Validation of the Absorption-Enhancing Ability of Oligoarginines Grafted onto a Backbone of Hyaluronic Acid through Animal Studies from Rodents to Primates.

The purpose of our research is to develop functional additives that enhance mucosal absorption of biologics, such as peptide/protein and antibody drugs, to provide their non-to-poor invasive dosage forms self-managed by patients. Our previous in vivo and in vitro studies demonstrated that the intranasal absorption of biologics in mice was significantly improved when coadministered with oligoarginines anchored chemically to hyaluronic acid via a glycine spacer, presumably through syndecan-4-mediated macropinocytosis under activation by oligoarginines. The present mouse experiments first revealed that diglycine-L-tetraarginine-linked hyaluronic acid significantly enhanced the intranasal absorption of sulpiride, which is a poor-absorptive organic compound with a low molecular weight. However, similar enhancement was not observed for levofloxacin, which has a similarly low molecular weight but is a well-absorptive organic compound, probably because its absorption was mostly dominated by passive diffusion. The subsequent monkey experiments revealed that there was no species difference in the absorption-enhancing ability of diglycine-L-tetraarginine-linked hyaluronic acid for not only organic compounds but also biologics. This was presumably because the expression levels of endocytosis-associated membrane proteins on the nasal mucosa in monkeys were almost equivalent to those in mice, and poorly membrane-permeable/membrane-impermeable drugs were mainly absorbed via syndecan-4-mediated macropinocytosis, regardless of animal species. Drug concentrations in the brain assessed in mice and monkeys and those in the cerebral spinal fluids (CSFs) assessed in monkeys indicated that drugs would be delivered from the systemic circulation to the central nervous system by crossing the blood-brain and the blood-CSF barriers under coadministration with the hyaluronic acid derivative. In line with our original hypothesis, this new set of data supported that our oligoarginine-linked hyaluronic acid would locally perform on the mucosal surface and enhance the membrane permeation of drugs under its colocalization.

Dissipative Particle Dynamics Simulations for Shape Change of Growing Lipid Bilayer Vesicles.

The characteristic shape changes observed in the growth and division of L-form cells have been explained by several theoretical studies and simulations using a vesicle model in which the membrane area increases with time. In those theoretical studies, characteristic shapes such as tubulation and budding were reproduced in a non-equilibrium state, but it was not possible to incorporate deformations that would change the topology of the membrane. We constructed a vesicle model in which the area of the membrane increases using coarse-grained particles and analyzed the changes in the shape of growing membrane by the dissipative particle dynamics (DPD) method. In the simulation, lipid molecules were added to the lipid membrane at regular time intervals to increase the surface area of the lipid membrane. As a result, it was found that the vesicle deformed into a tubular shape or a budding shape depending on the conditions for adding lipid molecules. This suggests that the difference in the place where new lipid molecules are incorporated into the cell membrane during the growth of L-form cells causes the difference in the transformation pathway of L-form cells.

Characterization of UV-Sensitive Marker Constituents of Polygala Root for TLC: Applications in Quality Control of Single Crude Drug Extract Preparations.

Polygala Root (the root of Polygala tenuifolia WILLDENOW; Japanese name "Onji"), a well-known crude drug, traditionally used as an expectorant and sedative, has been attracting increased interest in recent years owing to its newly found pharmacological effect related to neuroprotection. However, there is no specific method for identifying and estimating the quality of this crude drug in the Japanese Pharmacopoeia, 17th edition. Therefore, in order to develop a TLC-based simple and convenient identification method using characteristic chemical marker(s) for the drug and its extract products, UV-sensitive constituents of Polygala Root were first investigated. A total of 23 aromatic compounds were isolated and characterized. Two new compounds, namely, polygalaonjisides A (1) and B (2), were characterized as syringic acid 4-O-(2'-O-ß-D-apiosyl)-ß-D-glucoside and 2-O-(ß-D-glucosyl)-3'-O-benzoylsucrose, respectively. Based on these phytochemical results, a TLC method focusing on three marker spots with Rf value of approximately 0.4-0.5 due to tenuifolisides A and B and 3,6'-di-O-sinapoylsucrose was proposed as a simple and convenient test to identify Polygala Root or its single-extract products on the market. The data presented in this paper could be useful in stipulating a confirmation test to identify Polygala Root.

Evaluation of topical external medicine for 5-fluorouracil-induced oral mucositis in hamsters.

Oral ulcerative mucositis is a common and painful toxicity associated with chemotherapy for cancer. Current treatment for chemotherapy-induced oral mucositis is largely palliative, and no adequate treatment with conclusive evidence exists. The purpose of this study was to evaluate the potential effectiveness of the topical external medicines used in clinical settings, and the authors investigated the effects of 1% azulene ointment, 0.12% dexamethasone ointment, and polaprezinc-sodium alginate suspension on an animal model for oral mucositis induced by chemotherapy. Oral mucositis was induced in hamsters through a combination treatment of 5-fluorouracil and mild abrasion of the cheek pouch. Each drug was administered topically to the oral mucosa of hamsters, and the process of healing of damaged oral mucositis was examined by measuring the size of the mucositis. Azulene ointment did not reduce the size of the mucositis compared with the vaseline-treated control group. Polaprezinc-sodium alginate suspension significantly improved the recovery from 5-fluorouracil-induced damage. In contrast, local treatment with dexamethasone exacerbated the mucositis markedly. These results suggested the healing effect of polaprezinc-sodium alginate suspension and the risk of steroids to severe oral mucositis induced by chemotherapy.

Antidepressant-like action of nicotine in forced swimming test and brain serotonin in mice.

An antidepressant-like action of nicotine has been suggested in the forced swimming test. The aim of the present study was to evaluate the relationship between the antidepressant-like action of nicotine and brain serotonin (5-HT) in mice. Nicotine at a dose of 0.2 mg/kg significantly (p < 0.05) decreased the duration of immobility time in forced swimming test. However, nicotine (0.01-1 mg/kg, s.c.) had no effect on locomotor activity in open-field test. Dopamine turnover in mouse whole brain was increased by nicotine (0.01-1 mg/kg, s.c.) in a dose-dependent manner, and nicotine at a dose of 0.05 mg/kg showed a significant increases in 5-HT turnover. Nicotine at a dose of 0.05 mg/kg markedly enhanced head twitch responses induced by (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a selective 5-HT2A/2C receptor agonist. These findings suggest that the involvement of nicotinic and serotonergic systems in the antidepressant-like effects of nicotine.