In vitro effect of gelatins on murine cell proliferation.

Porcine skin (PS) gelatin suppressed proliferation of a murine hepatic cell carcinoma cell line, MH134, a murine fibrosarcoma cell line, Meth A and a murine T cell lymphoma cell line, RL Male 1. The magnitude of suppression of the proliferation by cold water fish skin (CWFS) or bovine bone (BB) gelatin was lower than that by PS gelatin. On the other hand, BB gelatin stimulated proliferation of murine spleen cells. The magnitude of stimulation of the proliferation by CWFS gelatin was lower than that by BB gelatin. PS gelatin slightly suppressed proliferation of murine spleen cells. PS gelatin induced apoptosis but not necrosis of MH134 tumor cells. CWFS gelatin induced weaker apoptosis of the cells than PS gelatin. DNA histogram indicated that PS and CWFS gelatins acted on MH134 tumor cells to increase ratios of G2 + M-phase.

Mitogenic activity of gelatin to murine spleen cells.

We reported previously that gelatin stimulates the growth of spleen cells in vitro. Tritium thymidine (3H-TdR) uptake into phytohemagglutinin (PHA)-stimulated spleen cells as well as intact spleen cells was augmented by gelatin. These findings suggest that gelatin serves as a mitogen for lymphoid cells. In this study, the target of action of gelatin was investigated. Tritium thymidine uptake into T cell-rich fraction was enhanced by incubation with 7.5 mg/ml of gelatin for 48 hours. The level of 3H-TdR uptake into B cell-rich fraction was not definitely increased by gelatin. Flow cytometric analysis confirmed these findings. Namely, it showed that treatment of spleen cells with 7.5 mg/ml gelatin increased a ratio of CD3-positive cells and decreased that of CD19-positive cells. Tritium thymidine uptake into natural killer cell-rich fraction was augmented by gelatin in a similar fashion to T cell-rich fraction. Tritium thymidine uptake into macrophages was very low and not affected by gelatin. Tritium thymidine uptake into macrophage-precursors was very low but was enhanced by gelatin. These findings suggest that gelatin could be used as an agent of cancer biotherapy.

Microdialysis assessment of 5-fluorouracil release from thermosensitive magnetoliposomes induced by an electromagnetic field in tumor-bearing mice.

The current study was designed to evaluate the properties of thermosensitive magnetoliposomes (TMs), a new drug carrier proposed by the authors, in an electromagnetic field pertaining to their selective heating and drug release under an in vivo condition. TMs containing 5-fluorouracil (5-FU) were prepared by reverse-phase evaporation, injected into the tumor mass of B 16-BL6 melanoma in mice, and selectively heated by a 500-kHz electromagnetic field. The release profile of 5-FU from TMs was examined by using a microdialysis technique. The temperature of TMs in the tumor was effectively elevated to 42 degrees C and maintained at this temperature, overcoming the "cooling effect" of blood flow and surrounding tissues. The release kinetics of 5-FU from TMs was successfully analyzed by physiological modeling, which allows the prediction of intratumor drug concentrations during electromagnetic field exposure under various conditions. In conclusion, this study first demonstrated an in vivo evidence for the electromagnetic field-induced thermosensitive release of a drug from TMs in a tumor with the use of microdialysis.

Microdialysis assessment of fibrin glue containing sodium alginate for local delivery of doxorubicin in tumor-bearing rats.

This study was designed to assess a local drug delivery system of an anticancer agent, doxorubicin (DOX), using fibrin glue (Beriplast P) as a drug carrier. In vitro release of DOX from the fibrin glue was examined by a dialysis method in the presence and absence of sodium alginate. The in vitro mean dissolution times of DOX with solution, fibrin glue, and fibrin glue containing sodium alginate were 3.7 h, 8.7 h, and 81 h, respectively, indicating a sustained release of DOX from fibrin glue, especially in the presence of sodium alginate. Fibrin glue containing 6 mg of DOX and 2.5 mg of sodium alginate was applied on the surface of an AH60C tumor at the back of rats. DOX concentrations in the tumor extracellular fluid were monitored by a microdialysis method. Local application of DOX using fibrin glue containing sodium alginate to the tumor resulted in extremely higher concentrations in the tumor extracellular fluid than those in plasma (AUC ratio > 800), indicating an advantage of the site-specific delivery of DOX using fibrin glue with sodium alginate. The tumor volumes were inversely correlated with tumor extracellular fluid-to-plasma AUC ratios (r = 0.882), suggesting the relevance of tumor size in the drug efflux from tumor to blood. In conclusion, the site-specific delivery of DOX using fibrin glue with sodium alginate to the tumor was demonstrated to be advantageous with regard to the extent and duration of drug concentrations in the tumor extracellular fluid, as assessed by a microdialysis technique.

Rectal absorption of ozagrel from a suppository containing its commercial tablet in healthy human subjects.

A suppository containing an ozagrel tablet was prepared using Witepsol H-15 as a base, and its rectal absorption was studied in male human volunteers. In comparison, a commercially available ozagrel tablet was administered orally to all the individuals in a cross-over design. After rectal dosing, ozagrel was absorbed rapidly at a Tmax of 0.75 h, and its elimination half-life was longer than after oral dosing. The extent of absorption of ozagrel after both administration routes was similar. However, the bioavailability of the rectal suppository is 92 +/- 37% (mean +/- S.D.; n = 6) relative to the oral tablet. The tablet-containing suppository is easy to prepare, with its content being accurate and reproducible. Thus, the present study suggests that the rectal administration of an ozagrel suppository is a practical and promising alternative to oral administration, especially for patients who cannot take tablets orally. This study demonstrated for the first time the possibility of an ozagrel suppository in human subjects.

Pharmacokinetics of a Chinese traditional medicine, danshensu (3,4-dihydroxyphenyllactic acid), in rabbits using high-performance liquid chromatography.

An injectable solution of Danshen was prepared and its in vivo disposition was examined in rabbits. The presence of Danshensu, one of the active components of Danshen, in the obtained solution was confirmed by a simple high-performance liquid chromatographic (HPLC) method. The pharmacokinetics of Danshensu in rabbits was evaluated by the HPLC method for plasma Danshensu. The calibration curve for Danshensu was linear (r = 0.998) over the concentration range of 0.25-40.0 micrograms/ml. The intra-assay coefficients of variation (CVs) were 3.8, 3.1, and 3.1% at 1, 10, and 50 micrograms/ml, respectively, and the inter-assay CVs were 5.3, 5.3, and 2.9% at 1, 10, and 50 micrograms/ml, respectively. The analytical recovery of Danshensu in plasma averaged 95.2%. From the plasma concentration profile of Danshensu after its intravenous administration, the t1/2, mean residence time (MRT), Vdss, and Cltot were determined as 32 min, 48 min, 149 ml/kg, and 3.13 ml/min/kg, respectively.

Pharmacokinetic study of taxol-loaded poly(lactic-co-glycolic acid) microspheres containing isopropyl myristate after targeted delivery to the lung in mice.

This study describes the pharmacokinetic behaviours of taxol after intravenous administration of taxol-loaded poly(lactic-co-glycolic acid) microspheres containing isopropyl myristate (namely, Taxol-IPM-PLGA-MS) and taxol saline solution to mice. Taxol-IPM-PLGA-MS were prepared using a solvent evaporation technique. The drug content and trapping efficiency of taxol in the microspheres were 5.09% (w/w) and 98%, respectively; the average diameter of the microspheres was 30.1 microns. Scanning electron microscopy showed that Taxol-IPM-PLGA-MS were spherical with a smooth surface. After administration of the drug saline solution (3 mg taxol/kg), taxol disappeared rapidly from plasma within 4-6 h and distributed extensively in various tissues. The tissue levels and AUCfinite of taxol in the lung were obviously higher than those in plasma but relatively lower than those in kidneys, bile, and liver. The biodistribution of taxol after administration of Taxol-IPM-PLGA-MS (3 mg taxol/kg), on the other hand, was altered significantly from the control (taxol solution) group. No taxol was detected in plasma or bile within 3 weeks, and only very low level of taxol was detected in the kidneys or liver within 48 h. However, taxol concentrations in the lung were increased significantly with the microsphere group; the peak concentration of taxol and AUCfinite in the lung was three times and 500 times higher than those with the taxol solution group, respectively. It was also noticed that the taxol levels in the lung were maintained at relatively high levels (> 10 micrograms/ml) for 3 weeks. Thus, the present study demonstrated the effective targeted delivery of taxol to the lung of mice using Taxol-IPM-PLGA-MS.

Optimization of the formulation design of chitosan microspheres containing cisplatin.

This study describes an orthogonal experimental design to optimize the formulation of cisplatin (CDDP)-loaded chitosan microspheres (namely, CDDP-DAC-MS) which were produced by an emulsion-chemical cross-linking technique. Seven factors and three levels for each factor that might affect the formulation of microspheres were selected and arranged in an L27(3(13)) orthogonal experimental table. A desirability function (df) calculated according to the trapping efficiency of CDDP, the drug content (%, w/w), and the size distribution of each batch of microspheres was introduced as an index of the microsphere formulation. The overall desirability functions (DF) were produced and treated by a statistic analytical system to optimize the formulation. Moreover, the contour maps were produced to analyze the influence of the seven factors on the size distribution, the drug content, and the drug trapping efficiency. The established optimum procedure was reproducible. Scanning electron micrographs showed that CDDP-DAC-MS were spherical with a coarse surface. The average diameter, drug content, and drug trapping efficiency of CDDP-DAC-MS were 74.8 microns, 20.8% (w/w), and 77.5%, respectively. The in vitro release of cisplatin from chitosan microspheres in saline was retarded compared with that from saline solution; the release of CDDP from chitosan microspheres was suggested to be controlled by the dissolution and diffusion of the drug from the chitosan matrix.

Preparation and characterization of poly(lactic-co-glycolic acid) microspheres for targeted delivery of a novel anticancer agent, taxol.

This study describes the preparation and characterization of poly(lactic-co-glycolic acid) microspheres containing a novel anticancer agent, taxol (namely, Taxol-PLGA-MS). A solvent evaporation technique was utilized to prepare Taxol-PLGA-MS. The trapping efficiency of taxol in the microspheres was greater than 90% and reproducible. The in vitro release rate of taxol from the microspheres was very low, and less than 15% of the initial amount of taxol was released in three weeks, irrespective of the drug loading level. When a chemical additive, isopropyl myristate (IPM), was introduced at the level of 30% (w/w), the release of taxol increased significantly; approximately 70% of the initial amount of taxol was released at a nearly constant rate for three weeks. Elevation of the loaded IPM level to 50% (w/w) produced a more rapid release of the drug. Scanning electron microscopy showed that Taxol-PLGA-MS were spherical with a smooth surface. More than half (55-65%) of the microspheres had a diameter of 20-45 microns. Incorporation of IPM had no significant influence on the particle size, surface morphology, or degradation behavior of the microspheres. It was strongly suggested that the release of taxol from the microspheres was dominated mainly by the drug diffusion in the matrix. As evaluated from the particle size, drug content, and in vitro release property, IPM-containing Taxol-PLGA-MS may be suitable for chemoembolization therapy of cancer diseases.