• Toxicological Research
• /
• v.31 no.2
• /
• pp.137-149
• /
• 2015

Human hepatocytes, with complete hepatic metabolizing enzymes, transporters and cofactors, represent the gold standard for in vitro evaluation of drug metabolism, drug-drug interactions, and hepatotoxicity. Successful cryopreservation of human hepatocytes enables this experimental system to be used routinely. The use of human hepatocytes to evaluate two major adverse drug properties: drug-drug interactions and hepatotoxicity, are summarized in this review. The application of human hepatocytes in metabolism-based drug-drug interaction includes metabolite profiling, pathway identification, P450 inhibition, P450 induction, and uptake and efflux transporter inhibition. The application of human hepatocytes in toxicity evaluation includes in vitro hepatotoxicity and metabolism-based drug toxicity determination. A novel system, the Integrated Discrete Multiple Organ Co-culture (IdMOC) which allows the evaluation of nonhepatic toxicity in the presence of hepatic metabolism, is described.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.6
• /
• pp.471-481
• /
• 2005

In Korea, generic drug and bioequivalence test are the hot issues since a new medical system of separation of dispensary from medical practice was started in 2000. The KFDA(Korea FDA) had revised several times ${\ulcorner}Guidance\;for\;bioequivalence\;test{\lrcorner}$. In vitro dissolution test has been extensively used as a quality control tool for solid oral dosage forms. In an effort to minimize unnecessary human testing, in vitro/in vivo correlations (IVIVC) between in vitro dissolution and in vivo bioavailability are increasingly becoming an integral part on extended release drug product development. The recently published US guidance, ${\ulcorner}Extended\;release\;oral\;dosage\;forms\;:\;development,\;evaluation,\;and\;application\;of\;in\;vitro/in\;vivo\;correlations{\lrcorner}$ will be helpful for us to make our own guideline.

• Environmental Mutagens and Carcinogens
• /
• v.21 no.1
• /
• pp.30-33
• /
• 2001

Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, SAL), a dopaminergic isoquinoline neurotoxin, has been implicated to contribute the etiology of Parkinson's disease and neuropathology of chronic alcoholism. In our previous results, SAL was reported to have the mutagenicity and clastogenicity not in bacteria but in mammalian cells, and its genotoxic potential was known to be potentiated in the presence of rat liver S-9 fraction. This may indicate that some metabolite(s) of SAL was involved in the mutagenic potentials. To investigate the SAL metabolites, the metabolism studies of SAL were conducted in vitro rat liver S-9 fraction and in vivo using rats by high performance liquid chromatography and gas chromatography/mass spectrometry. The methylated metabolite of SAL was found in urine of rats, while the same methylating form of metabolite was not produced from the in vitro metabolism system using rat liver S-9 fraction.

• The Korean Journal of Physiology and Pharmacology
• /
• v.21 no.1
• /
• pp.45-54
• /
• 2017

Our study aims to determine the metabolism and excretion of novel pulmonary-targeting docetaxel liposome (DTX-LP) using the in vitro and in vivo animal experimental models. The metabolism and excretion of DTX-LP and intravenous DTX (DTX-IN) in New Zealand rabbits were determined with ultra-performance liquid chromatography tandem mass spectrometry. We found DTX-LP and DTX-IN were similarly degraded in vitro by liver homogenates and microsomes, but not metabolized by lung homogenates. Ultra-performance liquid chromatography tandem mass spectrometry identified two shared DTX metabolites. The unconfirmed metabolite $M_{un}$ differed structurally from all DTX metabolites identified to date. DTX-LP likewise had a similar in vivo metabolism to DTX-IN. Conversely, DTX-LP showed significantly diminished excretion in rabbit feces or urine, approximately halving the cumulative excretion rates compared to DTX-IN. Liposomal delivery of DTX did not alter the in vitro or in vivo drug metabolism. Delayed excretion of pulmonary-targeting DTX-LP may greatly enhance the therapeutic efficacy and reduce the systemic toxicity in the chemotherapy of non-small cell lung cancer. The identification of $M_{un}$ may further suggest an alternative species-specific metabolic pathway.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.7
• /
• pp.1049-1056
• /
• 2007

This study was conducted to compare the methane ($CH_4$) production estimated by in vivo (sulfur hexafluoride tracer technique ($SF_6$)) with that of two in vitro rumen simulation (RUSITEC) and gas production (IVGPT)) techniques. Four adult dry Holstein cows, aged $7.4{\pm}3.0$ years and weighing $697{\pm}70$ kg, were used for measuring methane production from five diets by the $SF_6$ technique. The experimental diets were alfalfa hay ($D_1$), corn silage + soybean meal (SBM) (910: 90, $D_2$), Italian rye grass hay +SBM (920: 80, $D_3$), rice straw +SBM (910: 90, $D_4$) and Sudan grass hay +SBM (920: 80, $D_5$). Each diet was individually fed to all 4 cows and 5 feeding studies of 17 d each were conducted to measure the methane production. In the RUSITEC, methane production was measured from triplicate vessels for each diet .In vitro gas production was measured for each of the diets in triplicate syringes. The gas produced after 24 and 48 h was recorded and gas samples were collected in vacuum vials and the methane production was calculated after correction for standard temperature and pressure (STP). Compared to the $SF_6$ technique, estimates of methane production using the RUSITEC were lower for all diets. Methane production estimated from 24 h in vitro gas production was higher (p<0.001) on $D_1$ as compared to that measured by $SF_6$, whereas on $D_2$ to $D_5$ it was lower. Compared to $SF_6$, methane production estimated from 48 h in vitro gas production was higher on all diets. However, methane estimated from the mean of the two measurement intervals (24+48 h/2) in IVGPT was very close to that of $SF_6$ (correlation 0.98), except on $D_1$. The results of our study confirmed that IVGPT is reflective of in vivo conditions, so that it could be used to generate a database on methane production potential of various ruminant diets and to examine strategies to modify methane emissions by ruminants.

• The Korean Journal of Pharmacology
• /
• v.1 no.1 s.1
• /
• pp.37-46
• /
• 1965

1. In the tortoise, Amyda japonica, a cold-blooded animal readily available in this country, the role of catecholamines in the regulation of free fatty acids(FFA) metabolism was investigated in both in vivo and in vitro studies. 2. Norepinephrine elevated both FFA and glucose levels in plasma. 3. When $50{\mu}g/kg$ of Epinephrine, Norepinephrine and Isopropylarterenol were administered intravenously, the relative effectiveness of mobilizing FFA was in the descending order of potency-Epinephrine, Norepinephrine and Isopropylarterenol. 4. In order to exclude the 'tonic influence of the endogenous catecholamines', reserpine was given to some animals. Two days after the reserpine-treatment, glucose showed a significant increase over the solely vehicle treated controls, FFA but an insignificant one. Excised auricles from those animals showed a diminished response to tyramine. Seven days after the treatment, however, when the depletion of catecholamines from the tissue stores seemed to be complete, judged from the absence of the response of isolated auricles to tyramine, both FFA and glucose levels were definitely lowered. 5. In in vitro experiments Epinephrine enhanced the FFA-release from the adipose tissue. The effect increased proportionately with the concentration until a maximal effect was attained at a concentration of 1x $10^5$ g/ml. 6. The order of potency in releasing FFA from adipose tissue in vitro was the same as in vitro, i.e., Epinephrine, Norepinephrine and Isopropylarterenol, but the differences were much less marked. 7. Ergotamine exerted no lipolytic action, but inhibited the lipolytic effect ef Epinephrine significantly. 8. Nethalide showed a slight lipolytic effect per se but inhibited the Epinephrine-induced lipolysis significantly. 9. Catecholamines play an important role in regulating FFA metabolism in the cold-blooded animal, just as in the warm-blooded animals, and the tortoise, Amyda japonica, may be used in the studies of fat metabolism as well as the rat.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.10
• /
• pp.1389-1394
• /
• 2012

Sheanut cake (SNC), expeller (SNE) and solvent extractions (SNSE) samples were evaluated to determine their suitability in animal feeding. The CP content was highest in SNSE (16.2%) followed by SNE (14.7%) and SNC (11.6%). However, metabolizable energy (ME, MJ/kg) was maximum in SNC (8.2) followed by SNE (7.9) and SNSE (7.0). The tannin phenol content was about 7.0 per cent and mostly in the form of hydrolyzable tannin (HT), whereas condensed tannin (CT) was less than one per cent. The in vitro gas production profiles indicated similar y max (maximum potential of gas production) among the 3 by-products. However, the rate of degradation (k) was maximum in SNC followed by SNE and SNSE. The $t^{1/2}$ (time taken for reaching half asymptote) was lowest in SNC (14.4 h) followed by SNE (18.7 h) and SNSE (21.9 h). The increment in the in vitro gas volume (ml/200 mg DM) with PEG (polyethylene glycol)-6000 (as a tannin binder) addition was 12.0 in SNC, 9.6 in SNE and 11.0 in SNSE, respectively. The highest ratio of $CH_4$ (ml) reduction per ml of the total gas, an indicator of the potential of tannin, was recorded in SNE (0.482) followed by SNC (0.301) and SNSE (0.261). There was significant (p<0.05) reduction in entodinia population and total protozoa population. Differential protozoa counts revealed that Entodinia populations increased to a greater extent than Holotricha when PEG was added. This is the first report on the antimethanogenic property of sheanut byproducts. It could be concluded that all the three forms of SN byproducts are medium source of protein and energy for ruminants. There is a great potential for SN by-products to be incorporated in ruminant feeding not only as a source of energy and protein, but also to protect the protein from rumen degradation and suppress enteric methanogenesis.

• Investigative Magnetic Resonance Imaging
• /
• v.20 no.1
• /
• pp.53-60
• /
• 2016

Purpose: To develop a technique for quantifying the $^{13}C$-metabolites by performing frequency-selective hyperpolarized $^{13}C$ magnetic resonance spectroscopy (MRS) in vitro which combines simple spectrally-selective excitation with spectrally interleaved acquisition. Methods: Numerical simulations were performed with varying noise level and $K_p$ values to compare the quantification accuracies of the proposed and the conventional methods. For in vitro experiments, a spectrally-selective excitation scheme was enabled by narrow-band radiofrequency (RF) excitation pulse implemented into a free-induction decay chemical shift imaging (FIDCSI) sequence. Experiments with LDH / NADH enzyme mixture were performed to validate the effectiveness of the proposed acquisition method. Also, a modified two-site exchange model was formulated for metabolism kinetics quantification with the proposed method. Results: From the simulation results, significant increase of the lactate peak signal to noise ratio (PSNR) was observed. Also, the quantified $K_p$ value from the dynamic curves were more accurate in the case of the proposed acquisition method compared to the conventional non-selective excitation scheme. In vitro experiment results were in good agreement with the simulation results, also displaying increased PSNR for lactate. Fitting results using the modified two-site exchange model also showed expected results in agreement with the simulations. Conclusion: A method for accurate quantification of hyperpolarized pyruvate and the downstream product focused on in vitro experiment was described. By using a narrow-band RF excitation pulse with alternating acquisition, different resonances were selectively excited with a different flip angle for increased PSNR while the hyperpolarized magnetization of the substrate can be minimally perturbed with a low flip angle. Baseline signals from neighboring resonances can be effectively suppressed to accurately quantify the metabolism kinetics.

• Biomolecules & Therapeutics
• /
• v.3 no.2
• /
• pp.171-175
• /
• 1995

Effects of $Biozyme_{R}$ and $\textrm{Business}_{R}$ on alcohol metabolism in rats, and on the activities of alcohol dehydrogenase(ADH) and acetaldehyde dehydrogenase(ALDH) were studied in vitro. Alcohol concentration in rat blood was decreased after the treatment of Business(3.3 mι/kg, Biozyme 1.67 mg/wι) and Biozyme(3.3 mι/kg, 1.67 mg/mι) prior to the administration of ethanol(25%, 0.83 g/kg). And the acetaldehyde concentration of rat blood was also decreased when compared with control values in the same condition. Effects of Biozyme on ADH and ALDH activity were also studied. While the ALDH activity was elevated in the presence of Biozyme(2 $\mu\textrm{g}$/assay), the ADH activity was not influenced by Biozyme at the concentration range from 2 $\mu\textrm{g}$/assay to 0.2 mg/assay. In summary, Biozyme accelerated the rate of ethanol metabolism and the acceleration might be due to the increase in ALDH activity.vity.

• Journal of Ginseng Research
• /
• v.9 no.1
• /
• pp.112-118
• /
• 1985

It has been known that the ginseng extracts activate the lipid metabolism in animal body. The experiments were undertaken to elucidate the effects of total, diol, and trial saponin of ginseng on the activities of acyl Co-A synthetase and hydroxyacyl Co-A dehydrogenase involved in fatty acid metabolism in normal albino rat liver. The acyl Co-A synthetase activity, in vitro, was increased by 20% with treatment of 2.5${\times}$10-3% total saponin, by 14% with 2.5${\times}$10-3% diol saponin, arid 30% with 2.5${\times}$10-4% triol saponin, respectively. And the enzyme activity was increased by 27% at 2 hours after intraperitoneal injection of total saponin. Hydroxyacyl Co-A dehydrogenase activity, in vitro, was increased by 77% with 10-4% total saponin, by 64% with 10-2% diol saponin, and by 72% with 10-3% triol saponin, respectively. Also, the enzyme activity, in vivo, was increased by 15.3% and 33% at 2 hours and 4 hours.