جستجوی مقالات مرتبط با کلیدواژه "controlled release" در نشریات گروه "فنی و مهندسی"

Today, the most common method for wound treatment is to use engineered wound dressings. In the present study, a film wound dressing based on xanthan biopolymer, containing niosomal nanocarrier, was prepared for the local release of spirulina algae extract. Niosomal nanocarriers containing the spirulina extract were prepared using thin film hydration method. Then, a film wound dressing was produced by uniformly combining xanthan, glycerol emollient, and niosomes containing spirulina. According to scanning electron microscopy, the morphology of the niosomes were spherical with an average size of about 200 nm, and the percentage of drug loading within the niosomes was 72%. Moreover, 25% of the drug was released from the structure of the film containing niosomes within 20 days. Additionally, the wound dressing containing niosomes exhibited a 35% weight loss within 20 days. Through cytotoxicity testing conducted within 24 hours, it was revealed that up to a concentration of 200 μg/ml of the spirulina drug, cell viability remained higher than 80% compared to the control sample. In summary, the results of this study indicate that the niosomal carrier within the xanthan film structure could serve as an effective local drug delivery system for wound treatment.

Surface modification with biomolecules can overcome Graphene Oxide (GO) restrictions in biocompatibility, cellular internalization, and drug delivery effectiveness, hence  suitable for a wide range of biomedical applications. In this study, a biocomposite (L-glutamine-functionalized magnetic graphene oxide (L-Gln/MGO)) was prepared and used as a suitable nanoscale carrier with high drug loading capacity and excellent release properties for 5-fuorouracil (5FU), an anticancer drug. The optimum pH for maximum drug adsorption was determined as 4 at 293 K and as the temperature increased, the adsorption capacity decreased due to the exothermic nature of the adsorption process. Some well-known models, including pseudo-first-order, pseudo-second-order, and Intraparticular Diffusion (IPD), were applied to examine the kinetics of adsorption. Additionally, the Langmuir, Freundlich, and Redlich-Peterson models were used to investigate the adsorption isotherms. The obtained results showed that the adsorption process adhered to the Langmuir isotherm and pseudo-second-order kinetic models. Nearly 26% of 5FU was released in the simulated stomach fluid at the pH of 1.2 and temperature of 37 °C in the first 30 minutes while 32% of which was released in the simulated intestinal fluid at the pH of 7.4 during the next 30 hours. The obtained results might be helpful for designing a controllable loading and targeted 5FU drug delivery system.

In recent years, dendrimers as a new class of polymeric materials have attracted lots of attention due to their unique properties, especially as drug delivery systems. In this process, dendrimers can deliver medicine directly to the affected part of the patient's body. Dendrimers can be defined as macromolecular structures with several advantages, which may undergo changes depending on the chemical nature of the drug to be delivered. Dendrimers can be defined as macromolecular structures with several advantages that depending on the chemical nature of the drug to be delivered, they may change. The reason for the high attention paid to dendrimers in drug delivery is that they have properties such as uniform size, water solubility, modifiable surface performance, high degree of branching, being multivalent, well-defined molecular weight, and available internal cavities. In addition, the high level of control over dendritic architecture distinguishes them as ideal carriers. Also, the use of dendrimers in biomedicine has attracted the attention of many scientists. Biomedicine is one of the main fields of study of dendrimers due to their capacity to improve solubility, uptake, bioavailability and targeted distribution, and their value in diagnosis and treatment. In the last decade, anti-neoplastic research on dendrimers has been widely developed and several types of poly amidoamine (PAMAM) and poly propylene imine (PPI) dendrimer complexes with doxorubicin, paclitaxel, cisplatin, melphalan, and methotrexate have been improved compared to the drug molecule alone.

Silymarin (SM) is a flavonoid mixture that has been extensively studied owing to its proven anti-diabetic effects. In the present study SM-loaded gum tragacanth-whey protein isolate cryo- and xerogels were prepared and their physico-chemical, textural, mechanical and microstructural properties were analyzed by Fourier transform infrared spectroscopy (FTIR), texture analyzer, N2 adsorption-desorption technique and scanning electron microscopy. Moreover, swelling rate of gels and their SM release profile were investigated in acidic and basic conditions. The results indicated that cryogels were highly porous incorporating a network of interconnected open pores. In contrary, xerogels microstructure was quite compacted with internal closed and isolated pores. The addition of gum tragacanth markedly improved physic-chemical, textural, mechanical and morphological properties of the gels, while silymarin increased porosity and weakened the mechanical strength and morphological characteristics of the gel networks. SM loading also decreased the swelling ratio of gels. These macroscopic changes were linked to molecular interactions amongst gum tragacanth, whey protein isolate and silymarin as confirmed by FTIR spectra. The results of release measurements revealed that cryogels lost 80% of their silymarin content during exposure to acidic and basic condition, but xerogels strongly retained it within their matrix and underwent only a 30% loss. Both types of gels showed the highest release rate in phosphate buffer solution compared to acidic pH. Data fitting with release kinetics models indicated that the dissolution mechanism was controlled by Korsmeyer-Peppas model.

In this study, the synthesis of nano-porous calcium magnesium silicate was performed and studied to improve drug properties and drug release. This synthesis was carried out by using the tetraethyl ortho silicate precursor (TEOS) and the Cetyltrimethyl ammonium bromide surfactant (CTAB) in a sol-gel alkaline environment; and the product was heat treated at 600° C and 800° C temperatures. The purpose of this study is to investigate the effect of the calcination temperature on the potential for ibuprofen release by the production produced compound. The product was studied using X-ray diffraction patterns (XRD), Nitrogen adsorption / desorption, Fourier-transform infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV) and Transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). The results of Nitrogen absorption-desorption assay showed a surface area of 42-140 m2 /g The drug release after 240 hours showed that the calcite sample had a lower release at 600 ° C, temperature that which was is due to the smaller size of the cavities and the more surface area, as compared tothan the other specimens. Also, calcium and magnesium elements increased the loading capacity, and createcreating a suitable substrate for for the slower drug release. Overall, This this study showed that nano-porous magnesium silicate calcium has had the ability to load and release the ibuprofen and can could be, therefore, used as a modern drug delivery system in the bone tissue engineering field.

In this study the stability and release of microencapsulated fish oil prepared by different wall materials (fish gelatin, κ -carrageenan and fish gelatin+ κ carrageenan), physical and chemical methods (coacervation, spray drying and freeze drying) were examined. In-vitro controlled release of the microcapsules and peroxide (PV); ρ-Anisidine values during 10 days storage at accelerated conditions (45 °C) were investigated. The results of solubility of protein powders and oxidative stability showed that fish gelatin was the best wall material and coacervation was the best method to encapsulation of fish oil. These powders had higher solubility and lower PV, p-AV than the other treatments. The highest and lowest core releases were observed by coacervation method (93.16 and 80 %). At spray and freeze drying methods, gelatin had more release than the other wall materials. Comparison of the different methods and wall materials confirmed that combination of matrices, drying methods are effective on physical characteristics and oxidative stability of encapsulated fish oil.

Hypothesis: Core-shell nano-fibrous structures obtained from biodegradable and biocompatible polymers such as silk fibroin (SF) have potential applications in drug delivery and tissue engineering. In this work, coaxial electrospinning of silk fibroin as shell and salicylic acid (SA)/polyvinyl alcohol (PVA) blends as core was studied to fabricate core-shell nano-fibrous structures.
Silk fibroin was extracted from cocoon and dissolved in formic acid. An assembled coaxial nozzle was used to fabricate core-shell nanofibers of SF as shell and PVA/salicylic acid as core components, respectively.
Findings: Effects of variation in viscosity and electrical conductivity of the electrospinning solutions on the final nanofibers morphology, diameters and SA release behaviors were studied using Fourier transforms infrared spectroscopy (FTIR), viscometry, electrical conductometry, ultraviolet spectrophotometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Finally, a suitable model for release behaviors of the fabricated core-shell nanofibers was suggested. It was found that the final diameter of fabricated core-shell nanofibers varied from 110 (±22) to 250 (±71) nm and diameter of the core section varied from 40 to 80 nm. The experimental results showed that the shell solution concentration had a significant effect on the final core-shell nanofiber diameter, but increase in the core solution concentration had an insignificant effect on the final nanofibers diameter. It was concluded that the core solution concentration was not the only effective parameter in determining the final diameters of electrospun nanofibers, and the viscosities of shell and core solutions and their electrical conductivities were just as important parameters. According to the results of release profiles, the ratio of the components in core and shell was the effective parameter affecting the profiles of SA released from these structures. The higher PVA concentration in the core increased both the amount of SA and its release rate from fabricated core-shell nanofibers.

In order to control microbial growth in foods and improve their shelf-life and safety، the actions of different antimicrobial agents were studied by mixing them with food formulations، or they were applied onto food surface by spraying. Incorporation of antimicrobial agents directly into food is appropriate when there is a risk of microbial growth at both surface and internal parts of final food products. However، when the main cause of spoilage of food is microbial growth at its surface، the use of excessive amounts of chemical additives into food would be necessary. Thus، this traditional strategy does not fit into the current trend of food technology to develop healthier processed foods by using minimum amounts of chemical additives. The use of polymers as packaging materials containing antimicrobial agents is an alternative to overcome these limitations. Antimicrobial food packaging is based on controlled release of antimicrobial agents on packed food surfaces to maintain a predetermined concentration of the active compound for a determined period of time to reduce، inhibit or retard the growth of pathogenic microorganisms. In this article، different types of food packaging with controlled release properties of antimicrobial agents are studied and some mathematical models are presented to describe the release kinetics of active compound.

In this study, Silica nanoparticles with the size of 50 to 80 nm with were synthesized using a Sol-gel method and different amounts of Lanthanum Nitrate hexahydrate formed during the reaction of the particles, was added to the material. To examine the ability of these Nanostructures in a controlled release of drug such as Lanthanide, SBF (Simulated Body Fluid) was prepared and the release of Lanthanide 10 minute intervals for 48 hours was investigated and released Lanthanide concentration was evaluated by ICP (Inductively Coupled Plasma). According to the results of ICP, loaded Lanthanide was not released from the silica network. Loaded Lanthanides in the mesoporous can be used in radiotherapy, especially in cases of liver cancer.

Layered double hydroxides (LDHs) are layered solid materials having positively charged layers. A variety of negatively charged biomolecules can be hybridized with LDHs to evolve into bio-LDH Nano hybrids, including vitamins, drugs and DNA strands as well as simple organic acids. In this research, Mg-Al-LDH containing drug was synthesized by coprecipitation and anion exchange methods. The LDH structure was characterized by X-Ray Diffraction XRD, FTIR, SEM and STA techniques. The in vitro release profile of nano hybrids was analyzed by UV spectrophotometer. It was concluded that the present biocompatible hydrotalcite-like compound can be an excellent host material for encapsulating Ibuprofen and can play a role as a delivery vehicle for a controlled release.

Polyurethane micro spheres have been synthesized by solvent evaporation technique with castor oil, Polycaprolacton (PCL), Hexamethylen diisocyanate (HMDI) and Ethyl diamine (ED) as carriers for controlled drug delivery systems. Release behavior of micro spheres has been investigated using Bromocresol purple die. Fourier transmission infrared (FTIR), Scanning Electron Microscope (SEM), Optical microscope, dissolution instrument and UV spectrophotometer were used to investigate the polymerization process, surface morphology, particle size, rate of release and calibration curve respectively. Results showed that urethane bonds were formed at 3300-3400cm-1 and 1650-1700 cm-1. SEM micrographs showed surface irregularities as a result of solvent evaporation. Particle sizes were higher for castor oil/HMDI rather than PCL/HMDI microbe ads and in both cases, particle size and Bromocresol purple die release increased with rising NCO/OH ratio.