ABSTRACT
The surface and interface,as the transition region between two phases,belongs to the category of physical chemistry.At present,it is widely used in materials and other scientific fields.Meanwhile,this property also plays an important role in pharmaceutical research.The interface layer involved in the progress of pharmaceutical preparations is connected with the two-phase or three-phase between gas,liquid and solid closely.The interface effect will affect the final shaping of pharmaceutical preparations and the dissolution and absorption of drugs in the human body.In this paper,the surface and interface characteristics(specific surface area,surfacial and interfacial tension and surface Gibbs free energy) were compared,and the application of interface phenomena(wetting,solubilization and emulsification) in pharmaceutical research were introduced.From the points of view of the progress control of pharmaceutical preparations and the effectiveness of their products,the article expounds the important role of properties of surface and interface in the field of pharmaceutical preparations.Therefore,it is necessary to pay attention to the properties of surface and interface,one of the key physical properties of drugs,and to apply them in the pharmaceutical research.
ABSTRACT
This study was designed to establish the method of characterization of surface free energy(SFE)and evaluate the compaction properties of pharmaceutical materials based on SFE. We investigated the contact angles of materials with water and diiodomethane under different compression pressures. The contact angles of materials at 353 MPa compression pressure were utilized to calculate the related parameters of SFE ultimately. The area under tensile strength-compression pressure curve(AUTSC)and pressure yield(Py)were employed to evaluate the compactibility of material. Additionally, Pearson correlation analysis was utilized to analyze the relationship between the SFE and the compaction properties of pharmaceutical materials. The results exhibited that SFE had a significant correlation with the compaction properties of materials(P < 0.05). Moreover, the related parameters of SFE, i.e., cohesive work(Wco)and polarity index(PI)of SFE, were positively correlated with Py of Heckel equation and negatively related with AUTSC. The higher values of Wco and PI, the stronger repulsive force among the particles, led to a worse compaction behavior. In this study, we established the method for characterization of the compaction behavior of materials based on SFE initially. This study also demonstrated that SFE could evaluate the compaction behavior effectively, which provides a better understanding of compaction behavior for pharmaceutical researchers.
ABSTRACT
Presently interests are growing in the field of surface free energy(SFE). With the further research, more particle design engineering based on SFE are summarized via characterizing the related properties of SFE during the process of particle design. SFE of materials will vary with changing the physical properties of particles via modifying the surface of particles with particle design. In this study, we summarized the application of SFE in powder micronization, particle modification, mixing, coating, pelletilization and granulation, etc. Dispersive-polar model and adhesion-cohesion model were established based on the parameters of SFE. The application of the two models were also illustrated in the particle design engineering.
ABSTRACT
INTRODUCTION: Regenerative therapies using biomaterials require accurate information on interactions between the implanted material and the human body. To improve the process of bone regeneration it is necessary to obtain a better understanding of the influence of the surfaces on the early stages of osseointegration. This work aims to investigate the dynamic interaction between simulated body fluid (SBF) and titanium surfaces (Ti cp) immediately after their first contact. METHODS: Ti cp samples were passed through physicochemical treatments after immersion in acid solution, alkaline solution and solutions containing TiO2 and Ca2+, to obtain three different surfaces. These were characterized by electron microscopy and free energy estimates. The evaluation of the interaction with SBF was performed by measuring the dynamic contact angles after contacting the surfaces. RESULTS: The effects of SBF wettability were more significant on surfaces according to high energy estimates. A comparative analysis of the three types of surfaces showed that fluid spreading was greater in samples with greater polar components, indicating that the surface nature influences interactions in the early stages of osseointegration. CONCLUSION: The results indicate the influence of polar interactions in the dynamic wettability of the SBF. It is possible that these interactions can also influence cellular viability on surfaces. Based on these results, new experiments are being designed to improve the presented methodology as a tool for the evaluation of biomaterials without the need for in vivo experiments.
ABSTRACT
OBJECTIVE: Surface characteristics of dental materials play an important role in bacterial adhesion. The purpose of this study was to investigate surface characteristics of 5 different light-cured orthodontic adhesives (1 fluoride-releasing composite, 3 non-fluoride-releasing composites, and 1 resin-modified glass ionomer). METHODS: Surface roughness was measured using a confocal laser scanning microscope. Contact angle and surface free energy components were analyzed using the sessile drop method. RESULTS: Surface roughness was significantly different between adhesives despite a relatively small variation (less than 0.05 micrometer). Lightbond and Monolok2 were rougher than Enlight and Transbond XT. There were also significant differences in contact angles and surface free energy components between adhesives. In particular, considerable differences in contact angles and surface free energy components were found between resin modified glass ionomer and the composites. Resin modified glass ionomer showed significantly smaller contact angles in 3 different probe liquids and had higher total surface free energy and stronger polarity, with notably stronger basic property than the composites. CONCLUSION: Resin modified glass ionomer may provide a more favourable environment for bacterial adhesion than composite adhesives.