On the occasion of receiving the Pharmaceutical Society of Japan Award 2020, I explained our research activities on the total syntheses of polycyclic alkaloids as an invited review. The structure of lundurine B, which has an unstable cyclopropane fused indoline skeleton, was proved firstly by the total synthesis. I also describe the total syntheses of optically active lundurine B and rapidilectine B utilizing asymmetric desymmetrization of the spiro intermediate. We developed an intramolecular bond formation reaction between the 2-position of the furan ring to the iminium cation (furane-iminium cation cyclization) to synthesize manzamine alkaloids. The reaction was applied to the total synthesis of the core skeleton of nakadomarin A and ircinal A. A ring-closing metathesis reaction effectively applied to the synthesis of medium and large heterocyclic rings containing the cis double bond found in the structures of nakadomarin A and ircinal A. The total synthesis of schizocommunin, a metabolite of Schizophyllum commune isolated from a patient with human allergenic bronchopulmonary mycosis, was accomplished. We could correct the error in the proposed structure by total synthesis of the natural product. A part of the mechanism of cytotoxicity expression was clarified using newly synthesized shizocommunin.
Organic compounds isolated from natural resources are called “natural products” and are important seed compounds for medicinal chemistry. Total synthesis of natural products is basic research for drug development by structure determination, including absolute stereochemistry and investigation of their chemical and physical properties. Many alkaloids show strong biological activities among the natural products and have been recognized as a drug or a drug candidate. Here, total syntheses of polycyclic natural products, Kopsia alkaloids, manzamine alkaloids, are discussed.
Over the past few decades, the effectiveness of antibiotics has been diminished owing to the emergence of antimicrobial resistance resulting from the overuse of antibiotics. Antimicrobial stewardship aims to improve the appropriateness of antibiotic use to reduce antimicrobial resistance and benefit patients. Antimicrobial stewardship requires structural prerequisites for implementing antimicrobial stewardship programs (ASPs), such as the presence of a multidisciplinary antimicrobial stewardship team (AST), to ensure appropriate antimicrobial use at healthcare facilities. However, manpower shortage for ASTs in most Japanese hospitals has resulted in limited implementation of ASPs. Our study provided a directive for promotion of comprehensive ASPs including various outcome measures. Our findings would provide useful benchmarks for hospitals planning to implement ASPs in Japan as well as around the world. This review provides a framework for evaluating the outcome measures and benchmarks of ASPs based on our study.
Individuals vary in their susceptibility to adverse reactions to medications, some of which can be potentially life-threatening. Idiosyncratic drug toxicity (IDT) has been shown to be strongly associated to specific polymorphisms in genes encoding human leukocyte antigens (HLAs) by recent genome-wide association studies. However, the pathogenic mechanisms governing such reactions remain unclarified, at least in part because of a lack of suitable experimental animal models to assess IDT. This review describes our work on the specific allele/drug combination of HLA-B*57:01 and abacavir, an antiretroviral drug targeting the human immunodeficiency virus. As abacavir is known to trigger an HLA-dependent immune response, we engineered a transgenic mouse model—HLA-Tg—by partially substituting the mouse HLA sequence for the corresponding human sequence. Local abacavir exposure was found to trigger a significant immune response in an HLA-dependent manner, and oral administration induced liver injury partially via concurrent activation of the innate immune system. Additionally, we developed a technique for evaluating structural alterations in HLA complexes resulting from drug exposure based on phage display to ensure specificity. Further scrutiny of the mechanism(s) underlying drug-induced immune reactions using the HLA-Tg model, as well as enhanced methods for predicting adverse event incidence, are anticipated to help resolve issues surrounding HLA-associated drug hypersensitivity.
The dose of direct oral anticoagulants (DOACs) must be determined based on package insert recommendations. There are reports on the rate of inappropriate DOAC dose usage defined as a dose deviating from the approved dose in the package insert but no reports on factors that led to such deviations. Thus, patients who were admitted to the Suzuka Kaisei Hospital between 1 April 2016 and 31 March 2017 were chosen as subjects. Moreover, the factors that during hospitalization led to dose deviation from the package-insert DOAC dose were retrospectively examined. The characteristics of patients administered doses deviating from the package insert were compared with those of patients in the appropriate-dose group. The finding was that the proportion concomitantly administered antiplatelet agents was higher in the underdose group. In contrast, deviations from the recommended dose did not occur when DOACs were combined with CYP3A4 inhibitors or P-glycoprotein (P-gp) inhibitors. It was suggested that increase in the risk of hemorrhage by antiplatelet agents in combination with oral anticoagulants could explain deviations from the stipulated DOAC dose. In addition, a higher proportion of patients in the overdose group showed depressed Ccr, and gastrointestinal bleeding. In future, it will be necessary to propose principle-based dose changes for patients administered doses deviating from the package insert. If an underdose is administered, it is important to make a dose change that takes the concomitant drugs into consideration.
Previous studies have reported the inappropriate administration of medication at nursery schools by the staff and a lack of drug-related information from caregivers at the time of request. However, the situation concerning medication administration at nursery schools from the mothers' perspective is unknown and it is not clear what information the mothers provided to nursery staff at the request. We conducted an online survey between April and May 2019 regarding the administration of medication at the nursery school with input from 600 mothers. Overall, 510 (85%) individuals replied that the requests to administer medication were acceptable for all or some of the medications. Application forms for medications were used by 91% of the 301 mothers who had previously made such requests. Although information including the child's name, medication times, illness of the child, parent's name, and dosage form was specified by over 70% of mothers, drug-related information such as effectiveness, side effects, and drug interactions was insufficient. In total, 41 instances of inappropriate medication administration by staff were reported by 35 mothers. It is suggested that the drug information sheets provided by community pharmacies should make up for inadequate drug-related information on application forms for medications to avoid the risk of adverse events and reduce staff burden. Toward this end, it is necessary to provide easily understandable information sheets for nursery staff, as the medication is usually administered by nursery staff, not a nurse. Community pharmacists should support these measures as pharmaceutical professionals.
Denosumab is a fully monoclonal antibody against the receptor activator of nuclear factor kappa-B ligand (RANKL), and prevents skeletal-related events by bone metastasis. Hypocalcemia is the most typical adverse effect of denosumab use. We have developed a management system for the more efficient and safer management of denosumab administration, and evaluated pharmaceutical interventions for the better control of hypocalcemia. All pharmaceutical interventions in the system from April 2016 to March 2020 were retrospectively evaluated. We have also assessed the incidence of hypocalcemia in 158 patients who were administered denosumab for six months or more in the period. A total of 282 pharmaceutical interventions (7.0% of the total administration) were conducted. The most conducted intervention was regarding hypocalcemia, which involved the suspension of the injection and/or the increase of calcium and vitamin D supplement with 65% adoption and 17% temporary treatment suspensions. Other interventions were about hypercalcemia, request of laboratory examination and ordering supplements, dental consultation, and poor renal function. A total of 199 interventions (70.6%) were adopted, with 33 administrations suspended. The frequency of hypocalcemia was 27.8% with just one patient having grade 2 hypocalcemia, suggesting that there were no severe cases. Moreover, hypocalcemia was significantly normalized following pharmaceutical intervention and/or handling by physicians (p=0.02) according to the system. Conversely, the normalization rate in hypercalcemia did not differ according to the countermeasures. In conclusion, pharmaceutical interventions according to our management system benefit safe denosumab treatment, especially in severe hypocalcemia prevention.
In Japan, the use of mothproofing agents [dieldrin and 4,6-dichloro-7-(2,4,5-trichlorophenoxy)-2-trifluoromethylbenzimidazole; DTTB] in textiles is regulated by the Act on the Control of Household Products Containing Harmful Substances. Since official analytical methods for these agents have been in place for approximately 40 years, we developed an improved method in a previous study. In the present study, we validated this method. Accordingly, six laboratories analyzed the sample prepared at 3 μg/g (1/10 of the regulation value) and 30 μg/g (the regulation value). The high accuracy of the results for these samples in almost all the cases (accuracy: 70-120%, repeatability: <10%, reproducibility: <15%), confirmed the validity of the method. In addition, we examined three samples that were distributed before the introduction of the regulation. The analysis results for these samples showed little variation between laboratiories, indicating that our method is also applicable to actual samples. Meanwhile, the quantitative value was clearly lower in one laboratory than in the others. We presumed that the enhanced effect of the sample matrix (matrix effect) on the internal standards in GC-MS analysis was the main cause for this trend. Therefore, we examined the analytical method using polyethylene glycol 300 (PEG) as an analyte protectant. As PEG minimized the GC-MS response difference between the standard solution and the matrix-containing solution, GC-MS analysis with PEG would be useful for matrix effect measurements in this method.
Some controlled substances, such as stimulants and narcotics, have asymmetric carbons in their molecules. Because the enantiomers do not always show the same pharmacological effects, and there are substances with different controls due to differences in their stereochemistry, a simple and unambiguous method for assessment of the composition of enantiomers is necessary. In this study, to develop a simple and rapid stereoscopic identification method for methamphetamine and its raw materials (ephedrine and pseudoephedrine), the 1H-NMR method was studied using three commercially available chiral solvating agents (CSAs); 1,1'-bi(2-naphthol)(BINOL), 2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE) and α-methoxy-α-(trifluoromethyl)phenylacetic acid (MTPA). In addition, the accuracy of the optical purity, which was measured using samples mixed with enantiomers in various ratios, was investigated. The NMR peaks of the enantiomers were separated by adding (R)- or (S)-form of BINOL, TFAE or MTPA to the chloroform-d solution of methamphetamine, ephedrine or pseudoephedrine. A sufficient discrimination of enantiomers was obtained by adding about 10 equal amounts of each CSA to the solutions. With regard to the optical purity, it was possible to determine accurately the mixing of small amounts of enantiomers of about 5% even if the NMR peaks did not reach the baseline separation, when impurity peaks do not overlap. This method will be one of the useful techniques for the rapid and simple discrimination of enantiomers of illegal methamphetamine and its raw materials.