Embedding of the well-known coronary therapeuticum nifedipine into a modified silica matrix by the sol-gel technique allows its releasing behavior to be controlled to a high degree. The liberation rate is proportional to temperature and is increased by the addition of penetration agents such as sorbitol, but is inversely proportional to particle size and is decreased by modification of the silica matrix with methyl-triethoxysilane or polyethylene-glycol. It is presumed that the drug is dispersed in the gel matrix and that diffusion occurs through solvent-filled capillary channels. The liberation rate is governed by the relationship between the rates of dissolution and diffusion. 相似文献
Diabetes mellitus (DM) is the most prevalent non‐contagious disease, which has affected a large number of people all over the world. Among all treatments known to have a positive influence in the control of DM, insulin therapy is the most common and effective one. Nowadays, various methods of insulin delivery are under investigation, which are able to reach a plausible bioavailability with ignorable side effects instead of insulin injection. This article presents a comprehensive review of the insulin therapy approach with a focus on modified methods in insulin delivery strategies and current advances in engineered insulin delivery systems. 相似文献
Sericin removal from the core fibroin protein of silkworm silk is a critical first step in the use of silk for biomaterial‐related applications, but degumming can affect silk biomaterial properties, including molecular weight, viscosity, diffusivity and degradation behavior. Increasing the degumming time (10, 30, 60, and 90 min) decreases the average molecular weight of silk protein in solution, silk solution viscosity, and silk film glass‐transition temperature, and increases the rate of degradation of a silk film by protease. Model compounds spanning a range of physical‐chemical properties generally show an inverse relationship between degumming time and release rate through a varied degumming time silk coating. Degumming provides a useful control point to manipulate silk's material properties.
New strategies to efficiently treat bacterial infections are crucial to circumvent the increase of resistant strains and to mitigate side effects during treatment. Skin and soft tissue infections represent one of the areas suffering the most from these resistant strains. We developed a new drug delivery system composed of the green algae, Chlamydomonas reinhardtii, which is generally recognized as safe, to target specifically skin diseases. A two-step functionalization strategy was used to chemically modify the algae with the antibiotic vancomycin. Chlamydomonas reinhardtii was found to mask vancomycin and the insertion of a photocleavable linker was used for the release of the antibiotic. This living drug carrier was evaluated in presence of Bacillus subtilis and, only upon UVA1-mediated release, growth inhibition of bacteria was observed. These results represent one of the first examples of a living organism used as a drug delivery system for the release of an antibiotic by UVA1-irradiation. 相似文献
The intracellular survival of pathogenic bacteria requires a range of survival strategies and virulence factors. These infections are a significant clinical challenge, wherein treatment frequently fails because of poor antibiotic penetration, stability, and retention in host cells. Drug delivery systems (DDSs) are promising tools to overcome these shortcomings and enhance the efficacy of antibiotic therapy. In this review, the classification and the mechanisms of intracellular bacterial persistence are elaborated. Furthermore, the systematic design strategies applied to DDSs to eliminate intracellular bacteria are also described, and the strategies used for internalization, intracellular activation, bacterial targeting, and immune enhancement are highlighted. Finally, this overview provides guidance for constructing functionalized DDSs to effectively eliminate intracellular bacteria. 相似文献
C?H bond activation of 2‐methoxyethylamino‐bis(phenolate)‐yttrium catalysts allowed the synthesis of BAB block copolymers comprised of 2‐vinylpyridine (2VP; monomer A) and diethylvinylphosphonate (DEVP; monomer B) as the A and B blocks, respectively, by rare‐earth‐metal‐mediated group‐transfer polymerization (REM‐GTP). The inherent multi‐stimuli‐responsive character and drug‐loading and ‐release capabilities were observed to be dependent on the chain length and monomer ratios. Cytotoxicity assays revealed the biocompatibility and nontoxic nature of the obtained micelles toward ovarian cancer (HeLa) cells. The BAB block copolymers effectively encapsulated, transported, and released doxorubicin (DOX) within HeLa cells. REM‐GTP enables access to previously unattainable vinylphosphonate copolymer structures, and thereby unlocks their full potential as nanocarriers for stimuli‐responsive drug delivery in HeLa cells. The self‐evident consequence is the application of these new micelles as potent drug‐delivery vehicles with reduced side effects in future cancer therapies. 相似文献
Novel carboxymethyl chitosan (O-CMCS) microspheres containing an anti-tumor drug chelerythrine (CHE) have been successfully prepared by an emulsion crosslinking method using glutaraldehyde. The optimized microsphere formulation was characterized for particle size, shape, morphology, crystallinity and in vitro drug release. Results for mean particle size, drug loading content, entrapment efficiency and in vitro drug release of chelerythrine loaded microspheres were found to be 12.18 μm, 4.08%, 54.78% and 35.30% at pH 7.4 in 20 h, respectively. The optimized microspheres had an imperfect crystalline lattice and a spherical, rough morphology and the CHE release from O-CMCS microspheres followed the Higuchi matrix model. All these results suggested that O-CMCS microspheres are a promising carrier system for controlled drug delivery. 相似文献
This review describes the role of contact lenses as an innovative drug delivery system in treating eye diseases. Current ophthalmic drug delivery systems are inadequate, particularly eye drops, which allow about 95% of the active substance to be lost through tear drainage. According to the literature, many interdisciplinary studies have been carried out on the ability of contact lenses to increase the penetration of topical therapeutic agents. Contact lenses limit drug loss by releasing the medicine into two layers of tears on either side of the contact lens, eventually extending the time of contact with the ocular surface. Thanks to weighted soft contact lenses, a continuous release of the drug over an extended period is possible. This article reviewed the various techniques to deliver medications through contact lenses, examining their advantages and disadvantages. In addition, the potential of drug delivery systems based on contact lenses has been extensively studied. 相似文献
Abstract We demonstrate, and review the very small, but growing body of literature regarding a recently discovered application of layered compounds, which involves the ability of layered materials to sequester and later release molecules of chemical and biological significance. The application relies upon intercalation chemistry; a reversible process whereby atoms, molecules, macromolecules, and polymers may be inserted into the interstices of a layered matrix. We demonstrate that layered materials are able to effectively getter water‐soluble atoms and molecules from aqueous dispersions, and further demonstrate that the absorbed molecules can be later released from the interlayer region to perform a desired chemical function. Work in our laboratory involving the application of layered hybrid materials in photographic media is described in detail and we establish two general release mechanisms whereby intercalated functional chemistry can be first sequestrated and later delivered via a chemical switch to perform a desired function. The process has enormous potential as a general method for the controlled, temporal release of materials of chemical and biological significance. 相似文献
A system of pH-responsive and imaging nanocarriers was developed using mesoporous silica nanoparticles (MSNs), in which gadolinium (Gd) was doped through in situ doping (Gd2O3@MSN). Sodium alginate (SA) was attached to the surfaces of the amino groups of MSNs (NH2-Gd2O3@MSN) through the electrostatic adsorption between the amino groups and the carboxyl groups with the formation of hybrid SA-Gd2O3@MSN nanoparticles (NPs). The SA-coated NPs were spherical or near-spherical in shape with an average size of nearly 83.2 ± 8.7 nm. The in vitro drug release experiments of a model rhodamine B (RhB) cargo were performed at different pH values. The result confirmed the pH-responsiveness of the nanocarriers. The results of the cytotoxicity studies indicated that the SA-Gd2O3@MSN NPs were not cytotoxic by themselves. The results of the in vivo safety evaluation and the hemolysis assay confirmed that the system is highly biocompatible. It is noteworthy that the T1 contrast of the system was significantly enhanced by the Gd, as indicated by the result of the MR imaging. This study confirms that the synthesized hybrid nanosystem is promising for pH-responsive drug delivery and MR imaging for cancer diagnosis and treatment. 相似文献
Rapid developments in materials science and biological mechanisms have greatly boosted the research discoveries of new drug delivery systems. In the past few decades, hundreds of nanoparticle‐based drug carriers have been reported almost on a daily basis, in which new materials, structures, and mechanisms are proposed and evaluated. Standing out among the drug carriers, the hybrid nanoparticle systems offer a great opportunity for the optimization and improvement of conventional chemotherapy. By combining several features of functional components, these hybrid nanoparticles have shown excellent promises of improved biosafety, biocompatibility, multifunctionality, biodegradability, and so forth. In this Personal Account, we highlight the recent research advances of some representative hybrid nanoparticles as drug delivery systems and discuss their design strategies and responsive mechanisms for controlled drug delivery. 相似文献