In this study, we developed highly dispersible polylactic glycolic acid (PLGA) copolymer microparticles (MRPs) in aqueous fluid. A solution containing both dissolved aripiprazole as a model drug and PLGA were spray-dried to make MRPs. The resultant MRPs were further co-processed with water-soluble additives and a surfactant to improve their dispersion behavior. The granules containing MRPs and additives, termed granulated microparticles (G-MRPs) were prepared by a newly established drop freeze-drying technique. The physicochemical properties of MRPs and G-MRPs were evaluated as a long-acting release depot injectable. The MRPs were spherical particles with diameters of approximately 1 to 20 µm and strongly assembled to one another in the aqueous phase, forming large aggregations. In contrast, the G-MRPs were spherical granules with diameters of approximately 200 to 400 µm that displayed a microparticles-in-granule structure in which small MRPs were embedded in the porous matrix inside the granules. When the G-MRPs were placed in water, the porous matrix base was immediately dissolved, and each embedded MRP was individually released, thus inducing monodispersion and significantly improved dispersibility. The excellent dispersibility was attributed to the water-soluble porous network structure mainly composed of D-mannitol and the steric hindrance effects derived from the polymeric molecular chains. These properties may give rise to the excellent passage of PLGA microparticles through needles for use in depot formulation suspensions. A crystalline evaluation of the G-MRPs suggested that the drug and PLGA molecularly interacted and that their thermodynamic stability was improved.

In the presence of charge–transfer complexes between iodine and tertiary amines, the aqueous-medium atom-transfer radical reactions proceeded under visible light irradiation without the typical photocatalysts.

Permeation enhancers are required to deliver drugs through the skin efficiently and maintain effective blood concentrations. Studies of the barrier function of the stratum corneum using l-menthol, a monocyclic monoterpene widely used in medicines and foods, have revealed an interaction between characteristic intercellular lipid structures in the stratum corneum and permeation enhancers. The variety of permeation enhancers that can be used to contribute to transdermal delivery systems beyond l-menthol is increasing. In this study, we focused on nerolidol and levulinic acid and investigated their influence on stratum corneum lipid structures. Nerolidol, a sesquiterpene, has been reported to enhance the permeation of various drugs. Levulinic acid is reported to enhance the permeability of buprenorphine and is used as a component of the buprenorphine^® patch. Synchrotron X-ray diffraction and attenuated total reflectance Fourier transform IR spectroscopy measurements revealed that nerolidol disturbs the rigidly arranged lipid structure and increases lipid fluidity. Levulinic acid had a smaller effect on stratum corneum lipid structures, but did increase lipid fluidity when co-administered with nerolidol or heat. We found that nerolidol has an effect on stratum corneum lipids similar to that of l-menthol, and levulinic acid had an effect similar to that of oleic acid.

Disease-associated alterations of enzymatic functions are potentially useful as disease biomarkers, and here we show that an enzymomics (omics of active enzymes) approach, in which enzymatic activities are screened with panels of substrates, can be an effective way to identify such alterations. In the present study, we used a panel of fluorogenic substrates to search for altered enzyme activities in bronchoalveolar lavage fluid (BALF) from a mouse model of lung inflammation. We found that acylamino acid releasing enzyme (APEH) activity was highly elevated, apparently reflecting the increased population of immune cells in the inflamed lung.

Arginine-rich cell-penetrating peptides (CPPs) including Tat, Penetratin and oligoarginine peptides are a series of short peptides that can be efficiently internalized into cells and have been widely used as carriers for intracellular delivery of bioactive molecules. In the early phase of the study, CPPs, as well as their conjugates, were thought to rapidly enter cells by direct penetration through membranes, which was later found to be an experimental artifact that was concluded from observations in fixed cells. Although re-evaluation using living unfixed cells revealed that endocytosis has a major role in internalization of these peptides, there are a number of studies reporting that, even if fixation is avoided, direct translocation across plasma membranes and cytosolic distribution of arginine-rich CPPs are still observed in cells without membrane perturbation. In addition, amphiphilic counteranions such as pyrenebutyrate dramatically accelerate direct translocation of these peptides into cells. These results suggest that there are at least two pathways, i.e., endocytosis and direct translocation, both of which would contribute to cellular internalization of arginine-rich CPPs. In this review, we first introduce the story of fixation artifact, which indeed led to the critical progress in CPP study, and then summarize the current understanding for direct translocation of arginine-rich CPPs. Comprehensive understanding of direct translocation of these peptides and its mechanistic elucidation would provide useful knowledge for developing methodologies that would enable efficient intracellular delivery.

Nitric oxide (NO) is a gas that plays various roles in physiological signal transduction, for example, in vasodilation, neural transmission, and biodefence. Recently, other gaseous signal mediators such as carbon monoxide (CO) and hydrogen sulfide (H₂S) have also been found to have important biological activities. Since experimental studies with gaseous mediators are difficult, chemicals that enable controlled release of these gases are indispensable. We have developed a range of photocontrollable releasers that generate NO, H₂S, and related species with fine spatiotemporal control, and we have also employed these caged compounds in various applications. This paper briefly reviews our work on photocontrollable NO, H₂S, and HNO releasers, and presents some typical applications illustrating the suitability of our compounds for controlled release of these biologically active species in cellular and tissue systems. These compounds also appear to have potential for future therapeutic applications.