Papers by Keyword: Drug Release

Abstract: Wound healing is accompanied by keloids, it is important to develop a wound dressing which can inhibit keloid and relieve pain and pruritus in patients. In this paper, bacterial cellulose/triamcinolone acetonide (BC/TA) composites are prepared by easy solution impregnation method, which the structures of BC/TA composites were analyzed by fourier transform infrared spectroscopy (FTIR). The drug release and inhibition of L929 cells were also analyzed. It can be concluded that BC/TA composites have a sustained release effect on TA and can effectively inhibit proliferation of L929 in the range of 0.5-2.0 mg/cm².

Abstract: Lactide (LA) and PEG as raw materials, 2,2-Dimethylol Propionic Acid (DMPA) as initiator, hexamethylene diisocyanate (HDI) as coupling agent, amphiphilic block copolymer PLA-PEG with side carboxyl group was synthesized. A novel PLA-PEG-PTX pro-drug was prepared through the esterification reaction between the side carboxyl group on copolymer and hydroxyl group on paclitaxel. Its structure was characterized with ¹H-NMR and FT-IR. The pro-drug micelles were prepared by solvent evaporation method. The particle size of the micelles was determined by nanoparticle tracking analyzer, the micro structure of the micelles was determined by TEM, and the drug release properties were investigated by dialysis experiments. Results showed that the pro-drug micelles are spherical with core-corona structure and major particles size in 55-85nm. The PLA-PEG750-PTX (molar ratio of LA to DMPA as 40 to 1) pro-drug micelles released paclitaxel slowly and steadily without obvious burst release in buffer solution with pH=7.0, and its cumulative release rate reached to 36% in 10 hours. PLA-PEG750-PTX pro-drug micelles have a certain sustained-release effect, which is beneficial to improve the anti-tumor effect of paclitaxel.

Abstract: Hyperthermia is a promising cancer therapy due to its minimally-invasive procedure, and the cancer therapeutic efficacy can be improved by magnetic hyperthermia combined with pharamacotherapy. Iron oxide (IO) nanoparticle is a popular medium for hyperthermia treatment, and hydroxyapatite (HA) has been widely used for bone filling and augmentation. IO nanoparticle embedded on hydroxyapatite (HAIO) was synthesized through co-precipitation method, and chitosan or poly (N-isopropylacrylamide) (PNIPAAM) were coated on the HAIO with calcium alginate to form the spheres (Chitosan coated HAIO and PNIPAAM coated HAIO). HAIO, Chitosan coated HAIO and PNIPAAM coated HAIO were used as carriers of 5-fluorouracil (5-FU), one of the drugs for cancer chemical therapy, and the 5-FU release behavior in PBS solution was investigate at ambient and elevated temperatures. The amount of the released 5-FU from the HAIO, Chitosan coated HAIO and PNIPAAM coated HAIO are almost the same at ambient temperature. But at elevated temperature, that from Chitosan coated HAIO was reduced while that from the PNIPAAM coated HAIO was increased.

Abstract: Lipid implants have been attracting attention in recent years. However, to better understand these systems, more fundamental studies are required. The objective of this work was to evaluate the effect of some formulation parameters, namely lipid and drug type, implant shape/surface area and lipid blend ratio, on drug release rate. The developed implants were cylindrical or spherical in shape with an even surface. Caffeine release from glycerol-trimyristate implant was very fast when compared with glycerol-tristerate matrix. The latter allowed a 4 month controlled release in contrast with glycerol-trimyristate matrix (~ 5 days). Caffeine and theophylline presented similar release rates, despite their different aqueous solubilities. In addition, different lipid blend ratios provided different release profiles for caffeine.

Abstract: The objective of this study was to develop and evaluate curcuminoids effervescent floating tablet. The system consists of a curcuminoids-containing core tablet coated with a gas forming layer (tartaric acid layer and sodium bicarbonate layer divided by a protective layer (hydroxypropyl methylcellulose)) and a gas-entrapped membrane (Eudragit^® RL 30D), respectively. The floating tablets using lactose as a filler showed higher drug release than those using microcrystalline cellulose (MCC) or MCC:lactose as a filler. However, type of core tablet fillers did not affect time to float of the floating tablets in 0.1 N HCl. Increasing amount of gas forming agent reduced time to float and increased drug release from the floating tablets. The floating tablets showed good floating properties in 0.1 N HCl, however, curcuminoids released was very slow. Addition of surfactant (1%w/v sodium lauryl sulfate (SLS)) in 0.1 N HCl could improve drug release of the floating tablets but it increased time to float and caused the floating tablet ruptured. The floating properties and drug release from curcuminoids effervescent floating tablets seemed to depend on formulation variables. The higher coating level or another type of gas-entrapped membrane may be need for further study.

Abstract: The aim of the present study was the in vitro investigation of a synthetic bone graft substitute loaded with individual antibiotics for the treatment of osteomyelitis and infectious bone disease. The elution of gentamicin, an aminoglycoside antibiotic, from the NanoBone^® products NanoBone^® S granules (NBG) and lyophilized NanoBone^® (NBP) putty was tested over a period of one week. An indirect photometrically-based detection system was used to measure the released antibiotic concentration. Both materials showed very different release behaviour. After one day lyophilized NanoBone^® putty delivered 100% of the gentamicin value, whereas NanoBone^® S granules released one-fifth of the used gentamicin level.

Abstract: A novel and facile process called “alternative loop immersion method” formed bioactive and biocompatible Zn-doped calcium silicate coating over the drug-loaded titania nanotube arrays to improve the properties of drug release. The samples were characterized by scanning electronic microscope (SEM), x-ray diffraction (XRD) and fourier transform infrared (FT-IR). The results show that TNTs modified by Zn-doped calcium silicate coating possess improved drug release characteristics with reduced burst release (from 83% to 66%) and prolonged drug release (from 11 days to over 15 days). This approach provides an alternative to tailor the surface of TNTs and offer considerable propects for diverse biomedical applications.

Abstract: For the purpose of drug carrier and delivery, the polylactide was modified by polyethylene glycol blending with the weight percentage of 80/20 by two methods: solvent-casting and melt-compounding. Characterizations of X-ray diffraction, Scanning Electron Microscope and degradation experiments have been done to study the crystallization, miscibility and degradation behavior. The melt-compounding provides a better miscibility associated with longer degradation time, however the heating procedure effects the polymers. Because of the heating and cooling cycle, the polymers had an opportunity to crystalize and the crystal peak can be seen in the XRD results. While the solvent-casting avoids the high temperature experience of blend with an amorphous state, and provides lower miscibility and short degradation time. These significant features will be considerable factors in drug carrier design.

Abstract: In this paper, we reported a facile strategy to synthesize hyaluronic acid (HA) conjugated porous silica nanoparticles (pSiO₂) as drug carrier. The pSiO₂ were prepared by solid nano-silica nanoparticles with “surface-protected etching”. Morphologies of solid and porous silica nanoparticles were characterized by SEM and TEM. Amino groups were introduced on pSiO₂ to graft HA as cancer targeting ligand. Then rifampicin used as model drug was loaded in pSiO₂-HA. The results indicate that pSiO₂ can perform a certain degree of slow release. Overall, the system might open the door to a new generation of carrier system for site-selective, controlled-release delivery of anticancer drugs.

Abstract: The octane-succinyl-chitosan (C₈-SCCHS) was synthesized by modifying chitosan (CHS) , characterized by IR, ¹H NMR, WAXD and octane-succinyl-chitosan/polyethylene glycol (C₈-SCCHS)/PEG interpenetrating polymer network (IPN) hydrogel was prepared by croslinking of C₈-SCCHS and PEG. The swelling behaviors of hydrogels in different pH solutions have been studied. The pH sensibility were researched. Micromorphology of the external surface of the hydrogels were imaged by scanning electron microscopy (SEM). Aciclovir as a model drug to study the performance of their release. The results show that the gels have porous cross-linked network structure, which is beneficial to absorbing water or drug, and have ability of controlled release for aciclovir.