[Research progress in medicines on protease-activated receptor 2].

Protease-activated receptor 2(PAR2) is a member of protease-activated receptors(PARs). PAR2 distributed in tissues and cells(such as skin, airway epithelial cell, pancreas, etc.) has a broad biological effects, and is involved in pathogenesis of many diseases, such as mechanical pain, asthma, pain of pancreatic cancer, inflammation, pruritus, etc. Intervention of PAR2 will help us to identify the role of PAR2 in the mechanisms of diseases and in the development of new drugs. This article concentrates on the research progress of agonist, antagonist, and pepducin on PAR2.

Automated On-Line Microdialysis Sampling Coupled with HPLC for Synchronous Determination of Puerarin in Subcutaneous Tissue and Plasma Following Topical Administration.

BACKGROUND: Studies on transdermal administration have shown that puerarin can permeate rat skin rapidly with long-term drug delivery, but there are no reports demonstrating whether topical use of puerarin can provide a steady plasma concentration to produce therapeutic effects. The aim of the study is to evaluate the percutaneous penetration and plasma concentration of puerarin after transdermal administration in experimental rats. METHODS: The skin and plasma concentration of puerarin was quantified by microdialysis, and the recovery was determined by retrodialysis. Puerarin microdialysate concentrations were measured by on-line high-performance liquid chromatography (HPLC). Puerarin release from gels was determined by analysis of the amount of remaining drug after dermal application to hairless skin. RESULTS: The average recoveries of puerarin in the skin and plasma over an 8-hour period were 31.49% and 15.5%. Puerarin was rapidly absorbed with transdermal administration, with the C(max) values of 30.64 µg/mL and 3.53 µg/mL, the AUC0 t-values of 11.60 and 1.48 µg/mL per minute, for skin and plasma, respectively. CONCLUSIONS: The results indicate that the automated on-line microdialysis technique can be used to detect the skin and plasma pharmacokinetics of puerarin and that the use of skin gel can provide an effective means of puerarin administration.

Identification of natural Rutaecarpine as a potent tobacco mosaic virus (TMV) helicase candidate for managing intractable plant viral diseases.

BACKGROUND: Naturally occurring alkaloids are particularly suitable for use as pesticide precursors and further modifications due to their cost-effectiveness, unique mechanism of action, tolerable degradation, and environmental friendliness. The famous tobacco mosaic virus (TMV) is a persistent plant pathogenic virus that can parasitize many plants and severely reduce crop production. To treat TMV disease, TMV helicase acts as a crucial target by hydrolyzing adenosine triphosphate (ATP) to provide energy for double-stranded RNA unwinding. RESULTS: To seek novel framework alkaloid leads targeting TMV helicase, this work successfully established an efficient screening platform for TMV helicase inhibitors based on natural alkaloids. In vivo activity screening, enzyme activity detection, and binding assays showed that Rutaecarpine from Evodia rutaecarpa (Juss.) Benth exhibited excellent TMV helicase inhibitory properties [dissociation constant (Kd ) = 1.1 µm, half maximal inhibitory concentration (IC50 ) = 227.24 µm] and excellent anti-TMV ability. Molecular docking and dynamic simulations depicted that Rutaecarpine could stably bind in active pockets of helicase with low binding energy (ΔGbind = -17.8 kcal/mol) driven by hydrogen bonding and hydrophobic interactions. CONCLUSION: Given Rutaecarpine's laudable bioactivity and structural modifiability, it can serve as a privileged building block for further pesticide discovery.

Identification of Novel Bisamide-Decorated Benzotriazole Derivatives as Anti-Phytopathogenic Virus Agents: Bioactivity Evaluation and Computational Simulation.

As a notorious phytopathogenic virus, the tobacco mosaic virus (TMV) severely reduced the quality of crops worldwide and caused critical constraints on agricultural production. The development of novel virucides is a persuasive strategy to address this predicament. Herein, a series of novel bisamide-decorated benzotriazole derivatives were elaborately prepared and screened. Biological tests implied that the optimized compound 7d possessed the most brilliant antiviral inactive profile (EC50 = 157.6 µg/mL) and apparently surpassed that of commercial ribavirin (EC50 = 442.1 µg/mL) 2.8-fold. The preliminary antiviral mechanism was elaborately investigated via transmission electron microscopy, microscale thermophoresis (MST) determination, RT-qPCR, and Western blot analysis. The results showed that compound 7d blocked the assembly of TMV by binding with coat protein (Kd = 0.7 µM) and suppressed TMV coat protein gene expression and biosynthesis process. Computational simulations indicated that 7d displayed strong H-bonds and pi interactions with TMV coat protein, affording a lower binding energy (ΔGbind = -17.8 kcal/mol) compared with Ribavirin (ΔGbind = -10.7 kcal/mol). Overall, current results present a valuable perception of bisamide decorated benzotriazole derivatives with appreciably virustatic competence and should be profoundly developed as virucidal candidates in agrochemical.

[Mechanism of psoriasis generation in animal models].

Psoriasis is a chronic inflammatory disease related to genome-wide and surroundings, it is important to develop a suitable animal model to research psoriasis pathogenesis and evolve pharmacotherapeutics. With the development of transgenetic technology in the past few years, psoriasis virulence gene animal model become a hotspot. Research of animal model of human psoriasis genes is reviewed in the paper.

Novel spiro[chromanone-2,4'-piperidine]-4-one derivatives as potential inhibitors of fatty acid synthesis in pathogens: Design, synthesis, and biological evaluation.

Bacterial survival depends on membrane lipid homeostasis that enables to regulate lipid composition to adapt and optimize their growth in diverse environments. Therefore, the development of inhibitors that interfere with the bacterial fatty acid synthesis process is considered to be a promising tactic. In this study, 58 novel spirochromanone derivatives were prepared and their structure-activity relationship (SAR) was investigated. The bioassay results showed that all most of the compounds showed excellent biological activities, exampled by compounds B14, C1, B15, and B13, which had outstanding inhibitory activities toward various pathogenic bacteria with EC50 values of 0.78 µg/mL ∼3.48 µg/mL. Preliminary antibacterial behavior was studied by a series of biochemical assays including, but not limited to, fluorescence imaging patterns, GC-MS analysis, TEM images, and fluorescence titration experiments. Notably, compound B14 decreased the lipid content of the cell membrane, and increased cell membrane permeability, thereby destroying the integrity of the bacterial cell membrane. Further qRT-PCR results indicated that compound B14 interfered with the mRNA expression levels of fatty acid synthesis process-related genes including ACC, ACP, and Fab family genes. Herein, we highlight the promising bactericidal skeleton based on the spiro[chromanone-2,4'-piperidine]-4-one as a potential inhibitor of fatty acid synthesis.

A modified LC-MS/MS method for determination of tetramethylpyrazine in microdialysis samples and calibration of home-made linear probes.

Tetramethylpyrazine (TMP) is one of the most important active ingredients of a Chinese herb Ligusticum wallichii Franchat, which is widely used for the treatment of cardiovascular diseases. Several factors may affect TMP exposure after topical administration, resulting in large variability and demanding further elucidation of drug distribution. This paper describes a new efficient reliable LC-MS/MS assay for the determination of TMP in dermal microdialysate, where TMP was separated on an Agilent C(18) column (3.5 µm, 100 mm × 2.1 mm i.d.) using a mixture of methanol, water and acetic acid (50:50:0.6, v/v/v) at a flow-rate of 0.3 mL/min. The retention time was 1.89 min for TMP and 1.17 min for the internal standard (caffeine). Histological analysis confirmed an inflammatory response to the microdialysis probes and the presence of a collagen capsule. The membrane extraction efficiency (percentage delivered to the tissue space) for TMP was not altered through the implant lifetime. The validation and sample analysis results showed that the method is precise, accurate and well suited to support dermal microdialysis experiments.

Pharmacokinetics of aconitine in rat skin after oral and transdermal gel administrations.

The purpose of this study was to evaluate percutaneous penetration and arrhythmogenic effects of aconitine after transdermal administration, compared with the oral route. Skin penetration of aconitine was tested by a microdialysis technique in rats and in vivo recovery was determined by retrodialysis. After oral and transdermal administration of aconitine, dialysate was sampled at 20 min intervals until the end of the experiment for the determination of concentration of aconitine in skin. Blood samples were collected and analyzed using a validated HPLC-MS/MS method. In addition, we concurrently recorded the electrocardiogram (ECG). The in vivo recovery of aconitine in the skin was calculated to be 39.59%. The C(max) values for aconitine absorbed into the skin after oral and transdermal administration were 1.51 ± 0.53 and 2723.8 ± 848.8 ng/mL, respectively, and within the plasma, 215.86 ± 79.29 and 20.92 ± 3.15 ng/mL. The C(max) value for the plasma concentration of aconitine after oral administration was approximately 10 times higher than with the transdermal route. For oral administration, the ECG revealed various types of arrhythmias at a period of T(max) , which is normal in transdermal gel administration. These results indicate that transdermal aconitine gel is a safe formulation that can deliver the drug in sufficient amounts and safe concentrations to produce therapeutic action in rats.

[The preparation of paeonol transdermal delivery systems based on the microemulsion-based gels and its pharmacokinetics characters].

Investigation of the pharmacokinetics of paeonol microemulsion, microemulsion-based gels and marketed paeonol ointments by the skin-blood synchronous microdialysis coupled with LC/MS is reported in this study. The microdialysis systems were established by linear probes and concentric circles probes. In vivo recovery of paeonol in skin is (69.7 +/- 4.8) % and in blood is (51.6 +/- 7.2)%. The paeonol microemulsion, microemulsion-based gels and marketed paeonol ointments were administered to rats. PBS (pH 7.4) served as perfused solution. The perfusion rate was 5 microL x mL(-1) and the microdialysis samples were collected every 20 min intervals. The paeonol concentration in perfused solution was determined by LC/MS. The results showed that paeonol microemulsion and microemulsion-based gels significantly raised the drug concentrations in skin more than that of paeonol ointments. The paeonol microemulsion-based gels has similar bioavailability as the paeonol ointments in blood, but its blood drug concentrations were steadier. The paeonol microemulsion-based gels may be developed into a new preparation for dermis eczema. The skin-blood synchronous microdialysis technique proved to be a new method for the pharmacokinetics study of transdermal delivery systems.

[Pharmacokinetics of scopolamine hydrobromide oral disintegrative microencapsule tablets in Beagle dogs determined with LC-MS/MS].

The study aims to elucidate the characteristics of pharmacokinetics of scopolamine hydrobromide oral disintegrative microencapsule tablets in healthy Beagle dogs. Chromatographic separation was performed on a C18 column (100 mm x 3.0 mm, 3.5 microm) with methanol - 2 mmol x L(-1) ammonium formate (25 : 75) as the mobile phase. A trip-quadrupole tandem mass spectrum with the electrospray ionization (ESI) source was applied and positive ion multiple reaction monitoring mode was operated. Six Beagle dogs were randomly devided into two groups. They received oral single dose of scopolamine hydrobromide oral disintegrative microencapsule tablets 0.6 mg (test tablet) or scopolamine hydrobromide normal tablets (reference tablet). Plasma samples were collected at designed time. Plasma concentration of scopolamine hydrobromide was determined by LC-MS/MS and pharmacokinetic parameters were calculated. The pharmacokinetic parameters of test tablet vs reference tablet were as follows: C(max): (8.16 +/- 0.67) ng x mL(-1) vs (3.54 +/- 0.64) ng x mL(-1); t1/2: (2.83 +/- 0.45) h vs (3.85 +/- 0.82) h; t(max): (1.25 +/- 0.27) h vs (0.42 +/- 0.09) h; AUC(0-12h): (25.06 +/- 3.75) h x ng x mL(-1) vs (9.59 +/- 1.02) h x ng x mL(-1); AUC(0-infinity): (26.30 +/- 3.92) h x ng x mL(-1) vs (10.80 +/- 1.45) h x ng x mL(-1); MRT(0-12h): (3.38 +/- 0.34) h vs (3.86 +/- 0.26) h; MRT(0-infinity): (3.98 +/- 0.63) h vs (5.37 +/- 1.00) h. The absorption rate and AUC of test tablet is different from that of reference tablet. The bioavailability of test tablet is better than those of reference tablet.

[Preparation of scopolamine hydrobromide nanoparticles-in-microsphere system].

This study is to prepare scopolamine hydrobromide nanoparticles-in-microsphere system (SH-NiMS) and evaluate its drug release characteristics in vitro. SH nanoparticles were prepared by ionic crosslinking method with tripolyphosphate (TPP) as crosslinker and chitosan as carrier. Orthogonal design was used to optimize the formulation of SH nanoparticles, which took the property of encapsulation efficiency and drug loading as evaluation parameters. With HPMC as carrier, adjusted the parameters of spray drying technique and sprayed the SH nanoparticles in microspheres encaposulated by HPMC was formed and which is called nanoparticles-in-microsphere system (NiMS). SH-NiMS appearances were observed by SEM, structure was obsearved by FT-IR and the release characteristics in vitro were evaluated. The optimized formulation of SH nanoparticles was TPP/CS 1:3 (w/w), HPMC 0.3%, SH 0.2%. The solution peristaltic speed of the spray drying technique was adjusted to 15%, and the temperature of inlet was 110 degrees C. The encapsulation product yeild, drug loading and particle sizes of SH-NiMS were 94.2%, 20.4%, and 1256.5 nm, respectively. The appearances and the structure of SH-NiMS were good. The preparation method of SH-NiMS is stable and reliable to use, which provide a new way to develop new dosage form.

Mannose 6-phosphate-modified bovine serum albumin nanoparticles for controlled and targeted delivery of sodium ferulate for treatment of hepatic fibrosis.

OBJECTIVES: The aim was to prepare neoglycoprotein-based nanoparticles for targeted drug delivery to hepatic stellate cells, and to evaluate their characteristics in vitro and in vivo. METHODS: The neoglycoprotein of bovine serum albumin modified with mannose 6-phosphate was synthesised from mannose, and used as wall material to nanoencapsulate the model natural antifibrotic substance sodium ferulate using a desolvation method. The morphology, drug loading capacity, release in vitro and biodistribution in vivo of the nanoparticles were studied. Selectivity of the nanoparticles for hepatic stellate cells was evaluated by immunohistochemical analysis of fibrotic rat liver sections. KEY FINDINGS: The spherical nanoparticles were negatively charged with zeta potential ranging from -2.73 to -35.85 mV, and sizes between 100 and 200 nm with a narrow size distribution. Drug entrapment efficiency of about 90% (w/w) and loading capacity of 20% (w/w) could be achieved. in vitro, the nanoparticles showed an initial rapid continuous release followed by a slower sustained release. After intravenous injection into mice, the nanoparticles showed a slower elimination rate and a much higher drug concentration in liver compared with the sodium ferrate solution, and less distribution to the kidneys and other tissues. Immunohistochemistry indicated that the neoglycoprotein-based nanoparticles were taken up specifically by hepatic stellate cells. CONCLUSIONS: The nanoparticles may be an efficient drug carrier targeting hepatic stellate cells.

Development of a novel HPLC-MS/MS method for the determination of aconitine and its application to in vitro and rat microdialysis samples.

A sensitive and selective LC-MS/MS method was developed and validated for the determination of aconitine in microdialysate and rat plasma. Extraction of plasma sample was conducted by use of 1% trichloracetic acid and acetonitrile solution with 10 ng/mL internal standard (propafenone) spiked. Microdialysates were analyzed without sample purification. After sample preparation, 2 microL were injected and separated with an isocratic mobile phase consisting of acetonitrile:0.1% formic acid (60:40, v/v) at a flow rate of 0.3 mL/min. The Agilent G6410A triple quadrupole LC/MS system was operated under the multiple-reaction monitoring mode (MRM) using the electrospray ionization technique in positive mode. Overall, the assay exhibited good precision and accuracy. The diffusion properties of aconitine investigated in in vitro microdialysis experiments revealed unfavourable concentration dependence avertable by keeping a constant pH 5.77 using isotonic phosphate buffer solution as perfusate. The mean relative recoveries were 48.23% [coefficient of variation (CV 4.47%)] and 55.38% (CV 2.89%) for retrodialysis and recovery experiments, respectively. The in vivo recovery of aconitine was 34.48% (CV 3.05%) and was stable over the 6 h study period. Following characterization of aconitine both in vitro and in vivo microdialysis, the developed setting is suitable for application in pharmacokinetics and pharmacodynamics studies.

Anchoring of ulex europaeus agglutinin to chitosan nanoparticles-in-microparticles and their in vitro binding activity to bovine submaxillary gland mucin.

Focused on the natural biodegradable material of chitosan (CS), this investigation concerned its spray-dried nanoparticles-in-microparticles (NiMPs) modified with ulex europaeus agglutinin (UEA). Chitosan nanoparticles were obtained by ionotropic gelation process with pentasodium tripolyphosphate as gelatinizer. Then UEA lectin was bound onto the CS nanoparticles activated by glutaraldehyde. The conjugated spherical UEA-CS-NiMPs, prepared by spray drying method, exhibited 12-85% coupling efficiency of UEA depending upon the amount of activator glutaraldehyde. And the UEA-grafted particles showed additional higher binding tendency with bovine submaxillary gland mucin as compared to the plain chitosan microparticles. Furthermore, the activity and intrinsic fucose-specificity of UEA were still maintained after the covalent modification. It is thus evident that the UEA anchored CS-NiMPs might be used as a potential drug delivery system targeted to the specific regions of gastrointestinal tract.

[Enzyme kinetics of ligustilide metabolism in rat liver microsomes].

To study the enzyme kinetics of ligustilide metabolism and the effects of selective CYP450 inhibitors on the metabolism of ligustilide in liver microsomes of rat, a LC-MS method was established for quantitative analysis of ligustilide in liver microsomes incubation system with nitrendipine as internal standard. The determination m/z for ligustilide was 173, and for nitrendipine, 315. An optimum incubation system was found and various selective CYP inhibitors were used to investigate their inhibitory effects on the metabolism of ligustilide. The results showed that enzyme kinetics of ligustilide could be significantly inhibited by ketoconazole, trimethoprim and a-naphthoflavon but scarcely inhibited by omeprazole, 4-methylpyrazole and quinidine. Therefore, CYP3A4, CYP2C9 and CYP1A2 are the major isoenzyme participated in in vitro metabolism of ligustilide.

Preparation and characterization of sodium ferulate entrapped bovine serum albumin nanoparticles for liver targeting.

Sodium ferulate (SF) loaded nanoparticles were prepared by desolvation procedure and subsequent cross-linking of the wall material of bovine serum albumin (BSA). Several factors in the nanoencapsulation process, such as the addition rate of the desolvation agent, composition of BSA and SF solution, amount of the cross-linker glutaraldehyde, were investigated to elucidate their influences on the particle size, zeta potential, drug loading and encapsulation efficiency of the resulted nanoparticles. The obtained spherical nanoparticles were negative charged with zeta potential from -20 to -40 mV, and characterized between 100 and 200 nm with a narrow size distribution. In the condition of introducing 1.0 mL 8% glutareldehyde per mg of BSA, the drug entrapment efficiency (EE) of 80% (w/w) and loading capacity of about 16% (w/w) could be achieved for the cross-linked BSA nanoparticles with SF encapsulated (SF-BSA-NP). And the drug EE was decreased along with the increasing amount of glutareldehyde used for cross-linking. The in vitro drug release properties of SF-BSA-NP behaved with an initial burst effect and then sustained-release stage. To some extent, the drug release rate could be adjusted by cross-linking with different amount of glutaraldehyde. Compared with SF solution, SF-BSA-NP showed a much higher drug distribution into liver and a lower drug concentration in other tissues, after intravenously injected to mice. So, BSA based nanoparticles might be a suitable controlled released carrier for the freely water-soluble drug SF and further hepatic targeted drug delivery.

[Effect of cetirizine hydrochloride on the expression of substance P receptor and cytokines production in human epidermal keratinocytes and dermal fibroblasts].

To investigate the effect of cetirizine hydrochloride on the expression of neurokinin 1 receptor (NK-1R) and cytokines production induced by substance P (SP) in HaCaT cells (a human epidermal keratinocyte cell line) and dermal fibroblasts. The effect of cetirizine on the expression of NK-1R protein was detected by flow cytometry and Western blotting analysis. The modulation of cetirizine on the production of interferon (IFN)-gamma, interleukin (IL)-1beta, IL-6 and IL-8 in HaCaT cells and fibroblasts was measured by ELISA. The results showed that cetirizine significantly inhibited the expression of NK-1R in HaCaT cells and fibroblasts. SP induced the production of IFN-gamma, IL-1beta and IL-8 in both cell types. Cetirizine 1-100 micromol x L(-1) inhibited SP-induced IL-1beta and IL-8 production in HaCaT cells and fibroblasts, while had no effect on the production of IFN-gamma in both cells. Both SP and cetirizine had no effect on the secretion of IL-6 in HaCaT cells and fibroblasts. These findings suggest that cetirizine may be involved in the treatment of SP-induced skin inflammation by inhibiting the expression of substance P receptor and regulation the production of IL-1beta and IL-8 in epidermal keratinocyte and dermal fibroblasts.

Effect of matrine on the expression of substance P receptor and inflammatory cytokines production in human skin keratinocytes and fibroblasts.

Matrine is a kind of alkaloid found in certain Sophora plants, which has been extensively used in China for the treatment of viral hepatitis, cancer, cardiac diseases and skin diseases (such as atopic dermatitis and eczema). It also has been confirmed that substance P (SP) and its receptor (neurokinin-1 receptor, NK-1R) are involved in the pathogenesis of inflammatory skin disorders. So the present study was designed to investigate the effect of matrine on the expression of NK-1R and cytokines production induced by SP in HaCaT cells (a human epidermal keratinocyte cell line) and dermal fibroblasts. In addition, cell viability was also evaluated. The results showed that matrine inhibited the expression of NK-1R in HaCaT cells and fibroblasts. SP induced the production of interleukin (IL)-1beta, IL-8, interferon (IFN)-gamma, and monocyte chemotactic protein (MCP)-1 in both cell types. Matrine 5-100 microg/mL had little effect on cell viability. It inhibited SP-induced IL-1beta, IL-8 and MCP-1 production in HaCaT cells and fibroblasts, while it increased the production of IFN-gamma in HaCaT cells. Both SP and matrine had no effect on the secretion of IL-6. These findings suggest that matrine may have potential treatment function on SP related cutaneous inflammation by inhibition of the expression of substance P receptor and regulation of the production of inflammatory cytokines.

Development of a gradient reversed-phase HPLC method for the determination of sodium ferulate in beagle dog plasma.

A gradient reversed-phase HPLC assay has been developed to determine sodium ferulate (SF) in beagle dog plasma with tinidazole as an internal standard. Chromatographic separation was made on a C(18) column using 0.5% acetic acid and acetonitrile (80:20, v/v) as mobile phase. UV detection was performed at 320 nm. The calibration curve for SF was linear in the range of 0.05-10 microg/ml, and the achieved limit of quantification (LOQ) was 51.4 ng/ml. The results of linearity, within- and between-day precision, and accuracy demonstrate that this method is reliable, sensitive and sufficient for in vivo beagle dog pharmacokinetic (PK) studies of SF.

[Oral vaccination and vaccine-entrapped microparticle delivery system].

In order to elucidate the physiological basis for mucosal immunity of oral vaccination and to present the essential carrier of microparticles or nanoparticles used to investigate the orally delivered vaccine, the features of antigen presentation and mucosal immunereaction in gut-associated lymphoid tissues were analyzed. Considered the morphological and physiological barriers of the gastrointestinal tract, absorption and transport of particulates were further discussed. And the studies about particulate dosage forms for oral vaccine delivery were also summarized in this review. Peyer s patches and M-cells, involved in immunoregulation, are significant areas performing the critical role in oral vaccine. The applied vesicle of microparticles could overcome the barriers of gastrointestinal tract. Oral vaccination was endued with new connotation, especially the enhanced transport and immunization efficiencies promoted by the lectin anchored particles. In conclusion, oral vaccination mediated by particulate carrier via mucosal immune system, would contribute to the site-specific triggering and signal magnification. For vaccines, the prospects for the application of these promising carrier systems might have potential attraction for scientific research and commercial development.