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??OBJECTIVE To prepare and optimize meloxicam nanosuspensions fast dissolving sublingual films (MLX-NS-FDSFs) and to evaluate its in vitro dissolution characteristics. METHODS Meloxicam nanosuspensions (MLX-NS) were prepared by pH-dependent dissolving-precipitating/high speed shearing method and then transformed into fast dissolving sublingual films (FDSFs). The formulations of MLX-NS-FDSFs were optimized by employing Box-Behnken design-response surface methodology with the amount of HPMC-E30, PEG-400 and MLX-NS as investigation factors, and particle size of reconstituted nanoparticles from MLX-NS-FDSFs, disintegration time and stretch length as indexes. The morphology, content uniformity and in vitro dissolution of the optimal formulation were also evaluated. RESULTS The MLX-NS-FDSFs prepared by optimized formulation (35 mg??mL^-1 HPMC-E30, 40 mg??mL^-1 PEG-400, 10 mL MLX-NS) could fast disintegrate in (26.08??1.76) s, the tensile length was (1.51??0.13) mm, and the particle size of reconstituted nanoparticles from MLX-NS-FDSFs was (186.4??6.3) nm. There was a little deviation between the theoretically predicted value and the measured value. It showed that this model had a good prediction. Morphological analysis showed that well-dispersed MLX nanoparticles embedded in MLX-NS-FDSFs. The conformity of drug content was up to standard. MLX could be released in vitro as much as (91.75??8.05)% within five minutes. CONCLUSION Using Box-Behnken design and response surface method to optimize MLX-NS-FDSFs is effective and feasible. MLX-NS-FDSFs can significantly increase the cumulative dissolution of MLX.     

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??OBJECTIVE To enhance dissolution rate of silymarin (SM) by forming SM nanoparticles (SM-NA) with supercritical anti-solvent (SAS) method. MOTHODS Single-factor test was employed to investigate the influencing factors of particle size and yield of SM-NA, such as pressure, temperature, flow rate, and concentration of the solution. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to determine the state of SM-NA. The dissolution characteristics in vitro were investigated with 0.3% SDS aqueous solution as the solvent and compared with the SM powder. RESULTS Taking size distribution as well as yield of SM-NA as the evaluation indexes, the optimal prepration parameters were selected as followings:pressure 15 MPa, temperature 35 ??, flow rate 1.5 mL??min^-1, concentration 100 mg??mL^-1. The XRD and DSC of SM-NA described the decrease of SM in crystallinity, and it was transformed mostly with the amorphous state, compared with the SM powder. The accumalte release rate of SM-NA achieved 80% within 10 min, markedly higher than that of the SM powder and its commercial preparation. CONCLUSION The SM-NA prepared by SAS has remarkablly smaller particle size thus can greatly improve the in vitro release of SM.
     

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??OBJECTIVE To prepare atorvastatin-loaded tetracycline-PEG-PLGA(TC-PEG-PLGA/ATO) polymeric micelles, and investigate its pharmaceutical characteristics and targeting function in vitro. METHODS The amphiphilic TC-PEG-PLGA conjugate was synthesized via an esterification reaction and identified by the ¹H-NMR. Water insoluble atorvastatin was loaded on TC-PEG-PLGA conjugate micelles via dialysis method. The morphology of TC-PEG-PLGA/ATO micelles was observed under transmission electron microscope. The particle size distribution and Zeta potential of TC-PEG-PLGA/ATO micelles were determined by dynamic light scattering method. The drug loading and encapsulation efficiency were measured by HPLC, and in vitro release behavior was investigated via dialysis method. In vitro cytotoxicity was assessed via MTT assay, and bone-targeting activity was investigated via binding to the hydroxyapatite powder. RESULTS TC-PEG-PLGA/ATO micelle was prepared successfully, and its particle size and Zeta potential were (47.2??4.7) nm and (-14.25??0.31) mV. The encapsulation efficiency and drug loading rate were(98.2??1.51)% and (8.71??0.23)%, respectively. Moreover, the accumulative release of ATO in vitro was about 70% in 48 h, which indicated that the drug was released slowly from the micelles. In vitro cell evaluation showed that TC-PEG-PLGA conjugate micelles were great biocompatibility with MC3T3-E1 cells within the concentration range of 100-500 ??g??mL^-1. In vitro targeting performance indicated that the proportion of the TC-PLGA NPs bound to Hap(87.94%) was greater than the bound proportion of PLGA NPs(18.59%). CONCLUSION The TC-PEG-PLGA/ATO micelles exhibit small partical size and good stability, and significantly increased ATO content in aqueous solution. TC-PEG-PLGA/ATO micelles have good delayed release behavior, safety and binding efficacy to the hydroxyapatite powder.     

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??OBJECTIVE To establish a measuring method for microdialysis probe recovery of ginsenoside Rg₁ and investigate the effects of flow rate, concentration and using times of probe on the recovery in vivo and in vitro. METHODS Dialysis method and retrodialysis method were used for the study. The concentration of ginsenoside Rg₁ in brain and blood dialysate was determined by LC-MS/MS and the probe recovery was calculated. RESULTS The recoveries of brain and blood microdialysis probes showed good stability within 10 h, with average values of 17.0% and 34.4% respectively for ginsenoside Rg₁ at 1.5 ??L??min^-1. Concentrations (50,200,500,1 000 ng??mL^-1) had no obvious effect on recovery. At the same concentration, the recovery of brain and blood probes for ginsenoside Rg₁ decreased with the increase of flow rate (0.5, 1.0, 1.5, 2.0, 3.0 ??L??min^-1) in vitro and in vivo. The dialysis recoveries of brain and blood probes in vitro were (40.6??4.3)%, (23.5??2.3)%, (17.7??0.8)%, (12.2??1.1)%, (8.8??0.6)% and (70.6??3.6)%, (46.0??2.1)%, (32.9??1.6)%, (25.6??0.7)%, (18.2??1.3)%, respectively. The recoveries of dialysis and retrodialysis in vitro were approximately equal, and the recovery detected by retrodialysis in vivo was similar with the in vitro results. Probe used for no more than 3 times still kept high transmittance by flushing with 2% heparin sodium and ultrapure water successively. CONCLUSION Retrodialysis method can be used to study brain and blood probe recovery in vivo, and microdialysis can be used for simutaneous pharmacokinetic studies of ginsenoside Rg₁ in intercelluar fluid and blood.     

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??OBJECTIVE To prepare nano-micelles with amphiphilic self-assembly poly (ethylene glycol)-co-poly (propylene sulfide) (PEG-PPS) copolymer as carrier to study the release characteristics of tilianin and investigate its activity to against H9c2 cell apoptosis in vitro. METHODS An amphiphilic diblock PEG-PPS polymer was used as a carrier material to prepare the tilianin-containing nano-micelles by solvent evaporation. The morphology, particle size and distribution, drug loading and encapsulation rate and in vitro drug release behavior were characterized, H9c2 rat myocardial cell injury model was established by hypoxia/reoxygenation process. Using propranolol (Pro) as a positive control, the morphology of injured cardiomyocytes was observed by microscope. Cell proliferation and cell apoptosis was detected to evaluate the protective effect of blank micelles, tilianin and tilianin loaded nano-micelles on H9c2 cells induced by hypoxia/reoxygenation. RESULTS Tilianin-loaded nano-micelles was spherical with uniform particle size distribution. The drug loading was 3.82%. The average particle diameter of tilianin-loaded nano-micelles was 137 nm, polydispersity coefficient was 0.162 and the encapsulation efficiency was 91.45%. In vitro drug release studies showed that there was no drug-induced burst release of tilianin-containing nano-micelles and sustained release characteristics, and the presence of hydrogen peroxide significantly promoted the release of tilianin from the nano-micelles. In vitro cytotoxicity experiments showed that when the concentration of tilianin 5 ??g??mL^-1, the cell viability of tilianin-loaded nano-micelles was significantly higher than the corresponding concentration of tilianin and PEG-PPS polymer nano-micelles. In vitro anti-apoptotic activity experiments show that tilianin-loaded nano-micelles on H9c2 cell apoptosis induced by hypoxia-reoxygenation have a significant inhibitory effect and was provided inhibition of apoptosis with propranolol. CONCLUSION Tilianin-loaded nano-micelles have uniform particle size and distribution, sustained release and oxidation characteristics, has a significant protective and apoptosis-inhibiting effect on H9c2 cell injury induced by hypoxia-reoxygenation, which can be used as a promising drug delivery system for the treatment of myocardial ischemia-reperfusion injury.     

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??OBJECTIVE To evaluate the effects of drug concentration and perfusion rate on the recoveries of self-made linear microdialysis probes for further ocular pharmacokinetic study. METHODS Brimonidine tartrate was selected as the model drug. The in vitro recovery was determined using positive dialysis and retrodialysis at different perfusion rates and drug concentrations. And the in vivo recovery was determined using retrodialysis method. RESULTS The microdialysis recoveries of brimonidine tartrate were inversely proportional to perfusion rate,while independent of drug concentration. The positive dialysis and retrodialysis recoveries in vitro were different at 1.0 ??L??min^-1, but no significant difference at 2.0 and 3.0 ??L??min^-1. The in vitro recoveries were greater than those in vivo. CONCLUSION The self-made microdialysis probe has stable recovery and can be used in ocular pharmacokinetic study of brimonidine tartrate.     

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??OBJECTIVE To prepare docetaxel liposomes by freeze-drying of tert-butyl alcohol (TBA)/water cosolvent system and evaluate the in vitro and in vivo properties. METHODS The formulation was optimized by single factor screening experiments. The effects of TBA/water ratio, lipid/drug ratio, sucrose/lipid ratio and mixing temperature on encapsulation efficiency were investigated. The in vitro release profiles were also investigated with docetaxel injection(Duopafei^?k) as control. RESULTS The formulated liposomes had a mean size of 263 nm with entrapment efficiency of (88.45??1.63)% at TBA/water ratio 50??50, lipid/ drug ratio 10??1, sucrose/lipid ratio 5??1 and mixing temperature 60 ??. In vitro drug release from liposomes lasted for 48 h. CONCLUSION Freeze-drying of TBA/water cosolvent system method may be feasible to prepare docetaxel liposomes.     

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??OBJECTIVE To prepare lappaconitine(LA)-loaded chitosan/ sodium ??-glycerophosphate(CS/??-GP) thermosensitive hydrogels and investigate its phase transition mechanism of gel formation process and release properties in vitro. METHODS The injectable CS/??-GP thermosensitive hydrogels were prepared with biodegradable CS as carrier material and ??-GP as coagulation accelerator. The release behavior in vitro was studied by dynamic dialysis, and the phase transition mechanism of gel formation process was further investigated by rheological method. RESULTS The optimized process condition was as follows:the concentration of ??-GP and CS was 560 and 22 mg??mL^-1, respectively, CS was dissolved by 0.1 mol??L^-1 HOAc, and the valume ratio of CS to ??-GP was 8.75??1.25(V/V), the gelation time of CS/??-GP thermosensitive hydrogels with volume ratio of 8.75??1.25(V/V) at 37 ?? was 5 min 38 s. The in vitro release study showed that these injectable CS/??-GP thermosensitive hydrogels had sustained release effect for LA, and the release behavior could be well described by the Higuchi model and Korsmeyer-Peppas model. The mechanism of LA releasing from CS/??-GP thermosensitive hydrogels was attributed to drug dissolution and diffusion. Rheological studies showed that the CS/??-GP thermosensitive hydrogels belonged to thixotropic system and exhibited non-Newtonian and shear-thinning fluid behavior as well as ??solid-like?? gelatin behavior. CONCLUSION LA-Loaded CS/??-GP injectable thermosensitive hydrogels with good elasticity and gel strength properties are prepared successfully, and they show sustained release effect of LA in vitro.     

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??OBJECTIVE To prepare the tulobuterol crystal reservoir patch, and to evaluate morphology, stability and crystallization factors of the crystal in the patch, adhesive force, dissolution, transdermal properties in vitro and the pharmacokinetics in rabbits. METHODS The transdermal patch was prepared on the basis of drug recrystallization and characterized by morphology, stability and crystallization factors using microscope and adhesive force using initial adhesion tester, adhesion tester and peel tester. The dissolution and transdermal properties were evaluated by using the dissolution tester and transdermal tester. In addition, pharmacokinetics was studied using New Zealand rabbits as experimental animals. RESULTS The drug crystals were evenly distributed in the form of filaments, which had average width of (4.4??1.8)??m and kept stable at 2-40 ??. The crystallization in patches is affected by tulobuterol supersaturation and temperature. The adhesive force of patch was suitable and its dissolution matched standard which can be fitted by the Higuchi equation. In the diffusion cell in vitro, the drug penetrated through the skin in a Zero-order kinetic equation, and the cumulative penetration percentage and skin retention concentration were 92.04% and 10.36 ??g??cm^-2 with in 24 h. The pharmaceutic parameters showed that the tulobuterol blood concentration can be maintained within 24 h, whose t_max and ??_max were (6.67??3.06)h and (3.08??1.32) ng??mL^-1, respectively. CONCLUSION The tulobuterol crystal reservoir patch can be established by control of recrystallization conditions. The patch has good adhesive properties and sustained release characteristics in vitro and in vivo, which has the practical significance for further study.