Gradient elution LC-ESI-MS determination of tramadol in rat plasma

A sensitive and simple liquid chromatography/electrospray mass spectrometry (LC-ESI-MS) method for determination of tramadol in rat plasma using one-step protein precipitation was developed. After addition of ketamine as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on an SB-C18 (2.1 mm × 50 mm, 3.5 μm) column with methanol-0.1 % formic acid as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selected ion monitoring (SIM) mode was used to quantification using target fragment ions m/z 264.0 for tramadol and m/z 237.8 for the IS. Calibration plots were linear over the range of 5-500 ng/mL for tramadol in rat plasma. Lower limit of quantification (LLOQ) for tramadol was 5 ng/mL. Mean recovery of tramadol from plasma was in the range 92.8 %-97.4 %. RSD of intra-day and inter-day precision were both less than 10 %. This method is simple and sensitive enough to be used in pharmacokinetic research for determination of tramadol in rat plasma.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Simultaneous Determination of Three Bioactive Compounds in Traditional Chinese Medicine Patent Prescription Zuojin Pill by HPLC

A high-performance liquid chromatography (HPLC) method coupled with ultraviolet (UV) detection has been developed and validated for simultaneous quantification of berberine hydrochloride, evodiamine and rutaecarpine in Zuojin Pill. Chromatographic separation were achieved on a ODS-C18 column (250×4.6 mm i.d., 5.0 μm particle) through a 25 min gradient delivery of a mixture of A (acetonitrile) and B (0.3 % phosphoric acid-0.3 % triethylamine) at a flow rate of 0.8 mL/min at 40 °C. All of the analytes showed good linearity (r > 0.999). The method was validated for repeatability, precision, stability, accuracy and selectivity. The validated method was applied to quality control of Zuojin Pill from different manufacture.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Determination of emodin, chrysophanol, and physcion by HPLC in the chinese medicine rumex japonicus houtt.

A high performance liquid chromatography (HPLC) method for determination of emodin, chrysophanol and physcion in Rumex japonicus Houtt. from different places in Zhejiang Province (China) was established. The samples were separated on a Agilent Zorbax SB-C18 column (2.1 × 150 mm, 5 μm) at at a flow rate of 0.4 mL/min using acetonitrile-water as the mobile phase, with a gradient elution. The column oven temperature was 30 °C and the wavelength of detection used was 285 nm. The three anthraquinones were well separated by this HPLC method. Linearities of emodin, chrysophanol, and physcion were good in the ranges of 0.23-46 (r = 0.998), 0.2-50 (r = 0.9999), and 0.5-50 (r = 0.9997) μg/mL, respectively. The average recoveries were 99.01 % for emodin, 100.73 % for chrysophanol, 101.12 % for physcion, with RSD 1.23, 1.09 and 3.42 %, respectively. The method is simple, accurate, reproducible, and it can be used to quality control of Rumex japonicus Houtt.Colegio de Farmacéuticos de la Provincia de Buenos Aire

The microstructure evolution and tensile properties of Inconel 718 fabricated by high-deposition-rate laser directed energy deposition

In order to meet the requirements for rapid manufacturing of large-scale high-performance metal components, the unique advantages of high-deposition-rate laser directed energy deposition (HDR-LDED, deposition rate ≥1 kg/h) technology have been attracted great attention. HDR-LDED technology significantly improves the efficiency by simultaneously increasing the mass and energy input on basis of conventional laser directed energy deposition (C-LDED, deposition rate ≤ 0.3 kg/h), which dramatically changes the solidification condition and thermal cycling effect compared to C-LDED processes. Based on this, Inconel 718 bulk samples were fabricated with a deposition rate of 2.2 kg/h and a height of 75 mm. Through experimental observation combined with finite element simulation, the precipitation morphology, thermal cycling effect and tensile properties at room temperature of the block samples at heights of 6mm (bottom region), 37mm (middle region) and 69mm (top region) from the substrate were investigated. The results show that both temperature interval and incubation time satisfy the precipitation conditions of the second phases because of the intense thermal cycling effect so that δ, γ" and γ' phase are precipitated in the bottom and middle region of the as-deposited sample during the HDRLDED process. As a result, the micro-hardness and the yield strength of the bottom region (385 HV;745.1 ± 5.2 MPa) are similar to those of the middle region (381 HV; 752.2 ± 12.1 MPa), respectively. And they are both higher than those of the top region (298 HV; 464.7 ± 44.2 MPa). The tensile fracture mechanism is shown in both fracture and debonding of the Laves phase. The inhomogeneous microstructures and corresponding mechanical property differences of Inconel 718 fabricated by HDR-LDED along the deposition direction suggest the necessity to conduct further research of the post heat treatment in the future