RESUMO
Objective The fat-soluble artemisinin (Art), which is poorly soluble in water, was loaded with porous starch to form Art microspheres, and its physical and chemical properties were better than the original powder, so as to improve the water solubility of Art. Methods The porous starch particles were loaded on Art powder by physical adsorption method. The physical and chemical properties of Art microspheres loaded with porous starch were characterized and analyzed by SEM, BET, FTIR, XRD, DSC, and TG respectively. The saturated solubilities of porous starch loaded Art microspheres in water, artificial gastric juice and artificial intestinal fluid were determined. Results In the characterization test, we found that under the optimal preparation conditions, porous starch had successfully loaded Art to form microspheres with drug loading of (20.37 ± 0.61)% and entrapment efficiency of (81.86 ± 3.06)%. In the process of loading Art with porous starch, only physical changes happened. The original Art powder had been completely loaded by porous starch, showing that it had the same amorphous structure as porous starch, thus improving the water solubility of the original Art powder. The saturated solubility of the porous starch loaded Art microspheres was significantly improved, and the water, artificial gastric juice and artificial intestinal fluid were 3.77, 1.64, and 1.72 times higher than the original Art powder, respectively. Conclusion This paper significantly improved the water solubility of Art powder and provided important research basis for solving the clinical application of insoluble drugs.
RESUMO
PURPOSE: The aim of this study was to evaluate the stability of arginine-glycine-aspartic acid (RGD) peptide coatings on implants by measuring the amount of peptide remaining after installation. MATERIALS AND METHODS: Fluorescent isothiocyanate (FITC)-fixed RGD peptide was coated onto anodized titanium implants (width 4 mm, length 10 mm) using a physical adsorption method (P) or a chemical grafting method (C). Solid Rigid Polyurethane Foam (SRPF) was classified as either hard bone (H) or soft bone (S) according to its density. Two pieces of artificial bone were fixed in a customized jig, and coated implants were installed at the center of the boundary between two pieces of artificial bone. The test groups were classified as: P-H, P-S, C-H, or C-S. After each installation, implants were removed from the SRPF, and the residual amounts and rates of RGD peptide in implants were measured by fluorescence spectrometry. The Kruskal-Wallis test was used for the statistical analysis (alpha=0.05). RESULTS: Peptide-coating was identified by fluorescence microscopy and XPS. Total coating amount was higher for physical adsorption than chemical grafting. The residual rate of peptide was significantly larger in the P-S group than in the other three groups (P<.05). CONCLUSION: The result of this study suggests that coating doses depend on coating method. Residual amounts of RGD peptide were greater for the physical adsorption method than the chemical grafting method.
Assuntos
Adsorção , Implantes Dentários , Isotiocianatos , Microscopia de Fluorescência , Oligopeptídeos , Poliuretanos , Espectrometria de Fluorescência , Titânio , TransplantesRESUMO
Se preparan carbones activados por pirólisis de cáscara de naranja, residuos lignocelulósicos, por activación química mediante impregnación con soluciones de ácido fosfórico a diferentes concentraciones (32 %, 36 %, 40 % y 48 % p/V), a una temperatura de 373 K y un tiempo de residencia de 3 h, presentando rendimientos alrededor del 36 %. La caracterización de la textura porosa de los carbones activados obtenidos se determina por adsorción física de N2 a 77 K. El análisis isotérmico muestra para los carbones materiales activados obtenidos áreas superficiales entre 940 y 1200 m²g-1 con características de materiales mesoporosos. El estudio mediante técnicas de equilibrio como las titulaciones tipo Boehm y la determinación del fósforo residual, así como técnicas espectroscópicas como el infrarrojo (IR) permiten observar cómo la variación en la concentración del agente activante muestra una influencia sobre la química superficial del material carbonoso a obtener.
Activated carbons are prepared by pyrolysis of orange peel, lignocellulosic wastes by chemical activation by impregnation with phosphoric acid at different concentrations (32 %, 36 %, 40 % and 48 % w/V), at a temperature of 373 K and a time residence of 3 h, showing about 36 % yield. The characterization of the porous texture of the activated carbons obtained is determined by physical adsorption of N2 at 77 K, the isothermal analysis sample to the activated carbons obtained surface areas between 940 and 1200 m2g-1 with characteristics of mesoporous materials. The study by equilibrium techniques such as: the titrations type Boehm and determination of residual phosphorus, and spectroscopic techniques such as infrared (IR) can observe how variation in the concentration of activating agent shows an influence on surface chemistry of the carbonaceous material to obtain.
Carbonos ativados foram preparados a partir da pirólise de casca de laranja, resíduos lignocelulósicos, por activação química mediante impregnação com soluções de ácido fosfórico em diferentes concentrações (32 %, 36 %, 40 % e 48 % p/V), a uma temperatura de 373 K e um tempo de residência de 3 h, mostrando cerca de 36 % de rendimento. A caracterização porosa textural dos carbonos ativados obtidos foi determinada por adsorção física de N2 a 77 K, e a análise isotérmica apresenta para os materiais obtidos, áreas superfíciais entre 940 e 1200 m²g-1 caracterizando materiais mesoporosos. A partir de estudos por meio de técnicas de equilíbrio, tais como titulações tipo Boehm e determinação de fósforo residual, e técnicas espectroscópicas tais como infravermelho (IR) puderam-se observar como a variação na concentração de agente de ativação apresenta uma influência sobre a química superfícial do material carbonoso obtido.