A novel snake venom-derived GPIb antagonist, anfibatide, protects mice from acute experimental ischaemic stroke and reperfusion injury.

BACKGROUND AND PURPOSE: Ischaemic stroke is a serious disease with limited therapy options. Glycoprotein (GP)Ib binding to von Willebrand factor (vWF) exposed at vascular injury initiates platelet adhesion and contributes to platelet aggregation. GPIb has been suggested as an effective target for antithrombotic therapy in stroke. Anfibatide is a GPIb antagonist derived from snake venom and we investigated its protective effect on experimental brain ischaemia in mice. EXPERIMENTAL APPROACH: Focal cerebral ischaemia was induced by 90 min of transient middle cerebral artery occlusion (MCAO). These mice were then treated with anfibatide (4, 2, 1 µg·kg(-1) ), injected i.v., after 90 min of MCAO, followed by 1 h of reperfusion. Tirofiban, a GPIIb/IIIα antagonist, was used as a positive control. KEY RESULTS: Twenty-four hours after MCAO, anfibatide-treated mice showed significantly improved ischaemic lesions in a dose-dependent manner. The mice had smaller infarct volumes, less severe neurological deficits and histopathology of cerebrum tissues compared with the untreated MCAO mice. Moreover, anfibatide decreased the amount of GPIbα, vWF and accumulation of fibrin(ogen) in the vasculature of the ischaemic hemisphere. Tirofiban had similar effects on infarct size and fibrin(ogen) deposition compared with the MCAO group. Importantly, the anfibatide-treated mice showed a lower incidence of intracerebral haemorrhage and shorter tail bleeding time compared with the tirofiban-treated mice. CONCLUSIONS AND IMPLICATIONS: Our data indicate anfibatide is a safe GPIb antagonist that exerts a protective effect on cerebral ischaemia and reperfusion injury. Anfibatide is a promising candidate that could be beneficial for the treatment of ischaemic stroke.

Protective effect of iridoid glycosides from Paederia scandens (LOUR.) MERRILL (Rubiaceae) on uric acid nephropathy rats induced by yeast and potassium oxonate.

Iridoid glycosides of Paederia scandens (IGPS) are an active component isolated from Chinese herb P. scandens (LOUR.) MERRILL (Rubiaceae). Uric acid nephropathy (UAN) is caused by excessive uric acid, which results in damage of kidney tissue via urate crystals deposition in the kidneys. This study aimed to investigate the protective effects of IGPS on UAN in rats induced by yeast and potassium oxonate. Treatment groups received different doses of IGPS and allopurinol (AP) daily for 35 days respectively. The results showed that treatment with IGPS significantly prevented the increases of uric acid in serum and the elevation of systolic blood pressure (SBP), attenuated renal tissue injury, improved renal function and reserved the biological activity of NOS-1. IGPS also inhibited the biological activity of TNF-α and TGF-ß1, and suppressed the mRNA expressions of TNF-α and TGF-ß1 in renal tissue. Taken together, the present and our previous findings suggest that IGPS exerts protective effects against kidney damage in UAN rats through its uric acid-lowering, anti-inflammatory and immunomodulatory properties. Furthermore, decreasing SBP by up regulation of NOS-1 expression and down regulation of TNF-α and TGF-ß1 expression are involved in the effect of IGPS on high uric acid-induced nephropathy.

Trans-resveratrol loaded chitosan nanoparticles modified with biotin and avidin to target hepatic carcinoma.

Conventional liver targeted system focuses on delivering drugs to liver, bringing toxicity on hepatic normal tissues. The purpose of this study is to construct a new system capable of specially targeting to hepatic carcinoma instead of the whole liver. Based on the fact that nanoparticles (NPs) bound with either biotin or avidin tend to accumulate in tumors and avidin-attached reagents were quickly eliminated from blood circulation and assembled in liver, trans-resveratrol loaded chitosan nanoparticles (CS-NPs), CS-NPs with the surface modified either by biotin (B-CS-NPs) or by both biotin and avidin (A-B-CS-NPs) were prepared and their physiochemical properties were investigated. The in vitro release profiles of the three NPs all conformed to bioexponential equation. Pharmacokinetic experiment indicated that A-B-CS-NPs rapidly assembled in liver after injection, with the highest liver targeting index of 2.70, while the modification of biotin attenuated the liver targeting ability of NPs. Inhibitory study on HepG2 cells declared that compared to trans-resveratrol solution and CS-NPs, both B-CS-NPs and A-B-CS-NPs significantly improved the anticancer activity. When incubated with HepG2 cells at high concentration for longer time, A-B-CS-NPs exhibited superior cytotoxicity than B-CS-NPs. This study exclaims that A-B-CS-NPs may be a potent drug delivery vector specially targeting to hepatic carcinoma.

The effect of deacetylated gellan gum on aesculin distribution in the posterior segment of the eye after topical administration.

The aim of the present work was to evaluate the effect of deacetylated gellan gum on delivering hydrophilic drug to the posterior segment of the eye. An aesculin-containing in situ gel based on deacetylated gellan gum (AG) was prepared and characterized. In vitro corneal permeation across isolated rabbit cornea of aesculin between AG and aesculin solution (AS) was compared. The results showed that deacetylated gellan gum promotes corneal penetration of aesculin. Pharmacokinetics and ocular tissue distribution of aesculin after topical administration in rabbit eye showed that AG greatly improved aesculin accumulation in posterior segmentsrelative to AS, which was probably attributed to conjunctivital/sclera pathway. The area-under-the-curve (AUC) for AG in aqueous humor, choroid-retina, sclera and iris-ciliary body were significantly larger than those of AS. AG can be used as a potential carrier for broading the application of aesculin.

[In vivo distribution and pharmacokinetics of multiple effective components contained in Panax notoginseng saponins after intratympanic administration].

OBJECTIVE: To investigate in vivo distribution and pharmacokinetics of ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1 ) and sanchinoside R1 (R1) after intratympanic administration (IT) or intravenous administration (IV) of Panax notoginseng saponions (PNS) solution, and provide a novel route for delivering traditional Chinese medicine (TCM) to the brain. METHOD: The guinea pigs were employed as experimental animal. Perilymph (PL), cerebrospinal fluid (CSF), brain tissue and plasma were collected periodically after IT and IV of PNS solution. The concentrations of Rb1, Rg1 and R1 were measured by high performance liquid chromatography (HPLC), and statistic program DAS was applied to the calculation of pharmacokinetic parameters. The self-defined weighting coefficients based on area under curve (AUC) of each component were created to obtain the holistic pharmacokinetic profiles of PNS. The integrated pharmacokinetic parameters were then calculated from non-compartmental model analysis. RESULT: Rb1, Rg1 and R1 diffused through the round window membrane into PL of the inner ear, and then transported to the brain after IT of PNS solution. However, the pharmacokinetic parameters showed significant differences between the three components. Based on the self-defined AUC weighting coefficients integration approach, the holistic pharmacokinetic profiles of PNS were obtained, from which the integrated pharmacokinetic parameters were calculated. The C(max) in CSF and brain tissues following IT were respectively 1.5 and 0.4-fold higher than those following IV. After IT, the AUC in CSF and brain tissues increased by 0.5 and 1.2 times compared with IV. Furthermore, the C(max) and AUC in plasma following IT were respectively 45.9% and 33.1% lower than those following IV. CONCLUSION: This novel intra-cochlear administration might serve as a potential and promising alternative to TCM delivery with enhanced brain-targeted efficiency.

Formulation and evaluation of in situ gelling systems for intranasal administration of gastrodin.

Gastrodin is the major bioactive constituent of the traditional Chinese drug "Tianma." It is used in the treatment of some nervous system diseases and can be transported to the brain via intranasal administration. In the current paper, the development of a novel ion-activated in situ gelling system for the nasal delivery of gastrodin is discussed. An in situ perfusion model was used to determine the absorption-rate constant of gastrodin through rat nasal mucosa. The optimal formulation was determined by measuring the critical cation concentration, anti-dilution capacity, gel expansion coefficient, water-holding capacity, and adhesive capacity. The best formulation consisted of 10% gastrodin, 0.5% deacetylated gellan gum as the gelatinizer, and 0.03% ethylparaben as the preservative. The rheological properties of gastrodin nasal in situ gels were also investigated. The viscosity and elasticity sharply increased at temperatures below 25°C. When physiological concentrations of cations were added into the preparation, the mixture gelled into a semi-solid. The results of an accelerated stability test show that gastrodin nasal in situ gels can be stable for more than 2 years. Mucociliary toxicity was evaluated using the in situ toad palate model and the rat nasal mucociliary method; both models demonstrated no measurable ciliotoxicity. Pharmacodynamic studies suggest that similar acesodyne and sedative effects were induced following intranasal administration of 50 mg/kg gastrodin nasal in situ gels or oral administration of 100 mg/kg gastrodin solution. The in situ gel preparation is a safe and effective nasal delivery system for gastrodin.

Quantification of aesculin in rabbit plasma and ocular tissues by high performance liquid chromatography using fluorescent detection: application to a pharmacokinetic study.

A simple and sensitive high performance liquid chromatography method with fluorescence detection (HPLC-FD) was described for the determination of aesculin (AL) at low concentrations in rabbit plasma and ocular tissues. After deproteinization by methanol using pazufloxacin mesilate (PM) as an internal standard (I.S.), supernatants were evaporated to dryness at 40°C under a gentle stream of nitrogen. The residue was reconstituted in mobile phase and a volume of 20µL was injected into the HPLC for analysis. Analytes were separated on an Ultimate XB-C18 column (250mm × 4.6mm i.d., 5µm particle size) and protected by a ODS guard column (10mm × 4.0mm i.d., 5µm particle size), using acetonitrile-0.1% triethylamine in water (adjusted to pH 3.0 using phosphoric acid) (12:88, v/v) as mobile phase with a flow rate of 1.0mL/min. The wavelengths of fluorescence detector (FD) were set at 344nm for excitation and 466nm for emission. The lower limit of quantitation (LOQ) for AL was 0.80ng/mL for plasma and vitreous body, 1.59ng/mL for aqueous humor, and 6.55ng/g for iris and 1.66ng/g for retina. The method was used in the study of AL concentrations in plasma and ocular tissues after topical administration of AL eye drops.

Receptor-mediated gene delivery by folate-poly(ethylene glycol)-grafted-trimethyl chitosan in vitro.

Folate-poly(ethylene glycol)-grafted-trimethyl chitosan (F-PEG-g-TMC) and methoxypolyethylene glycol-grafted-trimethyl chitosan (mPEG-g-TMC)/pDNA complexes were prepared and characterized concerning physicochemical properties including cytotoxicity, condensation efficiency, particle size, and zeta potential. Furthermore, cellular uptake and transfection efficiency of the complexes were evaluated in vitro and compared with that of folate-trimethyl chitosan (folate-TMC) synthesized by our group to elucidate the effect of PEGylation. The cellular uptake of the F-PEG-g-TMC/pDNA with a copolymer nitrogen-to-DNA phosphate ratio (N/P ratio) of 20 in KB cells was specifically increased up to 1.68-fold compared with that of the mPEG-g-TMC/pDNA (N/P ratio 20) resulting in 1.5-fold and 1.4-fold increased transfection efficiency in KB cells and SKOV3 cells (folate receptor-overexpressing cell lines), respectively. The intracellular uptake and transfection efficiency of the F-PEG-g-TMC/pDNA were significantly enhanced relative to the folate-TMC/pDNA in folate receptor-overexpressing cells due to stabilizing effect of PEGylation. Subcellular localization of the complexes in the process of intracellular transportation was observed by confocal laser scanning microscopy suggesting quicker association of the F-PEG-g-TMC/pDNA. In conclusion, the F-PEG-g-TMC/pDNA complexes are potential vehicles for improving the transfection efficiency and specificity of gene.

Preparation, characterization, and in vivo evaluation of mitoxantrone-loaded, folate-conjugated albumin nanoparticles.

Folic acid was covalently conjugated to bovine serum albumin nanoparticles (BSANP) to target the nanoparticles to SKOV3 cells expressing folate receptors. Mitoxantrone was incorporated into the folate-conjugated albumin nanoparticles, and the final nanoparticle size was 68 nm, as measured by a laser light scattering particle analyzer. The cytotoxic activity of mitoxantrone- loaded, folate-conjugated albumin nanoparticles (MTO-BSANP-folate), which was quantitated by (3)H-thymidine incorporation, was higher than mitoxantrone-loaded BSANP (MTO-BSANP) and MTO solution, and could be inhibited by free folic acid. MTO-BSANPfolate may be endocytosed via the folate receptor on the surface of SKOV3 cells. MTO-BSANPfolate also inhibited tumor growth better than the MTO-BSANP and MTO solution in vivo. These results indicate that folate-conjugated BSANP may have therapeutic potential as a vector for anticancer drugs in cancer chemotherapy.

Preparation and characterization of folate-poly(ethylene glycol)-grafted-trimethylchitosan for intracellular transport of protein through folate receptor-mediated endocytosis.

To develop a receptor-mediated intracellular delivery system that can transport therapeutic proteins to specific tumor cells, folate-poly(ethylene glycol)-grafted-trimethylchitosan (folate-PEG-g-TMC) was synthesized. Nano-scaled spherical polyelectrolyte complexes between the folate-PEG-g-TMC and fluorescein isothiocyanate conjugated bovine serum albumin (FITC-BSA) were prepared under suitable weight ratio of copolymer to FITC-BSA by ionic interaction between the positively charged copolymers and the negatively charged FITC-BSA. Intracellular uptake of FITC-BSA was specifically enhanced in SKOV3 cells (folate receptor over-expressing cell line) through folate receptor-mediated endocytosis compared with A549 cells (folate receptor deficient cell line). Folate-PEG-g-TMC shows promise for intracellular transport of negatively charged therapeutic proteins into folate receptor over-expressing tumor cells.

Receptor mediated gene delivery by folate conjugated N-trimethyl chitosan in vitro.

Folate conjugated N-trimethyl chitosan (folate-TMC) that was used for intracellular delivery of protein before was studied as a gene delivery carrier in this study using N-trimethyl chitosan (TMC) as a reference. MTT assay indicated that the two polymers were much less toxic than PEI. Agarose gel electrophoresis indicated that the two polymers effectively condensed pDNA. TMC/pDNA complex and folate-TMC/pDNA complex were nano-scale spherical particles confirmed by atomic force microscopy. Cellular uptake of the folate-TMC/pDNA complex containing YOYO-1 labeled pDNA in KB cells was enhanced compared with that of the TMC/pDNA complex and was inhibited by free folate (1 mM) in the medium. Transfection efficiency of the folate-TMC/pDNA complex in KB cells and SKOV3 cells (folate receptor over-expressing cell lines) increased with increasing N/P ratio and were enhanced up to 1.6-fold and 1.4-fold compared with those of the TMC/pDNA complexes, however, there was no significant difference between transfection efficiencies of the two complexes in A549 cells and NIH/3T3 cells (folate receptor deficient cell lines). It was concluded that the increase in transfection efficiencies of the folate-TMC/pDNA complexes were attributed to folate receptor mediated endocytosis. Subcellular distributions of both of the complexes at different time points in the process of cellular uptake were examined by confocal laser scanning microscope, which suggested that different intracellular trafficking pathways were employed by the two complexes.

[Study on preparation and release mechanism of effervescent osmotic pump tablet of compound Danshen].

OBJECTIVE: To prepare effervescent osmotic pump tablet (EOPTs) according to the rhythm of coronary heart disease based on efficacy material and the mechanism of compound Danshen and to study the mechanism of drug released of that tablets. METHOD: Since compound Danshen consist of compounds with polyphenolic groups or carboxyl groups, such as phenolic acids, flavonoids, and triterpenoids that they were acidic. EOPTs were prepared from tablet cores which containing NaHCO3 as effervescent, NaCL and manitol as osmotic agents, HPMC as retarding agents coating with CA membrane. And study the mechanism of drug released according to the change of tablet osmotic pressure. RESULT: The results of in vitro experiments showed that no difference was observed among the profiles of Danshensu, protocatechuic aldehyde, ginsenoside Rg1, Rb1, notoginsenoside R1 release EOPTs. The drug was completely released from the device with a zero-order release rate over 12 h. CONCLUSION: EOPTs are Successfully obtained EOPT which the drug is released from the device over 12 h and the release mechanism of EOPTs is explained.

[Influence of solid dispersion technique combination on dissolution of tanshinone IIA].

OBJECTIVE: To compare the influence on the dissolution of tanshinone IIA (TS IIA) solid dispersions in complex carriers and single, which used in preparation of TS IIA solid dispersions, and further enhance the dissolution of TS IIA. METHOD: The TS IIA solid dispersions were prepared by solvent technique with polyvinylpyrrolidone K30 (PVPK30), poloxamer188 (F68) and combination of PVPK30 and F68 as carriers, respectively. The physical characteristics of TS IIA solid dispersions was studied using differential scanning calorimetry (DSC). Dissolution rates were studied using small cup method (CHP XC III). The solubility of TS IIA with the solid dispersions and pure drug form were determined by HPLC method. RESULT: The DSC analysis suggested that TS IIA was dispersed as an amorphous form in the combination of PVPK30 and F68. Dissolution profile of the prepared solid dispersions could be described by Weibull equation (R>0.99). For tested three carries, Td value (calculated time to 63.2% of total drug release according to Weibull equation) were (90.40 +/- 2.82) min, (204.5 +/- 8.20) min and (25.83 +/- 0.13) min, respectively. The PVPK30/F68-TS IIA solid dispersion resulted in a significant increase of TS IIA solubility compared with prepared PVPK30-TS IIA and F68-TS IIA solid dispersions (P<0.01). CONCLUSION: As compared to single use of PVPK30 or F68, the combination of PVPK30 and F68 improve the dissolution rate and solubility of TS IIA significantly in the prepared solid dispersions (P<0.01). The application of complex carriers in solid dispersion technology should be paid more attention to improvement of poorly soluble drugs dissolution in the future.

[Therapeutic effect and toxicity of compound vincristine liposome on breast cancer in nude mice].

This study was intended to assess the therapeutic effect and toxicity of Compound vincristine liposome on breast cancer in nude mice. The mammary cancer models of BALB/c nude mice were set up using MCF-7 cells, and were divided into seven groups: MTO-VCR-LP, MTO-VCR-Soln, VCR-LP, VCR-Soln, MTO-LP, MTO-Soln and 0.9% NaCl. After the first treatment in the same day of transplantation, different treatments were given respectively. According to the design, the BLAB/c nude mice were given the therapy, the weight of nude mice and tumor volume were measured, and the tumor growth inhibitory rate was calculated. Bone marrow smears and extravasation injury were observed. The tumor growth inhibitory rates were higher in MTO-VCR-LP and MTO-VCR-Soln groups than in other groups. MTO-VCR-Soln, VCR-Soln and MTO-Soln led to severe local extravasation injury. MTO-VCR-Soln cause serious bone marrow inhibition of nude mice. The average weight of nude mice in the three liposome groups was higher than that in the three solution groups. So the use of liposome as the carriers of the two anticancer drugs could improve the cure rate of cancer and decrease the side-effects. This work, which not only expanded the research field of liposome but also brought in new ideas and new methods to treat cancer. Furthermore, the findings in this research may have the potential for use in clinical practice.

[Preparation and release characterization in vitro of pulsed-release tablets of compound Danshen].

OBJECTIVE: To prepare pulsed-release tablet (PTS) according to the rhythm of coronary heart disease based on efficacy material and the mechanism of compound Danshen. METHOD: PTS were achieved by coating the core which contains drugs, CMS-Na, lactose, succinic acid and MCC with separation layer (Eudragit RL), swelling layer (HPMC E5), and controlled-release membrane (Eudragit RS-RL-EC). RESULT: The results of in vitro experiments showed that no difference was observed among the profiles of Danshensu, protocatechuic aldehyde, ginsenoside Rg1, Rb1, notoginsenoside R1 release from the two-step release system. And it indicated that swelling was the basis and prerequisite for drug release from PTS, and the diffusion, organic acid-induced, and osmotic pumping mechanism were involved in drug release, but the latter they were the dominant factors. CONCLUSION: Successfully obtained the PTS of a certain lag-time behind the rapid release which indicate that after bed time administration of such device, the drug plasma concentration-time curve CAN meet the requirements of chronotherapy of cardiovascular disease.

Preparation and characterization of folate conjugated N-trimethyl chitosan nanoparticles as protein carrier targeting folate receptor: in vitro studies.

Folate conjugated N-trimethyl chitosan (folate-TMC) was synthesized and characterized using Fourier transform infrared (FTIR) and (1)H spectroscopy. The fluorescein isothiocyanate conjugated bovine serum albumin (FITC-BSA) loaded TMC-nanoparticle (FB-TMC-NP) and FITC-BSA loaded folate-TMC-nanoparticle (FB-f-TMC-NP) were prepared by ionic cross-linking of TMC or folate-TMC with sodium alginate. Single factor analysis method was used to optimize the formulation of nanoparticles. The encapsulating efficiencies of FB-TMC-NP and FB-f-TMC-NP produced by optimal formulation were 98.3 +/- 1.9% and 98.7 +/- 2.7% (n=3), respectively. In addition, the mean diameters of FB-TMC-NP and FB-f-TMC-NP were 184.3 +/- 8.3 nm and 176.1 +/- 5.0 nm (n = 3), respectively. Transmission electron microscope (TEM) showed that the nanoparticles were of spherical shapes. The intracellular uptake of FB-f-TMC-NP by SKOV3 cells (folate receptor overexpressing cells) was 3.7-fold more than that of FB-TMC-NP and could be inhibited by the presence of 1 mM folate in the culture medium, although there was no significant difference between the intracellular uptake of FB-f-TMC-NP in A549 cells (folate receptor-deficient cells) and that of FB-TMC-NP in the same cells. In conclusion, the enhancement of cellular uptake of FB-f-TMC-NP by SKOV3 cells in a specific way was attributed to the folate receptor-mediated endocytosis. FB-TMC-NP was a promising carrier for protein.

[Studies on in vivo release of berberine hydrochloride from carboxymethyl konjac glucomannan pellets in rats].

OBJECTIVE: To observe the absorption and concentration of berberine hydrochloride (BH) in gastric, entric, colonic tissue after intragastric administration of BH-containing carboxymethyl konjac glucomannan pellets for evaluating colon-specific drug delivery characteristics of the pellets. METHOD: BH-containing carboxymethyl konjac glucomannan pellets (pellets group) and BH-containing carboxymethyl cellulose suspension (control group) were intragastric administrated to rats at the dose of 50 mg x kg(-1), respectively. A high performance liquid chromatography method determinated BH concentration in rat plasma and tissue. Drug delivery index (DDI) was calculated. RESULT: The range of BH in plasma and tissue in rats were 0.025 2-2.52 mg x L(-1) (r = 0.999 2) and 0.126-25.22 mg x L(-1) (R > 0.99),respectively. The detection of BH in plasma and tissue were 10 microg x L(-1) and 8 microg x L(-1), respectively. The area under the curve (AUC(0 --> infinity)) in the plasma samples of pellets group was 0.477 times that of the control group; in the gastric, entric, colonic tissue, the AUC(0 --> infinity) of pellets group was as much as 0.187, 0.228, 2.00 times that of the control group, respectively. The DDI of the pellets was 0.392 4, 0.478 6, 4.193 in the gastric, entric, colonic tissue of the rat, respectively. CONCLUSION: Carboxymethyl konjac glucomannan pellets may be a useful carrier of BH for colon-specific delivery.

[Effect of several penetration enharcers on transdermal permeation and skin accumulation of artemether].

OBJECTIVE: To investigate penetration characteristics of artemether and the effect of different permeation enhancer on transdermal permeation of artemether through rat skin. METHOD: The permeation experiments were performed using rat skin on modified Franz diffusion cells in vitro. The concentrations of artemether in receptor compartment at specified time points were determined by HPLC. RESULT: The permeating ratio through human skin of artemether solution was Js (2.78 +/- 0.78) microg x cm(-2) x h(-1), the quantity of drug penetrated through and accumulated in the skin by the end of the experiment were (69.07 +/- 3.01) microg x cm(-2), (58.93 +/- 3.56) microg x cm(-2) respectively. Four different permeation enhancers can improve the transdermal permeation of artemether. CONCLUSION: Artemether have the potential to be developed to new transdermal preparation.

[Preparation of self-microemusifying drug delivery system for volatile oil from rhizome of ligusticum Chuanxiong].

OBJECTIVE: To search on the optimum formula for the seif-microemulsifying drug delivery system of volatile oil from rhizome of ligusticum Chuanxiong. METHODS: Through solubility experiment, orthogonal screen and drawing phase diagram, taking the degree of emulsifying, the volume of the rest oil and emulsion particle size as parameters, the appropriate proportion composed of Chuanxiong oil, nonionic surfactant and flux was screened for the optimum formulation of self-microemulsifying drug delivery system. RESULTS: In the formulation of self-microemulsifying drug delivery system for volatile oil from rhizome of ligusticum Chuanxiong, taking S1 as the nonionic surfactant and C1 as the co-surfactant could get the best effect of emulsifying. CONCLUSION: The optimum formula for seif-microemulsification of volatile oil from rhizome of ligusticum Chuanxiong is volatile oil from rhizome of ligusticum Chuanxiong, S1 and C1, with their proportion being 10 : 9 : 1.

[Study on drug release of gastrodin ion-activated nasal in situ gel in vitro].

OBJECTIVE: To study on the drug release characteristics and mechanism of gastrodin ion-activated nasal in situ gel in vitro. METHOD: Regularity and mechanism of the drug release of gastrodin nasal in situ gel were studied by using the diffusion cell model and the membrane-less dissolution model, respectively. A novel kinesis diffusion cell model was designed according to the characteristics of release environment of nasal cavity. It was used to investigate the effect of adhesiveness on the release of the in situ gel. RESULT: Drug release of gastrodin nasal in situ gel followed the one order release model. Erosion rate of the gel was low and not linearly correlated with the release rate. Compared with gastrodin solution, the nasal in situ gel could increase release time and release amount. CONCLUSION: Gastrodin in the nasal in situ gel is released mainly by diffusion rather than erosion. Release amount of the in situ gel in nasal cavity may be obviously increased because of its adhesiveness.