Rheological Properties and Composition Affecting the Skin Permeation of a Model of a Hydrophilic Drug in Lecithin Reverse Wormlike Micelles

We investigated the effect of the rheological properties and composition of lecithin reverse wormlike micelles (LRWs) on the skin permeation of a model of a hydrophilic drug to determine whether LRWs support uniform hydrophilic drug/oil-based formulations and good drug penetrate into skin. Here, we prepared LRWs with D (-)-ribose (RI) or glycerol (GL) as polar compounds, liquid paraffin (LP) or isopropyl myristate (IPM) as oils, and 6-carboxyfluorescein (CF) as a model for a hydrophilic drug, and evaluated the rheological properties and skin penetration characteristics of the preparations. The LRWs showed moderate viscosity at 25 °C, a typical storage temperature, but decreasing viscosity at 32 °C, the surface temperature of human skin, suggesting that the LRWs would penetrate the microstructure of skin (e.g., wrinkles and hair follicles). The highest skin permeability of CF was observed when IPM was used as the oil, suggesting that both the stratum corneum and hair follicle routes are involved in drug permeation. The penetration of CF into hair follicles is influenced not only by the rheology of the formulation but also by the interaction between IPM and sebum in the hair follicles.

Effect of the Physicochemical Properties of Liquid Paraffin on the Phase State and Rheological Properties of Lecithin Reverse Wormlike Micelles

Lecithin reverse wormlike micelles (LRWs) have been studied recently for dermal application dosage use but the effects of the physicochemical properties of oils on the formation and rheological properties of LRWs have not been investigated. We studied the effect of oil on the formation of LRWs using 5 types of liquid paraffin (LP) with kinematic viscosities ranging from 4.00 to 88.0 mm²/s. Partial phase diagrams of lecithin/water/LP systems indicated that LPs with low molecular weights could form LRWs with only a small amount of water, but LPs with high molecular weights could not form LRWs, regardless of the water concentration. The solubility of lecithin in LPs was higher for low molecular weight LPs, thus possibly affecting the formation of LRWs. The zero-shear viscosity and relaxation time of LRWs initially increased with increasing water concentration, and then decreased. The water concentration providing the maximum value was dependent on the molecular weight of the LP, whereas the maximum amount and length of the LRWs were independent of the water concentration. Our results indicate that the molecular weight of LP affects the ease of formation and the viscoelasticity of LRWs.

A Method for Measuring the Surface Free Energy of Topical Semi-solid Dosage Forms

Our aim was to determine the surface free energy (SFE) of semi-solid dosage forms (SSDFs) by establishing a reproducible method for measuring the contact angle of liquids to SSDFs. Four SSDFs were used: petrolatum, an oil/water (O/W) and a water/oil (W/O) cream, and an alcohol-based gel. The SSDFs were evenly spread on a glass slide, and the change in contact angle over time was measured by dropping water, glycerol, diiodomethane and n-hexadecane as the test liquids. Depending on the combination of test liquid and SSDF, the contact angle was either constant or decreased in an exponential manner. Contact angles may have decreased in an exponential manner because the reaction between the test liquid and the SSDF altered the interfacial tension between the two phases and changed the surface tension of the test liquid and the SFE of the SSDF. The contact angle of the test liquid to the SSDF could be determined reproducibly using the initial contact angle immediately after dropping the liquid on the SSDF as the contact angle before reaction. Using the obtained contact angles and the Owens-Wendt-Rabel-Kaelble equation, we calculated the SFE and its component for the SSDFs tested and found that the results reflect the physicochemical properties of SSDFs. Furthermore, the work of adhesion (W_A) of the SSDF to Yucatan micropig skin was calculated using the SFE for the SSDFs. Interestingly, the W_A values for all SSDFs tested were comparable.

Characteristics of an Emulsion Obtained Using Hydrophobic Hydroxypropyl Methylcellulose as an Emulsifier and a High-Pressure Homogenizer

Hydrophobically modified hydroxypropyl methylcellulose (HM-HPMC), a polymer in which a small amount of HPMC is stearoxyl substituted, was used as an emulsifier of emulsion-type lotion. A high-pressure homogenizer (microfluidizer) was used. The viscosity of the 1% HM-HPMC aqueous gel decreased after passing through the microfluidizer from 5.5 to 2.7 Pa·s. When liquid paraffin (LP) was used as the oil phase, a stable emulsion was obtained with an LP ratio of 1-40%. The apparent viscosity decreased with LP ratios up to 20%, and then increased with increasing LP concentration. The emulsions with an LP ratio <20% presented a pseudo-viscous flow, similar to that of the diluted polymer solution. HM-HPMC likely adsorbed onto the oil with a stearoxyl group; thus, the interaction between the stearoxyl group, which explained the high viscosity of HM-HPMC, decreased, reducing the viscosity of the emulsion. The LP ratio was 40%, and the emulsion presented a plastic flow, which is typical of concentrated emulsions. The size of the droplet in the emulsion was approximately 1 µm regardless of the LP ratio. When low-viscosity LPs or monoester-type oils such as isopropyl myristate were used, some of the emulsions presented creaming. An emulsion using HM-HPMC as an emulsifier and an appropriate oil homogenized with a microfluidizer is stable, has low viscosity, and can be easily spread on skin.

The Molecular Mechanisms Underlying Prostaglandin D2-Induced Neuritogenesis in Motor Neuron-Like NSC-34 Cells

Prostaglandins are a group of physiologically active lipid compounds derived from arachidonic acid. Our previous study has found that prostaglandin E2 promotes neurite outgrowth in NSC-34 cells, which are a model for motor neuron development. However, the effects of other prostaglandins on neuronal differentiation are poorly understood. The present study investigated the effect of prostaglandin D2 (PGD2) on neuritogenesis in NSC-34 cells. Exposure to PGD2 resulted in increased percentages of neurite-bearing cells and neurite length. Although D-prostanoid receptor (DP) 1 and DP2 were dominantly expressed in the cells, BW245C (a DP1 agonist) and 15(R)-15-methyl PGD2 (a DP2 agonist) had no effect on neurite outgrowth. Enzyme-linked immunosorbent assay demonstrated that PGD2 was converted to 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) under cell-free conditions. Exogenously applied 15d-PGJ2 mimicked the effect of PGD2 on neurite outgrowth. GW9662, a peroxisome proliferator-activated receptor-gamma (PPARγ) antagonist, suppressed PGD2-induced neurite outgrowth. Moreover, PGD2 and 15d-PGJ2 increased the protein expression of Islet-1 (the earliest marker of developing motor neurons), and these increases were suppressed by co-treatment with GW9662. These results suggest that PGD2 induces neuritogenesis in NSC-34 cells and that PGD2-induced neurite outgrowth was mediated by the activation of PPARγ through the metabolite 15d-PGJ2.

[Preparation and Rheological Properties of Cross-linked Liposomes Using Hydroxypropylmethylcellulose Bearing a Hydrophobic Anchor]

Hydrophobically-modified hydroxypropylmethylcellulose (HM-HPMC) is a thickener with a long hydrophobic alkyl side chain. In this study, we investigated the gelation ability and rheological properties of a liposome/HM-HPMC mixed solution. The liposome suspension and the HM-HPMC aqueous solution each had low viscosities, but the viscosity increased rapidly when they were mixed. This is thought to be due to the formation of a 3D network structure caused by the hydrophobic group of HM-HPMC penetrating into the liposomal bilayer membrane, crosslinking the liposomes together. This hypothesis was supported by the fact that gelation did not occur when hydroxypropylmethylcellulose without a hydrophobic group was used. The viscosity of the liposome/HM-HPMC mixed solution decreased rapidly when a shear was applied, but immediately returned to the original gel state when the shear was removed, indicating a reversible reaction. When a strong shear is applied, the hydrophobic group of HM-HPMC detaches from the liposome. When the shear is removed, the liposome is again cross-linked by HM-HPMC. From these results, it was revealed that liposome cross-linked gels can be prepared when HM-HPMC is used.

[Prediction of Wettability and Adhesion of Lotion to Skin Based on the OWRK Method]

In this study, we propose a new technique for evaluating wetting and adhesion of lotions to skin using surface tension measurements, contact angle measurements and calculations based on the Owens-Wendt-Rabel-Kaelble (OWRK) method. Three prescription lotions (Napageln^® Lotion 3%, Sumilu_® Lotion 3% and Felbinac Lotion 3% ｢Rakool｣） and two over-the-counter lotions (Feitas_® Lotion and Salomethyl^® FB Lotion α) were used. Based on the dispersive and polar components of the surface free energy of Yucatan micro pig (YMP) skin, isograms of contact angle (wetting envelope) and adhesion work of the YMP skin surface were constructed. Plotting the surface tension and its polar component of lotions on this isogram revealed that it is possible to predict the wettability and adhesion of lotions to YMP skin. Such diagrams can be easily constructed even using the surface free energy of other types of skin, such as that of humans and hairless mice. This evaluation method may be applicable to other external use medicines.

[Optimum Volume of Water Needed for the Paste State of Pediatric Powders: Considerations Based on Yield Values and Applications to Generic Medicine]

To clarify the volume of water required to paste pediatric powders, we herein established a standard for the powder paste state by measuring yield values when water was added to powders. The powders used in the present study were selected from 8 types including original and generic drugs. Tipepidine hibenzate is prescribed in the pediatric field in combination with ambroxol hydrochloride and l-carbocysteine. The volumes of water needed to achieve the paste state of ambroxol hydrochloride between the original and generic drugs were similar. However, the volumes of water needed for l-carbocysteine markedly differed between the original and generic drugs due to differences in their additives. The spreadability of the mixture when water was added to the powders was evaluated using a spread meter. Among the powders tested in the present study, the yield value to achieve a paste state with the addition of water was approximately 1000 dyne/cm². The optimum volume of water estimated from this yield value using the linear proportional relationship for the amount of powder may be applied to the mixture of each pediatric power for dosage/body weight.

The Comparison of Surface Free Energy of Human, Yucatan Micropig, and Hairless Mouse Skins and Influence of Surfactant on Surface Free Energy of the Skin

Surface free energy (SFE) is an important factor for evaluation of wettability or adhesion. Thus, the SFE of a Yucatan micropig (YMP) skin and a hairless mouse (HM) skin, which are commonly used in skin permeation studies instead of human skin, were compared with the human skin. Contact angles of water and 1-bromo naphthalene to skin were measured and the SFE was calculated using the Owens-Wendt equation. The SFE of the human abdominal skin was 40 mN/m and its polar component σ_s^p was as low as 2 mN/m, which was similar to that of the low sebum skin reported previously. In the case of the YMP skin, σ_s^p was high on the surface but similar to that obtained after the skin was tape-stripped twice. The HM skin showed similar SFE as that of the human skin. When the surfactant was applied on the skin, wiped, and dried, the remaining surfactant increased the SFE in σ_s^p; however, the original SFE was obtained after rinsing with water. The YMP skin and HM skin is similar to the human abdominal skin with a low sebum level. Thus, they are also good skin models for studying wettability or adhesion of a substance.

Application of Pickering Emulsion with Cyclodextrin as an Emulsifier to a Transdermal Drug Delivery Vehicle

The emulsion prepared with β-cyclodextrin as an emulsifier (βCDE) is considered to be a Pickering emulsion. We examined the characteristics of βCDEs using captopril (CP) as a model drug, and studied the in vitro skin permeation of CP from βCDEs through hairless mouse skin. The stability of βCDE was increased with increasing βCD concentration and conversely decreased with increasing CP concentration. The yield stress value from the rheological measurement results was suggested to be one of the factors determining the stability of the βCDE, and βCDEs with higher yield stress values were more stable. We found that the skin permeability of CP could be improved by using βCDE with isopropyl myristate as the oil phase and that the flux of CP depended on the free CP concentration in the water phase of βCDE.

Highly Viscoelastic Reverse Wormlike Micellar Systems from a Mixture of Lecithin, Polyglycerol Fatty Acid Monoesters, and an Oil

We report new lecithin reverse wormlike micelles with high viscoelasticity formed using lecithin/polyglycerol fatty acid monoester (PGLFA)/oil systems. In this study, the influence of the amphiphilicity (i.e., hydrophile-lipophile balance, HLB) of PGLFA on the phase behavior and rheological properties of reverse wormlike micelles was investigated in detail. PGLFAs with degrees of polymerization of polyglycerol varying between 6-40 and constituent fatty acids with chains between 6-18 carbon atoms long were used. Partial phase diagrams of the lecithin/PGLFA/n-decane systems indicated that the appropriate PGLFA could change the lecithin/oil solution into a highly viscoelastic solution comprising reverse wormlike micelles. Rheological measurements showed that all systems that formed reverse wormlike micelles exhibited an unusual phenomenon called "shear-thickening". Furthermore, reverse wormlike micelles grew as the PGLFA concentration increased and the zero-shear viscosity (η₀) of the solution rapidly increased. Our results indicate that the magnitude of the maximum η₀ depends on the degree of polymerization of the constituent polyglycerol in the PGLFA, while the size of the reverse micellar region and the highly viscous region in the phase diagram depends on the HLB value of the PGLFA.

Formation and characterization of emulsions using beta-cyclodextrin as an emulsifier

The preparation and characterization of n-alkane/water emulsions using beta-cyclodextrin (beta-CD) were studied. The prepared n-alkane/water emulsions were of the oil-in-water (O/W) type, and the stability of emulsions was in the order of n-hexadecane > n-dodecane > n-octane. From observations using polarized light microscopy and powder X-ray diffraction measurement, it was suggested that the formation of a dense film at the oil-water interface and the three-dimensional structural network created by precipitated complexes in the continuous phase are associated with the stability of emulsion. Furthermore, it was clarified that O/W-type emulsions were formed because the contact angle (theta ow) which the precipitate makes with the interface was theta ow < 90 degrees in all compounds (oils) used in this study.

Study on preparation and formation mechanism of n-alkanol/water emulsion using alpha-cyclodextrin

Surfactants are usually used for the preparation of emulsions; however, some have an adverse effect on the human body such as skin irritation, hemolysis, and protein denaturation, etc. In this study, we examined the preparation and formation mechanism of n-alkanol/water emulsions using alpha-cyclodextrin (alpha-CD) as an emulsifier. Emulsions were prepared by mixing oil and water phases for 4 min at 2500 rpm using a vortex mixer. The mechanism of emulsification was investigated with some physico-chemical techniques. From phase diagrams of n-alkanol/alpha-CD/water systems, the emulsion phase extended as the chain length of n-alkanols and the amount of alpha-CD added increased. Furthermore, the emulsion was not formed in the region where the n-alkanol/alpha-CD complex didn't precipitate; however, the emulsion was formed in the region where the complex precipitated. In addition, it was clear that the emulsions have a yield stress value and correspond to the Maxwell model from rheological measurement. Our experiments clearly showed that the stable emulsions are formed because the precipitated complexes form a dense film at the oil-water interface and prevent aggregation among dispersed phases. Furthermore, it is suggested that the creation of a three-dimensional network structure formed by precipitated complexes in the continuous phase contributes to the stabilization of the emulsion. Thus, we concluded that the n-alkanol/water emulsions using alpha-cyclodextrin were a kind of the Pickering emulsion.

Carboxyfluorescein Leakage from Poly(ethylene glycol)-Grafted Liposomes Induced by the Interaction with Serum

The effects of fetal bovine serum (FBS) on carboxyfluorescein (CF) leakage from poly(ethylene glycol)-grafted liposomes (PEG-liposomes) were investigated. PEG-liposomes were prepared from dipalmitoylphosphatidylcholine (DPPC) and distearoyl-N-monomethoxy poly(ethylene glycol)-succinyl-phosphatidylethanolamines (DSPE-PEG) having PEG molecular weights of 1000, 2000, 3000 and 5000. The presence of FBS dramatically increased CF leakage from liposomes near the gel-liquid crystalline phase transition temperature, but had little effect at lower and higher temperatures. The CF leakage from PEG-liposomes whose molecular weight in PEG units was above 2000 was suppressed compared with that of liposomes without PEG. And, there was hardly any difference in the effect of the PEG molecular weight of the PEG-lipids on CF leakage from PEG-liposomes with FBS when PEG-lipids with a molecular weight in PEG units above 2000 were used. On the other hand, the leakage of CF from liposomes containing 0.145 mol fractions of DSPE-PEG1000 was larger than that of liposomes without PEG. Furthermore, the effects of FBS on the cooperative units of lipid molecules during the gel-liquid crystalline phase transition of liposomes were examined. However, the cooperative units of liposomes with FBS had little change compared with that of liposomes without FBS.

Calorimetry and Cryo-Transmission Electron Microscopic Studies of PEG2000-Grafted Liposomes

The phase behavior of poly(ethylene glycol) grafted liposomes (PEG-liposomes) was investigated by differential scanning calorimetry (DSC), dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM). PEG-liposomes were prepared from mixtures of dipalmitoyl phosphatidylcholine (DPPC) and distearoyl phosphatidylethanolamine with a covalently attached PEG molecular weight of 2000 (DSPE-PEG2000). From the results of DLS measurements, the coexistence of PEG-liposomes and small molecular assemblies were confirmed at mole fractions of DSPE-PEG2000 above about 0.1. Moreover, it was confirmed that small molecular assemblies were disk micelles by cryo-TEM. However, the phase transition enthalpies of PEG-liposomes were hardly changed according to the DSC measurement, though the mole fraction of the PEG lipid increased. From these results, it was suggested that the phase transition enthalpies hardly changed despite mixed micelles being formed because the bilayer structure of the disk micelle maintains high cooperativity between the DPPC molecules.

Effects of poly(ethylene glycol) (PEG) concentration on the permeability of PEG-grafted liposomes

Poly(ethylene glycol)-grafted liposomes (PEG-liposomes) were prepared from dipalmitoylphosphatidylcholine (DPPC) with various amounts of distearoyl-N-monomethoxy poly(ethylene glycol)-succinyl-phosphatidylethanolamines (DSPE-PEG) with PEG molecular weights of 1000, 2000, 3000 and 5000. The effects of DSPE-PEG concentration on the permeability of PEG-liposomes were investigated using carboxyfluorescein (CF). In the gel state, the CF leakage from PEG-liposomes was decreased with increasing mole fractions of DSPE-PEG for all PEG molecular weights. In the liquid-crystalline state, the CF leakage from PEG-liposomes containing DSPE-PEG1000 gradually increased with increasing mole fractions of DSPE-PEG, while that of PEG-liposomes whose molecular weight in PEG units was above 2000 rapidly decreased by the addition of DSPE-PEG. Furthermore, no effect of PEG molecular weight on CF leakage was observed. The relationship between the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) (or 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH)) and the mole fraction of DSPE-PEG for PEG-liposomes was also investigated. No significant changes in fluorescence polarization of DPH for liposomal bilayer membranes was observed in the gel and liquid-crystalline states due to the addition of DSPE-PEG, while that of TMA-DPH was decreased compared with that of liposomes without DSPE-PEG in both states.

Preparation and Clinical Application of Indomethacin Gel for Medical Treatment of Stomatitis

The preparation and clinical applications of indomethacin (IM) gel were investigated in the treatment of stomatitis resulting from chemotherapy and radiotherapy for cancer. IM gel was prepared by adding various water-soluble polymers [hydroxypropyl cellulose (HPC), etc.] to IM aqueous solution. The release rate of IM from IM gels was found to decrease with increasing polymer concentration and viscosity and to follow a first-order reaction rate equation. The release rate of IM from the IM gel with HPC was decreased gradually with increasing polymer concentration and to be easily controllable compared with gels with other polymers. The time before pain relief occurred after application of the IM gel was slightly shorter and the duration of pain relief was longer compared with the IM aqueous solution. It was confirmed that IM gel is useful in the treatment of stomatitis.

A modified method using static head-space gas chromatography for determining the stability constants of 1-alkanol/alpha-cyclodextrin complexation

A modification of the conventional static head-space gas chromatography method (SHSGC method) to determine stability constants for 1-alkanol/alpha-CD inclusion complexes was investigated. The 1 : 1 stability constants determined by this modified SHSGC method are in reasonable agreement with the corresponding values reported previously. The modified SHSGC method precludes the necessity of the calibration curve by the use of Henry's law constant of guest. Consequently, the modified SHSGC method is more advantageous than the conventional SHSGC method because the experimental time required for determination of the stability constant is markedly reduced.

Effects of poly(ethylene glycol) (PEG) chain length of PEG-lipid on the permeability of liposomal bilayer membranes

The effects of poly(ethylene glycol) (PEG) chain length of PEG-lipid on the membrane characteristics of liposomes were investigated by differential scanning calorimetry (DSC), freeze-fracture electron microscopy (FFEM), fluorescence polarization measurement and permeability measurement using carboxyfluorescein (CF). PEG-liposomes were prepared from mixtures of dipalmitoyl phosphatidylcholine (DPPC) and distearoyl phosphatidylethanolamines with covalently attached PEG molecular weights of 1000, 2000, 3000 and 5000 (DSPE-PEG). DSC and FFEM results showed that the addition of DSPE-PEG to DPPC in the preparation of liposomes caused the lateral phase separation both in the gel and liquid-crystalline states. The fluidity in the hydrocarbon region of liposomal bilayer membranes was not significantly changed by the addition of DSPE-PEG, while that in the interfacial region was markedly increased. From these results, it was anticipated that the CF leakage from PEG-liposomes is accelerated compared with DPPC liposomes. However, CF leakage from liposomes containing DSPE-PEG with a 0.060 mol fraction was depressed compared with regular liposomes, and the leakage decreased with increasing PEG chain length. Furthermore, the CF leakage from liposomes containing DSPE-PEG with a 0.145 mol fraction was slightly increased compared with that of liposomes containing DSPE-PEG with a 0.060 mol fraction. It is suggested that the solute permeability from the PEG-liposomes was affected by not only properties of the liposomal bilayer membranes such as phase transition temperature, phase separation and membrane fluidity, but also the PEG chain of the liposomal surface.

Complexation of butylbenzenes with 2-hydroxypropyl-cyclodextrins in aqueous solution

The stability constants for the inclusion of butylbenzenes (BBs) with 2-hydroxypropyl-cyclodextrins (2HP-CDs) in aqueous solution have been determined using the static head-space method. The 1:1 stability constants were obtained by this method. For the complexation of BBs by 2HP-alpha-CD, the order of stability constants was n-BB > isoBB > tert-BB. In contrast, the order for complexation of BBs by 2HP-beta-CD was the opposite: tert-BB > isoBB > n-BB. The order of the stability constants by 2HP-gamma-CD was similar to that of 2HP-beta-CD, but the values of the stability constants were not significantly different in the BB types. In addition, the binding effects are discussed in relation to the different alkyl groups of BBs.

Solubilization of (+)-limonene by anionic/cationic mixed surfactant systems

The combined effects of sodium n-octyl sulfate (SOS) and cetyltrimethylammonium bromide (CTAB) on the solubilization of (+)-limonene in aqueous solution were studied using a headspace gas chromatography technique. The findings showed the mixing of SOS and CTAB resulted in positive synergistic effects on the solubility of (+)-limonene. The positive synergistic effects are explained from the perspective of the phase behavior of this mixed surfactant system.

Determination of the stability constants in alkanol/alpha-cyclodextrin mixed system

The simultaneous determination of the stability constants for inclusion of alkanols with alpha-cyclodextrin (alpha-CD) was investigated in a mixed alkanol system using static head-space gas chromatography (SHSGC). The 1:1 stability constants obtained were in fair agreement with those obtained previously using other methods. The time required for determination of the stability constant was markedly reduced using this simultaneous SHSGC method.

High rate of induction of human autologous cytotoxic T lymphocytes against renal carcinoma cells cultured with an interleukin cocktail

A high rate of induction (9 of 10 cases) of human autologous cytotoxic T lymphocytes (CTL) was achieved in vitro from peripheral blood mononuclear cells of renal carcinoma patients by applying an interleukin (IL)-cocktail consisting of IL-1, -2, -4, and -6. The CTL specifically lysed their own target carcinoma cells within 24 h but did not kill neighboring autologous normal kidney cells or allogeneic renal cancer cell lines. In the case of TUHR4TKB, for which autologous CTL were not induced, no expression of MHC class-I molecules was observed on the surface of these carcinoma cells, although they were sensitive to autologous natural killer cells. The results imply that adoptive immunotherapy for metastasized renal carcinoma will be feasible with autologous CTL in combination with natural killer cells.

[Establishment and characterization of human cholaginocarcinoma, MEC, producing carbohydrate antigen 19-9]

A new tumor cell line MEC was established from pleural effusion of a patient of cholaginocarcinoma. In tissue culture, the cell line grew in the sheet of variant cells and showed the epithelial-like pattern. Histologically, the cell line almost showed the same pattern as those in bile and preural effusion from the patient. Electron microscopic observation of this cell line showed the irregular microvilli on the surface of the cell and the desmosome between cells. The doubling time of the cell line was 40.8 hours. Chromosome counts ranged from 61 to 86. The cell line had 9 marker chromosomes and some variant chromosomes. The cell line was transplanted into the subcutaneous of nude mice and formed the tumor. It showed the moderately differentiated tubular adenocarcinoma the same pattern as the primary tumor. We have recognized the producing and releasing of CA19-9 in the serum from the tumor bearing nude mouse and supernate of the medium as the serum from the patient. The presentation of CA19-9 in the cytosol of the cell line and the tumor cells of nude mouse was recognized in Avidin-Biotin-Peroxidase Complex in immunoloperoxidase techniques. The cell line can grow in serum-free medium. On September, 1990, the cell line has been maintained from 70 passages during about 800 days.