Injuries of myocardial cells and changes of myocardial enzymes after firearm wound-induced intestinal perforation in porcine abdomen.

This study aims to observe the changes of myocardial injuries after the firearm wound-induced intestinal perforation in porcine abdomen. 42 healthy Landrace piglets were randomly divided into the control group and the injury group, which was then subdivided into the post-injury 1 h, 2 h, 4 h, 8 h, 12 h and 24 h subgroup. the LDH, CK and CK-MB levels of each group, as well as the plasma endotoxin, were determined and compared. The plasma endotoxin levels of the experimental groups were significantly higher than the control group, and the light microscope observation revealed that the 8 h, 12 h and 24 h subgroup appeared the gradually-aggravated myocardial cell edema and degeneration; the electron microscope revealed that the 4 h, 8 h, 12 h and 24 h subgroup appeared the mitochondrial swelling and dissolution gradually; the serum levels of LDH, CK and CK-MB of each experimental group were higher than the control group. The abdominal firearm wound-induced intestinal perforation would lead to the damaged changes of myocardial morphology and enzymes, which would aggravate as time went along.

[Determination of serotonin in rat brain microdialysate after i. p. administration of fluoxetine hydrochloride by high performance liquid chromatography].

The concentration of serotonin (5-HT) in rat brain microdialysate before and after i. p. administration of fluoxetine hydrochloride was determined through precolumn derivatization by reversed-phase high performance liquid chromatography (RP-HPLC). A baseline separation of serotonin was achieved on a Hypersil C18 column (250 mm x 2. 0 mm, 5 microm) with acetonitrile-20 mmol/L sodium acetic solution (pH 5. 0) (45: 55, v/v) containing 20 mmol/L of sodium octanesulfonate as the mobile phase. Fluorescence detection with the excitation wavelength at 330 nm and emission wavelength at 455 nm was used for serotonin. There was good linear relationship between the peak area and concentration in the range of 0. 25 - 5. 0 nmol/L( r =0. 999 1). The limit of quantitation was 0. 25 nmol/L. The method is simple, accurate and can be applied to the determination of serotonin in biological specimen.

Determination of nifedipine in human plasma and its use in bioequivalence study.

A sensitive atmospheric pressure chemical ionization liquid chromatographic-mass spectrometric (APCI-LC-MS) assay with positive ion mode has been developed for the determination of nifedipine in human plasma. In this method, nifedipine was extracted from human plasma using diethyl ether with dimethoxanate as the internal standard. Analysis was achieved on a BDS C(18) column with methanol-H(2)O (66:34, v/v) as the mobile phase. Sustained-release nifedipine tablets from DiSha (test, Weihai, China) and from GuoFeng (reference, Qingdao, China) were evaluated following a single 20mg oral dose to 20 healthy volunteers. Bioequivalence between the products was determined by calculating 90% confidence intervals (90% CI) for the ratio of C(max), AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The 90% confidence intervals for the ratio of C(max) (86.6-105.2%), AUC(0-t) (97.8-110.9%) and AUC(0-infinity) (96.5-110.4%) values for the test and reference products are within the interval (80.0-125.0% for AUC, and 70-143% for C(max)), proposed by State of Food and Drug Administration [SFDA, 2005. Guidance for Bioavailability and Bioequivalence Studies for Chemical Drug Products in Human Being. China, p. 19]. It was concluded that the two sustained-release nifedipine tablets are bioequivalent in their rate and extent of absorption and, thus, may be used interchangeably.

Determination of tropisetron in human plasma by high performance liquid chromatographic method with UV detection and its application to a bioequivalence study.

A simple and sensitive high performance liquid chromatography method with UV detection was described for the determination of tropisetron in human plasma. The prepared sample solution was injected onto BDS-C(8) reversed column using a mixture of ammonium acetate (100 mM, PH adjusted to 4.3 with glacial acetic acid) and acetonitrile (80:20, v/v) as mobile phase. The wavelength of UV detector was set at 285 nm. No interference from any endogenous substances was observed during the elution of tropisetron and internal standard (ondansetron hydrochloride). The lower limit of quantification was evaluated to be 1 ng/mL. The method was used in a randomized crossover bioequivalence study of two different tropisetron preparations in 20 healthy volunteers.