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OBJECTIVE: To prepare gossypol nanosuspensions and investigate their physicochemical properties and intestinal absorption behavior in rats. METHODS: Gossypol nanosuspensions were prepared by a high pressure homogenization method. Nanosuspensions' characteristics were investigated from particle size distribution, Zeta potential, particle morphology, crystal physical state, storage stability, saturation solubility, and in vitro release. Nanosuspensions' intestinal absorption characteristics were also observed in rats. RESULTS: The nanosuspensions existed as uniform rods. The mean particle size was (217±23) nm, and Zeta potential was -22.7 mV. Gossypol existed in crystalline form. Long-term stability test showed that gossypol nanosuspensions were stable at 4°C for 3 months. The experiment of intestinal absorption showed that the nanosuspensions could be absorbed through passive diffusion with significant variation at different sections. The experiment also showed that the absorption process was not affected by the efflux of P-glyco-protein (drug efflux pump). CONCLUSION: Gossypol nanosuspensions are successfully developed. The solubility in water and the release in vitro of the nanosuspensions are enhanced compared with the bulk drug of gossypol. This study provides a reference for the further pharmaceutical study of gossypol.
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OBJECTIVE: To prepare a new puerarin self-microemulsion to reduce the toxicity of traditional self-microemulsion and maintain the characteristics in vitro and in vivo.
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OBJECTIVE: To investigate the absorption characteristics of dauricine in rat intestine. METHODS: In situ single-pass perfusion model was used and the concentrations of dauricine in perfusate were determined by HPLC. The effects of perfusion rates, intestinal segments and drug concentrations on the intestinal absorption of dauricine were studied. RESULTS: The absorption rate and absorption degree of dauricine increased with the perfusion rates(0.1, 0.2 and 0.4 mL · min-1)(P0.05); at high, middle and low concentrations, the drug absorption rate constants(Ka) were (2.36±0.0073) × 10-2, (3.73 ± 0.0052) × 10-2 and(5.62 ± 0.0136) × 10-2 min-1, respectively, the apparent permeation coefficients(P.,) were(2.02±0.0002) × 103, (3.10±0.0007) × 10-3 and (5.31±0.0010) × 10-3 cm · min-1, respectively, the absorption percentages(P%) were 8.66%, 10.17% and 19.06%, respectively, and the accumulate absorption amount and accumulate absorption percentages of different concentrations at different time were very low. CONCLUSION: The absorption degree of dauricine increases with perfusion rates; there is no specific absorption site in the whole rat intestinal tract; the absorption of dauricine is very poor and the active transport is involved in the absorption mechanism of dauricine.
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0.05).But the P_ eff values were significantly increased in the presence of P-glycoportein(P-gp)inhibitor,verapamil or digoxin.CONCLUSION:Rhamnosylvitexin can be classified into high penetrating drug.Passive diffusion dominates the absorptive transport behavior of rhamnosylvitexin in HLF.There is not a preferential absorption zone in the intestine for rhamnosylvitexin.The absorption and secretion of rhamnosylvitexin in HLF are mediated by the efflux transport system,P-gp.