[Design of Microdialysis-CLC Method for Measurement of Drug Behavior in Lacrimal Fluid after Instillation].

The ophthalmic application is the main route for the therapy of glaucoma, and is well-accepted by glaucoma patients. Therefore, it is important to measure the drug behavior in lacrimal fluid after instillation of eye drops. In this study, we used ophthalmic formulation (eye drops) containing timolol maleate (TM), in anti-glaucoma eye drops, and attempted to measure the drug behavior after instillation of TM eye drops. First, we collected the lacrimal fluid (5 µL) every 10 time after instillation using micropipette, and measured by the HPLC method. The TM concentration in lacrimal fluid was 21.2 µg/mL at 5 min after the instillation, and the TM was remained for 30 min after the instillation. Next, we collected the lacrimal fluid via the dialysis prove, and measured by the HPLC method. The retention of TM in lacrimal fluid was observed for 45 min after the instillation, and the measurement accuracy was enhanced by system with an automatic injection of TM solution via dialysis prove (microdialysis-HPLC method). In addition, the measurement accuracy increased more by using a capillary liquid chromatography (CLC) instead of an HPLC (microdialysis-CLC method), and the retention time of TM in lacrimal fluid was extended to 75 min after the instillation. In conclusion, we showed that the microdialysis-CLC method was suitable to measure the drug behavior in lacrimal fluid after instillation. These findings provide significant information that can be used in the design and evaluation of ophthalmic formulation.

Co-administration of Magnesium Ion Prevents Indomethacin-Induced Intestinal Ulcerogenic Lesions in Adjuvant-Induced Arthritis Rats.

In a study to find ways to prevent the side effects of indomethacin (IMC), we previously reported that magnesium ion (Mg2+) can prevent the onset of IMC-induced gastric mucosa in adjuvant-induced arthritis (AA) rats, a model for rheumatoid arthritis (RA). In this study we investigated whether the co-administration of IMC and Mg2+ prevents the formation and aggravation of intestinal ulcerogenic lesions in AA rats. The single oral administration of an excessive dose of IMC (40 mg/kg) induces hemorrhagic lesions and nitric oxide (NO) production via inducible nitric oxide synthase (iNOS) in the jejunal and ileal mucosa of AA rats, and the extent of the lesions, as well as iNOS and NO levels in AA rats are higher than in normal rats. On the other hand, the co-administration of 200 mg/kg Mg2+ attenuates intestinal ulceration and the elevation in the iNOS and NO levels in AA rats. Further, hemorrhagic lesioning and enhanced iNOS and NO levels in AA rats also result from the repetitive oral administration of 3 mg/kg IMC (therapeutic dose) for 42 d (once a day), and these changes are also prevented by the co-administration of 200 mg/kg Mg2+. In conclusion, the co-administration of Mg2+ suppresses the ulcerogenic response to IMC in the jejunal and ileal mucosa of AA rats, probably by preventing the elevation of iNOS and NO levels in the region.

Improvement of Dissolution Rate and Stability in a Pirenoxine Ophthalmic Suspension by the Bead Mill Methods.

Foreign matter sensation and blurred vision following instillation of ophthalmic suspension are often observed, and remaining of solid particle on cornea is related these side effects. In addition, low dispersion stability in the ophthalmic suspension affects the therapeutic effect. In this study, we have attempted to enhance the dissolution rate and stability of commercially available pirenoxine ophthalmic suspension (CA-pirenoxine eye drops), anti-cataract eye drops, by changes in particle size. Methylcellulose, zirconia beads (0.1 mm) and Micro Smash were used to mill the pirenoxine (bead mill method), and the distribution of particle size was changed to approximately 60-900 nm (nanodispersions) from 70 nm-3 µm (CA-pirenoxine eye drops). The dissolution rate of pirenoxine increased by the bead mill, and the dissolution rate constant in pirenoxine nanodispersions was 2.1-fold than that in CA-pirenoxine eye drops. Moreover, the dispersion stability in nanodispersions also significant higher in comparison with the CA-pirenoxine eye drops. The dispersion ratio in CA-pirenoxine eye drops and pirenoxine nanodispersions at 2 d after suspension was 48%, 99%, respectively. In conclusion, we showed that the dissolution rate and dispersion stability of CA-pirenoxine eye drops were enhanced by the bead mill method. These findings provide significant information that can be used in the design of ophthalmic suspension.

Combination Ointment Containing Solid Tranilast Nanoparticles and Dissolved Sericin Is Efficacious for Treating Skin Wound-Healing Deficits and Redness in Diabetic Rats.

We attempted to design a combination ointment containing solid tranilast nanoparticles and dissolved sericin as a wound-healing drug (TS-combination ointment), and evaluated its usefulness as therapy for wound-healing deficits in streptozotocin-induced diabetic rat (STZ rat) using kinetic analyses as an index. Solid tranilast nanoparticles were prepared by bead mill methods with low-substituted methylcellulose; the mean particle size of the tranilast nanoparticles was 70 nm. The ointment was designed to contain the tranilast nanoparticles plus sericin powder and/or Carbopol® 934. Skin wound healing in STZ rats begins significantly later than in normal rats. Although the skin wound healing rate in STZ rats treated with an ointment containing tranilast nanoparticles was lower than in STZ rats treated with vehicle, the ointment was effective in reducing redness. An ointment containing sericin enhanced the skin-healing rate, but the preventive effect on redness was weak. On the other hand, the combination of tranilast and sericin increased both the skin healing rate and reduction in redness. In conclusion, we have adapted kinetic analyses to skin wound healing in rats, and found these analyses to be useful as an index of wound healing ability by a wound-healing drug. In addition, we show that treatment with the TS-combination ointment enhances the skin wound healing rate and reduces redness. These findings provide information significant to the search for new wound-healing therapies and for the design of wound-healing drugs.

Ferulic Acid Suppresses Amyloid ß Production in the Human Lens Epithelial Cell Stimulated with Hydrogen Peroxide.

It is well known that oxidative stresses induce the production of amyloid ß (Aß) in the brain, lens, and retina, leading to age-related diseases. In the present study, we investigated the effects of ferulic acid on the Aß levels in H2O2-stimulated human lens epithelial (HLE) SRA 01/04 cells. Three types of Aß peptides (Aß1-40, Aß1-42, and Aß1-43) were measured by ELISA, and the levels of mRNA for the expressed proteins related to Aß production (APP, BACE1, and PS proteins) and degradation (ADAM10, NEP, and ECE1 proteins) were determined by quantitative real-time RT-PCR. H2O2 stimulation augmented gene expression of the proteins related to Aß production, resulting in the production of three types of Aß peptides. Treatment with 0.1 µM ferulic acid attenuated the augmentations of gene expression and production of the proteins related to the secretion of three types of Aß peptides in the H2O2-stimulated HLE cells. These results provided evidence of antioxidative functions of ferulic acid for lens epithelial cells.