ABSTRACT
Objective To investigate the influences of polyethylene glycol on the solubility and in vitro dissolution of m-nisoldipine,which could provide guidance for chosing formulations of m-nisoldipine. Methods Solid dispersions of m-nisoldipine were prepared by solvent-melting method with polyethylene glycol6000 matrix. DSC and XRD spectroscopy were applied to identify the solid dispersions. The solubility and in vitro dissolution were detected by UV spectroscopy. Results The DSC and XRD map were different from the crude drug and their physical mixtures. The dissolution rates(13,15,17) were faster(35. 31%,38. 71%,41. 48%) than that of the crude drug(26. 80%),and the dissolution rates of the solid dispersions in the same ratio were higher than the physical mixtures. Conclusion DSC analysis indicated that eutectic compounds were produced by the m-nisoldipine and polyethylene glycol,in which polyethylene glycol6000 acts as a carrier. The solubility and in vitro dissolution of m-nisoldipine can be increased.
ABSTRACT
Effects of different procedures of magnetic nanoparticles into the liposome structure on the distribution of magnetic particles in the liposome were investigated. Magnetic liposomes with high-encapsulating rate of cisplatin (CDDP) were obtained. Fe3O4 magnetic nanoparticles which was modified by organic functional group on surface was synthesized by an one-step modified hydrothermal method. The CDDP magnetic liposomes were prepared by a film scattering-ultrasonic technique and the concentrations of CDDP in the liposomes were measured by graphite furnace atomic absorbance spectroscopy. Magnetic liposomes with different microstructure were prepared by the two different procedures, where the magnetic particles were combined with phospholipid before the film preparation to form liposome in procedure I, and drug solution and the magnetic particles were mixed before hydrating the lipids film to form liposome in procedure II. The liposome structure was observed by transmission electron microscope (TEM). The CDDP magnetic liposomes were prepared by the optimized method which was selected by orthogonal test. Encapsulation rate of the magnetic particles distributed in the phospholipid bilayer through the procedure I was 34.90%. While liposome, produced by the procedure II technique, contained magnetic particles in the interior aqueous compartment, which encapsulation rate was 28.34%. Encapsulation rates of both I and II were higher than that of conventional liposome. The release profile of all the three different liposomes in vitro fitted with a first-order equation. Because of distribution of magnetic particles in the phospholipid bilayer, the skeleton of phospholipid bilayer was changed. The releasing tl/2 of magnetic liposomes produced by the procedure I technique is 9 h, which is shorter than that of the other two liposomes. Assemble of magnetic nanoparticles into the structure of liposome was succeeded by the procedure I, which showed superiority than by procedure II whatever in CDDP liposome encapsulation efficiency and content of the magnetic particles and would ensure sustained-release character.
ABSTRACT
OBJECTIVE:To prepare m-nisoldipine solid dispersion from poorly-soluble m-nisoldipine so as to improve its solubility and dissolution rate in vitro. METHODS: Solid dispersions of m-nisoldipine were prepared by coprecipitation method with poloxamer as carrier; Differential scanning calorimetry (DSC) was used to determine the status of nimodipine in carrier. The solubility and the dissolution rate of the solid dispersion in vitro were studied. RESULTS: DSC analysis indicated that eutectic mixture was formed from m-nisoldipine and poloxamer. The solubility of m-nisoldipine and the its solid dispersions prepared from m-nisoldipine and poloxamer at different ratio (1∶3, 1∶5, 1∶7) were 0.89, 4.50, 15.35, and 23.03 mg?L-1, respectively, and their 120 min dissolution rates were 26.80%, 38.57%, 41.38%, and 45.92%, respectively. In the same ratio, the dissolution rates of the solid dispersions were higher than those of their physics mixtures. CONCLUSIONS: The solid dispersion of m-nisoldipine prepared with poloxamer as carrier can increase the solubility and dissolution rate in vitro.