ABSTRACT
Oral administration is the most convenient way of drug delivery， but due to the existence of intestinal barrier， the oral bioavailability of drugs is generally low， especially for drugs with low water solubility， poor permeability and macromolecules. For decades， researchers have demonstrated that nano-delivery system is one of the most effective strategies to solve this problem， but nano-delivery systems have shown limited improvement in the oral bioavailability of drugs. Therefore， researchers have proposed to use transporter-mediated nano-delivery systems to promote the oral absorption of drugs. The intestinal tract were highly expressed as a transporter for ingesting various nutrients（such as glucose， oligopeptides and bile acids）， which was an excellent target of oral drug delivery system. Its substrate were modified on the nano-delivery system， and the loaded drugs could cross the intestinal barrier and enter the systemic circulation more efficiently through the targeting effect of transporters. At present， more and more evidences supported the potential of transporters in the field of oral drug delivery system. Therefore， this paper reviewed the research on intestinal transporters-mediated nano-delivery system to promote oral absorption of drugs， including the distribution of intestinal transporters， three strategies of transporter substrate modification， the transport properties of different types of transporters and their effects of mediating the nano-delivery system for promoting the oral absorption of drugs or treating diseases， with the aim of providing an important theoretical reference for the development of intestinal targeted nano-delivery systems.
ABSTRACT
OBJECTIVE:To investigate the preparation technique and optimal formulation of ketoconazole calcium alginate gel beads.METHODS:Ketoconazole calcium alginate gel beads were prepared by droplet method.The orthogonal experiment was carried out with encapsulation efficiency(EE)and drug loading(LD)as indexes to optimize the optimal formulation of the calcium alginate gel beads.The encapsulation efficiency and drug loading amount for the optimized formulation were determined,and the optimized formulation was compared with crude drug in respect of the in vitro drug release behavior.RESULTS:The result showed that the optimal formulation was as follows:2.0% Na-alginate and 0.3mol? L-1 CaCl2 with the ratio of Na-alginate:ketoconazole at 2∶ 1.The average EE and LD were(90.53? 2.32)% and(31.51? 2.08)%,respectively,and the slow-release was better as compared with that of the crude drug.CONCLUSION:The preparation procedure is simple,feasible,stable and reproducible.
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Objective To investigate the preparation technique and optimal formulation of Breviscapine Chitosan-alginate Microcapsula. Methods Breviscapine Chitosan-alginate Microcapsula was prepared by coacervate technology. The orthogonal test design by adopting the standard of drug encapsulation efficiency and drug loading was applied to obtain the optimal formulation of the microcapsula. Results The result showed that the optimal formulation was that Na-alginate 25 mg/mL, chitosan 2 mg/mL, CaCl2 0.2 mol/L, and Na-alginate-Breviscapine 1∶1. Conclusion The preparation procedure is simple, feasible, stable, and repeatable.
ABSTRACT
OBJECTIVE:To prepare aspirin chitosan-sodium alginate microcapsules(ACSPM)and to investigate its optimal formula and releasing mechanism.METHODS:The formula of ACSPM was optimized by the orthogonal design with entrapment ratio as index,and then ACSPM was prepared,with its release rate determined as well.The releasing mechanism of aspirin from the microcapsules was established by equation fitting of releasing kinetic model.RESULTS:The prepared microcapsules were uniform in size and contents.The optimized formula was as follows:the concentration of sodium polymannuronate and chitosan were 3.0% and 1.0%,respectively,and the proportion of polymannuronate to aspirin was 1∶ 4.The in vitro drug release was in line with both Higuchi equation and Peppas equation.CONCLUSION:This preparation technology was simple and the drug releasing mechanism of the preparation was chiefly characterized by drug diffusion including bulk erosion non-Fickian process.