Total pancreatectomized patients has similar pathophysiological aspects with insulin-dependent diabetes mellitus (IDDM) in absolute insulin deficiency, both hepatic and peripheral insulin resistance, and, the development of diabetic micro—as well as macroangiopathy due to long-term hyperglycemia. Glucagon deficiency in pancreatectomized patients, however, causes more frequent hypoglycemia due to delayed hepatic glucose production and less insulin requirement than in IDDM patients. The optimal insulin therapy for these pancreatectomized patients is discussed from the viewpoint of drug delivery system (DDS). 1. Targeting : The study of hepatic and peripheral glucose handling in pancreatectomized diabetic dogs revealed that intraportal insulin administration results in a smaller gain in hepatic glucose handling than peripheral insulin administration. This means the superiority of intraportal insulin delivery which appears to be safer and more suitable for attaining stable glycemic control in these patients. 2. Controlled-release : Closed-loop insulin infusion system is optimal especially for postprandial glycemic regulation in these patients because of unstable enteric nutritional absorption, whereas it is still not available due to the lack of glucose sensor for long-term clinical usage. Therefore, frequent insulin dose adjustment based on self-monitoring of blood glucose (SMSG) is the second best. 3. The necessity of safer intraportal indweling cannula for long-term clinical usage : Intraportal cannulation may provoke portal thrombosis as well as infectious disease. These problems in biocompatibility promoted intraperitoneal delivery in stead. From these viewpoints, ultimate goal of future therapy for diabetes mellitus is discussed.

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A monoclonal antibody (MoAb) against α-fetoprotein (AFP), 80G, was obtained by the cell fusion technique. This MoAb was quite difficult to inhibit with free AFP. Complexation of 80G with AFP did not lead to rapid clearance of 80G from circulation, and these immune complexes remained capable of binding to solidphase AFP. Furthermore, pharmacokinetic analysis showed the suitability of MoAb 80G as an active targeting carrier. These results encouraged us to further evaluate the potency of our MoAb 80G as a carrier for targeting AFP-producing hepatoma cells. Four immunotoxins composed of MoAb 80G and a type 1 ribosome-inactivating protein, gelonin, were prepared. They involve two disulfide-linked and two thioether-linked immunotoxins. These immunotoxins (190 kDa) were purified by using a combination of gel filtration and affinity chromatography. The binding activity of immunotoxins against AFP remained as high as that of intact 80G. The in vitro cytotoxic effects of all the immunotoxins were specific against AFP-producing human hepatoma cell line, HuH-7. Of these irnmunotoxins, two containing gelonin modified with 2-iminothiolane were more potent than the others. They showed selective antitumor activity against AFP-producing HuH-7N cells in nude mice(HuH-7 xenograft). However, the disulfide immunotoxin was more toxic to mice than the thioether immunotoxin. These results suggest that our MoAb 80G is a suitable carrier for targeting AFT-producing hepatoma cells, and that our non-cleavable thioether immunotoxin is promising as an AFT-producing hepatomatargeted drug delivery system.

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One of the urgent matter to be concerned regarding with antisense DNA as therapeutic reagent is low membrane permeability. The dominant mechanism of cellular uptake of antisense DNA is thought to be endocytosis, although a recent publication indicated heterogeneous uptake of oligonucleotide. The event of oligonucleotide after the entering cells is still unclear. In this study we synthesized phosphorothioate oligonucleotide complementary to AUG initiation codon overlapping sequence of mRNA of mdrl and studied on charactersitic of cellular uptake in multiple drug resistant mutant of Chinese hamster ovary cells(CH^RC5). Temperature dependent uptake suggested endocystosis as a uptake mechanism, Since non-labeled S-oligo inhibited cellular uptake of ³²P labeled S-oligo in a dose dependent manner either at 4°C or 37°C, S-oligo seemed to have binding site on cellular membrane which was responsible for uptake. Rhodamin labeled S-oligo was distributed punctately for 2 hours or 24 hours with showing little portion in nucleus. After the treatment of monensin, H⁺/Na⁺ exchanger, cellular distribution pattern was changed. From this observation, part of S-oligo was seemed to distributed in lysosome.

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Quantitative determination of human complement component 3 (C3) fragments on the liposomal surface is considered to give useful informations for speculation of the biological fate of liposomes. The determination method of C3 fragments on the liposomal surface with anti-human C3 monoclonal antibodies (MoAbs) is presented in this paper. Twelve MoAbs(KOCO2831∼2812) were prepared and two-site sandwich enzyme-linked immunospecific assay(Sandwich-ELISA) system was developed. It became apparent all antibodies obtained in this study recognize β-chain of C3 structure. KOCO2801 and biotinylated KOCO2804 gave an optimal combination for the ELISA system. C3 fragments bound to surface of cetyimannoside-modified liposome (Man-MLV) and non-modified liosomes (PC-MLV) were determined after incubation with fresh human plasma. After separation of liposomes from the plasma by centrifugation, lipids were removed by extraction with 1, 1, 2-Trichloro-1, 2, 2-trifluoroethane, and then C3 fragments were determined in the ELISA system. The results showed that C3 bound on the Man-MLV are more larger quantities than those of PC-MLV, This result confirmed that the ammount of C3 bound on liposomal surface correlates with the instability of the liposomes in the circulation and the enhancing hepatic uptake of the liposomes. Thus, this approach can be available for investigation of liposomal behaviour in the circulation.

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W/o/w type multiple emulsions containing vancomycin (VCM) in the internal aqueous phases were prepared by a modified two-stage emulsification procedure. We used a lipiodol-soybean oil mixture to minimize the difference in specific gravities between the aqueous phase and the oily phase. Emulsions with high entrapment efficiency (95.54%), good stabilities, small(19.41μm) and homogeneous droplet diameters were obtained by use of 0.5% VCM dissolved in the internal phase, 5% HCO-40 in the oily phase and 5% Pluronic F-88 in the external phase. In a release pattern from the emulsion in vitro, little drug was released for 2 days and then 3.5% of the drug was released in day 3. When 5% solution was entrapped in the internal phase, entrapment efficiency was 86.86%, mean diameter was 14.50 μm, but the formulation showed relatively rapid VCM release in vitro. Moreover from observation of microscopic photographs, each particles were stable in storage and under physiological conditions. Serum concentrations of VCM after administration of the emulsion were sustained. Especially after intraperitoneal administration, the concentrations of VCM released from the emulsion were kept at 1/5 of those after administration of a simple solution. The present findings suggest that the emulsion is stable in vivo and releases VCM gradually.

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Cisplatin is an anticancer drug with broad-spec-trum, that is especially effective against genitourinary tumors. But it shows serious toxicity in kidney and gastrointestinal tract in clinical use. In order to decrease nephrotoxicity of cisplatin, several approaches have been done, such as : (1) Change of administration route and combination therapy with other drugs ; (2) Development of new derivatives : (3) Novel dosage form (design of DDS forms) ; etc. In this paper, preparation of multiple-phase emulsion containing cisplatin and its combination therapy in mouse will be presented. The physicochemical properties and nephrotoxicity of the emulsion were also investigated.

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Carcinomatous peritonitis with resultant ascites can be the result of progression of gastrointestinal malignancies, especially of gastric origin. Various methods, including intraperitoneal and intravenous routs, have been tried to improve the efficacy of chemotherapeutic agents or biological response modifiers. Nevertheless, prognosis of such patients remains grim. Hydroxyapatite (HAp) has excellent compability with human tissues and has been used in orthopedic and dental procedures, and percutaneous devices for hyperalimentation. The drug carrier HAp particle has pores 23∼59 μm in diameter with a surface area of 25 m²/g. The efficacy of intraperitoneal administration of lentinan-loaded hydroxyapatite particles(HAp-LNTN) was explored using a Donryu rat model of tumor cell AH-130 carcinomatous peritonitis. The drug delivery system HAp-LNTN contained 200 mg HAp and 0.5 mg LNTN. The pharmacokinetics of LNTN following intraperitoneal administration of HAp-LNTN was studied. Serum levels of HAp-LNTN were elevated for 24hours compared with free-LNTN. Intraperitoneal administration of HAp-LNTN was effective in prolongation of survival of rats bearing AH-130 in the peritoneal cavity, day 35 to 55. Furthermore, the pharmocokinetics of carboplatin (CBDCA) following intraperitoneal administration of HAp-CBDCA was studied. Serum levels of CBDCA were higher in the HAp-CBDCA group compared to the free-CBDCA group from postdrug administration hour 6 until day 3. These results suggest that the efficacy of anticancer drugs is enhanced by utilizing HAp as a drug delivery system.

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There are three key points concerning the efficacy of CDDP in clinical use. First, anti-tumor response to CDDP is correlated not with C_max but with AUC (area under the curve). Secondarily, antitumor response to chemotherapy and survival of patients receiving chemotherapy is directly correlated with the dose intensity (DI : mg/m²/wk) of CDDP in advanced gynecologic cancer which is CDDP-sensitive. To augment AUC and DI, we developed a unique mode of administration—that is low-dose consecutive (LDC) CDDP (10 mg/m², day 1∼7) for intravenous administration. Successful clinical results with this method were already reported in both ovarian and uterine cancer. Lastly, CDDP can augment anti-tumor efficacy of 5-FU which is entirely time-dependent agent. Thus, we designed continuous 5-FU combined with LDC-CDDP, which were administered through the catheter whose tip is placed in the aorta abdominalis utilizing an external infuser pump for advanced or recurrent cervical cancer, whose lesion is limited within the pelvis. The present modality delivered a response rate (CR+PR/evaluable) of 62.4% out of 93 patients with recurrent cerival cancer in the pelvis after radiotherapy with significant survival impact. Further, this modality was also effective as a neoadjuvant for advanced cervical adenocarcinorma with response rate of 68.2% out of 22 cases. Generally, the rate of complete surgery performed for stage II patients has been lower than 20%. In contrast, we performed complete surgery in 16 patients out of 22 with stage IIb or IIIb following neoadjuvant chemotherapy (NC), with 6 having incomplete surgery. Thus, the present modality is considered to be promissing for advanced malignancies whose lesion is located in the pelvis.

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