after desiccation, high temperature and microwave treatment was used as sample, and using high-throughput sequencing technology, the unknown miRNA sequence was obtained. Results: Totally 9931049 small RNA sequences were identified from ARP by the high-throughput sequencing technology. After compared with all hairpin-forming precursors in miRBase 21 database, the miRNA library of ARP decoction was established, and one conserved miRNA and 9 novel miRNA sequences were confirmed. Twelve class I small interfering RNAs (siRNAs) were obtained by further bioinformatic analysis and we found that the 5' terminal was unstable while the 3' terminal was stable thermodynamically. Conclusion: The miRNAs expression profiles of ARP is first revealed by thermodynamic treatment. Our study suggests that class I siRNA can be used as a potential biochemistry components of phytomedicine, which might contribute to the epigenetic studies on Chinese materia medica.

Temperature effect on solution stability constants of metal complexes with schiff bases derived from 5-aldehydosalicylic acid – aniline and its related compounds.

Thermodynamic protonation constants of 5-aldehydosalicylic acid Schiff base with aniline and related compounds such as o-chloro aniline, o-nitro aniline, o-anisidine, o-toluidine and with 7-amino-4-methyl coumarin have been determined by Calvin-Bjerrum pH titration technique as used by Irving and Rosssotti. The solution stability constants of their complexes with bivalent metal ions Cu(II), Zn(II), Ni(II), Co(II), Cd(II) and Mg(II) with these ligands have been determined at four temperature in 50% water-ethanol mixture at an ionic strength of 0.1M (NaClO4). The order of solution stability constants was found to be Zn < Cu > Ni > Co = Cd > Mg which is in agreement with Irving – William’s order. The values of ΔGo, ΔHo, ΔSo have been calculated for the various complex equilibrium. The Copper chelates found to be more stable than Zn and Ni chelates due to difference in their configurations. Cu(II) forms square planar complex while Zn(II), Ni(II) form a tetrahedral or octahedral complex. The log K value for Zn chelate is found to be higher as compared to that of Ni chelate in case of above said all reagents used for investigation.

Role of temperature on stability constants of metal complexes in 50% (V/V) water-ethanol solution.

Thermodynamic protonation constants of 5-aldehydosalicylic acid-aniline Schiff base, [5ASAA], and o-, m-, p-Toluidine Schiff bases with 5-aldehydosalicylic acid have been determined by Calvin –Bjerrum pH titration technique as used by Irving and Rossotti. The thermodynamic formation constants of the chelates of Cu (II), Co (II), Ni (II), Zn (II), Cd (II) and Mg (II) with these four ligands have been determined at four different temperatures in 50% (v/v) water-ethanol mixture; the stabilities of complexes follow the Irving-William’s order.