Double-layer nanoparticles loaded with rhBMP-2 and SDF-1:Preparation,characterization and drug re-lease in vitro / 实用口腔医学杂志

Objective:To construct double-layered controlled release system containing SDF-1 and rhBMP-2 molecules and to study the release profile of the system in vitro.Methods:The polylactic acid/chitosan(PLA/CS)nanoparticles were prepared with “emulsification-solution evaporation method”,the preparation parameters were determined by orthogonal test design.The particle size was observed by nanoparticle size analyzer,the morphology of the nanoparticles was observed with electron microscope.Then rhBMP-2 and SDF-1 were loaded into the nanoparticles in the process of emulsification,the loading efficiency and encapsulation efficiency were calculated and in vitro release was observed.Results:The double-layer nanoparticles showed spherical geometry,smooth surface and complete separation. The average particle size of the nanoparticles was (542.33 ±14.38)nm;The drug loading and incorporation efficiency of rhBMP-2 were (82.41 ±1.05)% and (24.67 ±0.43)ng/mg,those of rhBMP-2 were (75.58 ±0.84)% and (22.63 ±0.41)ng/mg,respectively. The release time of the drug from the system sustained over at least 30 days,the release profile of both drugs showed “biphasic release”. The cumulative release rate of SDF-1 and rhBMP-2 was 72.85% and 91.01% in 30 days respectively.Conclusion:The SDF-1 and rh-BMP-2 loaded PLA/CS nanoparticles have excellent morphology,high entrapment and good sustained-release in vitro.

Preparation of lappaconitine-loaded chitosan/sodium β-glycerophosphate injectable thermosensitive hydrogels and research on its properties / 中国药学杂志

OBJECTIVE: To prepare lappaconitine (LA)-loaded chitosan/sodium β-glycerophosphate (CS/β-GP) thermosensitive hydrogels and investigate its phase transition mechanism of gel formation process and release properties in vitro. METHODS: The injectable CS/β-GP thermosensitive hydrogels were prepared with biodegradable CS as carrier material and β-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 rheologieal method. RESULTS: The optimized process condition was as follows;the concentration of β-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 β-GP was 8.75:1.25 (V/V), the gelation time of CS/β-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/β-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/β-GP thermosensitive hydrogels was attributed to drug dissolution and diffusion.Rheologieal studies showed that the CS/β-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/β-GP injectable thermosensitive hydrogels with good elasticity and gel strength properties are prepared successfully, and they show sustained release effect of LA in vitro.

Interpenetrating polymer network of cross-linked blend microspheres for controlled release of Acebutolol HCl.

Carbohydrate polymeric blend microspheres consisting of chitosan (CS) and poly (vinyl alcohol) (PVA) were prepared by water-in-oil (W/O) emulsion method. These microspheres were crosslinked with glutaraldehyde and loaded with Acebutolol HCl, an anti hypertensive drug. The microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), X-Ray diffraction (X-RD) and Scanning electron microscopy (SEM).The FTIR spectroscopy explains the crosslinking between the CS-PVA. DSC& X-RD indicated the molecular level distribution of Acebutolol HCl drug in the polymer matrix. The SEM of the microspheres suggested the formation of spherical particles. Swelling experiments on the microspheres provided important information on drug diffusion properties. Release data have been analyzed using an empirical equation to understand the nature of transport of drug containing solution through the polymeric matrices. The controlled release characteristic of the matrices for Acebutolol HCl was investigated in pH 7.4 media. The results indicate that the drug was released in a controlled manner up to 10 h.

Studies on cetyl-chitosan nanosphere as carriers for paclitaxel / 中草药

Object To prepare and study a suitable carrier for paclitaxel in water. Methods Cetyl chitosan (CTCS), prepared by reacting chitosan (CS) with chlorocetane under alkaline condition, was soluble and spontaneously formed nanosphere about 100 nm in diameter. And the release in vitro from paclitaxel loaded CTCS nanosphere was measured in phosphate buffer solution (PBS, pH=7 4). Results The balanced release concentration of paclitaxel was deceased and half release time (t 1/2 ) was delayed with the increase of substitution degree of alkyl. Conclusion This kind of nanosphere is an excellent carrier for paclitaxel in water.