The effects of vacuum ultraviolet (VUV) treatment on surface chemical composition morphology and albumin adsorption for low-density polyethylene (LDPE) and high-density polyethylene (HDPE) were investigated. The attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra and contact angle measurements indicated the formation of oxygen-containing polar groups and double bonds under VUV photooxidation in the presence of air or under VUV irradiation in vacuum. Scanning electron microscopy revealed the development of regular structure with the period about 1 microm on the surface of LDPE and HDPE during VUV photooxidation. The correlation between amount of tightly adsorbed albumin and surface concentration of carboxyl groups generated by VUV irradiation was found. The aging effect for protein adsorption during long storage of VUV irradiated samples in air or phosphate-buffered saline (PBS) was studied. The obtained results prove the VUV irradiation provides a high potential to regulate protein adsorption on polymers for biomedical applications.
The activation of the complement system by polymer materials and their blood compatibility. One of the negative effects of the clinical application of various blood-containing biomedical devices is the activation of the complement system induced by a foreign surface. A method of determining the hemolytic activity of human serum complement before and after contact with polymers was chosen in order to elucidate the relationship between polymer surface types and the degree of complement activation. The complement activation of each donor proved to depend both on his own complement reactivity and the type of polymer surface. The role played by each constituent was estimated using the rate constants for spontaneous (ksp) and induced (kind) complement activation. The negative correlation (-0,88, p less than 0,001) between the degree of irreversible adsorption of 131I-serum albumin and relative kind was determined. Thus, we propose the use of kind for the criterion of conformational alterations of protein macromolecules induced by the adsorption/desorption processes on blood/surface interface, leading to complement activation.
Abstract:In experiments in vivo using diffusion chambers, the morphology and composition of calcium-containing deposits on natural and artificial biomaterials that had no direct contact with cells were studied using scanning electron microscopy with energy dispersion X-ray microanalysis. It was revealed that the formation of a protein layer containing protein-calcium complexes is the key event in biomaterial calcification. A mechanism of formation of a calciumcontaining protein matrix that creates the conditions for supersaturation of the crystal-forming medium over critical value has been proposed. The formation of nuclei of insoluble calcium phosphate starts predominantly deep in an adsorbed protein layer enriched by calcium ions.
Introduction. The widespread use of immunomodulators in medical practice contributes to the development of their new dosage forms.Aim. The aim of this work is to develop a transdermal therapeutic system (TTS) Galavit® and to study a diffusion of the drug from it through the Strat-M membrane in vitro.Materials and methods. The medicinal substance was Galavit® in the form of a powder for the preparation of a solution for intramuscular administration («SELVIM», Russia). Saline solution, sodium dodecyl sulfate, apricot kernel oil, Decaglyn PR-20 and others were used as excipients. Heidolph DIAX900 dispersant (Germany) and ultrasonic homogenizer Heilscher UIS250V (Germany) were used to make the emulsion compositions. The delamination time and particle size of emulsion compositions were determined using the LUMiSizer dispersion analyzer (LUM, Germany). Diffusion studies of Galavit® from TTS through the Strat-M membrane (25 mm in diameter, Merck Millipore) were carried out on the Copley diffusion analyzer (UK). Quantitative determination of Galavit® was performed by spectrophotometry (UV-2600 Shimadzu, Japan) in the wavelength range 294–298 nm in model media.Results and discussion. The characteristic parameters of emulsion compositions were determined during the study: the particle size varied from 0.1 to 2 µm, the delamination time – from 9 to 95 min depending on the composition. The maximum yield of the drug from the TTS was 30 % through the membrane.Conclusion. The possibility of transdermal transfer of Galavit® from TTS is shown in model experiments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.