The pharmacokinetics of paeoniflorin (PAE) was examined after an iv dose of 20, 40, or 100mg/kg in rats. The decline of plasma concentration was biexponential after each dose. Dose, however, had a marked effect on the pharmacokinetics, with a greater than proportional increase in AUC at 100mg/ kg, even though the increase was proportional at the dose range from 20 to 40mg/kg. There was also significant decrease of the steady-state distribution volume (Vd_ss), and total body (CL_tot), and renal (CL_R) clearances at the high dose (p<0.01 or 0.05), without a significant difference between the two low doses. Plasma unbound fraction (0.75) was constant over the observed range of plasma PAE concentrations (0.8 ?? 700μg/ml). The decrease of Vd_ss was ascribed to the dose-dependent Kp values in liver, kidney, gastrointestinal tract, and skin. The significant decrease of biliary clearance (CL_B) at 100mg/kg as compared with that at 20 and 40mg/kg contributed to the decrease of CL_tot. It was suggested that the decreases of CL_B and CL_R may be a consequence of saturable transport from plasma into liver, and the significant decrease of glomerular filtration rate (p<0.05) at the higher steady-state plasma level than at the lower plasma levels might be owing to a decreasing effect of PAE on renal plasma flow, because transport from liver to bile did not appear to be saturable, and the excretion into urine seemed to occur only by glomerular filtration. Thus, the pharmacokinetics of PAE in rats was dosedependent.

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The absorption and excretion of ¹⁴C-MF in rats and rabbits were studied following topical application of 0.1% dermal formulations mostly as a form of ointment.
1. When the ointment was applied to the intact skin, radioactivity was not detected in plasma of both rats and rabbits. Less than lOng equiv./ml of radioactivity was detected after application to the stripped skin in both animal species, and it disappeared 24 or 48hr after application.
2. The absorption of radioactivity from the ointment in rats, estimated as the sum of urinary and fecal excretion, was 5 ?? 10% of the applied dose in intact skin and 30 ?? 50% in stripped skin. In rabbits, it was lower than those of rats.
3. Radioactivity was predominantly excreted in feces than in urine in both animal species, and this difference was more prominent in rats than in rabbits.
4. Female rats showed slightly higher absorption ratio as compared to male rats. It probably was due to the difference of skin thickness, less thinner skin was observed in females than in males.
5. When ¹⁴C-MF was applied as a cream or lotion to intact skin of rats, almost same results as those of ointment were obtained.

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The absorption, distribution and excretion of radioactivity following a single or multiple subcutaneous administration of ¹⁴C-MF in rats were studied.
1. When ¹⁴C-MF was administered at 0.5 or 1 mg/kg, a dose independent values of C_max (26 ?? 30ng equiv./ml in male and 31 ?? 32ng equiv./ml in female) and of T_max(ca.2hr in male and 3 ?? 4hr in female) were observed in rats. However, T1/2 and AUC changed depending on the dose. C_max in rabbits was lower than rats (11ng equiv./ml). In rats, the elimination of whole blood radioactivity was slower than that of plasma.
2. Plasma protein binding of ¹⁴C-MF in vitro was more than 99% in rats, rabbits and humans and those in vivo were more than 94% in rats and rabbits. Distribution of ¹⁴C-MF into blood cell in vitro was 0 % in rats, 30% in rabbits and 4 ?? 7 % in humans.
3. The highest radioactivity level was found in the liver and followed by the kidney, intestine and fatty tissues. Radioactivities in tissues other than blood, liver and kidney disappeared with almost similar rate as that of plasma and decreased to undetectable level at 168 hr after administration.
4. Radioactivity was excreted predominantly into feces via bile in both animal species. Approximately 20% of the biliary radioactivity was reabsorbed from the intestinal tract in male rats.
5. After multiple administration, radioactivity levels in the plasma and most tissues reached nearly steady-state after 4 ?? 8 times dosing. However, levels in blood increased with dosing time, and it disappeared very slowly after the last dose. Most of the radioactivities in blood cell and liver after multiple administration were recovered from the cytoplasmic lipid and protein fractions.
6. Excretion profile was not altered by multiple administration.

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Foeto-placental transfer and excretion into the milk of radioactivity was studied following subcutaneous administration of ¹⁴C-MF to pregnant or lactating rats at the dose of 0.5mg/kg.
1. On day 13 of gestation, no radioactivity was detected in the fetus based on the whole-body autoradiography.
2. On day 19 of gestation, the highest level of radioactivity, found within the fetus, was observed in the intestinal contents, and almost similar levels as that of mother plasma were observed in the liver and lung as determined by theradioactivity measurement and wholebody autoradiography.
3. Radioactivity level in the milk was nearly two-fold higher than that of plasma at 4hr after administration but it disappeared below detection limit at 72 hr after administration.

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Metabolic fate of ¹⁴C-MF in the rat and the rabbit was studied after subcutaneous administration at 0.5mg/kg dose. The metabolites were analyzed by two-dimensional TLC, located by autoradiography and quantitated by TLC scraping and counting of the radioactivity. Identification of the metabolites was tentatively made by co-chromatography with corresponding reference standards. Three major biotransformation pathways of MF were proposed. 1) Substitution of a 21-hydroxyl group for a chlorine : 2) 6β-Hydroxylation : 3) Defuroylation at 17 : Combination of these processes and subsequent reactions resulted in the formation of numerous metabolites.
Plasma metabolites ; In the animals studied, the main component was the unchanged MF at each time point examined, and its concentration near the peak (4hr after the administration) was 13.1ng/ml in the male rat, 22.4ng/ml in the female rat and 2.8ng/ml in the male rabbit.
Biliary metabolites ; About 78% of the dose was excreted in the bile within 24hr in the male and female rats. The main metabolite detected both in the free and the conjugate fraction was 17-OH compound (M-1), which amounts to 4.8% and 2.4% of dose respectively for the male, and 6.7% and 2.4% for the female. In the acidic fraction, the main metabolite was 6β-OH, 21-oic acid (M-27) in both sex and the amount found was significantly more in the male (5.9% of dose) than in the female (1.3%), indicating the sex-related differences. In the rabbit, about 19% of dose was excreted in the bile within 24hr. The main metabolite was M-1 (1.6%) in the free fraction, 6β, 21-(OH)₂ compound (M-13) (0.7%)in the conjugate fractionand 21-oic acid (M-32) (0.3%) in the acidic fraction.
Urinary metabolites ; In the rat, the radioactivity excreted within 24hr was 3 ?? 5 % of dose and was not so significant. A sole and main metabolite detected was 6β, 17, 21-(OH)₃ compound (M-14) (about 1 % of dose). In the rabbit, about 16% of dose was excreted in the urinewithin 72hr. The main metabolite both in the free and the conjugate fraction was M-14 (1.5% and 0.2% of dose respectively).

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Distribution of radioactivity in the stomach with acetic acid-induced ulcer was studied after oral administrations of ¹⁴C-KT1-32 to male rats.
1. The significantly high radioactivity was found in the site of the gastric ulcer at 6, 12 and 24hr after administration.
2. Radioactivity in normal mucosa was significantly higher than that in muscular layer at 1hr, but there were no significant differences between these tissues at 3, 6, 12 and 24hr.
3. Microautoradiography indicated that the density gradient of silver grains was found from the lumen to the muscular layer in glandular stomach at 3hr after administration. These results suggested that ¹⁴C-KT1-32 was located selectively in the lesion of the gastric ulcer induced with acetic acid for long period and penetrated throught the lumen to the muscular after oral administration.

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The intestinal absorption of tilactase (containing 6.7% β-galactosidase, 10, 000 ONPG unit/g) was studied following oral administration to rats of different age(1-, 7-, 14-, 17-, 21- and 49-days old). Concentrations of β-galactosidase in plasma, tissues and other body fluids were detected by radioimmunoassay(RIA) and/or o-Nitrophenyl-β-D-gactopyranoside (ONPG) methods.
1. After oral administration of tilactase at a dose of 4g/kg (β-galactosidase : 268mg/kg) to 49-days old rats, β-galactosidase was not detected in the plasma, liver and urine.
2. After oral administration of tilactase at a dose of 0.04 and 0.4g/kg to 7-days old rats, traces of β-galactosidase were detected in the liver.
3. After oral administration of tilactase at a dose of 4g/kg to 7-days old rats, the absorption of β-galactosidase from small intestine was observed with an estimated absorption ratio of 0.2%.
4. After intravenous injection of β-galactosidase (1.15mg/kg) to 7-days old rats, high level was especially observed in the liver and spleen. In the case of high dose (β-galactosidase 11.5mg/kg), hepatic uptake was saturated.
5. β-galactosidase-like immunoreactive substance, which was absorbed from small intestine of 7-days old rats, was found to have similar enzymatic activity and molecular size as that of administered β-galactosidase.
6. After intravenous injection to 7-days old rats, β-galactosidase was not excreted into bile and urine.
7. After intravenous injection of ¹²⁵I-β-galactosidase, a low molecular weight degradation products were observed in plasma as revealed by gel filtration radio-chromatography.

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The metabolism of emedastine difumarate(KG-2413) after oral administration in human was studied. In human urine, 5-hydroxy-and 6-hydroxyemedastine and their conjugated metabolites were found as major metabolites and emedastine corresponding to 3.6% of dose was also excreted. Moreover 5-hydroxy and 6-hydroxy-5'-oxoemedastine, and emedastine N-oxide were found as minor metabolites. The sum of urinary excretion ratio of emedastine and its metabolites was about 44% for 24h after dosing. Taking urinary excretion ratio and plasma concentration of emedastine into consideration, the extent of bioavailability of emedastine difumarate in human might be similar to that in guinea pigs. However, the metabolic pattern in human was similar to that in rats, in which 5-hydroxy and 6-hydroxyemedastine were urinary major metabolites and emedastine N-oxide was minor metabolites.

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The absorption, distribution and excretion of betamethasone butyrate prop ionate (BBP) were investigated in rats and rabbits after dermal application of ³H-BBP under non-occlusion or subcutaneous administration of ³H-BBP at a dose of 0.25 and 1.0mg/kg, respectively.
1. The systemic availability after dermal application of ³H-BBP, as ointment or cream to normal skin of animals was low, accounting for ca. 3 ?? 5% of the applied dose in male rats and ca. 14% in female rats and male rabbits. The availability from stripped skin was ca. 30 ?? 50% in rats.
2. The maximum blood concentration of radioactivity and its appearance time after dermal application to normal skin of animals were : 0.6 ?? 0.8ng/ml and 24hr in male rats, 4.7ng/ml and 8 hr in female rats, and 3.0ng/ml and 13hr in male rabbits. These values were 8.6 ?? 15.7ng/ml and 5hr in stripped skin of male rats.
3. Most of the radioactivity administered dermaly was excreted with feces in rats, while equally excreted with urine and in rabbits.
4. The maximum tissue radioactivity was observed at 8 or 24hr after dermal application to intact skin of male rats. High levels of radioactivity were noted in the liver, kidney, adrenal gland, seminal vesicle and urinary bladder. The disappearance of radioactivity from each tissue was slow, especially from blood. The microautoradiogram of application site of skin showed the routes of dermal absorption of BBP via appendage and through epidermis.
5. After the repeated dermal application to intact skin of male rats, blood and tissue radioactivity at 24hr after daily application rose with increasing of dosing times. After the 7th dermal application, the disappearance of radioactivity from the blood and tissues was slow and the radioactivity concentration in the blood, 54 days after dermal application, was 15% of the maximum radioactivity concentration. No difference of the excretion of radioactivity in the urine and feces was noted between the 7th dermal application and single application groups.
6. The placental transfer of ³H-BBP after subcutaneous administration was confirmed by whole body autoradiogram in pregnant rats, but no radioactivity remained in the fetal tissue.

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The metabolism of ³H-betamethasone butyrate propionate (BBP) in male rats and rabbits was studied after dermal application. Plasma protein binding was also investigated.
Except in epidermis and dermis, the unchanged BBP was not detected in any of studied specimen.
1. Dermal metabolites High ratios of unchanged BBP as 70 ?? 80% of radioactivity were observed in both epidermis and dermis of the topical skin of rats at 24hr after the application. The major metabolites were BM-17•B in both tissues and BM-21•B in epidermis.
2. Plasma metabolites The main metabolites in plasma were BM-17•B and BM-21•B, and the ratio of those decreased with time. On the other hand, the ratio of BM increased with time and it reached the highest 6hr after the application. After the repeated dosing, the main metabolite in plasma was BM, and the composition of the metabolites was similar to that after single dosing. In rabbits, the main metabolite in plasma was BM-17•B, and the ratio of BM-21•B was lower than that in rats.
3. Metabolites in liver and kidney The major metabolites in rat liver and kidney were BM-17•B-6-OH, BM-17•B and BM. Many kinds of minor unknown metabolites were also detected in both organs.
4. Urinary metabolies In rat urine, unknown metabolites U7, U8, U9, U11 and many minor metabolites including BM-17•B-6•OH, BM-6•OH, BM were detected. The similar composition was observed after the repeated dosing. In rabbit urine, unknown metabolites RU5, RU2 and many minor metabolites including BM-6•OH and BM were detected. After enzymatic hydrolysis of rabbit urine, increase of BM ratio was observed.
5. Fecal metabolites In rabbit feces, BM-6•OH and BM were observed as the major metabolites.
6. Plasma protein binding The in vivo plasma protein binding ratios of BBP after subcutaneous administration to rats were 86.4, 86.7and 59.7% at 1, 4 and 24hr, respectively. Those in vitro were as high as more than 97% both in case of rat and human plasma. Both ketotifen fumalate and chlorpheniramine maleate did not affect the in vitro bindings of BBP to rat and human plasma.

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The distribution, metabolism and excretion of ³H-angiotensin II (³H-A II) were investigated after intravenous administration to rats.
1. The radioactivity in the plasma, after bolus intravenous administration to male and female rats, declined with half-lives of 1.0 and 1.1 min, respectively, within first 2.5 min. The radioactivity increased once again within 10 ?? 20 min after administration and thereafter decreased again with half-lives of 3.0 and 1.1 day, respectively.
The radioactivity of AII, AIII, Tyr and p-HPPA declined rapidly with half-lives of 8.5, 7.9 sec and 5.2 and 5.9 min, respectively.
2. The radioactivity in the plasma of male and female rats increased slowly during intravenous infusion, and afterwards declined with half-lives of 2.2 and 2.4 min, respectively, within 2.5min after the infusion was stopped, and thereafter once again increased within 10 min after the end of infusion and finally a gradual decrease was observed.
The concentrations of AII, AIII, Tyr and p-HPPA declined rapidly after the end of infusion similarly as after bolus administration.
3. The radioactivity in the tissues reached maximum within 24 hr after infusion. The highest level of radioactivity was noted in the pancreas and followed by the liver, bone marrow, stomach, kidney, duodenum, adrenal gland and pituitary gland. The disappearance of radioactivity from each tissue was very slow.
4. After the end of the infusion, radioactive substances in the plasma consisted not only AII and its metabolites but also were found in volatile (9.1%) and protein fractions (25.3%). Volatile and protein fractions increased with time. The concentrations of A II in the liver and kidney were somewhat high, while only a minor amount of A II was noted in the lung and heart.
5. After intravenous infusion to male rats, the excretion of radioactivity in the urine, feces and expired air was 24.3, 9.8 and 5.8% of the dose, respectively. Within 168 hr after the end of infusion, the residual radioactivity in the carcass accounted for 56.6% of the dose. The profile of excretion in female rats was similar to that in male rats. The biliary excretion of radioactivity accounted for 15. 2% of the dose after 48 hr infusion. No AII and AIII were noted in the urine, feces and bile. Volatile fraction was mainly excreted, while the excretion of Tyr and p-HPPA was minor.

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Fifteen forms of carboxylesterase isozymes were purified to electrophoretic homogeneity from liver microsomes of rats, mouse, hamster, guinea pig, rabbit, beagle dog, pig, cow, crab eating monkey and humans by the same procedure used, and their physical, enzymological and immunological properties were compared with each others. The substrate specificity and immunological reactivity of liver microsomal carboxylesterase from above animals were also examined for comparison. The fifteen purified preparations have similar subunit weight (57, 000-64, 000), but their isoelectric point differ widely (4.7-6.5). The purification procedure of all isozymes include concanavalin A-Sepharose column chromatography. The isozymes were not eluted from the column with a high concentration of sodium chloride, but were efficiently eluted with alpha-methylmannoside. This observation suggested that the carboxylesterase studied are glycoproteins. All the isozymes except rat RL1and RL2 possess a high hydrolytic activity toward all the substrates examined. Long-chain monoacylglycerol was hydrolyzed by the purified carboxylesterase isozymes except rat RL1 and cow B1. Anti-rat RH1 IgG was found to possess high cross-reactivity with all isozymes tested, except monkey MK2, by immunoblotting analysis. The amino acid composition of carboxylesterase isozymes showed considerable similarities, except for monkey MK2. The amino-terminal amino acid sequences showed a striking homology, except for monkey MK2, though the first amino acid in the sequence was different in every isozymes. On the other hand, the well-known peroxisome proliferators, such as clofibrate, diethylhexylphtalate, and perfluorinated fatty acid treatment extraordinary induced the carboxylesterases in rats and mice, and slightly induced in hamsters. Whereas, guinea pig liver carboxylesterase was not induced. Hepatic microsomal carboxylesterases in mammals play an important role in drug and lipid metabolism in the endoplasmic reticulum, and it is noteworthy that the isozymes from various species examined here showed considerable similarities in physical, enzymatic, and immunochemical properties, but not similar in induction of peroxisome proliferators.

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