Effect of carrier size and surface morphology on the aerosolization of formulation in a capsule-based dry powder inhaler / 药学学报

The size and surface morphology of carrier lactose had influence on the aerosolization performance of dry powder inhalers. In this article, chlorpheniramine maleate was blended with two types of commercial carrier lactose, which were Lactohale 100® and Respitose SV003® (SV003), as formulation model. In vitro experiments were conducted using fast screening impactor at 30 L·min-1 and 60 L·min-1 respectively. Meanwhile, computational fluid dynamics (CFD) coupling with discrete element modelling (DEM) was applied to discuss the movements of those two carrier particles in Handihaler® at the flow rate mentioned above. The dispersion characteristics of two formulations and the dispersion mechanism of Handihaler® were analyzed by establishing the relationship between in vitro experiments and numerical simulation. The results of in vitro experiments and CFD-DEM demonstrated that the aerosolization performance of formulation with SV003 was better. The linear correlation (R2 = 0.940 1) between fine particle dose and total energy loss by carrier collision within the wall of device was found by comparing the in vitro experimental results with CFD-DEM results. It revealed that particle-wall collision in Handihaler® had direct impact on the dispersion results of formulation.

Surface morphology and mechanical properties of conventional and self-adhesive resin cements after aqueous aging

Abstract The stable long-term performance of resin cement under oral environmental conditions is a crucial factor to obtain a satisfactory success of the allceramic dental restoration. Objective: This study aimed at evaluating and comparing the surface morphology and mechanical property of conventional and self-adhesive resin cement after aqueous aging. Materials and Methods: Disc-shaped specimens of 3 conventional (C1: Multilink N, C2: Duolink, C3: Nexus 3) and 3 self-adhesive (S1: Multilink Speed, S2: Biscem, S3: Maxcem) types of resin cements were subjected to irradiation. After 24 h, the Knoop microhardness of each resin cement was evaluated. The specimens were immersed separately in distilled water and maintained at 37°C. A total of 5 specimens of each resin cement were collected at the following time intervals of immersion: 1, 6, 12 and 18 months. The samples were used to evaluate the Knoop parameters of microhardness, sorption and solubility. The surface morphology of the specimens after 18 months of immersion was observed by scanning electron microscopy. The sorption and solubility data were analyzed by two-way ANOVA. The Knoop microhardness was tested by the ANOVA repeated measures (P<0.05). Results: The sorption and solubility parameters of C1 and S1 exhibited significant fluctuations during the aqueous aging. The hardness of the S1 and S2 specimens decreased significantly after an 18-month water immersion. The S1, S2 and S3 specimens indicated higher filler exposure and stripping and apparent pores and cracks compared to specimens C1, C2 and C3, respectively. Conclusion: The surface of selfadhesive resin cements is more susceptible to aqueous damage than that of the conventional resin cements.

Effects of diferent salivary ph on the surface and roughness of different orthodontic wires

AIM: The aim of this study was to evaluate the effects of different salivary pH on the surface of orthodontic wires. MATERIAL AND METHODS: Two hundred and seventy wire segments of titanium-molybdenum alloy (TMA), and Cr-Ni stainless steel , subjected to saliva pH 2.0 , 5.0 and 7.6 , in three different times of storage, divided into 3 groups (n=30). Group 1: TMA (Morelli), Group 2: TMA (Ormco) and Group 3: Stainless steel Cr-Ni (Morelli). To read the roughness profilometer was used Mitutoyo Surftest Digital-301. Observation of the surface morphology was performed by scanning electron microscope (SEM). RESULTS: Between the results is that the lower the pH more roughness was found. No changes were observed on the wires roughness of group 3. In the evaluation of SEM, changes were found in surface TMA wires in pH 2 and 5, the steel wires no changes superficias. CONCLUSION: The acidic pH and time showed effects on TMA's wires. The stainless steel wires showed no changes. We conclude that the stainless wires have greater resistance to salivary pH.