Preparation, characterization and uptake by primary cultured rat hepatocytes of liposomes surface-modified with glycyrrhetinic acid.

3-succinyl-30-stearyl glycyrrhetinic acid (Suc-GLAOSt) was synthesized as a targeting molecule, and incorporated in ordinary to liposomes (LP) to prepare a liposome surface-modified with glycyrrhetinic acid (LP-GLA), which could bind to the hepatocyte through the specific binding site of glycyrrhetinic acid (GLA) on the surface of rat cellular membrane. The maximal molar ratio of Suc-GLAOSt to total lipids in LP-GLA was 1:10. Calcein loaded liposome (Cal-LP) and calcein loaded LP-GLA (Cal-LP-GLA) were prepared by an ethanol injection method. The average diameter of Cal-LP and Cal-LP-GLA was 65 nm +/- 16 nm and 68 nm +/- 21 nm, respectively. The characteristics of cellular uptake of the two types of liposome were investigated through cellular uptake and competitive inhibition experiments. The uptake of Cal-LP-GLA by rat hepatocytes was markedly higher (3.3-fold) than that of Cal-LP (P < 0.01). The uptake of Cal-LP-GLA was inhibited, but the uptake of Cal-LP was not influenced by adding extraneous GLA. LP-GLA may be internalized by hepatocytes via the specific binding site, and can be used as a novel and promising carrier for targeting drug delivery to hepatocytes.

[Comparison of two preparation methods applied in tanshinone II(A)-loaded PLGA nanoparticles].

OBJECTIVE: To optimize formulation of tanshinone II(A)-loaded PLGA nanoparticles and compare the difference of two methods in preparation and quality of nanoparticles. METHOD: The two methods were nanoprecipitation method and emulsion-evaporation method. Single factor experiments and central composite design and response surface method were used to optimize the formulation of nanoparticles. The nanoparticles were characterized at size, morphology, entrapment efficiency, drug loading, drug recovery rate, crystallinity and drug release in vitro. RESULT: The mean diameters were 225 nm and 183 nm, the entrapment efficiency were 95.49% and 87.99%, the drug loading were 2.03% and 0.16%, and the drug recovery rates were 38.42% and 17.59% respectively for nanoprecipitation method and emulsion-evaporation method. CONCLUSION: Nanoprecipitation method was better than emulsion-evaporation method for preparation of tanshinone II(A)-loaded PLGA nanoparticles.

[Studies on characteristics of absorption and separation of traditional Chinese medicine compound prescription by macroporous resin].

OBJECTIVE: Study the characteristics of absorption and separation of traditional Chinese medicine compound prescription using macroporous resin. METHOD: Study the techniquecs and characteristics of absorption and separation of a sample by macroporous resin, which is composed of coptis root, rhubarb and common anemarrhena rhizome, containing alkaloid, anthraquinone and saponin. RESULT: It is proved by qualitative and quantitative researches studies that after absorbed and separated by optimized technics process, most prime effective components or section fractions in traditional Chinese medicine compound prescription can be reserved maintained. CONCLUSION: If the techniquecs of separation is properly designed, the same kind of macropore resin can absorbd and separate various effective components or section in traditional Chinese medicine compound prescription which have with different chemical structures efficiently.

Uptake of albumin nanoparticle surface modified with glycyrrhizin by primary cultured rat hepatocytes.

AIM: To investigate the uptake difference between bovine serum albumin nanoparticle (BSA-NP) and bovine serum albumin nanoparticles with their surface modified by glycyrrhizin (BSA-NP-GL) and to develop a novel hepatocyte targeting BSA-NP-GL based on active targeting technology mediated by specific binding site of GL on rat cellular membrane. METHODS: Calcein loaded bovine serum albumin nanoparticles (Cal-BSA-NP) were prepared by desolvation process. Glycyrrhizin was conjugated to the surface reactive amino groups (SRAG) of Cal-BSA-NP by sodium periodate oxidization, which resulted in calcein-loaded bovine serum albumin nanoparticles with their surface modified by glycyrrhizin (Cal-BSA-NP-GL). The morphology of the two types of prepared nanoparticles (NP) was observed by transmission electron microscopy. The diameter of NP was measured with a laser particle size analyzer. The interaction between Cal-BSA-NP-GL and primary cultured hepatocytes was studied through cellular uptake experiments. The uptake amount of Cal-BSA-NP-GL and Cal-BSA-NP by rat hepatocytes was determined by fluorospectrophotometry. Uptake characteristics were investigated through experiments of competitive inhibition of specific binding site of GL. RESULTS: Both Cal-BSA-NP-GL and Cal-BSA-NP had regular spherical surfaces. The average diameter of Cal-BSA-NP-GL and Cal-BSA-NP was 77 and 79 nm respectively. The uptake amount of the two NP by hepatocytes reached its maximum at 2 h after incubation. The uptake amount of Cal-BSA-NP-GL by rat hepatocytes was 4.43-fold higher than that of Cal-BSA-NP. There was a significant difference in the uptake of Cal-BSA-NP-GL and Cal-BSA-NP by hepatocytes (P<0.01). The uptake of Cal-BSA-NP-GL was inhibited when GL was added previously to isolated rat hepatocytes, and the uptake of Cal-BSA-NP was not affected by GL. CONCLUSION: A binding site of GL is present on the surface of rat hepatocytes, BSA-NP-GL may be internalized via this site by hepatocytes and can be used as a drug carrier for active targeting of delivery drugs to hepatocytes.

[Preparation of bovine serum albumin nanoparticles surface-modified with glycyrrhizin].

AIM: To study the preparation of bovine serum albumin nanoparticles surface-modified with glycyrrhizin(BSA-NP-GL) targeting to hepatocytes. METHODS: The bovine serum albumin nanoparticles (BSA-NP) were prepared by desolvation process. Glycyrrhizin (GL) was oxidized by sodium periodate to be conjugated to surface reactive amino groups (SRAG) of the BSA-NP. The SRAG were quantified by spectrophotometric method using 2, 4, 6-trinitrobenzenesulfonic acid(TNBS). Glycyrrhetinic acid(GA) hydrolyzed from GL, which was on the surface of BSA-NP-GL was assayed by HPLC after isolation by sephadex G-50. Both methods were used to verify the conjugation achieved. HPLC was used to determine surface density of GL on BSA-NP-GL. RESULTS: The amount of SRAG of the BSA-NP-GL decreased by 19.6% compared with normal BSA-NP. The amount of GL molecule was 9.2% of the total determined SRAG of BSA-NP. The mean diameter of the BSA-NP-GL was 73 nm with round shape. The stability of BSA-NP-GL was constant when it was stored at 25 degrees C and 37 degrees C during 10 days. CONCLUSION: BSA-NP-GL was successfully prepared, which is considered to establish an experimental foundation for further research on its ability for targeting to hepatocytes.

[The study of characteristics of absorption and separation of different glycoside on macropore resins].

OBJECTIVE: To study the absorption and separation of different glycoside on different macropore resins. METHOD: Take baikal skullcap root, cape jasmine fruit and white peony root as samples and study the different characterstics of absorption and separation of these samples on macropore resins such as D101 and so on. RESULT: The static absorption effect of the the three aglycones on six different macropore resins is baicalin > lactiflorin > gardoside. Their elution are 75% CH3OH, 25% CH3OH, and 45% CH3OH. Their elution rates are 60%, 93%, and 93%. CONCLUSION: Similar molecules may not have similar absorption abilities on same macropore resins, but the effect of absorption has something to do with the structures of the molecules, the more double-bonds the molecules have, the greater the absorption force the resins have.