Development of water quality criteria for phenanthrene and comparison of the sensitivity between native and non-native species.

Phenanthrene (PHE) is a priority polycyclic aromatic hydrocarbon (PAH) which is toxic to aquatic organisms.However, there has been no paper dealing with water quality criteria (WQC) of PHE due to the shortage of toxicity data of different taxonomic levels. In the present study, toxicity data were obtained from 8 acute toxicity tests and 3 chronic toxicity tests using 8 Chinese native aquatic species from different taxonomic levels, and the water quality criteria was derived using 3 methods. Furthermore, differences of species sensitivity distributions (SSDs) between native and non-native species were compared. A criterion maximum concentration of 0.0514 mg/L and a criterion continuous concentration of 0.0186 mg/L were developed according to the US EPA guidelines. Finally, by using risk quotient (RQ) to assess the site-specific ecological risk in Liao River, the results indicated that the PHE might pose no risk to local aquatic species.

Derivatization of (5R)-hydroxytriptolide from benzylamine to enhance mass spectrometric detection: application to a Phase I pharmacokinetic study in humans.

(5R)-Hydroxytriptolide, a semisynthetic structural analog of triptolide, exhibits anti-inflammatory and immunosuppressive effect both in vitro and in vivo. The compound is currently undergoing Phase I clinical trials. This work describes the quantification of (5R)-hydroxytriptolide in human plasma based on chemical derivatization from benzylamine. Analysis through liquid chromatography-tandem mass spectrometry (LC-MS/MS) is performed for characterization. The primary reaction product between (5R)-hydroxytriptolide and benzylamine was identified as a 12,13-epoxide ring adduct. For quantification in plasma, (5R)-hydroxytriptolide and the internal standard (triptolide) were first extracted from diethyl ether-dichloromethane (3:2, v/v) and then converted to their benzylamine derivates at 80°C for 1 h. The analytes are separated on a Gemini 5 µm 100 Å column, using a gradient elution program with a solvent consisting of 0.77 mM ammonium hydroxide (pH 10.0) and acetonitrile. An API 4000 tandem mass spectrometer operated in positive ion mode and equipped with an electrospray ionization source is used as detector. This method allows for a lower limit of quantification of 0.030 ng mL(-1). The validation results show accuracy (%RE<11.7) and precision (%RSD<8.6) at a broad linear dynamic range (0.030-100 ng mL(-1)). The simple and quantitative derivatization coupled with tandem mass spectrometric analysis yields a sensitive and robust method for the quantification of (5R)-hydroxytriptolide in Phase I pharmacokinetic studies.

[Determination of tanshinone II A and deoxyschizandrin in danshenwuweizi tablet by RP-HPLC].

OBJECTIVE: to set up a determination of tanshinone II A and deoxyschizaadrin in danshenwuweizi tablet by RP-HPLC. METHODS: two components were separated through Kromasil C18 (250 mm x 4.6 mm, 5 microm) column with methanol-water (85:15) by volume as a mobile phase. The flow rate was 1 ml x min(-1) and the detection wavelength were 270 nm (tanshinone II A) and 254 nm (deoxyschizandrin). RESULTS: The linear range of tanshinone II A and deoxyschizandrin were 0.3232 microg-1.616 microg and 0.525 microg-2.625 microg, respectively. The average recovery was 99.83% with RSD 0.36% for tanshinone II A and 100.2% with RSD 0.72% for deoxyschizandrin respectively. CONCLUSION: The method is simple, accurate and rapid with good reproducibility. It can be used for the quality control of danshenwuweizi tablet.

Identification of the 'wrong' active pharmaceutical ingredient in a counterfeit Halfan drug product using accurate mass electrospray ionisation mass spectrometry, accurate mass tandem mass spectrometry and liquid chromatography/mass spectrometry.

Methodology is presented for identifying an unknown active (pharmaceutical) ingredient (AI) in a counterfeit drug product. A range of mass spectrometric techniques, i.e., accurate mass mass spectrometry, tandem mass spectrometry (MS/MS) and liquid chromatography/mass spectrometry (LC/MS), has been employed to determine the AI in a counterfeit Halfan suspension, an antimalarial drug. In particular, use of LockSpray accurate mass MS/MS allowed identification of parts of the molecule from fragments, hence limiting the number of possible elemental compositions for the nominal mass of 278 found for the AI in the counterfeit product. The analysis of the isotope pattern observed for the protonated molecule further reduced the number of possible elemental compositions. A literature search for readily commercially available compounds of molecular formula C(12)H(14)N(4)O(2)S suggested that the AI was either sulfamethazine or sulfisomidine. An LC/MS separation of those two compounds and reference MS/MS spectra obtained for sulfamethazine and sulfisomidine led to the conclusion that the AI in the counterfeit Halfan suspension is sulfamethazine, which is an antibacterial agent.