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Drug Loading Capacity (drug + loading_capacity)
Selected AbstractsHollow Mesoporous Zirconia Nanocapsules for Drug DeliveryADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Shaoheng Tang Abstract Hollow mesoporous zirconia nanocapsules (hm -ZrO2) with a hollow core/porous shell structure are demonstrated as effective vehicles for anti-cancer drug delivery. While the highly porous feature of the shell allows the drug, doxorubicin(DOX), to easily pass through between the inner void space and surrounding environment of the particles, the void space in the core endows the nanocapsules with high drug loading capacity. The larger the inner hollow diameter, the higher their DOX loading capacity. A loading of 102% related to the weight of hm -ZrO2 is achieved by the nanocapsules with an inner diameter of 385,nm. Due to their pH-dependent charge nature, hm -ZrO2 loaded DOX exhibit pH-dependent drug releasing kinetics. A lower pH offers a faster DOX release rate from hm -ZrO2. Such a property makes the loaded DOX easily release from the nanocapsules when up-taken by living cells. Although the flow cytometry reveals more uptake of hm -ZrO2 particles by normal cells, hm -ZrO2 loaded DOX release more drugs in cancer cells than in normal cells, leading to more cytotoxicity toward tumor cells and less cytotoxicity to healthy cells than free DOX. [source] Fabrication and Drug Delivery of Ultrathin Mesoporous Bioactive Glass Hollow FibersADVANCED FUNCTIONAL MATERIALS, Issue 9 2010Youliang Hong Abstract Ultrathin mesoporous bioactive glass hollow fibers (MBGHFs) fabricated using an electrospinning technique and combined with a phase-separation-induced agent, poly(ethylene oxide) (PEO), are described. The rapid solvent evaporation during electrospinning and the PEO-induced phase separation process demonstrated play vital roles in the formation of ultrathin bioactive glass fibers with hollow cores and mesoporous walls. Immersing the MBGHFs in simulated body fluid rapidly results in the development of a layer of enamel-like apatite mesocrystals at the fiber surfaces and apatite nanocrystals inside the hollow cores. Drug loading and release experiments indicate that the drug loading capacity and drug release behavior of the MBGHFs strongly depends on the fiber length. MBGHFs with fiber length >50,µm can become excellent carriers for drug delivery. The shortening of the fiber length reduces drug loading amounts and accelerates drug release. The MBGHFs reported here with sophisticated structure, high bioactivity, and good drug delivery capability can be a promising scaffold for hard tissue repair and wound healing when organized into 3D macroporous membranes. [source] The Influence of Pendant Hydroxyl Groups on Enzymatic Degradation and Drug Delivery of Amphiphilic Poly[glycidol- block -(, -caprolactone)] CopolymersMACROMOLECULAR BIOSCIENCE, Issue 11 2009Jing Mao Abstract An amphiphilic diblock copolymer PG- b -PCL with well-controlled structure and pendant hydroxyl groups along hydrophilic block was synthesized by sequential anionic ring-opening polymerization. The micellization and drug release of PG- b -PCL copolymers using pyrene as a fluorescence probe were investigated for determining the influences of copolymer composition and lipase concentration on drug loading capacity and controlled release behavior. The biodegradation of PG- b -PCL copolymers was studied with microspheres as research samples. It has been concluded that the polar hydroxyl groups along each repeat unit of hydrophilic PG block in PG- b -PCL copolymer have great influences on drug encapsulation, drug release, and enzymatic degradation of micelles and microspheres. [source] Mathematics-aided quantitative analysis of diffusion characteristics of pHEMA sponge hydrogelsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2007X. Lou Abstract This study reports the current progress in quantitative analysis of the release characteristics of pHEMA spongy hydrogels using prednisolone 21-hemisuccinate sodium salt as a model drug. Extraction of effective diffusion coefficients of the drug from various pHEMA matrices was made using a novel mathematical model that handles both boundary layer and initial burst effects. Drug loading level and entrapment efficiency were also determined. The computed diffusion coefficients and the drug loading capacity in relation to the device porous structure and drug concentration of the loading solution, as well as the size of device are discussed. Mathematical modelling proves to be a powerful tool not only for establishing and interpreting structure and performance relationships but also for handling experimental ambiguity. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Formulation and evaluation of chitosan microspheres of aceclofenac for colon-targeted drug deliveryBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2010S. K. Umadevi Abstract The objective of this investigation was to develop novel colon specific drug delivery. Aceclofenac, a NSAID, was successfully encapsulated into chitosan microspheres. Various formulations were prepared by varying the ratio of chitosan, span-85 and stirring speed and the amount of glutaraldehyde. The SEM study showed that microspheres have smooth surfaces. Microspheres were characterised by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) to confirm the absence of chemical interactions between drug and polymer and to know the formation of microspheres structure. The microspheres were evaluated for particle size, encapsulation efficiency, drug loading capacity, mucoadhesion studies, stability studies, in vitro and in vivo drug release studies. Particle sizes, as measured by the laser light scattering technique, were of an average size in the range 41,80,µm. The swelling index was in the range 0.37,0.82 and the entrapment efficiency range was 51,75% for all the formulations. The optimised batch ACM13 released 83.6% at 8,h and 104% at 24,h in SCF containing rat caecal content. Eudragit coated chitosan microspheres prevented the release of the aceclofenac in the physiological environment of the stomach and small intestine and released 95.9±0.34% in the colon. With regard to release kinetics, the data were best fitted with the Higuchi model and showed zero order release with non-Fickian diffusion mechanism. The in vivo findings suggest that aceclofenac microspheres exhibit a prolonged effect of aceclofenac in rats and produce a significant anti-inflammatory effect. The findings of the present study conclusively state that chitosan microspheres are promising for colon targeting of aceclofenac to synchronise with chronobiological symptoms of rheumatoid arthritis. Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||