Colon-specific delivery of budesonide with azopolymer-coated pellets: therapeutic effects of budesonide with a novel dosage form against 2,4,6-trinitrobenzenesulphonic acid-induced colitis in rats.

The objective of this study was to achieve colon-specific delivery of budesonide using azopolymer-coated pellets and to accelerate healing of 2,4,6-trinitrobenzenesulphonic acid sodium salt (TNBS)-induced colitis in rats. After oral administration of azopolymer-coated pellets containing budesonide, a significant increase was observed in the therapeutic effects of the drug accompanied by a decrease in its systemic adverse effects when compared with oral administration in saline or rectal administration by enema. In addition, with the use of the colon-specific oral dosage form the dose of budesonide could be reduced. These results suggested that azopolymer-coated pellets may be a useful dosage form for the colon-specific delivery of budesonide as an anti-inflammatory steroid drug to bring about the healing of TNBS-induced colitis in rats.

Improvement of the pulmonary absorption of (Asu1,7)-eel calcitonin by various absorption enhancers and their pulmonary toxicity in rats.

The effects of absorption enhancers on the pulmonary absorption of (Asu1,7)-eel calcitonin (ECT) and their pulmonary toxicity were examined by means of in situ pulmonary experiments. The absorption of ECT from the lungs was estimated by its hypocalcemic effect. The pulmonary membrane toxicity of absorption enhancers was evaluated by the leakage of Evans Blue from the plasma into the lungs. In the absence of absorption enhancers, a slight hypocalcemic effect was obtained following intrapulmonary administration of ECT. However, we found significant hypocalcemic effects after the ECT administration with 10 mM n-lauryl beta-D-maltopyranoside (LM), 10 mM sodium glycocholate (NaGC), and 10 mM linoleic acid-HCO60 (hydrogenated caster oil) mixed micelle (MM). The plasma calcium levels decreased as the amount of LM coadministered with ECT increased. In contrast, 10 mM EDTA did not improve the pulmonary absorption of ECT. Overall, a correlation between the pulmonary absorption of ECT and local toxicity was observed in the presence of these additives. However, 1 mM LM, 10 mM NaGC, and 10 mM MM improve the pulmonary absorption of ECT with low pulmonary toxicity. These findings suggest that the use of these adjuvants would be a useful approach for improving the pulmonary absorption of ECT.

Safety and efficacy of intraperitoneal injection of etoposide in oil suspension in mice with peritoneal carcinomatosis.

We compared the safety and efficacy in mice with peritoneal carcinomatosis of two etoposide formulations: an aqueous solution (Etp-sol) and particles suspended in oil (the addition products of iodine and the ethyl esters of the fatty acids obtained from poppy-seed oil (Lipiodol) or sesame oil; Etp-oil). We also investigated tissue distribution of etoposide in rats treated with Etp-oil and Etp-sol. Etoposide was injected intraperitoneally at concentrations ranging from 52 to 392 mg/kg (increasing geometrically by a factor of 1.4). The 50% lethal dose (LD50), determined over a 2-week period of observation, was 135 mg/kg for Etp-oil and 108 mg/kg for Etp-sol. Autopsy findings included macroscopic intestinal bleeding, necrosis of the intestinal mucosa, and pulmonary congestion in mice from both treatment groups. In the efficacy trials. 10(6) P388 leukemia cells were transplanted into CDF1 male mice, and Etp-oil and Etp-sol were injected at doses of 20 mg/kg and 80 mg/kg. In the groups receiving the 20 mg/kg dose, 11 of 19 mice in the Etp-oil group survived to day 60 compared with 3 of 20 mice in the Etp-sol group. Toxicity-related deaths occurred in 1 of 20 mice treated with 80 mg/kg Etp-oil and in 8 of 20 mice treated with 80 mg/kg Etp-sol. No cancer-related deaths were associated with the 80 mg/kg dose in either treatment group. Our findings showed that the Etp-oil was associated with a lower toxicity and a higher efficacy than the Etp-sol. To evaluate tissue distribution, rats were injected intraperitoneally with 5 mg/kg body weight of Etp-sol or Etp-oil. The tissue distribution of etoposide was subsequently analyzed by high performance liquid chromatography. Compared with Etp-sol, Etp-oil delivered significantly greater amounts of etoposide and for a longer period to the omentum, taken as representative of the intraperitoneal tissue, and the etoposide concentration in blood plasma was increased more slowly and decreased more gradually.

Intestinal absorption enhanced by unsaturated fatty acids: inhibitory effect of sulfhydryl modifiers.

In vitro absorption of carboxyfluorescein was performed with everted colonic segments of rats. Oleic acid solubilized by a nonionic surfactant HCO-60, but not HCO-60 alone, markedly enhanced the permeation of the otherwise poorly permeant carboxyfluorescein through the colonic mucosa. The effect produced by oleic acid was reduced to different extents by pretreating the mucosa with several SH reagents, with N-ethyl-maleimide being the most effective. The inhibitory effect of N-ethylmaleimide was concentration dependent, with more than 5 mM completely blocking the enhancement of transmucosal permeability by oleic acid. The in vitro effect of N-ethylmaleimide in the absorption experiments was also observed in situ. The inhibitory effects of HgCl2 and iodoacetamide were comparable to that of N-ethylmaleimide, whereas PCMPS, an impermeant SH blocker, had no effect on the enhanced permeation. Various other amino-group modifiers had also no effect on the enhancement. On the other hand, the inhibition was accompanied by a significant reduction in the level of non-protein thiols as well as protein SH groups. Diethyl maleate, which reduced only the non-protein SH level, had no pronounced effect on the oleic acid-induced permeability change. These results suggest that the intact SH group of membrane-associated protein is necessary for the enhanced permeation of carboxyfluorescein elicited by oleic acid.

Biological and pharmaceutical factors affecting the absorption and lymphatic delivery of ciclosporin A from gastrointestinal tract.

Absorption site and some biological and pharmaceutical factors affecting the absorption and transport of ciclosporin A (CiA) from the gastrointestinal (GI) tract into both the thoracic lymphatics and the systemic circulation have been studied in rats. In a group of rats whose gastric emptying of orally administered CiA in HCO-60 formulation, 7.0 mg/kg, was physically prevented, both the lymphatic and the systemic availabilities of CiA were negligibly low. CiA was orally administered to another group of rats whose major intestinal lymphatics as well as thoracic lymph ducts were cannulated, and it was revealed that the amount of CiA delivered to the major intestinal lymphatics was about six times greater than that of CiA transferred into the thoracic lymphatics. In bile fistulous rats, the systemic availability of CiA was predominantly decreased but the lymphatic availability was not so decreased. In contrast, solvents such as propylene glycol and polyethylene glycol affected both the systemic and the lymphatic availabilities of CiA, which were also dependent on the absorption site. In particular, the lower small intestine does not contribute to the lymphatic availability of CiA.

Treatment of cystic hygroma and lymphangioma with the use of bleomycin fat emulsion.

Of the several types of treatment for cystic hygromas and lymphangiomas, surgical excision has been the preferred treatment. However, there is a high recurrence rate because lymphangiomas tend to infiltrate the surrounding tissues. Bleomycin in a microsphere-in-oil (S/O) emulsion was used in this study as a sclerosing agent for lymphangiomas. Experimental studies using domestic rabbits showed that the bleomycin emulsion caused more marked fibrotic changes at the injection site than other formulations, such as a blank emulsion and bleomycin solution. In clinical trials, 27 of 33 patients received bleomycin S/O emulsion injected directly into the tumors with satisfactory results. Histologic pictures of the clinically resected specimens confirmed the findings of the experimental studies. Comparative studies of treatments between bleomycin S/O emulsion and surgery indicated that injection therapy of bleomycin S/O emulsion would be more beneficial than surgical excisions.

[Studies on the metabolic fate of 14C-rokitamycin. III. Transmigration to fetus or milk].

Transmigration of 14C-radioactivity to fetus or milk were studied in 17-18 day-pregnant rats and mother rats on the 14th day after parturition after a single oral administration of 14C-rokitamycin (TMS-19-Q) at a dose of 200 mg/kg. The blood concentration of the drug in the mother reached a maximum level of 22.8 micrograms/ml at 2 hours after administration. Maximum concentrations of TMS-19-Q in placenta, ovary and uterus were attained in 2 hours, and were 28.9, 26.0 and 26.2 micrograms/g, respectively. The distribution to these tissues were considered good. The maximum concentration of TMS-19-Q in the amniotic fluid was attained in 2 hours, at a level of 5.4 micrograms/ml. The transmigration to the amniotic fluid was considered poor. The maximum concentration of the drug in the fetus was achieved in 2 hours at a level of 13.7 micrograms/g. Maximum concentrations of the drug in fetal liver and brain were attained in 4 hours, and were 32.8 and 11.4 micrograms/g, respectively. Whole body autoradiography was done when the radioactivity in maternal blood reached peak concentration. It was found that radioactivities in placenta and fetal membrane were similar to the radioactivity in maternal blood, while the radioactivity in fetal brain was considerably lower than that in maternal blood. Maximum concentrations were found at 1 hour in the blood and at 4 hours in the milk, and were 14.8 and 21.5 micrograms/ml, respectively. Transmigration to the milk was good.

The mode of enhanced enteral absorption of macromolecules by lipid-surfactant mixed micelles. I.

The enhancement of absorption of water soluble macromolecules by lipid-surfactant mixed micelles (MM) was performed in two in vitro experimental systems using rat large intestine, which were isolated epithelial cells containing transcellular route alone and everted sac involving trans- and paracellular routes. Four kinds of fluorescein isothiocyanate-labelled dextrans (FDs) having different average molecular weights (9K-70K) were used as models of water soluble macromolecules. In the absence of MM, very poor transport of FDs was observed in both isolated epithelial cells and everted sac experiments. Linoleic acid-polyoxyethylated (60 mol) hydrogenated castor oil (HCO60) MM enhanced the transport of FDs in both systems, especially for smaller size FDs. This promotive effect by MM decreased with an increase in molecular weight of FDs in both systems. Although enhanced transport of the largest FD (molecular weight, 70K) by MM was clearly demonstrated in the everted sac, the enhanced transport of the same FD in the isolated cells was negligible. These results suggest the possibility of participation of paracellular route as well as transcellular route in the enhancing effect of MM on the large intestinal absorption of water soluble macromolecules.

Enhancing effect of absorption promoters on percutaneous absorption of a model dye (6-carboxyfluorescein) as poorly absorbable drugs. II. Study on the absorption promoting effect of azone.

The percutaneous absorption of drugs was investigated in rats by measuring plasma levels, using mainly 6-carboxyfluorescein (CF) as a model of poorly absorbable drugs. Azone (AZ), a new useful promoter for the percutaneous absorption of drugs, was used instead of dimethylsulfoxide. We have examined the effects of the solubilized state and concentration of AZ on the percutaneous absorption of CF. AZ was dissolved with the aid of surface-active agents, beta-cyclodextrin (CD) or dimethyl-beta-cyclodextrin (DMCD). When AZ (2 v/v%) was dissolved completely by a surface-active agent (HCO-60: polyoxyethylene hardened castor oil derivative), plasma CF levels showed the highest value. Plasma CF levels following the administration of CF with AZ which formed a complex with CD or DMCD were scarcely increased as compared to that of CF alone. In the case of fluorescin (FL), which has a higher partition coefficient than CF, the percutaneous absorption of FL was more enhanced by the addition of AZ than in the case of CF.

Potentiation of antitumor effect of bleomycin by lipid-surfactant mixed micelles. I. In vivo and tumor-neutralizing activity against mouse Ehrlich ascites tumor and rat ascites hepatoma AH66.

Mixed micelles (MM) composed of polyoxyethylated (60 mol) hydrogenated castor oil (HCO60) as a harmless surfactant and linoleic acid (LA) as an essential fatty acid potentiated the antitumor activity of bleomycin (BLM). In the in vivo experiment, intraperitoneal administration of BLM with MM significantly prolonged the survival time of male ddY mice bearing Ehrlich ascites tumor and male Donryu rats bearing ascites hepatoma AH 66 inoculated intraperitoneally, compared with that of animals treated with BLM alone, BLM with HCO60, and BLM with LA, respectively, whereas MM had no antitumor effect to both tumors. Also in Winn-type tumor-neutralizing assay in which 10 male ddY mice were innoculated intraperitoneally with Ehrlich ascites tumor cells preincubated with a test material, BLM with MM showed a more marked enhancing activity with 3 surviving tumor-free mice than did BLM alone.

Promotion of the selective lymphatic delivery of cyclosporin A by lipid-surfactant mixed micelles.

The absorption of an immunosuppressive drug, cyclosporin A (CsA), with the aid of lipid-surfactant mixed micelles from the rat gastrointestinal (GI) tract and lymphatic delivery were studied. The administration of CsA in oily solution, sesame oil or linolic acid, into the rat duodenum indicated a small amount of CsA both in the plasma and lymph for about 6 h. The administration of CsA in the mixed micellar solution composing of linolic acid and HCO-60, polyoxyethylated (60 mol) hydrogenated castor oil, accelerated the absorption of CsA from the GI tract, and CsA was delivered into the lymphatics with an extremely high selectivity.

Surgical chemotherapy against lymph node metastases: an experimental study.

Accompanying surgical resection of the primary tumor is removal of its drainage lymph nodes. However, all of the minute regional lymph nodes cannot be identified and some may be left behind. If a certain anticancer agent in the form of an emulsion is injected topically into the lymph nodes, it may suppress the lymphatic metastases. Domestic rabbits were used as experimental animals, because transplantable VX2 tumors are available. The vermiform appendix was selected as the transplantation site because of its rich supply of lymph follicles, simulating lymph nodes histologically, and because the path of lymph drainage is very simple. The drainage lymph node, which is located at the root of the appendix, was selected for study. The rate of transfer of bleomycin into lymph nodes and of its sustained release from the nodes was extremely enhanced by the use of a sphere-in-oil-type emulsion--more than two times higher than in the use of a W/O emulsion. Although prolongation of survival time did not take place in animals receiving the bleomycin solution topically or intravenously, five of the seven rabbits receiving the local administration of bleomycin as a sphere-in-oil or a water-in-oil emulsion, between which differences were not found in tumor effects, survived with complete reduction of the lymph node metastases.