The profiles of hepatic drug metabolism were obtained by using young and old male and female rats. The profile obtained from old male rats was completely different from that from young male rats, while it was almost identical to those of females of any ages. This was due to the selective decrease in male hepatic enzyme activities showing higher activities than females to the activity levels of females which did not alter much with aging. Castration of young adult male rats caused a decrease in enzyme activities but did not result in the feminization of the metabolic profile. Administration of testosterone to old male rats resulted in the recovery of the profile of young male rats, but the levels of activities were not as high as young male rats. Plasma testosterone levels were found to decrease in parallel with drug metabolizing activities of male rats during aging. These results suggest that sex hormones play important roles in the alteration of drug metabolizing activities in male rats with aging. The loss of male characteristics in profile of drug metabolism during aging was evaluated by use of antibody to the male specific cytochrome P-450, P-450 ml. Anti-P-450 ml strongly inhibited imipramine N-demethylase activity, which showed marked sex (male>female) and age (young>old) differences, while this did not inhibit imipramine 2-hydroxylase activity, which showed no sex or age differences. The portion of N-demethylase activity inhibited by this antibody decreased in old rats while the portion not inhibited did not decrease with age. These results indicate that the decrease of sex specific cytochrome P-450 is responsible for the age-associated decrease in at least one of the drug metabolizing enzyme activities in male rats. It is suggested that some processes of the control mechanism of the gene expression of male specific cytochrome P-450 may be altered with old age.
In commercial powdered natural products for medicinal use containing various combined forms of hydroxyanthraquinone derivatives such as Sennae Folium, Cassiae Semen, Rhei Rhizoma and Aloe a considerable amount of stable free radicals (ca. 1017-1018 spin/g) was found to be contained by use of electron spin resonance (ESR) spectral measurements. It was also found that the vibratory milling of such powders in a metallic vessel enhanced the ESR spectral intensities, demonstrating the occurrence of mechanoradical formation. Separate experiments also demonstrated that the vibratory milling of various kinds of powdered hydroxyanthraquinone derivatives mixed with calcium oxalate has produced the mechanoradicals effectively, but they decayed gradually on standing at room temperature. It was suggested, therefore, that the mechanoradicals formed in the above natural products are metal complexes of the corresponding semiquinone anion radicals induced by solid state one electron transfer mechanism from the active metal surface, part of which is further immobilized in polymeric fibers or the like in the plant tissues.
The reaction of 5-oxo-4-phenyl-5, 6-dihydro-4H-1, 3, 4-thiadiazine (1a) with sodium methoxide in methanol at 35°C was found to give 2-anilino-4-oxo-1, 3-thiazoline (2a) in a quantitative yield via cleavage of the nitrogen-nitrogen bond. The mechanisms of formation of 2 were discussed by a few kinetic studies using 4-p-substituted phenyl-5-oxo-5, 6-dihydro-4H-1, 3, 4-thiadiazine (1b, c), and related reaction of 5-oxo-4-phenyl-4, 5-dihydro-4H-1, 3, 4-thiadiazole (3), 5-oxo-2, 4-diphenyl-5, 6-dihydro-4H-1, 3, 4-thiadiazine (4) and 5-oxo-2, 4-diphenyl-4, 5-dihydro-4H-1, 3, 4-thiadiazole (5).
In an attempt to evaluate the metabolic fate of "Kyushin", which is a traditional medicine containing Toad venom, a 3H-labeled compound of bufalin, which is one of the main active components, has been synthesized. The metabolic fate of the 3H-bufalin was studied after its single and repeated oral administration in rats. After a single administration of the 3H-bufalin (20 μg/kg), the radioactivity in the blood reached a maximum level at 15 min. The radioactivity in the blood declined in a triphasic manner with half-life times of 18 min, 2.6 and 86 h. Within 24 h after the single administration, the excretion of the radioactivity into the urine and feces amounted to 1.3% and 81% of the administered dose, respectively. Tissue radioactivity was higher in the stomach, small intestine, liver, lung, kidney and pancreas, while the radioactivity in other tissues was lower than that in blood. Radioactivity disappeared rapidly from any tissues. In case of repeated administration for 14 d, the disposition of radioactivity was almost same as the result after a single dosing, and radioactivity scarcely remained in any tissues after the last administration.
In the course of study of the metabolic fate of "Kyushin", a traditional medicine containing toad venom, the metabolic fates of bufalin and cinobufagin, main constituents of toad venom, have been studied. Six metabolites were detected in the extracts from incubation mixture of rat liver slice with bufalin, and one main metabolite shown by mass spectroscopy and high performance liquid chromatography (HPLC) to be 3α-bufalin. Serum levels of bufalin and 3α-bufalin were determined by HPLC after oral administration of 2000 μg/kg of bufalin, and both compounds appeared in the rat serum. On the other hand, only 3α-bufalin appeared after administration of 20 or 200 μg/kg. 3α-Bufalin levels increased dose dependently. Serum levels of cinobufagin and its metabolites and digitoxin were compared after repated intravenous administration (5 h interval) of cinobufagin or digitoxin. Although digitoxin was accumulated in the rat serum, cinobufagin and its metabolites were not. Inhibitory activities of metabolites of bufalin and cinobufagin on (Na++K+)-adenosine triphosphatase were less than those of original compounds.
Fifty-nine species of extracts of Chinese herbal medicinal prescription were tested for inhibitory activity of adenosine 3', 5'-cyclic monophosphate (cAMP) phosphodiesterase (PDE). Kanzo-shashin-to showed the highest activity in these prescriptions. Kanzo-shashin-to, Hange-shashin-to and Shokyo-shashin-to, whose constracting crude drugs were very similar, were especially studied among these prescriptions. Pinellia tuber acted as an ascent component for Scutellaria root and a mitigatory component for Giycyrrhiza. Jujube acted as a mitigatory component for Glycyrrhiza. Ginger acted as an additional component for Scutellaria root in cAMP PDE test. This additional effect of 6-gingerol, 6-shogaol from Ginger and baicalin from Scutellaria root were investigated.
A stable water/liquid paraffin system water-in-oil-in-water (W/O/W) multiple emulsion was prepared by the two-step procedure of emulsification using a variety of nonionic emulsifying agents, such as Span 80 and Tween 20. After comparison of the releasing properties of such water soluble drugs as cefadroxil, cephradine, 4-aminoantipyrine and antipyrine which were entrapped separately in the inner aqueous phase of the W/O/W multiple emulsion, a large difference was observed. It was ascertained that the difference in these releasing properties was due to no physical rupture by the microscopic observation and the results of the release test of W/O/W multiple emulsion with two kinds of drugs entrapped simultaneously in an inner aqueous phase. This reason was presumed to be dependent on permeation in the oily phase of the drug itself. It was proved that the differences of releasing properties tended to depend on the molecular weight and were closely related to the drug concentration of outer aqueous phase of W/O/W multiple emulsion containing the drug in both aqueous phases prepared as an experimental model. Therefore, two possible mechanisms for the releasing of drugs in W/O/W multiple emulsion may be interpreted as follows : the first is that the mixed and inversed micelles formed by Span 80 and Tween 20 agents in the oily phase act as a carrier of drugs, and the second is that drug molecules diffuse through small pore existing in very thin lamella of the emulsifying agents partially formed in the oil layer owing to the fluctuation of the thickness.