Analysis of green tea compounds and their stability in dentifrices of different pH levels.

In this study, green tea compounds (flavonoids, alkaloids, and phenolic acids) were analyzed in green tea-containing dentifrices, and their stability at different pH levels was evaluated. The compounds were separated under 0.01% phosphoric acid-acetonitrile gradient conditions and detected by photodiode array detector at 210, 280, 300, 335 nm. Column temperature was set at 20°C based on the results of screening various temperatures. Each compound showed good linearity at optimized wavelength as well as showing good precision and accuracy in dentifrices. Using this method, the stability of compounds was investigated in pH 4, 7, 8, and 10 solutions for 96 h, and in pH 7 and pH 10 solutions for 6 months. The green tea compounds were more stable at low pH levels; purine alkaloids were more stable than flavonoids. In particular, gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and myricetin almost disappeared in pH 10 solutions after 96 h. In dentifrices, the compounds were gradually decreased until 6 months in both pH types, while gallic acid was increased because of production of galloyl ester of other green tea compounds. Therefore, it is beneficial to adjust to as low a pH as possible when produce green tea-containing dentifrices.

Analysis of parabens in dentifrices and the oral cavity.

This study analyzed levels of parabens in commercial dentifrices and saliva. HPLC was performed using 35% acetonitrile and measuring absorbance at 254 nm. Thirteen toothpastes and five mouthwashes were analyzed. Of these, volunteers used three toothpastes and two mouthwashes, and levels of parabens were analyzed in saliva and water used for mouth rinsing. In toothpastes, the highest concentrations of methylparaben (MP), propylparaben (PP) and n-butylparaben (nBP) were 1.86, 1.42 and 1.87 mg/g, respectively. In mouthwashes, the highest concentrations of MP and PP were 0.97 and 0.11 mg/mL, respectively. After volunteers used 500 mg toothpaste T-1, which contained 895 µg MP, the first and tenth mouth rinse samples contained means of 64.63 and 1.89 µg MP, respectively. After rinsing the mouth three or five times, 37 µg or 18 µg MP was calculated to remain in the oral cavity, respectively. After using 20 mL mouthwash S-1, which contained 19 mg MP, 1.53 mg MP was calculated to remain in the oral cavity. Immediately after using this mouthwash, the mean salivary concentration of MP was 237 µg/mL. The daily intake of parabens from dentifrices was predicted to be insignificant compared with the intake from food; however, parabens can be ingested from dentifrices.

Neutralization of ocular surface TNF-α reduces ocular surface and lacrimal gland inflammation induced by in vivo dry eye.

PURPOSE: The purpose of this study was to investigate the effectiveness of tumor necrosis factor (TNF)-α blocker for treatment of dry eye (DE)-induced inflammation and determine a more effective method to suppress lacrimal gland inflammation. Efficacy of topical versus systemic administration of TNF-α blockers was determined using a murine dry eye (DE) model. METHODS: The TNF-α blocker HL036 was developed by modification of the TNF receptor I. Protein purity, binding affinity, and clearance of TNF-α was compared with etanercept. Using DE-induced C57BL/6 mice, corneal erosion and goblet cell counts were measured after subcutaneous or topical treatment with etanercept or HL036. Inflammatory cytokines in cornea and lacrimal glands were determined by quantitative RT-PCR and ELISA. RESULTS: HL036 showed TNF-α binding affinity comparable to etanercept, as measured by surface plasmon resonance. HL036 concentration was significantly higher in cornea and anterior segment than etanercept and effectively eliminated TNF-α on ocular surfaces. Etanercept was preferentially concentrated in the posterior segment. Corneal erosion and goblet cell counts were improved only with topically applied etanercept and HL036. Ocular surface IFN-γ, IL-6, and IL-21 were significantly decreased by topical HL036. DE-induced lacrimal gland IFN-γ and IL-6 expression was effectively suppressed by topical etanercept and HL036. CONCLUSIONS: Topical TNF-α blockers effectively suppressed lacrimal gland and corneal inflammation by suppressing IFN-γ, IL-21, and IL-6. Differences in TNF-α affinity, clearance, and local concentration of blockers may account for the anti-inflammatory effects in different ocular regions.