[Study on intra-gastric floating beads of naringenin].

OBJECTIVE: To prepare calcium alginate-chitosan intra-gastric floating beads of naringenin combining with the solid dispersion method and investigate the in vitro floating characteristics, entrapment efficiency and drug release property of the beads. METHODS: The solid dispersion of naringenin was prepared by the Eudragit RLPO. Sodium alginate solution mixed with the powder of the solid dispersion of naringenin and frother was slowly dripped into chitosan-calcium chloride solution added with acetic acid. Calcium alginatechitosan intra-gastric floating beads of naringenin were obtained after drying. The effects of solid dispersion on in vitro release of naringenin were investigated. RESULTS: Intra-gastric floating beads of naringenin were acquired successfully. More than 70% of the beads kept floating in artificial gastric juice in 9 h, the release ratio of naringenin during 9 h was 65%-70% and the entrapment efficiency was about 70%-80%. CONCLUSION: The sustained release of naringenin in the calcium alginate-chitosan intra-gastric floating beads could be achieved by using the solid dispersion method and it provides some ideas of intra-gastric floating preparations.

Preparation, characterization, and in vivo evaluation of mitoxantrone-loaded, folate-conjugated albumin nanoparticles.

Folic acid was covalently conjugated to bovine serum albumin nanoparticles (BSANP) to target the nanoparticles to SKOV3 cells expressing folate receptors. Mitoxantrone was incorporated into the folate-conjugated albumin nanoparticles, and the final nanoparticle size was 68 nm, as measured by a laser light scattering particle analyzer. The cytotoxic activity of mitoxantrone- loaded, folate-conjugated albumin nanoparticles (MTO-BSANP-folate), which was quantitated by (3)H-thymidine incorporation, was higher than mitoxantrone-loaded BSANP (MTO-BSANP) and MTO solution, and could be inhibited by free folic acid. MTO-BSANPfolate may be endocytosed via the folate receptor on the surface of SKOV3 cells. MTO-BSANPfolate also inhibited tumor growth better than the MTO-BSANP and MTO solution in vivo. These results indicate that folate-conjugated BSANP may have therapeutic potential as a vector for anticancer drugs in cancer chemotherapy.

[Transdermal and lymph targeting transfersomes of vincristine].

Vincristine (VCR) is mainly used to treat acute lymphocytic leukemia, Hodgkin and non-Hodgkin lymphoma in clinic with definite therapeutic effect. But the obvious neurotoxicity and local stimulation of which limit its clinic use. In order to increase the lymph targeting to enhance the curative effect and to lower the adverse reaction of VCR, the VCR loaded transfersomes (VCR-T) were prepared with dry-film and ultrasonic dispersing methods, and the corresponding pharmaceutical properties, pharmacokinetical characteristics and the targeting ability were studied. The average particle size of VCR-T prepared was 63 nm with an entrapment ratio of 59%. The in vitro transdermal research with modified Franz cell showed that VCR-T permeated through the skin in accordance with polynomial equation, and with an accumulation permeation percentage of 67.4% up to 12 h. An HPLC method was utilized to determine the pharmacokinetics and tissue distribution of VCR. Compared with the iv injection of VCR solution, the retention time of VCR in blood was extended by 12 times with VCR-T, and the targeting index in rat lymph was increased by 2.75 times. As a result, transfersomes could penetrate the skin and enter into the systemic circulation carrying VCR with good lymph targeting ability, which makes it probably a new lymphtic targeting drug delivery system.

[Tumor cell targetability of folate receptor-mediated mitoxantrone albumin nanoparticles].

OBJECTIVE: To study the tumor cell targetability of folate-conjugated mitoxantone-loaded albumin nanoparticles (MTO-BSANP-folate). METHODS: Bovine albumin nanoparticles were prepared by desolvation method. The activated folic acid (N-hydroxysuccinimide ester of folic acid) was conjuated to the surface of BSANP via the amino groups. The MTO-BSANP-folate was prepared by mixing folate-conjugated albumin nanoparticles with mitoxantrone and then cross-linked by glutaraldehyde. 3HTdR and flow cytometry were used to evaluate the targetability of MTO-BSANP-folate. RESULTS: The encapsulation rate of folate-conjugated mitoxantrone albumin nanoparticles was (96.55 +/- 0.96)% and the drug loading was (9.66 +/- 0.10)%. The results of 3HTdR showed that the efficacy of MTO-BSANP-folate in killing SKOV3 cells was higher than that of MTO-BSANP-folate, and the results of flow cytometry showed that the apoptosis-promoting effect of MTO-BSANP-folate was 3.5-4.5 times higher than that of MTO-BSANP. CONCLUSION: MTO-BSANP-folate could be targeted, via folate receptor, to the tumor cells rich in folate receptors.

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.

[Study on the tumor cell targetability of folate-conjugated albumin nanoparticles].

OBJECTIVE: To study folate-conjugated albumin nanoparticles targeting to tumor cells via folate receptor-mediated endocytosis. METHODS: The activated folic acid (N-hydroxysuccinimide ester of folic acid) was conjuated to the surface of bovine serum albumin nanoparticles (BSANP) via the amino groups. The extent of the influence that concentration, incubation time and free folate exerted on the uptake of Folate-BSANP by ovarian cancer cells (SKOV3) was determined using fluorescence spectrophotometer. RESULTS: Folate-conjugated BSANP (Folate-BSANP) was successfully achieved. Uptake of Folate-BSANP by cancer cells was gradually increased with the extension of incubation time or the increase of Folate-BSANP concentration, and the uptake could be competitively inhibited by excess free folate. CONCLUSION: Folate-BSANP could be delivered into tumor cells via folate receptor-mediated endocytosis and significantly targeted to tumor cells with rich folate receptors.

[Preparation of liposomes surface-modified with glycyrrhetinic acid targeting to hepatocytes].

OBJECTIVE: To study the preparation of liposomes surface-modified with glycyrrhetinic acid targeting to hepatocytes. METHOD: 3-succinic-30-stearyl glycyrrhetinic acid(Suc-GAOSt), one of the amphiphilic glycyrrhetinic acid derivatives, was synthesized as targeting molecules, liposomes surface-modified with glycyrrhetinic acid has been produced with ethanol injection method. RESULT: Targeting molecules can be mixed into the liposomal membrane. It was confirmed that the targeting molecules is 9% of the total lipids at the most in the liposomes. CONCLUSION: Liposomes surface-modified with glycyrrhetinic acid was successfully prepared, which is considered to be a potential approach targeting 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.