ABSTRACT
Objective: To prepare the rhynchophylline nanosuspensions and lyophilized powder, and study its sustained-release tablets. Methods: Rhynchophylline nanosuspensions were prepared by microprecipitation combined with high pressure homogenization method, and the particle size and zeta potential were determined. Scanning electron microscopy (SEM) was employed to observe the appearances of nanosuspensions. Nanosuspensions were prepared into lyophilized powder using lactose as freeze-dried protectors. HPMC (hydroxypropyl methyl cellulose) was used as hydrophilic matrix to prepare the sustained-release tablets. Single factor investigation and orthogonal experiments were employed to optimize the formulation of rhynchophylline nanosuspensions sustained-release tablets, and the model fitting was also been studied. Results: The particle size and zeta potential of rhynchophylline nanosuspensions were (153.7 ± 4.9) nm and (-18.54 ± 1.32) mV, respectively. The appearances of rhynchophylline nanosuspensions were spherical or nearly spherical. After orthogonal optimization, the cumulative release rate of rhynchophylline nanosuspensions sustained-release tablets was 92.53% in 12 h. The optimized formulation of hydrogel matrix sustained-release tablets was better accorded with Higuchi model: ln(1-Mt/M∞)=0.286 0 t1/2-0.069 0 (r=0.992 4). The drug release from hydrogel matrix sustained-release tablets were controlled by diffusion and degradation. Conclusion: The obtained rhynchophylline nanosuspensions has small particle size. The prepared hydrogel matrix sustained-release tablets can control the release of rhynchophylline nanosuspensions in a slow characteristic.
ABSTRACT
Objective To prepare brucine solid lipid nanoparticles (SLN) and its lyophilized powder, and then hydrogel matrix sustained-release tablets (HMST) of brucine SLN (SLN-HMST) were prepared. The factors that may influence drug release in vitro and release mechanism were also investigated in present study. Methods Based on single factor test, orthogonal test was designed to gain the optimum prescription. Zero-order, First-order and Higuchi models were used for the model fitting of drug release. Ritger-Pappas models were employed to study release mechanism of brucine SLN-HMST. Results Brucine SLN-HMST was better agreed with First-order kinetics model. The equation was ln(1-Mt/M∞) = -0.212 1 t + 0.106 4 (r = 0.992 3). The cumulative release could achieve 91.48% in 12 h. The sustained release features were obviously. The drug release from the tablets was controlled by diffusion and degradation of the matrix. Conclusion The prepared brucine SLN-HMST can deliver drug continually for 12 h with good reproducibility.
ABSTRACT
Objective To prepare luteolin solid dispersions (Lut-SD) and luteolin phospholipids complex solid dispersions (Lut-PC-SD), and compare the effects of two kinds of solid dispersions on the bioavailability in vivo. Methods PVP K30 was employed as carrier, and solvent evaporation method was used to prepare Lut-SD and Lut-PC-SD. Their existential state of luteolin in solid dispersions was analyzed by X-ray power diffraction (XRPD). The solubility and dissolution rate were also studied. SD rats in each group were administered intragastrically with Lut, Lut-SD, and Lut-PC-SD, respectively. Their blood samples were collected at different time intervals. Diosmetin was used as internal standard, the concentration of Lut in blood was analyzed by HPLC, and the main pharmacokinetic parameters were obtained. Results The results of XRPD indicated that Lut showed an amorphous state in Lut-SD and Lut-PC-SD. The solubility of Lut was enhanced from (61.09 ± 0.09) μg/mL to (365.33 ± 0.38) μg/mL and (401.14 ± 0.19) μg/mL by Lut-SD and Lut-PC-SD, repectively. The dissolution of Lut was also improved greatly by the two kinds of solid dispersions. Compared to Lut, the bioavailability of Lut-SD and Lut-PC-SD was enhanced to 150.10% and 204.52%, repectively. Conclusion Lut-SD and Lut-PC-SD both could enhance the bioavailability of Lut in SD rats notably. In addition, Lut-PC-SD could give a better effect.
ABSTRACT
Objective To use the inclusion technology for improving the solubility and dissolution rate of baicalein from monolithic osmotic pump tablet containing inclusion complex of baicalein by observing the effects of the core and coating on in vitro drug release. Methods Baicalein-inclusion complex was prepared by the inclusion technique, and its solubility and dissolution rate were determined. The percent of cumulative release was used to evaluate the drug release profile in vitro. Single factor analysis was used to study the effects of NaCl and PEO amounts, coating weight and plasticizer amount on drug release. Then orthogonal design was used to select the optimal formulation of monolithic osmotic pump tablet containing baicalein-inclusion complex. Results The solubility and dissolution rate of baicalein were greatly enhanced when prepared into inclusion complex. Orthogonal design results indicated that PEO content in the tablet core and plasticizer PEG 400 in the coating had significant effects on the drug release, and the optimum formulation was: baicalein-inclusion complex 180 mg, NaCl 100 mg, PEO 80 mg, coating weight 4% and plasticizer 9%. The tablets with optimized formula achieved the desired zero-order release profile (r=0.997 8) within 12 hours and the cumulative release was higher than 88%. Conclusion Monolithic osmotic pump tablet of baicalein has been successfully prepared using inclusion complex as the intermediate, and the release behavior accords with zero-order kinetics equation.