Preparation and microscopy examination of alginate-poly-L-lysine-alginate microcapsules.

Ca-alginate-poly-l-lysine-alginate (APA-Ca) and Ba-alginate-poly-l-lysine-alginate (APA-Ba) microcapsules were prepared and their thickness and surface were examined by light microscopy and scanning electron microscopy. Specifically, light microscopy with frozen section was used to visualize and quantify the thickness of APA membrane, and monitor temporal changes in the thickness of microcapsules during a month long culture in vitro. The section graph of APA microcapsule represents the accurate measurement of layer thickness of APA-Ca with diameter 900 ± 100 and 500 ± 100 µm at 6.01 ± 1.02 and 9.54 ± 2.42 µm (p < 0.05), and layer thickness of APA-Ba with diameter 900 ± 100 and 500 ± 100 µm at 5.47 ± 0.90 and 8.21 ± 1.97 µm (p < 0.05), regardless of the alginate composition used to generate the microcapsules. The microcapsule was stable during the culture for 30 days in vitro. Field emission scanning electron microscopy with freeze drying method was used to detect the surface and thickness of dried microcapsules. From the results, the outer surface of APA-Ca and APA-Ba membrane were smooth and dense, the film thickness of the APA-Ca was about 450-690 nm, while the APA-Ba was approximately 335 nm. In vivo experiment, little significant difference was seen in the change of film thickness of microcapsules in intrapertioneal site for 30 days after transplantation (p > 0.05), except that the recovery of APA-Ba was higher than the APA-Ca microcapsules. The paper showed an easy method to prepare APA-Ca and APA-Ba, and examine their thickness and surface, which could be utilized to study other types of microcapsules.

Preparation and antitumor activity of bFGF-mediated active targeting doxorubicin microbubbles.

Characterization and antitumor activity of basic fibroblast growth factor-mediated active targeting doxorubicin microbubbles (bFGF-DOX-MB) were investigated. Pluronic F68 with chemical conjugation of doxorubicin (DOX-P) and peptide KRTGQYKLC-conjugated DSPE-PEG2000 were prepared. bFGF-DOX-MB had a normal distribution of particle size, with average particle size of 2.7 µm. Using A549 mouse model, bFGF-DOX-MB combined ultrasound showed the best inhibition effect on tumor volume growth among all the test groups. Similar conclusion was obtained from experimental measurements of tumor weight change and blood cell count. From the results, chemotherapeutic drug inhibition on tumor growth could be enhanced by local ultrasound combined with active targeting bFGF-DOX-MB, which might provide a potential application for ultrasound-mediated chemotherapy.

[Preparation and in vivo-in vitro evaluation of compound nanoparticles loaded with epirubicin hydrochloride and gadopentetate meglumine].

OBJECTIVE: To prepare and characterize the compound Epirubicin hydrochloride and Gadopentetate meglumine (Gd-DTPA) nanoparticles, and evaluate its properties from rabbits in vivo and in vitro. METHODS: The compound Epirubicin hydrochloride and Gd-DTPA nanoparticles were prepared by double emulsion-solvent evaporation method. The main effective factors were orthogonal designed. The characteristics such as drug entrapment efficiency, drug loading, and drug utilization were assayed in vitro. MR imaging effect of the VX2 rabbit hepatoma model were observed after injecting the drug-loaded nanoparticles through the hepatic artery intubation in vivo. RESULTS: The drug encapsulation efficiency of the nanoparticles, drug loading and drug utilization were 33.8% ± 3.4%, 0.225% ± 0.052%, and 69.6% ± 4.3% under the optimized prescription, respectively. The mean size of the nanoparticles was 180.6 nm, the drug release continued in 48 h with good MR imaging effect. CONCLUSIONS: Compound Epirubicin hydrochloride and Gd-DTPA Nanoparticles were in simply preparation and showed sustained drug release properties. These novel nanoparticles with detecting function could develop of epirubicin hydrochloride targeted therapy of liver cancer.

Experiment on formulation and drug release behavior of porosity asymmetric membrane capsules in vitro.

Porosity asymmetric membrane capsules were prepared to study the relationship between the capsule formulation and drug release. Cellulose acetate (CA) and pore formers were used in the capsule shell formulation as the main semipermeable membrane material. The capsules were permeable to both water and dissolved solutes. Using sparingly soluble drug acetaminophen as a model, cumulative release was calculated. The slope of the release profile from the distilled water had good relationship with the concentration of the pore formers F68. The release of acetaminophen was independent to the pH, osmotic pressure of dissolution medium, but influenced by intensity of agitation. When the concentration of pore former was low, zero-order release behavior was observed within 24 h which was consistent with Fickian diffusion model. When the concentration of pore former was high, however, Higuchi model release was found which is caused by Fickian diffusion and osmotic pressure release. With scanning electron microscope (SEM), the surface structure and cross-section of the capsule shell were also studied before and after drug delivery. With simple preparation and broad scope of drug application, porosity asymmetric membrane capsules can give desired drug extended release and show more convenience than controlled tablets with laser drilling.

Experiment on the feasibility of using modified gelatin nanoparticles as insulin pulmonary administration system for diabetes therapy.

Polymeric nanoparticles are widely used as targeted carriers for biomacromolecules. In this paper, modified gelatin nanoparticles were prepared and their feasibility as insulin pulmonary administration system was investigated. D: ,L: -glyceraldehyde and poloxamer 188 were used for gelatin nanoparticle preparation. Novel water-in-water emulsion technique was used to prepare insulin-loaded nanoparticles. Morphological examination of insulin-loaded nanoparticles was carried out using scanning electron microscopy (SEM). Intratracheal instillation of insulin-loaded nanoparticles was performed to evaluate animal hypoglycemic effect. With fluorescence labeling of insulin, alveolar deposition and absorption of insulin-loaded nanoparticles were investigated. Histological changes in the lung were also observed to evaluate the safety. From the micromorphology observation, insulin-loaded nanoparticles under gelatin-poloxamer 188 ratio at 1:1 showed smooth and uniform surface, with average particle size 250 nm and Zeta potential -21.1 mV. From animal experiment, insulin-loaded nanoparticles under gelatin-poloxamer 188 ratio at 1:1 promoted insulin pulmonary absorption effectively and showed good relative pharmacological bioavailability. Proved by alveolar deposition result, FITC-insulin-loaded nanoparticle group was characterized by an acute and rapid hypoglycemic effect. In addition, nanoparticles could guarantee the safety of lung by reducing insulin deposition in lung. A transient weak inflammatory response was observed at 1 day after administration. With good physical characterization, high bioavailability, fast and stable hypoglycemic effect, insulin-loaded nanoparticles might be developed as a novel insulin pulmonary system for diabetes therapy.

Comparing the enhancement efficiency between liposomes and microbubbles for insulin pulmonary absorption.

BACKGROUND: The present study investigated the enhancement efficiency between liposomes and microbubbles for insulin pulmonary absorption. METHODS: Two types of phospholipid-based vesicle-liposomes and microbubbles-were prepared, and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cytotoxicity test was used to evaluate their in vitro toxicity in A549 cells. Cellular uptake of insulin combined with liposomes or microbubbles was determined using A549 cells. With intratracheal insufflation of Sprague-Dawley rats, an insulin mixture with liposomes or microbubbles was administered to assess its potential for promoting drug pulmonary absorption. RESULTS: Both liposomes and microbubbles had a narrow and monodispersed size distribution with average diameter of 3.1 µm and 1.0 µm, respectively. From the MTT cytotoxicity test, a phospholipid-based vesicle concentration of <25% (vol/vol) in the final volume was the safe dosage range that could avoid severe cytotoxic effects. The intracellular uptake amount of insulin in the insulin-microbubble mixture was significantly higher than that in the insulin-liposome mixture. The minimum reductions of the blood glucose concentration produced by insulin-microbubble and insulin-liposome mixtures were 60.8% and 35.0% of the initial glucose levels, respectively, and their bioavailabilities relative to subcutaneous injection were 48.6% and 30.8%, respectively. CONCLUSIONS: Microbubbles have much better efficiency than liposomes in the rate and extent of insulin pulmonary absorption. Microbubbles might be recommended as a potential agent for enhancing protein intrapulmonary absorption.

[Preparation and quality control of compound epirubicin hydrochloride-loaded polymeric nanoparticles of L-lactic-co-glycolic acid].

OBJECTIVE: To prepare compound epirubicin hydrochloride-loaded polymeric nanoparticles of L-lactic-co-glycolic acid and establish their quality control. METHODS: The emulsion-solvent evaporation method was employed to prepare and freeze-dry the compound epirubicin hydrochloride-loaded polymeric nanoparticles of L-lactic-co-glycolic acid after the addition of lactose. The contents and cumulative release of epirubicin hydrochloride and dimeglumine gadopentetate were detected simultaneously by RP-HPLC (reverse phase-high performance liquid chromatography). RESULTS: The above nanoparticles were prepared and the quality standards for simultaneously determining the contents of epirubicin hydrochloride and dimeglumine gadopentetate established primarily. The contents of epirubicin hydrochloride and dimeglumine gadopentetate in compound preparation were 100.6% ± 1.6% and 99.1% ± 1.9% respectively. And two compositions could be completely released within 9 days. CONCLUSION: The preparation method of nanoparticles is simple and their quality control feasible.

Phospholipid-based ultrasonic microbubbles for loading protein and ultrasound-triggered release.

BACKGROUND: Ultrasonic microbubbles are used as ultrasound-triggered delivery carriers for protein drugs. AIM: This work was to prepare stabilized protein-loaded phospholipid-based ultrasonic microbubbles (PUM) and to determine its value as a protein delivery system. METHOD: Bovine serum albumin (BSA) was used as a model protein drug. BSA-containing PUM were prepared by dissolving lyophilized PUM powder in BSA solution. The particle size and microbubble concentration of BSA-containing PUM were measured. The BSA encapsulation efficiency as a function of BSA concentration was determined. Contrast enhancement of BSA-containing PUM in vivo was detected. The release profile of BSA from PUM was also investigated. RESULTS: The mean particle size and microbubble concentration of PUM were unchanged by the presence of BSA for at least 30 minutes after preparation. The net amount of BSA entrapped in PUM was maintained unchanged with increasing BSA concentration. BSA-containing PUM were shown easily to be visible in in vivo rabbit kidney. There was no difference in echogenicity between the loaded and unloaded PUM. Ultrasound duration had a positive relationship with BSA release. Ultrasound of 30 seconds stimulated 94.1% and 93.3% of BSA release from PUM solutions containing 0.3% and 1.5% BSA, respectively. CONCLUSIONS: Protein-loaded PUM exhibited satisfactory physical characteristics and were potent for using in ultrasound-triggered delivery.

[Study on cytomedicine of alginate-poly(L) lysine-alginate microencapsulated hybridoma cells].

AIM: To study the cytomedicine of alginate-poly (L) lysine-alginate (APA) microencapsulated hybridoma cells and their characteristics. METHODS: The spleen cells taken from BALB/C mice immunized with purified human IgG1 kappa type were fused with mouse myeloma cells SP2/0. The hybridoma cell lines secreting monoclonal antibodies (mAb) against human IgG1 kappa type was named JY-A1. The APA microencapsulated JY-A1 cells were prepared with a high-voltage electrostatic system. Microencapsulation parameters were optimized and their morphology was studied. The mechanical strength and chemical intensity of microcapsules were measured. The mAb secrete from APA microencapsulated JY-A1 cells was determined by ELISA kit. The microcapsules injected into mice abdominal cavity previously were recovered at intervals. RESULTS: The microcapsules prepared in the same condition of the high-voltage electrostatic system were round and homogeneous. The mAb secreted by the microencapsulated JY-A1 cells were shown to permeate the membranes of APA microcapsules in vitro. After an intraperitoneal injection to mice, APA microcapsules were recovered on day 7, 14, 28, 56. The electron microscopy study revealed that the majority of recovered microcapsules were intact, and no evidence of immunological reaction in terms of fibrosis. CONCLUSION: APA microencapsulated hybridoma cells prepared by high-voltage electrostatic system have good mechanical strength and chemical intensity. The APA microencapsulated hybridoma cells can maintain physiological functions in vitro, and the microcapsules have good biocompatibility in vivo.