Addressing the challenging field of chemoenzymatic dynamic kinetic resolution (DKR) of tertiary alcohols, for which so far only one example exists in the literature, we combined biocatalytic esterification and oxovanadium-catalyzed racemization, operating both steps in two different compartments of one reactor. The compartmentalization of the two heterogeneous catalysts, namely, immobilized lipase A from Candida antarctica (CAL-A) or its mutant and oxovanadium species on mesoporous silica, was achieved using a polydimethylsiloxane thimble, avoiding contact of the oxovanadium with water, thus maintaining the catalyst’s activity and thereby successfully improving the efficiency of the DKR. Utilizing the immobilized double mutant CAL-A V278S + S429G, the ester was obtained in 62% yield with excellent enantiomeric excess of >99% ee.

Nitric oxide (NO) is involved in numerous physiological activities including vasodilation, neurotransmission, and immune system regulation. NO-releasing small compounds are used to investigate the physiological activity of NO and to treat circulatory diseases, such as hypertension and angina pectoris. Among them, light-controllable NO releasers (caged NOs) enable spatiotemporal control of NO’s bioactivities. We previously reported NORD-1, a photoinduced electron transfer (PeT)-driven NO releaser that responds to red light. In the PeT-driven NO releasers, the NO release is triggered by photoinduced electron transfer from the N-nitrosoaminophenol to the light-harvesting dye. However, additional functionalization of PeT-driven NO releasers is required to enable introduction of tissue targeting groups or novel release triggers. As such, structure–activity relationship studies are needed to identify a suitable site for modification so as not to affect the NO-releasing efficiency of the PeT. Here, we investigated the functional impact of introducing substituents into the linker region connecting the light-harvesting antenna and NO releasing moiety. Although introduction of various substituents elicited only minor changes in NO-releasing efficiency and vasodilation activity, dialkylamino groups induced pH-dependent changes in NO-releasing reactivity. The structure–activity relationship of the linker moiety could provide fruitful information in further functionalizing PeT-driven NO releasers for biological applications.

Alkaline hydrolysis of the crude resin glycoside fraction from the leaves and stems of Ipomoea lacunosa L. (Convolvulaceae) yielded organic acid and glycosidic acid fractions. The organic acid fraction included n-decanoic and n-dodecanoic acids. Acidic hydrolysis of the glycosidic acid fraction yielded 3 monosaccharides (d-glucose, d-fucose, and l-rhamnose) and 2 known hydroxyl fatty acids (11S-hydroxytetradecanoic and 11S-hydroxyhexadecanoic acids). Treatment of the glycosidic acid fraction with trimethylsilyldiazomethane (in hexane) afforded 1 new glycosidic acid methyl ester (lacunosinic acid J methyl ester) and 6 known glycosidic acid methyl esters. Eight new resin glycosides (lacunosins V–XII) were isolated from the leaves and stems, along with 2 known resin glycosides. Their structures were determined using spectroscopic and chemical analyses. Three types of resin glycosides were identified: those with 18-membered macrolactone, those with 19-membered macrolactone, and those with non-macrolactone structures. All these compounds contained n-decanoic and n-dodecanoic acids as the organic acid components. Nine of the isolated resin glycosides were tested for cytotoxic activity against HL-60 human promyelocytic leukemia cells. One compound exhibited activity with an IC₅₀ value of 44.5 μM, while 3 compounds demonstrated moderate activity, with inhibition rates ranging from 53.5 to 68.7% at a concentration of 200 μM. In contrast, the remaining 5 compounds showed negligible effects even at 200 μM.

Characterizing the complex drug release profiles of nanoparticle-based pharmaceuticals is essential to ensure their efficacy and safety. In this study, we investigated the drug release of a representative liposomal drug, Doxil, to explore the applicability of the dynamic dialysis method (DDM), which offers the advantage of simple implementation. The DDM demonstrated considerable doxorubicin release from Doxil in response to increased ammonia concentration, supporting the hypothesis of ammonia-driven drug release from Doxil in tumor environments. To analyze the drug release of liposomal doxorubicin, we developed a mathematical model that (i) does not require strict sink conditions and (ii) avoids introducing numerous kinetic parameters. This model consolidates the complexities of drug partitioning into the liposomal membrane into a single apparent permeability constant. The release profiles of Doxil at 25°C and a physiological temperature of 40°C were successfully reproduced by the kinetic model, yielding reasonable permeability coefficients of 1.4 × 10⁻¹⁰ and 2.1 × 10⁻¹⁰ cm/s, respectively. Our model described the release behavior of the generic product Lipodox, yielding a permeability coefficient of 2.1 × 10⁻¹⁰ cm/s at 40°C, thereby confirming the utility of the DDM across products. Our results demonstrate that, with optimized conditions, the DDM can assess the drug release kinetics of liposomal doxorubicin. Furthermore, we believe that our study provides a valuable framework for evaluating and optimizing drug release phenomena in liposomal formulations.

Lipids, including fatty acids and phospholipids, play crucial roles in biological systems and are widely utilized in pharmaceutical and biomedical applications. However, their inherent hydrophobicity poses significant challenges for formulation and administration. In this study, we aimed to enhance the aqueous solubility of lipidic compounds by leveraging light-responsive molecular design. We synthesized azo-lipids by incorporating azobenzene units into a fatty acid and phosphatidylcholine, hypothesizing that light-induced trans–cis isomerization would improve solubility. The synthesized compounds exhibited reversible photoisomerization upon alternating UV (365 nm) and visible light irradiation, as confirmed by UV-vis spectroscopy and reverse-phase HPLC. The solubilization of these azo-lipids was quantified under UV-unirradiated and irradiated conditions. Azobenzene-incorporated phosphatidylcholine 2 exhibited a drastic increase in solubilization from 2.030 to 1008 µM (496-fold) after UV irradiation. This significant improvement was attributed to efficient photoisomerization and molecular bending in the cis, cis conformation, reducing intermolecular interactions. Our findings suggest that this on-demand aqueous solubilization strategy offers a novel approach for improving the handling, storage, and potential therapeutic administration of lipid-based compounds.

Silica powder is an essential pharmaceutical ingredient, which in some combinations with drugs, causes chemical instability of the drug adsorbed on it. NMR measurements have been used to determine the drug adsorption state; however, the relationship between drug chemical stability and NMR relaxation, one of the NMR processes, is yet to be thoroughly studied. This work investigated the relationship between the chemical stability of itraconazole (ITZ)-adsorbed silica and its NMR relaxation. NMR can specifically observe ¹H nuclei, and this feature was exploited to study only the T₁ relaxation of these nuclei in the drug, excluding the silica signal composed of Si and O. ITZ, a poorly water-soluble model drug, was physically adsorbed on nonporous silica (Aerosil 200, AER), and mesoporous silica (Sylysia 320), and the ¹H T₁ relaxation was measured before storage using the time domain (TD)-NMR technique. The amount of ITZ degradant adsorbed in the silicas was also measured after storage at humidified conditions. Then, the relationship between the degradant amount of ITZ-adsorbed silica after storage and the T₁ relaxation rate (1/T₁) before storage was investigated. The ITZ-adsorbed silicas showed a positive correlation between the degradant amount and the 1/T₁ value. ITZ-adsorbed AER showed a strong positive correlation (R² = 0.751). Thus, the 1/T₁ value may be an efficient parameter to determine the chemical stability of ITZ adsorbed on nonporous silica. The 1/T₁ value measurement by TD-NMR could provide new insight for evaluating the chemical stability of solid dosage forms containing silica.

The advent of mRNA medicine, initially implemented as a vaccine during the coronavirus disease 2019 (COVID-19) pandemic, has attracted interest in diverse therapeutic applications, including cancer vaccines and protein replacement therapies. Our group recently established a method for the complete chemical synthesis of mRNA. Although this approach has some advantages, chemically synthesized mRNA is limited to approximately 150 nucleotides in length and necessitates optimized designs for untranslated regions (UTRs) and coding sequences. To address this challenge, we investigated whether the non-reporter-based selection methods, including ribosome profiling and polysome profiling, which were often used for UTR optimization in long mRNA, could be adapted for short mRNA to identify highly translated UTR sequences. Using these methods, we collected mRNAs that interacted with ribosomes and analyzed their 5′-UTR sequences. We successfully identified a 9-nucleotide 5′-UTR that demonstrated approximately double the translation efficiency of the Kozak sequence, a widely used positive control. This work highlights the adaptability of ribosome-focused selection techniques for short, chemically synthesized mRNA and provides a foundation for effective sequence design. These findings advance the development of chemically synthesized mRNA as a viable alternative to in vitro-transcribed mRNA, paving the way for innovative therapeutic applications.

Mini-tablets (MTs) allow for dosage adjustments according to children’s weight and age. However, it is difficult to manufacture MTs with robust physical properties, and various formulation techniques are required. Adding cellulose nanofiber (CNF), a highly functional biomass material, to MTs improved the hardness and disintegration; however, the large variation in the weight and drug content of the resulting MTs remained a challenge. Therefore, this study analyzed the physical properties of CNF-containing MTs of different particle sizes and evaluated the effect of the particle size on MT manufacturing. CNF₃₀₀, with an average particle size of approximately 300 µm, was pulverized to prepare CNF₁₀₀, averaging 100 µm. The formulation included CNF (10, 30, and 50%), lactose hydrate, paracetamol, and magnesium stearate. The pharmaceutical powders mixed were loaded into a rotary tablet press equipped with a 3-mm multiple-tip tooling and compressed at 2, 5, and 8 kN forces. CNF₁₀₀-containing MTs were manufactured via direct powder compression, and they showed lower variations in weight and drug content than those containing CNF₃₀₀. The tensile strength of MTs containing CNF₁₀₀ was smaller than that of those containing CNF₃₀₀; however, a strength of ≥1 MPa (corresponding to ≥30 N hardness of a regular tablet) was obtained by setting the compression force to ≥5 kN. The MTs containing 30% CNF₁₀₀ disintegrated in ≤30 s, regardless of the compression force. Thus, using smaller CNF particle sizes enabled the manufacturing of an orally disintegrating MT with adequate hardness and disintegration properties while also minimizing variations in MT weight and drug content.

Four teleocidin analogs were isolated from Streptomyces eurocidicus, along with teleocidin B3. A combination of MS and NMR analyses elucidated their structures, revealing teleocidin A2 acetate and teleocidin B3 acetate as newly isolated metabolites. Teleocidins A2 and B3, known metabolites, exhibited weak antibacterial activities against Kocuria rhizophila and Bacillus subtilis. Notably, membrane vesicles of Burkholderia multivorans modulated the production levels of teleocidin analogs in S. eurocidicus, upregulating teleocidin biosynthesis but downregulating the subsequent acetylation step.

Veratridine is a neurotoxic compound classified into the cevanine group of the Veratrum alkaloids and is characterized by its highly functionalized hexacyclic structure. Here, we report the synthesis of the ABC-ring system of veratridine from a known cis-decalin. The cis-decalin was synthesized from 1,5-pentanediol by modification of a literature method. A site-selective acylation of the C3-hydroxy group with 3,4-dimethoxybenzoyl chloride, a chemo- and stereoselective (allyl)₂Zn-mediated C9-allylation, and ring closing metathesis were employed as key transformations to construct the ABC-ring system of veratridine.

The δ-opioid receptor (DOR) continues to attract attention as a therapeutic target for the development of safer analgesics due to its ability to mediate pain relief with a lower risk of adverse effects compared to the μ-opioid receptor (MOR). Building upon our previous findings on KNT-127, a DOR-selective agonist with a morphinan scaffold, this study further explores the structure–signal relationships between quinoline ring modifications and the signaling bias toward Gi-protein activation while minimizing β-arrestin-2 recruitment. Our findings highlight the critical role of the 5′-position in modulating signaling bias. Bulky hydrophobic substituents, such as isopropoxy and cyclohexanoxy groups, effectively reduce β-arrestin-2 recruitment without compromising DOR binding affinity or Gi-protein activation. Molecular-docking and molecular dynamics simulations provided mechanistic insights, showing that these modifications change ligand interactions with the V281^6.55-W284^6.58-L300^7.35 sub-pocket, thus selectively favoring Gi-protein signaling. These insights clarify the key interactions for the signaling bias in DOR agonists, offering a new framework for the design of DOR-targeted therapies with an improved therapeutic profile.

The pandemic of coronavirus disease 2019, caused by the new coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a serious concern worldwide. Although some effective vaccines have been developed, only a few anti-SARS-CoV-2 drugs have been approved for their clinical use. In this study, we designed and synthesized new anti-SARS-CoV-2 drugs based on the chemical structure of amodiaquine, which is known as an antimalarial drug. Consequently, we have identified amodiaquine analogs functionalized with dialkylamino-pendant aminophenol moieties that possess a high level of anti-SARS-CoV-2 activity with a low level of toxicity.

A concise approach is presented for preparing 4ʹ-modified thymidines from oxime imidates using readily generated 4ʹ-carbon radicals. This method produces 4ʹ-modified thymidines from natural thymidine using the Mitsunobu reaction, the protection of 3ʹ-hydroxy group (when necessary), and 1,5-hydrogen atom transfer (1,5-HAT)/intermolecular 1,4-addition with electron-deficient olefins. Moreover, using a one-pot synthesis involving 1,5-HAT/intermolecular 1,4-addition, followed by the hydrolysis of the imidate intermediate under basic conditions, 4′-modified thymidine was diastereoselectively isolated. This is because the 4′-isomer transferred to the water layer in the work-up process.

A squaramide organocatalyst was employed to efficiently promote asymmetric oxidative lactonization to construct spiro-fused 2-oxindoles in moderate-to-good yield and enantioselectivity (up to 81% enantiomeric excess (ee)). Herein, we report the first study accomplishing stereoselective oxidative cyclization from indole propionic acid using an organocatalyst, N-iodosuccinimide (NIS), and hydrogen peroxide under metal-free and mild reaction conditions.

Estrogen receptors (ERs) and their ligands regulate a variety of physiological processes in humans, and altered ER signaling is associated with serious disorders, including breast cancer. Estrogens also bind to other receptors such as G-protein-coupled receptor 30 (GPER), and so fluorescent estrogen ligands would be useful for various functional studies and for development of drug candidates. Here we describe fluorescent estrogen receptor ligands based on 3-aryl-7-hydroxycoumarin. Notably, these ligands also function as pH-dependent OFF-ON-OFF type fluorescent sensors, enabling the detection of specific ranges of pH.

Tableting is a critical process in the manufacture of pharmaceutical tablets that directly influences product quality. Ensuring consistent quality between the research and development phase and commercial-scale production is essential during scale-up. In this study, we investigated methods for evaluating time-dependent deformation behavior using four excipients that exhibit different compression deformation behaviors. Dicalcium phosphate dihydrate (DCPD) shows no viscoelasticity, whereas lactose monohydrate (LAC), cornstarch (CS), and microcrystalline cellulose (MCC) exhibit viscoelasticity and viscoplasticity, although the degree of viscosity varies between them. In addition to investigating the known strain rate sensitivity (SRS), we performed mechanical energy evaluation based on the area under the force–displacement curve and stress relaxation tests. A trapezoid waveform was applied during the test, with loading punch speeds of 0.5 and 100 mm/s, and a dwell time of 4.5 s. The SRS value for DCPD approached approximately one, indicating no speed dependence, and the SRS increased in the order of LAC < MCC < CS, consistent with previous studies that used a saw-tooth waveform. Among the mechanical energies, the ratio of plastic flow energy to plastic energy, which depends on dwell time, followed a similar trend to SRS for the three materials other than DCPD. We conclude that axial stress relaxation is affected by machine deformation, whereas radial stress relaxation provides insight into the viscous behavior of the material. Under the test conditions, the effects of the punch-displacement profile and compression pressure on the mechanical energy and stress relaxation were more pronounced than those of SRS.

Multivariate statistical process control (MSPC) has attracted considerable attention as a monitoring method for pharmaceutical continuous manufacturing. However, there are few examples of its application in pharmaceutical manufacturing, and previous studies have shown high false-positive rates. One of the reasons is the use of inappropriate scaling factors. In pharmaceutical processes, the number of experiments for MSPC modeling tends to be small because the active pharmaceutical ingredients are expensive. Subsequently, the standard deviation, a common scaling factor for some variables, becomes too small, and the model may become sensitive to small variations. In this study, we have proposed methods for determining the appropriate scaling factors. These methods were applied to granulation and drying processes in pharmaceutical continuous manufacturing. The MSPC model can detect changes in the process parameters and raw materials used during continuous wet granulation and fluidized bed drying using the proposed scaling method.

The δ-opioid receptor (DOR) is a promising target for developing novel analgesics due to its lower risk of causing side effects compared to the μ-opioid receptor (MOR), which is commonly associated with dependence, respiratory depression, and other adverse effects. KNT-127, a DOR-selective agonist with a morphinan skeleton, offers analgesic and antidepressant benefits without inducing convulsions at therapeutic doses, unlike the conventional DOR agonist SNC80. While previous studies have suggested that KNT-127 exhibits reduced β-arrestin recruitment, a signaling pathway implicated in adverse opioid effects, the ligand structural basis for this biased signaling remains unclear. In this study, we explored the structure–signal relationships of KNT-127, focusing on its quinoline moiety, which is known to serve as an address domain responsible for DOR selectivity. Modifying the quinoline moiety by removing the aromatic rings reduced DOR selectivity and potency in relation to G-protein activation while diminishing both the potency and efficacy of β-arrestin recruitment. These results suggest that the morphinan skeleton is critical for reduced β-arrestin recruitment, while the quinoline moiety differentially modulates G-protein activation and β-arrestin recruitment. Together, our study expands the message-address concept, previously limited to receptor selectivity, by providing structural insights into the G-protein-biased agonism of DOR agonists, thereby guiding the design of safer DOR-targeting therapeutics.

Building on our previously reported techniques, we developed a concise and highly stereoselective synthesis method for β,β-disubstituted α,β-unsaturated esters. This synthesis comprises 3 reactions: the aldol reaction of acetic ester derivatives with ketones, the acetylation of tert-alcohols, and an elimination reaction utilizing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). During the acetylation process, acetic anhydride and 4-dimethylaminopyridine (DMAP) facilitated the smooth acetylation of bulky tert-alcohols; however, employing DBU as a base reduced the yields. Additionally, the removal of excess DMAP effectively suppressed the formation of unwanted byproducts during the elimination step.

Prealnumycin (1), a benzoisochromanequinone compound, produces biologically active exfoliamycin or alnumycin through hybridization with D-ribose or oxidation. We report herein a concise and stereoselective synthesis of 1. The anionic annulation of phthalide 5 with enone 6, prepared via a transition metal-catalyzed enantioselective route, afforded tricyclic lactone 4. This intermediate then underwent a highly diastereoselective introduction of an n-propyl group through nucleophilic addition followed by silane reduction. Subsequent regioselective arene oxidation of 18 using cerium(IV) ammonium nitrate (CAN) afforded naphthoquinone 2. Further manipulations, including acidic deprotection and elimination, yielded prealnumycin in 8 steps.