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PH-triggcred structural change of polymer micelles composed of poly(methacrylic acid)-block-poly(2-bromethyl methacrylate) (PMAA-6-PBrEMA) was investigated with anomalous small-angle X-ray scattering (ASAXS) near the Br K edge. ASAXS revealed that the size of the hydrophobic core and the aggregation number of PMAA-b-PBrEMA micelles drastically decreased with an increase in the pH from 4.8 to 12.5. It was concluded that the drastic reduction of the size of PMAA-b-PBrEMA micelles in alkaline conditions was caused by the reduced electrostatic repulsion between anionic PAA chains in the corona layer of the micelles. [ABSTRACT FROM AUTHOR]

Copyright of Kobunshi Ronbunshu is the property of Society of Polymer Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Kobunshi Ronbunshu is the property of Society of Polymer Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

External-stimuli-responsive smart viscoelastic systems have the potential for diverse applications. Worm-like micelles (WLMs) are distinct viscoelastic systems. Several stimuli-responsive WLMs have been reported thus far, in which modifications are triggered by pH variations, redox reactions, temperature shifts, and light. However, sugar-responsive WLMs have not been reported. Phenylboronic acid (PBA) reversibly forms cyclic ester with cis-diol compounds; therefore, it serves as a cis-diol sensor for compounds such as glucose (Glc) and fructose (Fru). Adding PBA to cetyltrimethylammonium bromide (CTAB) in a basic medium induces the transition of spherical micelles to WLMs. This is accompanied by a substantial increase in the viscosity of the CTAB/PBA system. Notably, the addition of Glc to the CTAB/PBA system induces the transformation of the WLMs into spherical micelles or short rod-like micelles. In this review, we describe diol-responsive micellar systems based on PBA and their rheological properties.

This paper introduces the research of nanomachines utilizing boron chemistry. Boron neutron capture therapy (BNCT) has beeing attracting increasing attention as a minimally invasive cancer treatment, and p-boronophenylalanine (BPA) has been approved as a potent BNCT drug. However, intratumoral retention of BPA remains to be improved. Recently, we have developed a BPA delivery system [poly vinyl alcohol (PVA)-BPA] utilizing PVA. PVA-BPA altered the uptake pathway of BPA by cancer cells and significantly improved the intracellular retention in cancer cells. in the in vivo experiments, PVA-BPA showed improved tumor accumulation and a remarkable tumor growth inhibition upon thermal neutron irradiation. On the other hand, a useful delivery system of bioactive proteins has been strongly demanded. In this study, we have developed the ternary complex micelles for the protein delivery utilizing tannic acid (TA) and block copolymer containing a boronic acid group. The ternary micelles improved the blood retention and tumor accumulation of the loaded proteins, and realized a tumor tissue-selective enzymatic reaction in the enzyme delivery.

Amphiphilic compounds can aggregate to form micelles with various structures in aqueous solutions. Especially cationic lipids can complex with DNA, therefore they are expected to work as gene carriers for drag delivery systems (DDS). However, it is difficult to control the structures of micelles. In this study, we synthesized a cationic lipid with C12 alkyl chain and measured the structure of the micelles with small angle X-ray scattering (SAXS) at various pH. SAXS showed a structural transition from cylinder to lamellar structure between low pH and high pH. We confirmed these results by Transmission Electron Microscope (TEM). These results proof that this cationic lipid undergoes a pH dependent structural transition. [ABSTRACT FROM AUTHOR]

Poly(ethylene glyco1)-block-poly(partially benzyl-esterified aspartic acid), denoted by PEG-P(Asp(Bzl)), is one of the most examined blockcopolymers for drug carders. However, little is known about its fundamental physical properties. Nine samples of PEG-P(Asp(Bzl)) with different benzylation fraction (FBzl) and aspartic chain length (DPAsp) were synthesized and the aggregation number (Nagg), the core radius (Rc) and other structural parameters were determined with a combination of light scattering and synchrotron X-ray small-angle scattering. The major factor to determine Nagg and Rc was found to be FBzl, i.e., the hydrophobic nature of the core, even though FBzl was changed in a relatively small composition range from 66-89mol%. The overcrowding nature of the tethered PEG chains on the micelles increased about 1.5-3 times with increasing Nagg compared with the unperturbed state in solutions. [ABSTRACT FROM AUTHOR]

A ABC triblock copolymer (PHS18-b-PSS78-b-PVB18) composed of poly(4-hydroxy styrene) (PHS), sodium poly(styrensulfonate) (PSS), and poly(4-vinylbenzoic acid) (PVB) was prepared via reversible addition-fragmentation chain transfer (RAFT) controlled/living radical polymerization. The pH-responsive association behavior was studied with dynamic light scattering (DLS), static light scattering (SLS), and fluorescence probe techniques. At pH > 13, the triblock copolymer existed as a unimer. At a pH between 6 and 13, the triblock copolymer forms polymer micelles comprising the hydrophobic PHS18 block core and hydrophilic PSS78-b-PVB18 block. Furthermore, at pH < 6 intermicellar aggregates can be observed to form water-soluble aggregates. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were carried out to study the structure formation of polymers and the self-assembly of amphiphilic molecules In particular, the structure formation of an isolated single polymer chain isolated short chain molecules, and a single polymer chain in solution, and the spontaneous micelle formation in amphiphilic solution were investigated. From the detailed analyses of the structure formation processes, two characteristic features, the stepwise energy relaxation and the dynamic coexistence, are clarified as those common to the nonequilibrium dynamics in chain-like molecules and amphiphiles. We believe that these two findings will provide a key to the research on the universality of nonequilibrium dynamics. [ABSTRACT FROM AUTHOR]

We synthesized a cationic lipid benzyl amine derivative bearing a primary amine as the head group and evaluated its transfection efficiency as a DNA carrier. A lipoplex (complex of DNA and lipid micelle) was prepared by mixing BA and two neutral colipids (DOPE and DLPC). When we compared the transfection efficiency at various compositions, we found that B-lipoplex (BA/DOPE/DLPC = 1/2/1) was the most efficient while A-lipoplex (BA/DLPC = 1/1) showed no transfection. We compared A-lipoplex with B-lipoplex by use of SAXS, fluorescence spectrum of ethidium bromide and pyrene. These results indicated that A-lipoplex formed a lamellar or cylinder structure within which DNA molecules were trapped in the lipid alkyl chain, while B-lipoplex formed cylinders where DNAs were intercalated between the lipid micelle cylinders. [ABSTRACT FROM AUTHOR]

This article introduces a novel effect of an anionic surfactant, sodium dodecyl sulfate (SDS) on the protein structure in urea and thermal denaturations. The secondary structures of bovine and human serum albumins have been examined by the CD measurements. The coexistence of a slight amount of SDS protects the structures of these proteins in urea denaturation below 8 M and in thermal denaturation at 65°C. The late addition of the same amount of SDS reforms the protein structures disrupted by the urea denaturation. The SDS concentrations, where such effects have been observed, are too low to form micelles or micelle-like aggregates. These phenomena thus appear likely to be due to the cross-linking function of monomeric dodecyl sulfate ions among particular sites in the steric structures of these proteins. These novel effects of the ionic surfactant have been overlooked during the extensive of the two-component systems of only protein and surfactant, which have been made over the past 50 years. [ABSTRACT FROM AUTHOR]

Although generic anti-tumor agents are in wide clinical use, they have not in all cases been shown to be equivalent to the original agents after preparation. In the present study, original and generic docetaxel formulations were compared with respect to stability when prepared as a non-alcoholic solution for use. When the original formulation was diluted with physiological saline solution to make a non-alcoholic preparation, the concentration decreased with time, whereas no such decrease occurred when a preparation of the generic formulation was made in a similar manner. With both the original and generic formulations, no decrease in docetaxel concentration with time was found after dilution with 5% glucose solution. On the basis of these results, it is concluded that the behaviors of original and generic docetaxel formulations are not equivalent when prepared, but that the original and generic formulations can be taken to be equivalent if they are diluted with 5% glucose solution at preparation.

In general, the blood-brain barrier (BBB) poses a major challenge to drug development efforts targeting brain/central nervous system (CNS) diseases, since it limits the distribution of systemically administered therapeutics to the brain/ CNS. Therefore, the development of effective strategies for enhancing drug delivery to the brain has been a topic of great interest in both the clinical and pharmaceutical fields. Intranasal administration has been noted as a method for noninvasive delivery of a drug to the brain/CNS by bypassing the BBB via the "nose-to-brain" route. This nose-to-brain delivery system has the potential to be highly versatile, and a combination of this system with new drugs and siRNA shows promise in the treatment of CNS diseases. Cell-penetrating Tat peptide-modified block copolymer micelles have the potential for improving mucosal permeability and nose-to-brain transport efficiency. In addition, nano-sized drug carriers can improve nose-to-brain delivery through their ability to increase the stability of encapsulated drugs against biological degradation in the nasal cavity and brain/CNS. In this review, we introduce the assessment of and mechanisms for delivery to the brain after intranasal drug/siRNA administration with our cell-penetrating peptide-modified nano-sized polymer micelles. Our findings show that the use of polymer micelles with surface modification by cell-penetrating peptides for intranasal administration enables the noninvasive delivery of therapeutic agents to the brain/CNS by increasing the nose-to-brain transfer of the drug or siRNA administered from the nasal cavity.

Radiochromic hydrogel dosimeters are a useful tool for the verification of 3D dose distributions using optical CT scanners which are lower cost and with higher spatial resolution in a limited time than MRI scanners. In this paper, recent development of radiochromic micelle gel and genipin-gelatin gel dosimeters are described. They have the advantage of water equivalency, low or no diffusion property, and lower toxicity. Micelle gels consist of leuco dye, surfactant, radical initiator (halocarbons), and gelling agent. The dose sensitivities are affected by the concentration of each component and the temperature during irradiation. In non-diffusing genipin-gelatin gels, radiation induced bleaching is observed. The dose sensitivity is strongly affected by the concentration of genipin and sulfuric acid and by the blending time with gelatin. Higher dose sensitivity and standardization of the dose evaluation procedure will be the future issue.

High-risk HPV E6 and E7 oncogenes are an ideal targeting gene for treatment of cervical cancer. In this paper, we introduce researches on cancer-immunotherapy targeting HPV E7 through mucosal immunity and E6/E7-targeting siRNA therapy using PEGylated polymeric micelles. Therapeutic HPV vaccine has also attracted attention as a cancer immunotherapy agent. We have found homing of Integrin β7-positive intestinal mucosal lymphocyte on the cervical mucosa. In this study, we generated a novel therapeutic vaccine; an HPV E7-expressing Lactobacillus casei (LacE7) to induce anti-HPV cellular immunity directly to intestinal mucosa. Cervical lymphocytes (CxLs) and peripheral blood mononuclear cells (PBMCs) were counted E7 specific INFγ-producing cells (E7 cell-mediated immune responses: E7-CMI) by ELISPOT assay. We confirmed induction of anti-E7 IFNγ-producing cells in the cervix lymphocytes obtained from these patients. E6/E7 siRNA therapy requires a delivery system for its systemic intravenous administration. We here demonstrated that intravenous injection of HPV16 or 18 E6/E7 siRNA polymeric micelles suppressed excellently an increase in size of subcutaneous tumor formed by SiHa or HeLa cell, respectively. Our drug-delivery technology using polymeric micelles enabled the successful systemic administration of siRNA to exhibit anti-tumor effect.

Recently, the development of nanomedicines is progressing. These are designed to ensure high stability and to optimize the pharmacokinetics in vivo. The polymeric micelles and lipid nanoparticles are typical such examples. Because the unique size-specific interaction with biological systems or biodistribution may have significant impacts on the efficacy and safety of nanomedicines, regulatory science researches of nanomedicines are required. In this review, the authors introduce our initiatives of the regulatory science researches of nanomedicines.

The treatment of age-related macular degeneration (AMD) caused by choroidal neovascularization (CNV) is difficult. More effective therapy for regulating CNV is needed. We demonstrated that intravenous nonviral vectors based on the complex of plasmid DNA with synthetic cationic polymers accumulate in choroidal neovascularization (CNV) with high efficiency through an enhanced the permeability and retention (EPR) effect. This review shows the results of in vivo angiogenic control by intravenous injection of a polyplex micelle-encapsulating plasmid vector using a mice CNV model. Polyion complex (PIC) micelles consisting of plasmid DNA and poly (ethylene glycol)-b-poly (N-[N-(2-aminoethyl)-2-aminoethyl] aspartamidef block copolymers [PEG-b-PAsp (DET)] were used. These show minimal cytotoxicity and high transfection efficiency both in vitro and in vivo, and have been utilized for gene therapy against a mouse corneal neovascularization model by local administration of plasmid-encoding soluble vascular endothelial growth factor receptor 1 (soluble Fms-like tyrosine kinase-1: sFlt-1). Transfection of plasmid-expressing sFlt-1 with PEG-C6-P[Asp (DET)] polyplex micelles by intravenous injection into mice CNV models showed significant inhibition of developing CNV. We found that nonviral gene therapy has significant potential for regulation of CNV using plasmids with PEG-C6-P [Asp (DET)] polyplex micelles.

We applied a polymeric micelle carrier system for the targeting of a magnetic resonance imaging (MRI) contrast agent. Prepared polymeric micelle MRI contrast agent exhibited a long circulation characteristic in blood, and considerable amount of the contrast agent was found to accumulate in colon 26 solid tumor by the EPR effect. The signal intensities of tumor area showed 2-folds increase in T1-weighted images at 24 h after i.v. injection. To observe enhancement of the EPR effect by Cderiv pretreatment on tumor targeting, we used the contrast agent for the evaluation by means of MRI. Cderiv pretreatment significantly enhanced tumor accumulation of the contrast agent. Interestingly, very high signal intensity in tumor region was found at 24 h after the contrast agent injection in Cderiv pretreated mice. The contrast agent visualized a microenvironmental change in tumor. These results indicate that the contrast agent exhibits potential use for tumor diagnostic agent. To combine with a polymeric micelle carrier system for therapeutic agent, the usage of the combination makes a new concept of "theranostic" for a better cancer treatment.

The concept of drug delivery systems (DDS) promises the treatments for the refractory diseases such as cancer. Many kinds of multifunctional DDS have been developed, demonstrating enhanced drug accumulation and therapeutic efficiency. However, it is quite difficult to evaluate that the DDS really perform as expected under in vivo conditions. We have recently developed the intravital real-time confocal laser scanning microscopy (IVRTCLSM) characterized by rapid scanning and simultaneous multicolor detection, to visualize the behavior of DDS in living mice. IVRTCLSM revealed the dynamic states of DDS, which could not be observed by conventional in vitro/ex vivo methods, in the bloodstream, tumors, and other organs. IVRTCLSM will provide new facets in the DDS study, and will facilitate the development of DDS.

The world constructed by self-organization of some amphiphils was discussed on the basis of micelle formation, vesicle formation, and oriented-nano-wire formation. First, the micelle formation of a both water- and oil- soluble surfactant, Aerosol OT, was discussed. Solution states of micelles and monomer were discussed on the basis of thermodinamic and NMR spectroscopic analyses of micelle formation. Next, micelle-vesicle transition was discussed. It was proposed that the phospholipid LUV formation by removing detergents and destruction by adding detergents occurred via 4 stages. The 4 stage model instead of the 3 stage model could not only elucidate the complicated phenomena observed during micelle-vesicle transition, but predicted the size and properties of the vesicles formed by detergent removal from mixed micelles. Next, the vesicle formation of a fatty acid with a single hydrophobic chain different from phospholipid, which has two hydorophobic chains, was discussed. The vesicle formation was strongly affected by the presence of preformed vesicles and the size was biased on the preformed vesicles. It was shown there exist two pass ways in the process of micelle-vesicle transition by pH jump. One is fission of the preformed vesicles after transfer of monomers from newly added oleate micelles and the other is transition from the mixed micelles after partial solubilization by the oreate micelles. Then, the vesicle formation of HCO-10, which has 3 hydrophobic chains, the mixed vesicle formation of phosphatidylethanolamine and lysophosphtidylcholine, which can not form vesicles, and the phospholipid vesicle formation and destruction by removing and adding PEG-lipid, were discussed. Lastly, oriented nano wire formation of mulamyldipeptid-conjugated lipids with ca 5 nm of diameter was discussed.

Liposomes modified with polyethylene glycol (PEG) can stably exist in the bloodstream because the PEG on the liposomes attracts a water shell to the liposomal surface. Since these liposomes are long circulating nanocarriers, they are used as drug and gene delivery tools. Repeat injection of PEGylated liposomes, however, is known to induce the accelerated blood clearance (ABC) phenomenon. In the ABC phenomenon, PEGylated liposomes that are injected subsequent to the first injection are cleared rapidly from the bloodstream and accumulate in the liver, resulting in loss of their long-circulating characteristics. The induction of ABC phenomenon is related to the production of anti-PEG IgM from splenic B cells. To elucidate the mechanism of the phenomenon, we firstly examined the relationship between the induction of ABC phenomenon and the concentration of PEGylated liposomes, and observed that the high dose of those did not induce the phenomenon. Next, we investigated whether polymeric micelles trigger ABC phenomenon or not. Finally, the size-dependency of ABC phenomenon was investigated by use of variously sized PEGylated liposomes and polymeric micelles having PEG chains. Our data suggest that the initiation of ABC phenomenon would be size-dependent, and particles smaller than 30 nm did not induce ABC phenomenon. We anticipate that the elucidation of the ABC phenomenon will be helpful for the development of DDS formulations.

Recently, drug delivery systems(DDS)have received increasing attention as a medical application of nanotechnology. Among them, polymeric micelles, self-assemblies of block copolymers, are a promising nanocarrier, because they can incorporate a variety of therapeutic agents such as hydrophobic substances, metal complexes and charged macromolecular compounds. Also, polymeric micelles have been demonstrated to effectively accumulate in the tumor tissue and show remarkable antitumor efficacy. Indeed, polymeric micelles encapsulating adriamycin, paclitaxel, cisplatin and SN-38 have progressed to clinical trials. This review deals with the development strategy and recent progress of polymeric micelles for the delivery of chemotherapeutic agents.

Various attempts are under way to apply nanotechnology, in which remarkable progress has been made in recent years, to the diagnosis and treatment of cancer. For treating solid tumors, a system has been developed for more efficiently delivering nano-scale polymeric formulations to the tumors, utilizing the Enhanced Permeability and Retention( EPR)effect due to the characteristics of the tumor vascular system. Such nano-scale devices include a liposomal formulation, albumin-bound formulation and polymer micellar formulation, and each is currently under clinical development; some of these, such as doxorubicin-containing liposome(Doxyl), are already used in clinical practice. This paper describes the characterization of these nano-scale devices and ongoing clinical trials.

I have an opportunity to have co-operative studies with Chinese group of Kunming Institute of Botany. Since then, I have investigated the chemical constituents of a number of Chinese plants of Araliaceae, Umbelliferae, Labiatae, Cucurbitaceae and other families. This review describes the structural elucidation of the cucurbitane, oleanane and dammarane glycosides, and their biological activities under the joint studies on cucurbitaceous plants, Bolbostemma, Hemsleya, Siraitia and Neoalsomitra species. New oleanane glycosides having novel cyclic structure were isolated from Bolbostemma paniculatum. The potent solubilizing effect of these compounds was investigated. A number of cucurbitane glycosides were isolated from Hemsleya carnosiflora, H. panacis-scandens, Siraitia grosvenorii and S. siamensis. Some of these glycosides taste sweet, bitter or tasteless. The structure-taste relationships of the glycosides of a 3-alpha-hydroxy-cucurbit-5-ene-type triterpene have been discussed. Anti-tumor-promotion effects as well as the ecdysteroid agonist and antagonist activities of these cucurbitane glycosides were investigated. New dammarane glycosides were isolated from Neoalsomitra integrifoliola.

The mechanism of vesicle-to-micelle or micelle-to-vesicle transition was studied in order to control sizes and fluidities of vesicles during periods of preparation. Dependence of particle sizes measured by quasi-elastic light scattering, turbidities, fluidity parameters monitored by ESR spectroscopy, and morphological changes of mixed aggregates of egg yolk phosphatidylcholine (EPC) and a detergent (octylglucoside (OG) or sodium cholate (Na-chol)) on detergent concentration provided a model of vesicle destruction. It possessed three phase transition points, and proceeded in a stepwise fashion: vesicles, small particles containing large amounts of detergents (SUV(*)), intermediate structures, and mixed micelles. Vesicle formation on removal of detergents from micelles proceeded oppositely. Micelle-vesicle transition mechanism was common to all detergents examined. The feature of the mechanism was the presence of SUV(*). Next, SUV(*) was prepared by adding appropriate amount of a detergent to small unilamellar vesicles obtained by sonication. Time-dependent size growth of the SUV(*) was remarkable in the case of OG-containing SUV(*), but was insignificant in the case of Na-chol-containing SUV(*), suggesting the size determining step to be the stage of the SUV(*). The tendency to produce large or small vesicles from micelles was related to the absence or presence, respectively, of a net charge in the detergent molecule. The fluidities of EPC micelles containing small amounts of a detergent possessing a steroidal structure (e.g., Na-chol or CHAPS) were significantly smaller than the corresponding values of a detergent without a steroidal structure (e.g., OG), suggesting a method of control of orderliness of hydrocarbon chains in EPC vesicles.

Age-related macular degeneration (AMD) is a leading cause of legal blindness in developed countries. Even with the recent advent of several treatment options, treatment of exudative AMD, characterized by choroidal neovascularization (CNV), remains difficult. Thus, in this review article, we report on the investigation of novel approaches for the management of AMD, antiangiogenic therapy for CNV, and retinal regenerative therapy. Polyion complex(PIC) micelles have a range in size of several tens of nanometers formed through an electrostatic interaction, and accumulate in solid tumors through an enhanced permeability and retention(EPR) effect. In this study, we examined the distribution of the PIC micelles which encapsulate fluorescein isothiocyanate-labeled poly-L-lysine{FITC-P(Lys)} in experimental CNV in rats, to investigate whether PIC micelles can be used for the treatment of CNV. We demonstrated that PIC micelles accumulate in the CNV lesions and are retained in the lesions for as long as 168 hours after intravenous administration. These results raise the possibility that PIC micelles can be used for achieving an effective drug delivery system against CNV. Although photodynamic therapy (PDT) is a very promising treatment for AMD, most patients require repeated treatments. For effective PDT against AMD, the selective delivery of a photosensitizer to the CNV lesions and an effective photochemical reaction at the CNV site are necessary. The characteristic dendritic structure of the photosensitizer prevents aggregation of its core sensitizer, thereby inducing a highly effective photochemical reaction. We present an effective PDT for AMD employing a supramolecular nanomedical device, i.e., a novel dendritic photosensitizer encapsulated in a polymeric micelle formulation. With its highly selective accumulation in CNV lesions, this treatment resulted in a remarkably efficacious CNV occlusion with minimal unfavorable phototoxicity. Our results will provide a basis for an effective approach to PDT for AMD. Spatial control of gene transfection in the body is a core issue in the gene therapy for ocular diseases including AMD. Photochemical internalization (PCI) is a technology that effects light-induced delivery of DNA directly inside cells. PCI usually requires that a photosensitizer be added to the drug-delivery system to photochemically destabilize the endosomal membrane. We have developed a ternary complex composed of a core containing DNA packaged with cationic peptides and enveloped in the anionic dendrimer, phthalocyanine, which provides the photosensitizing action. Subconjunctival injection of the ternary complex followed by laser irradiation resulted in transgene expression only in the laser-irradiated site in rats. This PCI-mediated gene delivery system is potentially useful in gene therapy for ophthalmic diseases. Accumulation of lipofuscin is related to an increased risk of AMD. We report that a major lipofuscin component, A2E(N-retinyledin-N-retinylethanolamin), activates the retinoic acid receptor (RAR). In vivo experiments suggest that A2E accumulation results in the pro-angiogenic conversion of retinal pigment epithelial(RPE) cell phenotype. This physiological consequence of A2E accumulation may be related to a novel potential therapeutic target for CNV. To recover visual function damaged by AMD, retinal regenerative therapy is essential. We investigated whether subretinal transplantation of bone marrow mesenchymal stem cells(MSCs) promotes photoreceptor survival in a rat model of retinal degeneration. Morphological and functional studies in vivo, including histological analysis and electrophysiological studies, indicate that the subretinal transplantation of MSCs delays retinal degeneration and preserves retinal function. These results suggest that MSC is a useful cell source for cell-transplantation therapy for retinal degeneration. In order to elucidate the molecular mechanisms of development of the fovea, which is composed mainly of cone photoreceptors and is susceptible to injury from AMD, we performed a comparative gene expression analysis between the central and peripheral regions of the monkey retina using monkey (rhesus macaque) genome microarray chips. We then selected the clones which were expressed at significantly higher levels in the central region and confirmed their expression in the monkey retina by section in situ hybridization. This study sheds light on the mechanisms of foveal development and may lead to the development of regenerative medicine for cone photoreceptors.

The problems of cytotoxic agents have been attributed to their low therapeutic indices and limited efficacy due to the non selective nature of their molecular targets and their inability to accumulate selectively in cancer tissue. Passive targeting is based on the so-called enhanced permeability and retention (EPR) effect. To use the EPR effect to full advantage, several techniques have been developed, namely, modification of the structures of drugs and development of drug carriers. In this review article, the results of preclinical and clinical studies of doxorubicin-incorporating immunoliposome, MCC-465 and micelle -forming polymeric drugs such as doxorubicin-incorporating micelle, NK911 and taxol-incorpolating micelle, NK105.

Spicamycin, induced differentiation of human myeloid leukemia cells (HL-60), is found to show a potent antitumor activity by inhibiting protein synthesis. Among the various semisynthetic derivatives of spicamycin, KRN5500 showed a marked efficacy in human tumor xenograft model. KRN5500 itself has, however, only minor inhibitory effects on protein synthesis in cell free system. A metabolite, SAN-Gly, which is thought to be generated through metabolism of KRN5500 by a cytosomal enzyme, exhibited a marked inhibitory effect. KRN5500 is expected to be useful even for treatment of refractory solid tumors because of its unique antitumor mechanism. A phase I clinical trials underwent at the National Cancer Center Hospital in Tokyo and at the National Cancer Institute in the USA. Unfortunately, the drug toxicities in addition to grade 4 pulmonary disorders were occurred, partly caused by the organic solvents and chemical essential for its dissolution. To overcome such a severe adverse effects, we conducted to examine whether incorporation of KRN5500 into polymeric micelles (KRN/m) could reduce a pulmonary disorder using a bleomycin (BLM)-induced lung injury rat model or exhibit antitumor activity similar to KRN5500. In conclusion, this study demonstrated that KRN/m is superior to KRN5500 because the pulmonary toxicity was reduced and the potent antitumor activity of KRN5500 was retained after the incorporation of KRN5500 into micelles. We think that these results justify a clinical phase I trial of KRN/m.

In this review article, supramolecular nanocarriers for gene and siRNA delivery were introduced. They were formed through the multimolecular assembly of block copolymers, containing the DNA or siRNA inside the core of the micelle structure. Due to the excellent stability under the physiological conditions, low toxic effect, and controllable gene functions, this system should be a promising candidate for in vivo therapeutic applications including the non-lethal diseases and the tissue engineering.

Recently, medical applications of nanotechnology have received much attention. Among them, drug delivery systems (DDSs) are expected to be the leading technology in diagnostic and therapeutic medicine. An increasing number of DDSs have been approved for clinical use or are currently being studied in clinical trials. Polymeric micelles, self-assemblies of block copolymers, are one of the most refined and promising modalities of DDSs, since the critical parameters such as size, drug loading, and release can be controlled by engineering the constituent block copolymers. It has been demonstrated that polymeric micelles show unique disposition characteristics in the body suitable for drug targeting (e.g., prolonged blood circulation and significant tumor accumulation). Also, recent advances in polymer synthesis have allowed the development of polymeric micelles with integrated smart functions such as environmental sensitivity and targetability. Thus polymeric micelles might have great potential for nanotechnology-based DDSs for clinical use.

Background: Little is known about effect of ionic strength on local anesthetic toxicity. Using human erythrocytes, hemolytic action of dibucaine in solutions of various ionic strength was investigated., Methods: The critical micellar concentration (CMC) of dibucaine and the dibucaine level that causes destruction of half of the red blood cells in vitro (EC50 value) were determined in solutions of various ionic strength., Results: The mean CMC values of the dibucaine solutions adjusted to ionic strength 0.15, 0.30, 0.45 and 0.90 with NaCl, were 35.3, 22.6, 15.9 and 9.6 mM, respectively. The mean EC50 values of these solutions measured at 5 sec were 22.5, 16.0, 12.6 and 8.2 mM, respectively, and those at 30 min were 4.9, 4.5, 4.5 and 2.6 mM, respectively. There was a significant correlation between mean CMC values and mean EC50 values at 5 sec but not at 30 min in the solution of the same ionic strength., Conclusions: These findings indicated that the mechanism of dibucaine-induced hemolysis within a few seconds is through membrane lysis, whereas dibucaine-induced hemolysis at 30 min is caused by another mechanism. Because each mechanism is enhanced by high ionic strength, dibucaine dissolved in salt solution should not be administered intrathecally.

An extraction method based on the phase separation of aqueous micellar solutions of n-octyl-beta-D-thioglucoside (OTG) was applied to the concentrating conjugated bilirubin in urine. The analyte in sample solutions could be efficiently concentrated into a small volume of surfactant-rich phase, while hydrophilic matrix components including urinary protein, ascorbic acid, and saccharide remained in the aqueous phase. The concentrated OTG negligibly affected the diazo reaction and the subsequent spectrophotometric detection. Conjugated bilirubin was successfully determined in the concentration range from 0.05 microgram/ml to 5 micrograms/ml with a 96-well microplate reader absorption spectrophotometer.

Feasibility of anticancer drug targeting to solid tumors with nano-sized drug carrier systems by a passive targeting mechanism is discussed. Selective delivery to solid tumor sites can be done by utilizing EPR effect (Enhanced Permeability and Retention effect) of solid tumor sites. Essential factors of carriers systems based on this mechanism is size and chemical character of carriers. Size and chemical character must be in a range of several nm to 200 nm and neutral or weakly negatively charged surface, respectively. Present status and future perspective of four types of nano-carrier systems (water-soluble polymer, nanosphere, liposome, and polymeric micelle) are described with recent developments of each system.

This review paper deals with the development of novel vector system for gene and antisense oligonucleotides. The system is based on the self-association of poly(ethylene glycol)-poly(L-lysine) block copolymer with DNA to form polyion complex micelles with unimodel size distribution in the range of 50-100 nm. DNA molecules are compactly assembled into the core of the micelle, surrounding with the dense corona of poly(ethylene glycol). High resistance to nuclease attack was demonstrated for micellized DNA in the serum-containing medium, indicating the potential of micelle vector system to stabilize DNA in physiological condition. Significant gene expression was confirmed by luciferase assay using 293 cell-line for these micelle vector systems with slightly cationic character.

To fabricate the drug targeting system, it is very effective to combine passive targeting with intelligent polymeric system such as temperature-responsive polymers. We have been studying the passive targeting of anticancer drug bonded with or physically trapped in polymeric micelle derived from poly (ethylene oxide) (PEO) and poly (aspartic acid) block copolymer. On the other hand, Poly(N-isopropylacrylamide) (PIPAAm) is known to be a thermo-responsive polymer which has lower critical solution temperature (LCST, 32 degrees C). PIPAAm shows the reversible phase transition above and below LCST. Attempts to apply thermo-responsive drug carriers were made to enhance the site-specificity of polymeric micelle. Namely, novel type of polymeric micelle were prepared from block copolymers comprising N-isopropylacrylamide (IPAAm)-hydrophobic polymers. This temperature responsive micelles were expected to induce selective accumulation controlled by temperature modulation.

The effects of the oxyethylene chain length of poly(oxyethylene) hydrogenated castor oil (HCOn) on the micellar formation and on the micellar structure were investigated. Some physicochemical properties of HCOn (critical micelle concentration cmc, surface tension at cmc, free energy of micellization, and surface excess) concerning surface-activity were measured. These physicochemical properties were little affected by the oxyethylene chain length of HCOn. In addition, several physical techniques have been used to study the micellar structure of HCOn. It was found that HCOn micelles were spherical or nearly spherical, and that an increase in the oxyethylene chain length led to an increase in the looseness of HCOn micelle.

The effects of triglycerides on the gastrointestinal absorption of 2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-1H-pyrazolo[3,4-b]pyridin-1- yl]ethyl acetate (1) were investigated in dogs. The enhancing abilities of the triglycerides on the absorption of 1 were demonstrated as in the order of trilinolein greater than triolein greater than tristearin greater than tripalmitin. Among the series of fatty acids and monoglycerides, namely, digestive products of triglycerides by pancreatic lipase, linoleic acid and monolinolein showed the most potent solubilizing activities of 1 in a solution of bile salt. The incorporation of 1 into mixed micelle formed by lipids and bile salts was presumed to play an important role in the accelerated absorption of 1 after ingestion of triglycerides. On the basis of these findings, an emulsion containing 1 was prepared with soybean oil. The emulsion exhibited a remarkable improvement of the absorption of 1 compared to a suspension of the drug in methylcellulose solution.