The author and his group have been developing new reactions based on molecular structure characteristics; σ-symmetric bifunctional molecules, dipole-dipole repulsion, active amide structures, latent active species, orbital-orbital interactions, nonbonded interactions, strained structures, allenic structures, etc. Various new reactions such as asymmetric aminolyses and Dieckmann-type cyclizations of prochiral σ-symmetric dicarboxylic diamides, asymmetric aldol-type reactions onto γ-hydroxybutenolides and asymmetric imine alkylations onto ω-acetoxy lactams using chiral Sn(II) enolates, asymmetric Pummerer-type reactions, cascade reactions and endo-mode cyclizations exploiting α,β-unsaturated allenic esters and ketones, base- and palladium-promoted ring-expansion reactions, and syntheses of α-substituted serines and 1-azabicyclo[1.1.0]butane have been achieved. These new reactions were applied to the synthetic development of new seed and lead compounds (SH-enzyme inhibitors, tumor inhibitors, and antibiotics ) with the aim of synthesizing new drugs. Asymmetric syntheses of (+)-Prelog-Djerassi lactonic acid methyl ester, (+)-carbacyclin, ISP-I (myriocin), (+)-conagenin, Geissman-Waiss lactone, biapenem (a new carbapenem antibiotic), thienamycin-like γ-lactam, and bicyclic alkaloids were also achieved by utilizing these reactions. Evaluation and molecular design of the seed and model compounds for angiotensin II receptor antagonists, tumor inhibitors, and antibiotics have been investigated on the basis of QRSA and/or nonbonded S…X (X=O, N, S, halogens) interaction concepts.
Lithium trialkylzincates were known to be convenient and synthetically useful for transferring various organic moieties and for metallating aromatic halides or vinyl halides. The outer shell of the zinc atom in lithium trialkylzincates is filled with 16 electrons, and there is a room for an additional ligand to coordinate to form a favorable state with 18 electrons. As a new type of zincate, the reactivities of this tetraalkylorganozincates and related modified organozincates were then studied. 1H-NMR study of organozincates indicated the difference between these highly coordinated zincates and lithium trimethylzincate. And the studies on the reactivity disclosed the difference of regioselectivity for epoxide opening reaction and the different reactivity toward halogen-metal exchange reaction. These results support that these highly coordinated zincates should be distinguished from ordinary lithium trialkylzincates in the structure and the reactivity. On the other hand, various dialkylzinc hydride “ate” complexes were also designed and the reactivities of these zincates toward the carbonyl compounds were investigated. The results clearly reveal that dimethylzinc hydrides are the most powerful and selective zincate for the reduction of the carbonyl group.
A molecular biological approach was applied to the study of diversity and regulation of secondary metabolism in medicinal plants at various levels. For the inter-species diversity, RFLP (restriction fragment length polymorphysm) and RAPD (random amplified polymorphic DNA) analyses of genomic DNA were performed on the plants, belonging to the same genus or family and containing related compounds. Phylogenetic trees of lupin alkaloid containing plants and other medicinal plants, based on RFLP and/or RAPD profiles, showed the relationship between the diversities in genomes and secondary metabolisms. The chemotypes regarding anthocyanin production in Perilla frutescens var. crispa, were subjected to the study on intra-species diversity. The structural genes and the regulatory genes involved in anthocyanin biosynthesis were isolated and their expression in red and green forms was determined by Northern blot analysis. The expression of all structural genes examined was co-ordinately regulated in form-specific manner and by light illumination. The anthocyanin production was enhanced in transgenic plants over-expressing Myc homologue genes from perilla. These results suggested that a protein complex including bHLH factors might regulate the expression of a series of structural genes. Additionally, cDNAs coding anthocyanin 5-O-glucosyltransferase and anthocyanidin synthase were isolated and characterized using recombinant proteins for the first time. In conclusion, it was indicated that the molecular biological techniques are powerful tools for the investigation of diversity and regulation of and for the genetic engineering of secondary metabolism in medicinal plants.
β2-Adrenergic agonists have been widely used to treat patients with asthma. Usually, oral dosage forms of β2-agonists have been used, but side effects such as palpitation and tremor have been reported because of excessive serum levels around Tmax. It is said that circadian variations exist in the manifestation of asthma with maximum incidence of asthma attacks in early morning at around 4 a.m., the so-called morning dip. Chronotherapy for asthma based on circadian rhythm should be more efficient and have a lower frequency of side effects. Accordingly we developed a transdermal delivery system of the β2-agonist tulobuterol adapted to the circadian rhythm. The system is designed to administer the appropriate dose of the drug at an optimal time using the so-called Crystal Reservoir System. The superiority of the transdermal formulation of tulobuterol over the current therapy using oral formulations of β2-stimulants was indicated by its excellent pharmacokinetic profile, and confirmed by the results of clinical trials. This formulation is the first transdermal chrono-delivery system reported anywhere in the world, and is expected to provide more effective and safe treatment of asthma and related diseases not only in adults, but also especially in children.
Several novel methods using chiral reagents and biocatalysts for asymmetric reactions are described. Among those reactions, asymmetric reduction via a novel tandem Michael addition/Meerwein-Ponndorf-Verley reduction of acyclic α,β-unsaturated ketones using a chiral mercapto alcohol, asymmetric synthesis of allene-1,3-dicarboxylate via crystallization induced asymmetric transformation, and improved asymmetric nitroolefination of lactones and lactames at α-carbon using new chiral reagents were developed. In the reactions using biocatalysts, asymmetric dealkoxycarbonylation of bicyclic β-keto diesters having σ-symmetry with lipase or esterase to give optically active β-keto esters, the asymmetric reduction of bicyclic 1,3-diketones having σ-symmetry with Baker's yeast to give optically active keto alcohols, and the asymmetric aldol reaction of glycine with threonine aldolase were also developed. The above mentioned products were effectively utilized as chiral building blocks for the asymmetric synthesis of natural products and drugs.
On the therapy of constipation, there are few reports that surveyed the actual circumstance of patients taking laxatives and the effectiveness of the drug. In this study, we investigated the contents in prescription, the actual conditions of administration of laxatives, and the subjective symptoms of inpatients in all wards of Kanazawa University hospital (2000. 12. 1~2000. 12. 10). As a result of the investigation, the percentage of patients prescribed some laxatives was found to be about 31.5%(274) of all hospitalized patients (871), and among them about 16%(43) of the patients had some problems in defecation control. One of the causes leading to the problems for some patients (11) among them seemed to be due to the lesser amount of magnesium oxide takenper day. Then, in the ophthalmology ward we further investigated the proper use of laxatives and the defecation condition of the patient using a questionnaire paper and a record paper (20 cases). Patients became constipated by hospitalization, and although being administered some laxatives, they were often insufficient to control the defecation. Some patients (7) with changeable defecation control could be improved by change or addition of prescription. Pharmacist concerned 5 cases of patients with change or addition of prescription. This study indicates that pharmacists should actively offer information and rational usage of laxatives to doctors and patients.
Aspiration pneumonia is a major cause of death in the elderly. In this study, a water swallowing test was introduced as a method of evaluating the swallowing ability of patients, and a swallowing ability evaluation team investigated an appropriate procedure and evaluation method for the situation of our hospital. We also investigated the relationship between the swallowing ability of patients examined by the water swallowing test and underlying diseases, complications, and medicated drugs. In the water swallowing test, the water-drinking method was fixed, and evaluation was made based on the time required for drinking, profile, and episodes, by which patients suspected of swallowing disorder were detected, confirming the usefulness of this method. The frequency of developing swallowing disorder was significantly higher in patients with cerebrovascular disorders, Parkinson's syndrome (p<0.01, respectively) and symptomatic epilepsy, hypertension (p<0.05, respectively) as underlying disease/complication. Regarding medicated drugs, H2 blockers were related to swallowing disorder (p<0.05). It was confirmed that patients who were judged as having swallowing disorder (including suspected cases) by the water swallowing test, and patients with underlying diseases and complication that may cause the disorder, and patients medicated with drugs that may affect the swallowing ability require appropriate management by medical care staff.
A commonly used admixture of commercially available ointments and/or creams was selected from the prescribed sheets in our hospital, and questionnaire to dermatologists. To assess the relationship between permeability of corticosteroid through murine skin and clinical effects in human, we attempted to investigate the vasoconstrictor activity of these admixtures of topical corticosteroid by double-blind controlled study. Test samples were occluded at random on the back of 20 healthy volunteers for 4 hours. The vasoconstrictor activity of corticosteroid creams (Lidomex®) alone was significantly large as compared with that of ointments alone. The vasoconstrictor activity of corticosteroid in the admixture of Lidomex® ointment and urea ointments or heparinoid ointment was 1.5—2 fold significantly larger than that from ointments alone. The extent of the stability of the emulsion after mixing was related to the vasoconstrictor activity. These experiments demonstrated a close relationship between the vasoconstrictor activity of human skin and permeability of hairless mice skin. These results suggested that the vasoconstrictor activity of topical corticosteroids mixed with commercially available ointments and/or creams depends upon their physicochemical characteristics.
We have developed an adverse drug reaction (ADR) reporting system integrating it with Hospital Information System (HIS) of the University of Tokyo Hospital. Since this system is designed with JAVA, it is portable without re-compiling to any operating systems on which JAVA virtual machines work. In this system, we implemented an automatic data filling function using XML-based (extended Markup Language) files generated by HIS. This new specification would decrease the time needed for physicians and pharmacists to fill the spontaneous ADR reports. By clicking a button, the report is sent to the text database through Simple Mail Transfer Protocol (SMTP) electronic mails. The destination of the report mail can be changed arbitrarily by administrators, which adds this system more flexibility for practical operation. Although we tried our best to use the SGML-based (Standard Generalized Markup Language) ICH M2 guideline to follow the global standard of the case report, we eventually adopted XML as the output report format. This is because we found some problems in handling two bytes characters with ICH guideline and XML has a lot of useful features. According to our pilot survey conducted at the University of Tokyo Hospital, many physicians answered that our idea, integrating ADR reporting system to HIS, would increase the ADR reporting numbers.
To study the quality of toad venom dried on different metal plates by heating at 105°C, each 20g sample of fresh toad venom collected in Hei-Long-Jiang Province, China, was dried on (1) brass, (2) copper, (3) glass, (4) acrylic resins, (5) aluminum and (6) stainless-steel, respectively. Twelve bufadienolides, including bufalin and bufotalin, in each sample were then quantitatively analyzed by HPLC. The total levels of bufadienolides in 1000.0mg of the dried samples were (1)>(2)>(3)>(4)>(5)>(6), varying from 303.44mg to 420.72mg. Besides, the color of dried venom became darker in the order of (2), (4), (6), (3), (1) and (5). Though (1) was not in good color, it was superior to the others in chemical quality. These results suggest that it is possible to dry toad venom in short period by heating it at a high temperature on a tray made of brass. This will be a better method for making high quality toad venom than the traditional method. Moreover, the removal of impurities in the fresh venom by the process of filtration through silk succeeded in raising the bufadienolides content significantly.
The Residue on Ignition Test specified in General Tests, Japanese Pharmacopeia is a method to measure the weight of the residual substance not volatilized when the sample is ignited under a constant condition. Generally, this test is intended to determine the content of inorganic substances contained as impurities in an organic substance, and, occasionally, to determine the amount of inorganic substances contained as components in an organic substance. Our laboratories have adopted this test method for the above two purposes in the case of the quality control for drug substances, synthetic intermediates, starting materials in the course of drug development. Some validation studies have been conducted for this test in order to clarify the quantitation limit in the case of an application for the former purpose, and trueness and precision in the case of the latter purpose. Consequently, the quantitation limit was determined as around 0.50mg. The amount of sample should be determined based on this quantitation limit (mg) and the level of quantitation limit (%) or that of specification limit (%) should be considered from the view point of each testing purpose. The test method was also confirmed to have a good trueness and precision as the determination method for an alkaline salt, such as sodium, potassium or calcium salt, of organic compounds, as long as the test is operated with great care not to scatter the content out of crucible during ignition to incineration.