Transport behaviors of steroid hormones were investigated on a liquid membrane system with hexadecyltrimethylammonium bromide (HTAB) micelles as a carrier separating a hexane source phase and a hexane receiving phase. The experimental results are reasonably explained by a model which hormones transferred from the hexane source phase to the water membrane to be entrapped in HTAB micelles in a diffusion layer close to the hexane/water interface and transported through the membrane in an entrapping form in micelles and also in a free form. According to this analysis, the dynamical parameters for the transport were determined. The most suitable values for a length of the diffusion layer and a diffusion coefficient of HTAB micell were estimated to be 0.01 cm and 4.4 x 10^-6 cm²/s, respectively, from the experimental results of progesterone transport. In the case of hormone with a lower water/hexane partition coefficient, the uptake process from the hexane source phase to the water phase is rate-determining in the transport process and the hormone transport is accelerated by the addition of HTAB, while the rate-determining step is changed to the release process from the water phase to the hexane receiving phase with an increase of the partition coefficient. Then the transport process is governed by the hormone concentration of free form in the water membrane and the hormone transport is decelerated by the addition of HTAB, because the concentration of free form decreases inversely by the entrapping in micelles for the system having the restricted amount of hormone in the hexane source phase.

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The stereoselective hydrolysis of the long-chain substrate (p-nitrophenyl N-dodecanoylD( )-phenylalaninate) catalyzed by the tripeptide (N-(benzyloxycarbonyl)-L-phenylalanylL-histidyl-L-leucine) was found to be inhibited by flavonoids in the coaggregates composed of 59 mol% ditetradecyldimethylammonium bromide and 41 mol% hexadecyltrimethylammonium bromide.

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Organic thin films (azo-dye films) were prepared by micellar disruption method, under various electrolytic and solution conditions. This method is based on the deposition of a solubilizate onto an electrode, which is preceded by the micellar distruption and the subsequent release of the solubilizate in the vicinity of the electrode. The growth of the film depended on the rate of electrolysis (rpm), the amount of electricity (Q), the concentration of the surfactant ([surfactant]) and the solubilizate ([solubilizate]), and the type of the surfactant. The increase in the value of Q and [solubilizate] and the decrease in rpm promoted the growth of the film, while the increase in [surfactant] depressed the growth. These results were explained on the basis of solubilization and adsorption equilibrium for the azo-dye released from the micelle.
In addition, the experiments revealed that the film was formed in two stages: a layer of globular nuclei was formed on the electrode, followed by the growth of needle-like crystals on the layer, and that a pyridinium-type surfactant was preffered over alkylammonium-type ones in that the film grew more rapidly in the former surfactant systems than in the latter.

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The interaction between chlorophyll a (Chi) and N-methyl myristamide (NMMA) in waterorganic solvent binary solutions was investigated by means of absorption, fluorescence and resonance Raman spectroscopies. From previous studies on Chl-NMMA-surfactant systems, the 684 nm (absorption) and 687 nm (fluorescence) bands as well as the 1215 cm ^-1 Raman band are known to be marker bands characteristic of the interaction between Chl and NMMA. The marker absorption band located at 687 nm (Figs.3 and 4), the marker fluorescence band at 687 nm (Figs.5 and 6) and the marker Raman band at 1215 cm^-1 (Fig.8)were found in water-methanol, water-ethanol, water-1-propanol and water-acetone systems. These data indicate the formation of association complexes between Chl and NMMA in those systems. The association of Chl with NMMA was less promoted in the aqueous methanol system than in the aqueous ethanol, 1-propanol and acetone systems. This difference can be explained in terms of the coordination number of the central Mg atom of Chl. An another striking finding is that the association between Chl and NMMA take s place only in solutions containing an appropriate amount of water. Thus, the marker bands were observed in narrow ranges of water content, i. e., 45-60 vol%, 60-70 vol%, 75-90 vol% and 50-80 vol%, for water-methanol, water-ethanol, water-1-propanol and water-acetone systems, respectively. In order to correlate this effect with the properties of water-organic solvent mixtures, we estimated the value of molecular dielectric polarization (P) at pertinent contents of water. As seen in Table 1, the values of P seem to be independent of the kind of organic solvent. This finding suggests that the P of a binary solution is the determining factor in promoting the association of Chi with NMMA.

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Dioctadecyldimethylammonium acrylate (2 HTDA) or methacrylate(2 HTMET) were synthesized from the corresponding chloride (2 HT). Water dispersions of 2 HTDA and 2 H TMET were polymerized by photoirradiation. Properties of these polymerized vesicles were studied by means of ESR spin-labelling, average particle size, DSC, turbidity, electroconduc t ivity, and so on. Followings were found; ( 1 ) Anisotropy parameter (2 (A1 1-A1)) and surface charge for a polymerized 2 HTMET vesicle membrane were remained as same as th o se of 2 1 -1T. At higher temperature, the membrane has a higher anisotropy than that of 2 HT. However, the anisotropy of a polymerized 2 HTDA vesicle dispersion was different f r om that' of 2 HT. ( 2 ) Coagulated properties of a polymerized 2 HTMET vesicle dispe rsion were not dependent on the lyotropic number of cation species, but of anion s p ecies in inorganic salts which we used. ( 3 ) In order to strengthen a 2 HTMET vesicle membran e to anionic surfactant such as SDS, photopolymerization with N, N'-methylenebis(acr y lamide)(MBA) as a cross linking agent is efficient.

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There are many kinds of cooperative phenomena in nature. And so me of them are thought to play important roles in living body. In case of lipids, cooperativity is expected to exhibit among large amounts of molecules. However, highly cooperative phenomena among lipid molecules have not been reported so far. In this paper, gel/liquid crystalline phase transition of concentrated water suspension (molar ratio lipid: water=1: 500) of L-α-dipalmitoylphosphatidic acid was examined by using differential scanning calorimeter. Endothermic or exothermic enthalpy change of the main phase transition was more than 100 kJ.mo1^-1, which is about 3 times as large as already reported. Especially during the cooling process, as shown in Fig.2, at the several degrees lower than the endothermic peak, a very sharp exothermic peak was obtained. When the phase transition began, heat flow reached the maximum value within several seconds. As the transtion was accompanied with much release of heat, the temperature of the sample rose rapidly in spite of the cooling process. This phenomenon was always observed over a wide range of cooling rates from 10K.min^-1 to 0.01 K .min^-1 These are good evidence of high cooperativity among alkyl chain s of lipid molecules during the phase transition from liquid crystalline phase to gel phase. These phenomena were obtained in some restricted ranges of coexisting ion concentrations (see Fig.3). Similar results were obtained in case of DL-α-dipalmitoylphosphatidyl-L-serine. Some other glycerophospholipids were examined uner the same experimental conditions. However, similar results are not obtanied so far (see Table 1).

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Double-chain alkyl amphiphiles with polypeptide head-groups can form helical superstructures composed of uni-lamellar bilayer membranes in dilute aqueous solutions. In this study, various amphiphiles with an L-glutamic acid moiety was prepared as a model compound to study the structure of molecular aggregates. As a result, it was confirmed that the amphiphiles with three or more amide bondings per molecule could form helical aggregates and their mechanism of metamorphosis was similar to those of polypeptide amphiphiles. In addition, the helical aggregates had two phase transitions and showed chiral reversibility between negative to positive states around the first phase transition. We conclude that the plural amide bondings near the chiral carbon of qmphiphiles contribute to the production of helical aggregates and specific chirality change.

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There are many studies on the constitution of drug delivery systems and artificial cells from the viewpoint of the functionalization of liposome systems. N-Palmitoyl-DL-homoserine (PHS) and the related compounds were prepared according to Scheme 1. The entrapped calcein release was controlled by PHS as the pH-dependent functional amphiphile. The corresponding lactone (PHSL) gave a barrier function to the liposomes under acidic conditions. On the other hand, PHS sodium salt (PHS-Na) enhanced the permeation of the entrapped calcein across the liposomal bilayers depending on the pH under alkaline conditions (above pH 6 or so), as shown in Fig.6. The control mechanism cocerned may be interpreted that PHS can change the amphipathic function itself depending on the pH as shown in Fig.3. In fact, the inhibition action of PHS for the leakage of calcein is larger than the dihexadecyl hydrogen phosphate (DCP) containing liposome (Fig.6). Alternatively, PHS can get surface activities by converting its structure to PHS-Na as the amphiphile under alkaline conditions. It may be expected that liposomes containing PHS can be used as one of potential candidates for detecting and monitoring the pH conditions in the environments like acidic sensors.

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In order to construct the bilayer membrane which has the ability of cation selectivity, amphiphilic compounds 1, 2 composed of a single lipophilic chain containing a rigid biphenylylene moiety and a 15-crown-5 or 18-crown-6 ether ring as a hydrophilic moiety were synthesized. In the presence of potassium cation, especially potassium acetate, 18-crown-6derivatives 2a, b dispersed transparently and stably in water by sonication. The presence of particles including water phase in this solution was demonstrated by the entrapment of aqueous solution of carboxyfluorescein as a fluorescence probe. The size of particles, amounting more than 90-'98% in weight, measured by a light-scattering method was in the range of 120-380A. This size was affected a little by the size of lipophilic group. Different from vesicles formed with ionic compound, those formed with 2 could be destroyed by heating to release the inner aqueous solutions. Influence of fatty acid salts on the structure of the bilayer membrane was examined. And it was disclosed that potassium oleate stabilized the dispersing system markedly, and the volume of inner aqueous phase of the vesicle was affected.

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Chiral amphiphiles which possess a cyclic polyamine (cyclam) as the hydrophilic head group (2 C₁₆AspC₁₁14 N₄, 2 C₁₂GluAzoC₁₀14 N₄, C₁₂AlaAzoC_n 14 N₄) were prepared, and their aggregation behavior in water was investigated by electron microscopy, differential scanning calorimetry and circular dichroism spectroscopy. These amphiphiles and their meta l complexes formed bilayer membranes. The aggregate morphology, gel-to-liquid crystal phase transition and the molecular orientation depended on structures of hydrophilic and hydrophobic units of the amphiphiles. The self-organizing property of these bilayers deteriorated by replacement of the trimethylammonium head with the cyclam head and its metal complexes: -N⁺ > -14 N₄-Zn²⁺ = -14 N₄- 2 H⁺ >-14 N₄-Cu²⁺, - 14N4-Ni²⁺. The influence of the hydrophobic unit on self organization was as follow; C₁₂AlaAzoC, -<2 C₁₂G1uAzoCio- <2 C₁₆AspC₁₁-.

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Novel single-chain amphiphiles which contain diphenyl sulfide (DPS) chromophores were synthesized. Methyl substituents were introduced to various positions of the aromatic rings. Electron microscopy and differential scanning calorimetry (DSC) measurements confirmed the formation of stable bilayer membranes from all of the amphiphiles. Gel-to-liquid crystalline phase transition as well as the chromophore interaction in bilayer aggregates were significantly influenced by the number and position of methyl substituents. Introduction of the alanine residue into the amphiphile effectively improved the membrane stability and promoted development of the aggregate structure, due to the hydrogen-bond formation. It was possible to control the molecular orientation by methyl substituents on the rigid segment.

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As the mimick of metalloenzyme's, the activities of the complexes of imidazole ligand: metal ion in vesicular and micellar systems were investigated for the hydorlysis of p-nitrophenyl picolinate (PNPP). The vesicular reagents and imidazole ligands, having two longchain alkyl groups and a polar head in their side-chains, were synthesized and examined for the vesicular formation (300-500 Å diameter) after ultrasonic wave-irradiation over 80 °C. Monoalkyl imidazole ligand, surfactant, was also synthesized. Imidazole ligand-Cu²⁺ ion complexes were found to be highly effective for the hydrolysis of PNPP in vesicular and SDS micellar systems. The complexes appear to be active in the exovesicular side in t his vesicles.

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National Chemical Laboratory for Industry H igashi, T s ukuba, Ibaraki 305 Japan Amphiphilic compounds were synthesized for the fabrication of LB films with n ew functions and unique structures. Mixed layers of squarylium dye and fatty acid form the "supermonomolecular structure" where the monolayer or multilayer of the pure dye are existing below the monolayer of the fatty acid at the air-water interface. Long-chain derivatives of cyclodextrin formed monolayers and were used for constructing host-guest LB films. These host-guest LB films showed remarkable photochemical reactivity and the ability of molecular recognition. Amphiphilic compounds having charge-transfer complex moieties were synthesized and their electrical conductivities were studied. The metal(dmit)₂ derivatives formed charge-transfer complexes with long-chain ammonium ions. LB films were obtained with the above complexes, which showed high conductivities with metallic temperature dependence. The hydrophobic part of an amphiphilic charge-transfer complexes was functionalized by introducing a switching unit into it. In this case, azobenzene was used as the switching unit, which perceives an external stimulus such as light and heat, causing the change in the conductivities of the LB films.

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Higher order structure of molecular aggregates and membranes contains crystal structure and its disorder, molecular orientation, surface structure and depth distribution, structure of small area and defects, spatial distribution of composition and structure. They are mainly studied by various spectroscopic techniques from which four major ones are described in the present paper. A study of a transformation of a synthetic bilayer membrane and measurement of very thin LB films are carried out by FT-IR. Depth distribution of the higher order structure of a synthetic bilayer membrane is examined by the resonance Raman probe, and molecular orientation analysis of an organic thin film is done by the total reflection Raman spectroscopy. A new system of the small angle X-ray diffraction is described. It is used to study degree of disorder of LB films prepared under different preparation conditions. A new method to study the surface molecular orientation by XPS is described. Applications of this method to synthetic bilayer membranes, LB films and also ion complex LB films are expla ined.

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Molecular hyperpolarizability ( β) of 5-(p-dodecyloxyphenyl)pyrazine-2-carboxylic acid (C 12 PPy), and aggregation structure and second-order nonlinear optical properties in noncentrosymmetric Langmuir-Blodgett films of C 12 PPy were investigated. From the two level model, the value of C 12 PPy was esti mated to be 26 x 10^-30 esu. The large value is comparable to that of p-nitroaniline. By the alternating deposition of C 12 PP y monolayers and barium icosanoate monolayers, we succeeded in the preparation of noncentrosymmetric C 12 PPy LB films with enough thickness to be applied to a nonlinear optical waveguide. From the analysis of X-ray diffraction and second-harmonic generation measurements, it was proved that C 12 PPy molecules were oriented at about 30°with respect to the normal axis of the noncentrosymmetric LB films. Further, the LB films were demonstrated to possess the large value of second-order nonlinear susceptibility (1 x 10^-7 esu).

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Monolayer and bilayer characteristics of ion pair amphiphiles, such as (2-hydroxyethyl)dimethyloctadecylammonium octadecanoate 1 and 4-[10-[(2-hydroxyethy)dimethylammonio]decyloxy]-4'-octyloxyazobenzene octadecanoate 2, were investigated. Surface pressure-area isotherms showed that 1 forms stable condensed monolayers whereas 2 produces fairly expanded monolayers having two condensed phases at compressed areas. Sonic dispersions of 1 and 2produced bilayer assemblies, which were confirmed by electron microscopy and differential scanning calorimetory. The trapping test of riboflavin indicated the formation of vesicles from 1. The spectral changes by the mixing between bilayer membranes from 1 and 4[10-[(2-hydroxyethy)dimethylammonio]decyloxy]-4'-octyloxyazobenzene bromide suggested that the fusion takes place to a considerable extent even below their phase transition temperatures. The heating of the mixture brought about complete fusion and ion exchange reaction to form new bilayer membranes consisting of 1 and 2.

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Overturn of film molecules during the compulsory Z-type deposition using the gates was investigated. Molecular boundary of the hydrophilic and hydrophobic surfaces on the in situ-photopolymerized LB films of cadmium salt of 10, 12-pentacosadiynoic acid was visualized by the difference of the condensation ability of water vapor of both surfaces of LB samples which were precooled. This proved that overturn of film molecules occurs at the three-phase line of water/air/LB film when the substrate passes through the water surface. Escape of film molecules from LB films when the substrate passes through the clean water surface was also visualized by sprinkling the toner for xerography on the water surface. Whether film molecules may escape from the substrate or not depends on the experimental conditions, such as the kind of film molecules, the surface pressure, the temperature and the kind of ions in the subphase.

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We have synthesized a wide variety of squarylium d yes 2-[4-(dialkylamino)pheny1]-4[4-(dialkyliminio)-2, 5-cyclohexadienylidene]-3-oxo-1-cyclobuten-1-olate with different lengths of alkyl substituents. π-A isotherms and UV-Vis. absorption spectra were measured for these dye monolayers on water surface. It has been found that orientation and aggregation of the dyes in the monolayers can be controlled by combination of the alkyl substituents. J-aggregates of squarylium dyes were obtrained in the monolayers of bis[4-(N-p ropylalkylamino)phenyl]squaryliumdye s (when alkyl substituent is longer than propyl) on water surface. It is very interesting that two propyl substituents at both ends of the chromophore facing to water side cause to form the J-aggregete. On transfering to solid substrates by Langmuir-Blodgett method, these J-aggregates formed on water surface easily transform to other kinds of aggregates. However, LB-films containing J-aggregate can be deposited successively with mixed monolayer of Cd-icosanoate and bis[4-(dipropylamino)phenyl]squarylium dye in the molar ratio of 1: 1 at the surface pressure of 30 mN/m. In these conditions, the monolayer of squarylium dye at higher compression undergoes transition resulting in a multipiled (mainly triple) structure, where the J-aggregates of dye are stabilized by the surrounding monolayer of the Cd-icosanoate. In the monolayer of bis[4-(dibutylamino)phenyl] squarylium dye, reversible change of absorption spectra were observed among J-aggregete, H-aggregate and monomeric species by the compression and the expansion of the monolayer at the subphase temperature of 5°C. Almost pure H-aggregates were formed at 20°C. LB-films containing H-aggregates were deposited at the surface pressure of 20 mN/m at 20°C. These results indicate that aggregation forms of squarylium dye in LB-films can be controlled by the position and the length of the alkylsubstituents. The LB-films of J- and H-aggregates of squarylium dyes are expected to exhibit advanced functions for organic thin film devices, such as photoelectric devices, chemical sensors using fluorescence and so on.

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Amphiphilic spiropyrans and fulgides for Langmuir-B lodgett(LB) films were prepared, and their photochromism was studied.8-d8o-Mcoestahnooxyylo-6x-ynmitreoth-1y'1-o-6c-tanditerco y-1ls'-poircotapdyercaynl spiropy4ra an, 6-methox4y c-8, -niatrnod- 1'-tohcetiard ecydlesrpiivraotpivyerasn, amp4h ib-, philic Nitrospitopyrans 5 a-c and bromspiropyrans 6 b-c, were synthesized. Amphiphilic furylfulgides 9 a-c having a long alkyl chain on furan ring, α-position of the side chain, and on N-position of a nitrogen analog were also synthesized. An amphiphilic thienylsubstituted fulgide was synthesized by a similar procedure. Those compounds underwent photochromic reac tion in LB film as similar as in solutions. The colored forms of spiropyran 4 a, 4 c and 6c in LB film were found to form J-aggregation. LB films of fulgides showed thermal decomposition reaction by the ring opening at the anhydride part.

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Monolayers of alkylsilane amphiphiles were immobilized in a porous glass plate (average pore diameters were 50, 100, and 200 Å). Permeation rates of NaC1 and water-soluble fluorescent probe across the porous glass plate occluded with the monolayer were reduced largely compared with those across the original glass plate. The 100. Å glass plate occluded with the monolayer reduced permeabilities effectively compared with other pore sizes in the glass plate. The permeation rate could be regulated by phase transitions from solid to liquid crystalline states of the immobilized monolayer of dialkylsilane amphiphiles. The monoalkylsilane monolayers reduced the permeabilities only slightly and did not show the permeation change by the phase transition. The permeability were also influenced by the nature of the monolayer surface. The monolayer with the hydrophobic surface more reduced the permeation rate of NaCl than those with the hydrophilic surface. Permeation behaviors through the adsorbed monolayer were compared with those through the Langmuir-Blodgett (LB) monolayer transferred on a porous glass plate. The adsorbed monolayer reduced effectively as compared with the Langmuir-Blodgett (LB) monolayer on a porous glass plate. The LB monolayer was transferred only on the outer surface of the glass plate, while the adsorbed monolayer could ocllude both on the outer surface and inner core of the glass.

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In the present article, a novel method is proposed to evaluate the intrinsic property of dynamic surface tension in lipid monolayer. The dynamic surface tension is obtained when a lipid monolayer is repeatedly compressed and expanded. It is shown that nonlinear characteristics of a monolayer affords us useful information on its physico-chemical property. Nonlinearity in various models, i) dashpot and spring, ii) surface viscoelastic body, iii)two-dimensional gas, have been analyzed by use of the Fourier-Transformation. The twodimensional gas model is proposed to be the most useful for practical analysis. In addition to this, nonlinear effect due to ion-ion interactions is discussed based on the Debye-Hiickel type approximation. The effect of miscibility of lipid molecules into the subphase is also considered. As an application of our new method, we have studied the effect of taste compounds on the dynamic surface tension of dipalmitoylphosphatidylethanolamine (DPPE). Sweet compounds are found to exhibit marked effect on the nonlinear viscoelasticity.

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The processes of deposition of precursor LB films and imidization to polyimide LB films were monitored by weight change using a piezoelectric quartz plate as a microbalance. N-Octadecylpyrrolidine was better than N, N-dimethyloctadecylamine as a long alkyl amine to obtain the Y-type multilayer. Although imidizaion using the solution of acetic anhydride and pyridine was performed within several hyndred seconds in benzene, it did not complete in hexane, whereas initial imidization speed was faster in hexane. Swelling would be important factor for imidization process, because benzene make the LB film swell more than other solvents.

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A novel polymer membrane having a transmembrane permeation pathway (“channel”) was prepared from a polyvinyl-polypeptide graft copolymer. The transmembrane continuous phases of the hydrophilic polypeptide were found to be formed in the stable matrix from vinyl polymer and to function as a permeation pathway for polar substances; the polypeptide domain is regarded as membrane protein model. The infrared and circular dichroism spectra of the membrane showed the pH-dependent conformational change of the polypeptide segment. Regulation of the permeability and permselectivity was performed by pH, based on the conformational change of the channel-composing polypeptide. In addition, the membrane has been found to respond to divalent cations, cationic surfactants, and urea in terms of membrane permeability as well as conformational status of polypeptide. The membrane thu proved to be a good model of biological membrane but with a remarkable stability.

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2, 9-Dialkylquinacridones 6 and 2, 5, 9, 12-tetraalkylquinacridones 7 whose alkyl side chains are of the C₆, C₈, C₁₂ and C₁₈, were synthesized. Tetraalkylquinacridones 7 were obtained by N-alkylation of 6 with alkyl halide in the presence of the phase transfer catalyst.6and 7 showed reddish purple and orange color, respectively.7 were easily soluble in organic solvents as compared with 6 and their ¹H-NMR spectral data were reported.

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Silica gels containing hydrophobic hydrocarbon chains were prepared from tetramethoxysilane (TMOS) and octyltrimethoxysilane (C 8) by means of sot-gel process. As the hydrophobic hydrocarbon chains were expected to form micelle-like aggregates in the inorganic silica matrix, similary to the ordinal micelles in an aquenous surfactants solution, a dye (4hydroxyazobenzene; HAB) was used to monitor the structure change in the silica gel by an addition of hydrophobic octyl groups. As a result formation of micelle-like aggregates was strongly suggested. Moreover, solubilization of organic compound into the C 8-containing silica gel was carried out to make new organic-inorganic composite material. A liquid crystal (N-(4-methoxybenzylidene)-4-butylaniline: MBBA) was used for this purpose and the thermal properties of the composite materials were studied.

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In order to prepare new types of ferroelectric liquid crystals (FLC) with a large spontaneous polarization and a short response time toward electric field, the optically active compounds possessing a trifluoromethyl group at the chiral center were synthesized by use of optically active 1, 1, 1-trifluoromethy1-2-octanol 1. It was found that the compounds in which the core moieties were connected with 1 by an ester linkage unexpectedly revealed a relatively narrower temperature range of the Sc*phase and a smaller spontaneous polarization, whereas, the compounds 6 (4'-alkoxy-4-biphenylyl 4-(1-trifluoromethylheptyloxymethyl)benzoate) and 7 (4-(5-alkoxy-2-pyrimidinyl)phenyl 4-(1-trifluoromethylheptyloxymethyl)benzoate) in which the core moieties were connected with 1 by an ether linkage exhibited such remarkable FLC characteristics, as a wide temperature range of the So* phase, and a large spontaneous polarization with the range of 2000-3000 μC/m². The response times of these compounds showed a different temperature dependence with a different core structure. It was also found that 6 had favorable properties as a chiral dopant blended it with some achiral host liquid crystals.

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In the molecular design of membrane materials which have capability of separating optical isomers, we have been noting the high-ordered structures, such as oriented structure, anisotropic structure and phase-separated structure of polymeric membranes. a-Helical structured poly(amino acid)s were proved to have such characteristics as discriminating optical isomers in terms of chromatographic behavior' and taking well-ordered oriented stucture of liquid crystalline mesophase, so that we modified poly(amino acid) with amphiphilic compounds to regulate the microenvironmental feature in the membrane materials. Poly(glutamate) (NON 6-PLG) with amphiphilic side chains was prepared by an esterexchange reaction of poly(γ-methyl L-glutamate) with oligo(oxyethylene) nonylphenyl ether. NON 6-PLG retained α-helical structure in its cast film, as demonstrated by FT-IR measurements of amide I and II bands. Nematic or cholesteric texture was observed microscopically in NON 6-PLG films between crossed polarizers, indicating that NON 6-PLG molecules aligned along α-helical long axis in its film and took well-ordered packing structure. Linear dichroism of phenoxyl groups, which exist in the middle position of the side chains, was observed below 55°C. The result indicated that amphiphilic side chains adopted an anisotropic arrangement in the film. It should be noted that the anisotropic structure of side chain portion became stable when the polymer film was immersed in water. Thus, the anisotropic structure of the amphiphilic side chains was enhanced by growing phase separation of the side chain portion caused by water absorption.
Enantioselectivity of NON 6-PLG membrane in terms of differential permeation of amino acid isomers was examined by use of two-chamber transport apparatus. D-Isomers of Trp and Tyr were found to be preferentially permeated through NON 6-PLG membrane. A complete optical resolution of Trp isomers was achieved at certain permeation conditions. In addition to permeation temperature, annealing and casting condition of membrane markedly influenced permeation behavior of optical isomers of amino acid, revealing organized structure of the membrane plays a key role in the selective permeation of optical isomers. So far as our knowledge, this is the first success in the separation of optical isomers by means of a polymeric membrane.

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Photochemical reaction and spectrOscopic properties of an amphiphilic stilbazolium derivative have been studied in an aqueous solution and in a cast film. Absorption maximum of the aqueous solution moved from 366 nm to 348 nm at molar concentration higher than 1 x 10^-5M. The hypsochromic shift of the absorption spectrum was ascribed to the intermolecular stacking of the stilbazole chromophore. Absorption spectrum of the solid film cast from the aqueous solution was very similar to the aqueous solution. X-Ray diffractions from the cast film strongly suggested that the bilayer structure of the stilbazole amphiphile was immobilized in the cast film. Optically transparent film were prepared from the ionic complexes of the stilbazolium amphiphile and anionic polyelectrolites. Absorption spectrum of the ion complex film was strongly dependent upon the chem ical structure of the polyanion; e. g.341 nm for the complex film with dextran sulfate and 355 nm for chondoroitin sulfate. Photodimerization reaction forming a cyclobutane derivative was dominant in the aqueous solution because of the closed packing of the stilbazole chromophores. While in the liquid crystalline bilayer matrix of dialkylammonium amphiphile, a monomolecular process of the photoisomerization was observed. Photodimerization reaction was, however, strongly suppressed in the cast film from the aqueous solution. But the photochemical property of the aqueous solution was kept in the cast film of the polyion complex.

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The microscopic environment of the host-guest complexation with p-methyl red (p-MR)and amphiphilic amino-α-, β-, γ-cyclodextrins (C_nN-CDs) have been investigated on the basis of cis-trans isomerization of p-MR in the Langmuir-Bloodgett (LB) films, cast film, and chloroform solution.
In chloroform solution, the cis-isomer of p-MR (cis-p-MR) in the complex with C₁₆N-CDs was about 105-fold more stable compared with that of p-MR alone and reverted thermally to its trans-isomer by the first-order process (Fig.2, Table 1). The stability of cis-p-MR in the complex increased with an increase in the ratio of C16N-CDs: p-MR (Fig.3). Incorporation of cis-p-MR in the cavity of C₁₆N-βCD, heptakis(6-hexadecylamino-6-deoxy)β-cyclodextrin, was estimated to be 75% in the equimol mixture solution by calculations from rate constants.
In the L B films and cast film of the complex, the thermal isomerization deviated from the first-order kinetics, and cis-p-MR was more labile than that in the solution (Fig.2, Table 1). It has been found that the stability and kinetics of cis-p-MR is dependent on free volume and flexibility in the molecular assemblies, and that amino moieties of C₁₆N- CDs are essential for the stabilization and also for a tight inclusion of cis-p-MR into the cavity.

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Release control of prostaglandin E1 (PGE₁), as well as improvement of its chemical instability, were conducted by utilizing the complexation with alkylated β-cyclodextrin derivatives such as heptakis(2, 6-di-O-methyl)-β-cyclodextrin (DM-p-CyD) and heptakis (2, 6-di-O-ethyl)-β-CyD (DE-β-CyD). The chemical instability of PGE₁ was markedly improved by the complexation with these CyD, derivatives. The release of PGE, from tablets was accelerated by hydrophilic β-CyD and DM-β-CyD, while decelerated by hydrophobic DE-β-CyD, reflecting the dissolution characteristics of the complexes. The release rate from tablets of the complex was less affected by the change in pH of the release medium, while that of PGE, alone was increased with increase in pH. The matrix-type and doublelayer tablets consisting of the DM-β-CyD complex as a fast-dissolving fraction and the DE-β-CyD complex as a slow-dissolving fraction were prepared and their release was evaluated. The fast- and slow-dissolving characteristics of each fraction were clearly reflected in the release of the double-layer tablet, while the matrix-type tablet showed a near zero-order release. The present results suggest a possible utility of the hybridization of hydrophilic and hydrophobic CyD derivatives as release-control carrier.

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