ABSTRACT
Objective::To investigate the effect of polyethylene glycol 400 (PEG400) on rat bile excretion of baicalin and its main metabolite [baicalein 6-O-β-D-glucuronide (B6G)], and to analyze its mechanism of action. Method::Rats were randomly divided into baicalin+ water group and baicalin+ PEG400 group, the anesthesia was induced by intraperitoneal injection of 10% chloral hydrate (dose of 4 mL·kg-1) to prepare a rat bile duct intubation model. After the rats were fully awake, rats were given baicalin aqueous solution and baicalin PEG400 solution with dose of 168 mg·kg-1 for baicalin, respectively. And bile was collected from 0 h to 12 h after administration. UPLC-MS/MS was used to determine the concentration of drug excreted through bile at different time periods. Thermo Hypersil GOLD C18 column was used with acetonitrile (A)-0.1% formic acid solution (B) as the mobile phase for gradient elution (0-9 min, 90%-27%B; 9-10 min, 27%-90%B; 10-12 min, 90%B), the flow rate was 0.3 mL·min-1, the column temperature was 30 ℃, the injection volume was 5 μL. The mass spectra were obtained in positive ion mode with electrospray ionization (ESI). The effects of PEG400 on the activities and expressions in rat liver of uridine diphosphate glucuronyltransferase (UGT) 1A8 and UGT1A9 were studied in vitro incubation assay and enzyme linked immunosorbent assay (ELISA). Result::Compared with the baicalin+ water group, in the baicalin+ PEG400 group, the bile cumulative excretions of baicalin and B6G increased by 1.8 times and 2.1 times within 12 h, respectively. PEG400 increased the enzyme activities of UGT1A8 and UGT1A9 by 2.0 times and 1.5 times, and their concentrations in liver were increased by 2.2 times and 1.3 times, respectively. Conclusion::PEG400 can significantly increase the bile excretion of baicalin and its main metabolite B6G by enhancing the activities and expressions of UGT1A8 and UGT1A9, and its promoting effect on bile excretion of B6G is greater than that of baicalin, which provides a basis for the rational clinical application of PEG400 and the design of new dosage forms of flavonoids such as baicalin.
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In this study, the effect of D-cellobiose on oral bioavailability of gentiopicroside (GPS) was investigate. The influence of D-cellobiose on GPS was achieved by calculating the residual GPS after being degraded with β-glucosidase or intestinal flora, and the data demonstrated D-cellobiose could inhibit the degradation of GPS in intestines; in bioavailability experiment, D-cellobiose could significantly improve the oral bioavailability (P<0.05) of GPS at the mass ratio of 1∶5, 1∶10 (GPS-D-cellobiose). D-cellobiose applied in this study may improve the oral bioavailability of GPS through delaying the degradation in intestines.
ABSTRACT
Objective: To prepare and optimize the prescription of colchicine ethosomes containing D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) and to investigate its feasibility as a carrier for transdermal drug delivery. Methods: The colchicine ethosomes containing TPGS were prepared by the injection-sonication method. And the encapsulation efficiency (EE) was determined by minicolumn centrifugation method. The prescription of ethosomes was optimized by uniform design with EE as the evaluation index, and the physicochemical properties of the optimized ethosomes were investigated. Characterization of the vesicles was based on particle size, Zeta potential, entrapment efficiency, and transmission electron microscopy (TEM). The transdermal permeation characteristics of ethosomes, colchicine 30% ethanol solution, and colchicine ethosomes containing TPGS were compared by using Franz diffusion cells. Results: The optimized formulation was as follows: The contents of soybean phospholipid and TPGS were 350 and 50 mg, respectively. In addition, the concentration of ethanol was 36.44%. The average EE, particle size, polydispersity index, and Zeta potential were (74.71 ± 2.18)%, (89.6 ± 3.5) nm, 0.201 ± 0.008, and (-34.6 ± 2.7) mV, respectively. The in vitro experiment showed that the transdermal flux, permeation rate, and skin deposition of colchicine ethosomes were (64.49 ± 5.61) μg/cm2, (2.84 ± 0.23) μg/(cm2∙h), (128.22 ± 11.64) μg/cm2, and the transdermal flux, permeation rate, and skin deposition of colchicine ethosomes containing TPGS were (91.36 ± 7.11) μg/cm2, (4.73 ± 0.38) μg/(cm2∙h), and (182.84 ± 14.37) μg/cm2, respectively, which was significantly higher than those in ethosomes. Conclusion: The colchicine ethosomes containing TPGS show high EE and obviously enhance the percutaneous absorption of colchicine, which might be a potential carrier for transdermal drug delivery.
ABSTRACT
After teeth are replanted, there are two possible healing responses: periodontal ligament healing or ankylosis with subsequent replacement resorption. The purpose of this study was to compare the fatigue resistance of vertically fractured teeth after bonding the fragments under conditions simulating both healing modes. Thirty-two human premolars were vertically fractured and the fragments were bonded together with Super-Bond C&B. They were then randomly distributed into four groups (BP, CP, CA, BA). The BP and CP groups were used to investigate the periodontal ligament healing mode whilst the BA and CA groups simulated ankylosis. All teeth had root canal treatment performed. Metal crowns were constructed for the CP and CA groups. The BP and BA groups only had composite resin restorations in the access cavities. All specimens were subjected to a 260 N load at 4 Hz until failure of the bond or until 2 × 10⁶ cycles had been reached if no fracture occurred. Cracks were detected by stereomicroscope imaging and also assessed via dye penetration tests. Finally, interfaces of the resin luting agent were examined by scanning electron microscope. The results confirmed that the fatigue resistance was higher in the groups with simulated periodontal ligament healing. Periodontal reattachment showed important biomechanical role in bonded and replanted vertically fractured teeth.
Subject(s)
Humans , Biomechanical Phenomena , Microscopy, Electron, Scanning , Periodontal Ligament , Physiology , Stress, Mechanical , Tooth Fractures , Therapeutics , Tooth ReplantationABSTRACT
Anterior megalophthalmos (AM) is an uncommon developmental anomaly of the anterior segment of the eye with a constellation of findings that includes enlarged cornea, deep anterior chamber, posterior positioning of the iris and lens, iris stroma atrophy, hypoplasia of iris dilator, pupil displacement, large capsular bag, lens subluxation, prematurely cataract and the tendency to retinal detachment. AM, especially when symptoms are mild, is not an easy disease to diagnose. We present 3 AM cases that were misdiagnosed as congenital cataract with weak zonule and megalocornea. Intraocular lenses (IOLs) dislocated after standard cataract surgeries and subsequent surgery (replacing the dislocated IOLs with iris-claw intraocular lenses) achieved satisfactory outcome. Although rare, AM should be included in the differential diagnosis of enlarged cornea and we recommend implanting Artisan lens in AM patients.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Cataract Extraction , Diagnostic Errors , Eye Abnormalities , Diagnosis , Lens SubluxationABSTRACT
Nitrite oxidoreductase(NXR) is the key enzyme responsible for the oxidation of NO2-to NO3-in nitrite-oxidizing bacteria.Since NXR is a dissoluble enzyme,located at the inner side of the membranes of cells,its function is dependent on the electron transfer chain related to membranes.This paper reviews the advances in study on NXR,including the structure,catalysis mechanism and the impact of different factors.New techniques applied in recent studies and research prospects are also presented.