Discovery of SLC3A2 cell membrane protein as a potential gastric cancer biomarker: implications in molecular imaging.

Despite decreasing incidence and mortality, gastric cancer remains the second leading cause of cancer-related deaths in the world. Successful management of gastric cancer is hampered by lack of highly sensitive and specific biomarkers especially for early cancer detection. Cell surface proteins that are aberrantly expressed between normal and cancer cells are potentially useful for cancer imaging and therapy due to easy accessibility of these targets.

Isolation and identification of thiohomosildenafil and thiosildenafil in health supplements.

Two unknown compounds are detected and isolated from health supplements for the enhancement of sexual function. The structures of the unknown compounds are elucidated using high-resolution MS, ESI-MS/MS, NMR, UV and IR. One compound is identified as an analogue of sildenafil in which the oxygen atom is substituted with a sulfur atom in the pyrazolopyrimidine moiety, and an ethyl group instead of a methyl group is attached to the piperazinyl nitrogen.

Identification of benzamidenafil, a new class of phosphodiesterase-5 inhibitor, as an adulterant in a dietary supplement.

A sample labeled to be a natural herbal supplement for the enhancement of sexual function, was sent to Health Sciences Authority (HSA) of Singapore for testing. An unknown compound was detected and isolated from the product. The structure of the unknown compound was identified using LC-UV, high-resolution MS, ESI-MS/MS, IR, and NMR.

Structural identification of a new acetildenafil analogue from pre-mixed bulk powder intended as a dietary supplement.

An analogue of acetildenafil was detected in an extract of pre-mixed bulk powder. To our knowledge, the powder was destined to be encapsulated and sold as a dietary supplement. The structure was identified by NMR, HR-ESI-MS, ESI-MSn and FTIR analyses.

Structural elucidation of a tadalafil analogue found as an adulterant of a herbal product.

A tadalafil analogue and hydroxyhomosildenafil were isolated from a herbal product marketed for erectile dysfunction. The structure of the tadalafil analogue was elucidated using LC-UV, high resolution MS, ESI-MS/MS, IR, and NMR. The compound was determined to be (6R,12aR)-2-amino-6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydropyrazino[1',2':1,6] pyrido[3,4-b]indole-1,4-dione.

Simultaneous determination of synthetic phosphodiesterase-5 inhibitors found in a dietary supplement and pre-mixed bulk powders for dietary supplements using high-performance liquid chromatography with diode array detection and liquid chromatography-electrospray ionization tandem mass spectrometry.

A high-performance liquid chromatography-diode array detection (HPLC-DAD) method and a liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method were developed to screen for the presence of synthetic phosphodiesterase-5 (PDE-5) inhibitors and their analogues, namely sildenafil, vardenafil, tadalafil, homosildenafil, acetildenafil and hydroxyhomosildenafil. The methods were applied to pre-market samples submitted to the Health Sciences Authority of Singapore (HSA) for testing. One sample was in the form of capsules while six other samples were pre-mixed bulk powder samples for dietary supplements to be repackaged or formulated into the final dosage forms (usually capsules).

Microdialysis combined with liquid chromatography-tandem mass spectrometry for the determination of 6-aminobutylphthalide and its main metabolite in the brains of awake freely-moving rats.

6-Aminobutylphthalide (ABP) is a new drug candidate which is currently being developed for the treatment of cerebral ischemia. The pharmacokinetics and metabolism of ABP were studied using in situ microdialysis sampling in the brains of awake freely-moving rats. Two LC-MS/MS methods were used for the quantitative and qualitative analysis of microdialysate.

[Determination of tanshinone IIA in rat plasma and the pharmacokinetics by RP-HPLC method].

Aim: To develop a sensitive and rapid HPLC method for the determination of tanshinone IIA (TS) in rat plasma and to study its pharmacokinetics in rats.

Methods: TS and 4-chlorodiphenyl (internal standard) were extracted from plasma with ethyl acetate. After liquid-liquid extraction, the sample was analyzed by HPLC with YMC C18 column (5 microns, 150 mm x 3.

Effects of the aqueous extract from Salvia miltiorrhiza Bge on the pharmacokinetics of diazepam and on liver microsomal cytochrome P450 enzyme activity in rats.

The aim of this study was to determine the effects of the aqueous extract of Salvia miltiorrhiza Bge (danshen in Chinese) on the pharmacokinetics of diazepam and on liver microsomal cytochrome P450 enzyme activity in rats. Rats (n = 5) were pretreated with danshen extract (100 mg kg(-1) per day, p.o.