Latest ArticlesThis study aims to prepare lipid bilayer-coated calcium phosphate core-shell nanoparticles (LCAPNs), which can dissolve in an acidic environment to improve the tumor cell toxicity of antitumor drug. Paclitaxel (PTX) loaded lipid coated calcium phosphate nanoparticles (PTX-LCAPNs) were prepared by thin-film dispersion method. The morphology, particle size and in vitro release behavior were characterized. Meanwhile, the intracellular uptake, intracellular dissolution, cell toxicity of PTX-LCAPNs and intracellular accumulation of PTX were evaluated in human HCC cell line (Huh-7). The results suggested that the mean diameter of the spherical LCAPNs was 124.73±6.41 nm. The PTX-LCAPNs demonstrated little drug leakage in simulated normal physiological conditions, while a rapid release was observed in simulated intracellular condition in vitro. Moreover, the PTX-LCAPNs achieved 1.7 fold improvement in the intracellular PTX concentration leading to 5-fold reduction in half maximal inhibitory concentration (IC50) values of PTX compared with calcium phosphate nanoparticles loaded with PTX (PTX-CAPNs), demonstrating a stronger cancer cell lethality.
The mesoporous silica nanoparticles (MSN) in different pore size and sirolimus (SRL) loaded self-microemulsifying drug delivery system (SMEDDS) were prepared. The results in morphology were collected by scanning electron microscope, transmission electron microscope, small-angle X-ray diffraction, and N2 adsorption-desorption. The results showed that the prepared MSN has ordered nanochannels with a pore size of 6.3, 8.1, 10.8 nm, respectively. The particle size of SRL-SMEDDS were measured by particle sizing system, which was 20.6±1.3 nm. The stirring method was developed to prepare SRL-SMEDDS-MSN. It was found that the optimal ratio of SRL-SMEDDS to MSN was 2:1, while the drug loading rate was near 0.83%, and the flow properties of SRL-SMEDDS-MSN were of good condition. The differential scanning calorimetry results proving a molecular or amorphous dispersed state of SRL in MSN while the suspension experiment has shown great reconstitution properties of SRL-SMEDDS-MSN. There is no significant influence on maximum drug release rate of different pore size of SRL-SMEDDS-MSN in 250 mL water within 2 h, while the results of the first 40 min have an obvious difference. Above all, MSN might provide a new strategy for the solidification of SMEDDS.
Flexible liposomes are an excellent drug delivery nanocarrier, however, the leakage of drugs from liposomes has become common technical obstacle in the industry and also hindered its further application seriously. It is very urgent and necessary to avoid or reduce the leakage of drugs from liposomes. In this work, five kinds of essential oils such as Folium Artemisiae Argyi oil (FA), Folium Eucalypti oil (FE), Arabian Jasmine oil (AJ), Syzygium Aromaticum oil (SA) and Fructus Forsythiae oil (FF) were encapsulated in the lipid bilayer of palmatine chloride (PC) loaded flexible nano-liposomes (PFL), then the optimal essential oil and its dosage level were determined by the external leakage curve of PC. The female Japanese white rabbits were used to evaluate the vaginal irritancy potential of liposomes samples. The pharmaceutical properties such as encapsulation efficiency, particle size, zeta potential, deformability and structure of liposomes samples were evaluated. In order to investigate the permeability of liposomes samples to deliver PC across skin and mucous membrane in vitro, the side-by-side diffusion cells were used. The results showed that the leakage of hydrosoluble PC from PFL was reduced at different degrees by the essential oils in the lipid bilayer of PFL, however, the reduction in leakage degree was obviously higher for FA than thoses of FE, AJ, SA and FF (P < 0.05), and the highest reduction in leakage degree was obtained when the FA and lipid mass ratio was 1:6. The encapsulation efficiency, particle size, zeta potential and deformability of PFL were not significantly changed after FA was encapsulated in the lipid bilayer of the PFL (P > 0.05), so did the lamellar structure of PFL. In addition, the transdermal and transmucosal permeability of PC were also enhanced obviously by encapsulating FA in the lipid bilayer of PFL, and there was no vaginal/vulvar irritation observed in the rabbits. In summary, the drug leakage was reduced by encapsulating suitable essential oil (such as FA) in the lipid bilayer of flexible liposomes, and the vaginal mucosa permeability were improved for the drug. These results provide a novel technique in the improvement of flexible nano-liposomes for drug delivery.
This study was designed to establish a multiplex allele-specific polymerase chain reaction method for simultaneous identification of Dendrobium huoshanense, D. officinale and D. devonianum, which may resolve identification problems of caulis dendrobii. Internal transcribed spacer sequences and trnL-trnF sequences of the Dendrobium species were aligned by BioEdit software, then specific SNPs of the three species were analyzed for designing allele-specific primers and the multiplex allele-specific PCR reaction system was established. The different origin of Dendrobium huoshanense, D. officinale and D. devonianum was amplified and identified by the sizes of respective band. The results showed that 584 bp, 397 bp and 211 bp bands could be amplified by D. devonianum, Dendrobium officinale and Dendrobium huoshanense respectively, when the annealing temperature was 61 ℃ and the number of cycles was 35. The limit of detection (LOD) of D. devonianum and D. huoshanense were both 1.2 ng, while D. officinale was low than 0.24 ng. The detection limit of adulterates in D. devonianum, D. devonianum and D. huoshanense mixture sample was 1%, 1% and 5% respectively. This result suggests that the method of multiplex allele-specific PCR is useful to identify D. huoshanense, D. officinale and D. devonianum is accurate and specific.
Scorpion toxin BmK AngM1 has been reported to have a strong analgesic effect. However, its anti-inflammatory activity was unknown. In this study, the recombinant BmK AngM1 (rBmK AngM1) was expressed in Escherichia coli BL21 trxB (DE3). The purified rBmK AngM1 was obtained efficiently through the IMPACTTM-TWIN system. The anti-inflammatory activity of the recombinant protein was investigated. In order to improve the anti-inflammatory activity of rBmK AngM1, the potential active sites (Y5, Y42, R58) were substituted with different amino acids. The results showed that rBmK AngM1 and its mutants all have significant anti-inflammatory activity. The activities were significantly increased in the single mutant R58N and mutants Y5F/R58N, Y42F/R58N over the wild type protein. The data suggest that position 58 in BmK AngM1 plays a functional role in the anti-inflammatory activity. This study lays a foundation for the protein engineering design of BmK AngM1 to improve its pharmacological activity.
Strategies and techniques are extremely important to improve the evaluation efficiency and fully guarantee the consistency of dosage forms. For preparations with a structural feature as solid dosage forms and particulate dispersion systems, the structures of dosage forms are the outcome of the specific formulation and production process, which determine the drug delivery behaviors as well as the pharmacokinetics of the dosage forms. Conventional techniques failed to quantitatively determine the structures of dosage forms. Synchrotron radiation micro-computed tomography is a new generation of structural quantitative characterization technology in revealing the internal structure of dosage forms with unprecedented capability for quantitative characterization of the static and dynamic structures of dosage forms, enabling to reversely analyze the production process and identify the structure differences between the generics and brand products. Based on synchrotron radiation micro-computed tomography methodology researches and applications in static structures (powders, particulate systems, tablets, films, membranes, etc.), dynamic structures (hydration) and de-formulation of production process, we have classified the structures of dosage forms into four levels from macro-scope to molecular level as dosage forms, granular intermediates for formulation, dynamic structure and molecular structures, and proposed dosage form structure based new strategy for consistency evaluation. Along with conventional dissolution/ release behavior similarity, the internal structure consistency ensures high consistency between the brand product and the generics.
The appropriate regulation of intracellular bioenergy and nutrient metabolism is a basic requirement for proper function and survival of pancreatic beta cells, where mitochondria-endoplasmic reticulum (ER)-associations play crucial roles. Mitochondria are changed dynamically according to intracellular energy and nutrients, which provides material foundation for energy homeostasis; while ER regulates metabolic enzymes and protein synthesis in different pathways. This review sheds light upon the development of mitochondria-ER associations and its role in the regulation of insulin secretion in pancreatic beta cell. The impact on beta cell viability is discussed. Interruption of calcium and redox oxidative species results in reduction of glucose-stimulated insulin secretion, while intracellular calcium levels could be partial altered by depleting calcium from the ER. Given the tight link between ER and mitochondria, the association are crucial to the homeostasis and are an indicator of overall beta cell status, with a potential as a novel drug target for treatment of type 2 diabetes mellitus.
Transient receptor potential (TRP) channels are non-selective and cation-permeable channels in the cell membrane, widely distributed in tissues and organs of human body. As biosensors, TRP channels can regulate the functions of vision, hearing, taste, pain, and touch, etc. So far, more than 100 different kinds of natural modulators targeting TRP channels have been identified from 70 species of plants or animals. In this review article, we attempt to summarize the effect of known natural active compounds on TRP channels with focuses on their sources, structures, action features and mechanisms. Hopefully this review can provide some useful information that can facilitate discovery of more specific natural modulators, and development of innovative therapeutic drugs targeting TRP channels.
Acting as the key step of various cell signaling pathways, protein-protein interaction (PPIs) plays a significant role in the regulation of biological functions. Many of the proteins involved are potential drug targets, therefore manipulation of PPI would greatly a great interest in physiology and pharmacology. Most PPIs could not be directly targeted by small molecule drugs due to their flat and shallow interaction surfaces. Selective regulator may be obtained by extraction and chemical synthesis helical peptide that forms folding substructure scaffold in PPI. However, most peptides when separated from its protein progenitor are not able to maintain its biological active helical structure, but tend to form random coil conformation, which is vulnerable to enzyme and suffer low potency and drugability. By modification through all-hydrocarbon bridged cyclic peptide designating 'stapled peptide', it turned out to be the most effective and directive methodology to solve the drawbacks. Stapled peptide not only can boost its potency, but also its biostability and cell permeability. These significant advantages make peptide stapling an important way of modification, which may definitely generate more and more peptide drug candidates targeting PPIs in the foreseen future. In this paper, chemistry and bioactivity of the stapled peptides reported up-to-date are systematically reviewed and discussed.
Lymphoid-specific tyrosine phosphatase (LYP) is a phosphatase that is encoded by protein tyrosine phosphatase non-receptor type 22 and is mainly distributed in lymphoid. In psychological condition, LYP inhibits T-cell receptor (TCR) signaling in association with C-terminal kinase (CSK). While in pathological condition, mutant LYP dissociates with CSK, which augments the inhibition of TCR signaling and leads to autoimmune diseases. Consequently, LYP is now considered as a new target of type Ⅰ diabetes, rheumatic arthritis and Graves disease and some other autoimmune disorders. This review mainly focuses on the development of LYP inhibitors in their structures and activities.
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