Search

Purpose: Polymeric micelles were designed for targeting of a water-insoluble anticancer agent, camptothecin (CPT). Chemical structures of inner core segment were optimized to achieve high incorporation efficiency and stable CPT-loaded micelles., Methods: Poly(ethylene glycol)-poly(beta-benzyl L-aspartate) block copolymer (PEG-PBLA) was synthesized. The PBLA chain was modified by alkaline hydrolysis of its benzyl group followed by esterification with benzyl, n-butyl, and lauryl groups. Incorporation of CPT into micelles was carried out by an evaporation method. The stability of drug-loaded micelles was studied by gel-permeation chromatography (GPC), and their in vitro release behaviors were analyzed., Results: CPT was incorporated into polymeric micelles constructed by various block copolymers. Among the esterified groups, block copolymers with high benzyl ester contents showed high CPT loading efficiency and stable CPT-loaded micelles. In chain lengths, 5-27 Bz-69 showed the highest incorporation efficiency. In contrast, 5-52 Bz-67, which had a longer hydrophobic chain, showed low incorporation efficiency. Release of CPT from the micelles was dependent on the benzyl contents and chain lengths. Sustained release was obtained when the benzyl content was high., Conclusions: CPT was successfully incorporated into polymeric micelles with high efficiency and stability by optimizing chemical structures of the inner core segment.

Purpose: To develop paclitaxel carried by injectable PEGylated emulsions, an artificial neural network (ANN) was used to optimize the formulation--which has a small particle size, high entrapment efficiency, and good stability--and to investigate the role of each ingredient in the emulsion., Methods: Paclitaxel emulsions were prepared by a modified ethanol injection method. A computer optimization technique based on a spherical experimental design for three-level, three factors [soybean oil (X1), PEG-DSPE (X2) and polysorbate 80 (X3)] were used to optimize the formulation. The entrapment efficiency of paclitaxel (Y1) was quantified by HPLC; the particle size of the emulsions (Y2) was measured by dynamic laser light scattering and the stability of paclitaxel emulsions was monitored by the changes in drug concentration (Y3) and particle size (Y4) after storage at 4 degrees C., Results: The entrapment efficiency, particle size and stability of paclitaxel emulsions were influenced by PEG-DSPE, polysorbate 80, and soybean oil. Paclitaxel emulsions of small size (262 nm), high entrapment efficiency (96.7%), and good stability were obtained by the optimization., Conclusions: A novel formulation for paclitaxel emulsions was optimized with ANN and prepared. The contribution indices of each component suggested that PEG-DSPE mainly contributes to the entrapment efficiency and particle size of paclitaxel emulsions, while polysorbate 80 contributes to stability.

A water-insoluble anti-cancer agent, camptothecin (CPT) was incorporated to a polymeric micelle carrier system forming from poly(ethylene glycol)-poly(aspartate) block copolymers. Incorporation efficiency and stability were analyzed in correlation with chemical structures of the inner core-forming hydrophobic blocks as well as with incorporation methods. Among three incorporation methods (dialysis, emulsion and evaporation methods), an evaporation method brought about much higher CPT yields with less aggregation than the other two methods. By the evaporation method, CPT was incorporated to polymeric micelles in considerably high yields and with high stability using block copolymers possessing high contents of benzyl and methylnaphtyl ester groups as hydrophobic moieties. This indicates importance of molecular design of the hydrophobic block chain to obtain targeting using polymeric micelle carriers as well as importance of the drug incorporation method.

Cisplatin was encapsulated into multivesicular liposomes (MVLs) and the entrapment efficiency, size distribution, and in vitro drug release characteristics of the cisplatin-MVLs were studied. Pharmacokinetics, tissue distribution, and therapeutic efficacy of cisplatin-MVLs were compared against injection of cisplatin solution into mice inoculated with the murine carcinoma 180 (S180) tumor. The results showed that the cisplatin-MVLs were capable of high drug loading (0.148:1 mg cisplatin/mg lipid) and high encapsulation efficiency (>80%). The mean diameter of cisplatin-MVLs was 17 microm. In vitro studies of cisplatin-MVLs in saline solution showed that they sustained release of encapsulated drug for >7 days. Cisplatin-MVLs showed higher drug accumulation in the liver, spleen, and tumor regions than cisplatin solution, as well as higher plasma concentrations and a longer circulation time. The therapeutic efficacy of the cisplatin-MVL preparation against S180 tumor-bearing mice is significantly higher than that of cisplatin solution., (Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:1718-1724, 2004)

Novel folate-linked, cationic nanoparticles (NPs) were developed and evaluated for potential use for gene delivery to human oral cancer (KB cells) and human prostate cancer (LNCaP cells), which abundantly expressed folate binding proteins. Folate-polyethylenglycol-distearoylphosphatidylethanolamine conjugate (f-PEG-DSPE) was incorporated in NPs composed of 3([N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and Tween 80. NP-0.3FT, -1FT and -1FLT, which contain 0.3 and 1 mol% f-PEG2000-DSPE, and 1 mol% f-PEG5000-DSPE, respectively, showed about 100-200 nm in size. The NP/plasmid DNA complex (nanoplex) remained in an injectable size (230-340 nm) and slightly increased its size in serum. The association of NP-1FT with KB cells was enhanced by f-PEG2000-DSPE and was blocked by co-incubation with free folic acid in medium. In transfection activity, the NP-1FT, but not NP-1FLT, showed high activity into KB and LNCaP cells in the presence of serum. The NP-0.3FT also showed high activity into LNCaP cells, but not KB cells. In RT-PCR analysis, KB cells strongly expressed folate receptors mRNA, but LNCaP cells did not. In contrast, LNCaP cells expressed mRNA of prostate-specific membrane antigen (PSMA), which interacts with the folate substrate. Uptake mechanism of folate-linked NPs in LNCaP cells may be different from that in KB cells. This is the first report that folate-linked NPs selectively deliver the DNA to LNCaP cells, suggesting that such NPs are potentially targeted vectors to prostate cancer for gene delivery., (Coyright 2004 Elsevier B.V.)

Purpose: The aim of this study was to prepare a novel vaccine carrier particulate system (nanoparticles and emulsions) with chitosan and to evaluate the effect of this system on the immune response for intranasal delivery., Methods: Chitosan nanoparticles (NP) and chitosan-coated emulsions (CC-Emul) were prepared by improvement of the method previously reported and by modified ethanol injection methods, respectively. The rats were immunized with the particles adsorbed with ovalbumin (OVA) and cholera toxin (CT) by intranasal (i.n.) and intraperitoneal (i.p.) administration., Results: NP and CC-Emul could be prepared with particle diameter from about 0.4 microm to 3 microm. IgG induced by i.n. of NP was comparable with that by i.p., and IgA induced by i.n. of 0.4-microm- and 1-microm-size NP was significantly higher than control (OVA and CT). IgG and IgA induced by i.n. of 2-microm-size CC-Emul were significantly higher than those with control., Conclusions: The novel chitosan particles used simple preparation methods showed high OVA adsorption. When administered intranasally, NP and CC-Emul induced systemic immune response in rats. These findings suggested that CC-Emul and the smaller-size (0.4 microm) NP are effective for targeting to nasal-associated lymphoid tissues (NALTs) in nasal vaccine delivery.

Retinoic acid (RA), a potent inducer of cell differentiation, and N-(4-hydroxyphenyl)retinamide (4-HPR, fenretinide), a potent inducer of apoptosis, are well known as anticancer agents that are administered orally to patients for leukemia, breast and prostate cancer, respectively. However, it has not been studied whether both retinoids are effective on metastatic cancer. In mice implanted with M5076 cells, murine reticulum cell sarcoma survival times were prolonged by i.v. treatment of RA and 4-HPR entrapped in liposomes containing soybean-derived sterylglucoside mixture (SG), which accumulates in liver. In contrast, free RA and 4-HPR were inactive. These results indicate that RA and 4-HPR in SG-liposomes exhibit anticancer efficacy on metastatic cancers, and may have great potential for clinical use in the treatment of various cancers.

The aim of this study was to develop an intravenous delivery of all-trans retinoic acid (ATRA) for the treatment of cancer. Two kinds of liposomes composed of dipalmitoylphosphatidylcholine and cholesterol with sterylglucoside (SG) mixture (SG liposomes) or without SG (non-SG liposomes) were prepared. A limited amount of ATRA was incorporated into liposomes approximately 3mol%. ATRA-loaded SG liposomes were more stable at 4 degrees C with light protection for 24 days than non-SG liposomes; maintaining 83.1% ATRA and the average diameter 198.5 nm (36 days), and in 80% rat serum for 120 min. SG seems to increase the ATRA-loaded efficiency in liposomes and stability of liposomes compared with cholesterol. The mean survival time of mice given SG liposomes (18.2 days) indicated a greater antitumor activity than saline (14.1 days) (P<0.001) without change of mean body weight. It is concluded that the current ATRA-loaded SG liposomes are potentially applicable for hepatic metastasis of M5076 tumor.

Liposomes entrapped pirarubicin (THP, L-THP) were prepared by the modified dehydration-rehydration vesicle (DRV) method, and their pharmacokinetics and antitumor effects were evaluated in mice bearing M5076 liver metastasis tumor. After small unilamellar vesicles (SUVs) composed of egg lecithin, cholesterol (Ch), beta-sitosterol beta-D-glucoside (Sit-G) and oleic acid (OA) were freeze-dried with THP and sugars, rehydration of the lyophilized powders led to form the larger vesicles entrapping drugs, but the proper amounts of sugars and OA to lipids (sucrose/lipid=8 (w/w)) maintained the small particle size (about 340nm) with high entrapment (80.7%) of THP. After intravenous injection of L-THP, the accumulations of THP in the liver and heart were approximately 4-fold higher and half lower, respectively, than those of free THP (F-THP). L-THP had superior antitumor effect in 10mg/kg intravenous administration without significant body weight loss. L-THP is a potential drug dosage form of liver cancer treatment since the liposomes carry THP to the liver.

Nanoparticles (NP) are potential carriers for drug delivery to the targeted intestine. NP based on beta-sitosterol beta-D-glucoside (Sit-G) enhanced the colon-specific absorption of FITC-dextran 4,400 (FD-4), because the concentration-dependent increase of bioavailability appeared in only the colon. In a permeation study, the absorption enhancement in the colon was suppressed in the following conditions: (1) the addition of Sit-G NP to serosa; (2) a permeation study at 4 degrees C; (3) the addition of endocytosis inhibitor, cytochalasin B. NP based on sitosterol, the aglycon of Sit-G, did not increase the FD-4 colonic permeation. The addition of Sit-G NP to the mucosal side induced a decrease of transepithelial resistance (TEER), but this phenomenon was suppressed by an inhibitor of Na(+)-dependent specific glucose transporter, phrolidzin, which did not affect FD-4 permeation. These findings suggested that absorption enhancement by Sit-G NP may not be due to opening of a tight junction, but might be related to endocytosis via glucose residue of Sit-G., (Copyright 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:311-318, 2003)

In this study, injectable microemulsions of vincristine (M-VCR) were prepared and its pharmacokinetics, acute toxicity and antitumor effects were evaluated. In M-VCR, the surfactants were PEG-lipid and cholesterol, the oil phase was a vitamin E solution of oleic acid and VCR. The particle size distribution and zeta potential of M-VCR were measured by the laser light dynamic scattering method. The VCR-loading efficiency was measured by Sephadex G50 column chromatography. The stability of M-VCR was monitored by particle size, VCR-loading efficiency and VCR content changes of M-VCR stored at 7 degrees C. The pharmacokinetics, acute toxicity and antitumor effects of M-VCR were studied in C57BL/6 mice bearing mouse murine histocytoma M5076 tumors. When stored at 7 degrees C in the dark for 1 year, the average diameter and VCR-loading efficiency of M-VCR changed from 138.1+/-1.2 nm and 94.6+/-4.7% to 127.1+/-2.4 nm and 91.3+/-4.8% (n=3), respectively, while 7.4+/-0.3% VCR decomposition was observed (n=3). The plasma AUC of M-VCR was significantly greater than that of free VCR (F-VCR). The heart, spleen and liver AUC(0.08-12 h) of M-VCR were significantly smaller than those of F-VCR while the kidney AUC(0.08-12 h) of M-VCR was significantly greater than that of F-VCR. The tumor AUC(0.08-12 h) of M-VCR was significantly greater than that of F-VCR. M-VCR had lower acute toxicity and greater potential antitumor effects than F-VCR in M5076 tumor-bearing C57BL/6 mice. M-VCR is a useful tumor-targeting microemulsion drug delivery system.

The aim of this study was to examine the interaction of soybean-derived sterylglucoside (SG) with the human hepatoblastoma cell line HepG2 with regard to the penetration-enhancing effect of beta-sitosterol glucoside (Sit-G) to clarify the accumulation of SG-containing liposomes (SG-liposomes) to the liver in vivo. The approach was based on measurement of the association of SG-liposomes labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) in terms of asialoglycoprotein receptor (ASGP-R)-mediated endocytosis, affinity of Sit-G using lAsys and the association of FITC-dextran 4400 (FD-4) increased by Sit-G with the cells. The association of SG-liposomes was decreased by addition of asialofetuin, suggesting that SG-liposomes might be taken up via ASGP-R. Sit-G showed higher affinity with HepG2 cells than HeLa cells, and enhanced the association of FD-4 depending on the incubation time and Sit-G concentrations. Significant positive correlations were found between Sit-G and FD-4 association with the cells, indicating that Sit-G enhanced the drug penetration by distribution in cell membranes. The high degree of liver association of SG-liposomes in vivo might be related to recognition of glucose residues of SG by ASGP-R and to the high affinity and penetration-enhancing effect of Sit-G with hepatocytes.

The aim of this study was to prepare injectable emulsions of aclacinomycin A (E-ACM) and evaluate its acute toxicity, antitumor effects, and pharmacokinetics. In E-ACM, the surfactants were polyethylene glycol-lipid and cholesterol, and the oil phase was a vitamin E solution of ACM. The particle size distribution and the zeta potential of E-ACM were measured by the laser light dynamic scattering method. The ACM-loading efficiency was measured by using Sephadex G50 column chromatography. The acute toxicity, antitumor effects, and pharmacokinetics of E-ACM were studied in C57BL/6 mice bearing mouse murine histiocytoma M5076 tumors. The average diameter, zeta potential, and ACM-loading efficiency of E-ACM were 123.0 +/- 1.2 nm, - 12.67 +/- 1.35 mv, and 96.3 +/- 0.3% (n = 3), respectively. When stored at 7 degrees C in the dark for 1 year, the average diameter and ACM-loading efficiency of E-ACM changed into 126.3 +/- 2.3 nm and 97.4 +/- 0.8%, respectively, whereas 6.5 +/- 0.2% ACM decomposition was observed (n = 3). The plasma areas under the biodistribution curves (AUC)(0.03-48h) of E-ACM was significantly greater than that of free ACM (F-ACM). The heart, lung, and kidney AUC(0.03-48h) of E-ACM were significantly smaller than those of F-ACM whereas the liver and spleen AUC(0.03-48h) of E-ACM were not significantly different from those of F-ACM. The tumor AUC(0.03-48h) of E-ACM was significantly greater than that of F-ACM. E-ACM had lower acute toxicity and greater potential antitumor effects than F-ACM in M5076 tumor-bearing C57BL/6 mice. E-ACM is a useful tumor-targeting drug delivery system., (Copyright 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:1128-1134, 2002)

Falconensones A and B are new type of yellow pigment isolated from the mycelial extract of ascomycetous fungi, Emericella falconensis. To date, these falconensones and their derivatives, falconensone A p-bromophenylhydrazone and falconensone A dioxime are known to exhibit biological activities, which include growth inhibition and both induction of differentiation and apoptosis of HL60 human leukemia cells. The synthetic derivatives have been shown to be more potent than natural falconensone A and B in eliciting these activities. Herein, we investigate whether falconensones inhibit growth of other cancer cell lines in vitro, and we evaluate their ability to modify survival in C57 BL/6J mice using M5076 murine reticulosarcoma in vivo, which is established as the metastasis model. Falconensone A, falconensone A p-bromophenylhydrazone, and falconensone A dioxime inhibit growth of human myeloid leukemia cell lines, HL60 and HL60R, human hepatoma cell line HepG2, human prostate cancer cell line DU-145, and human breast cancer cell line MCF-7/Adr(R), whereas falconensone B, the 4'-nor-methyl derivative of falconensone A, shows extremely low or no activity. In contrast, all of the falconensones are active in growth inhibition of human breast cancer cell line MCF-7. Survival time of M5076-implanted mice was prolonged by treatment with falconensones, particularly falconensone A dioxime. These results indicate that falconensone A and its derivatives exhibit anticancer efficacy in a broad spectrum of cancer cell lines. These agents may have great potential for clinical use in the treatment of various cancers.

The mechanism of drug release from progesterone suppositories that consist of two types of hard fat (Witepsol W35 and Witepsol E85) was investigated. The strength, the thermodynamic characteristics, the surface structures, the drug release property, methylene blue penetration into suppositories, and change of surface structure after the dissolution test were employed for detecting characteristics of progesterone suppositories. The formulation with a mixing ratio of Witepsol W35 and Witepsol E85 at a 1:1 ratio showed the maximum strength value. The peak temperature of the suppositories showed a tendency to increase with increases in the ratio of Witepsol E85. The maximum height of the profiles measured with laser microscopy, from 20.8 microm to 29.2 microm, reached a maximum after 3 h of the dissolution test. When the suppositories were immersed in pH 7.4 phosphate buffer containing 0.5% methylene blue at 37 degrees C, the penetrating area increased with time. The weight of the suppositories also increased with time. According to these findings, it was suggested that the release of drug from a mixed type of suppository containing progesterone was via the matrix and pores.

A modified ethanol injection method for liposomes containing soybean phosphatidylcholine (SPC), cholesterol (Ch), beta-sitosterol beta-D-glucoside (Sit-G) and oleic acid (OA) was developed, that can produce homogeneous unilamellar liposomes without the use of sonication and dialysis. In this method, water is poured into a concentrated lipid-ethanol solution and then ethanol is removed in an evaporator. Dilution with water causes spontaneous formation of small and homogenous unilamellar vesicles from micellar aggregate. The size of liposomes can be controlled by the ratio of ethanol to water. OA and Sit-G were distributed at the surface of liposomes and were recognized by Concanavalin A, respectively. This easy and quick method for preparation of liposomes may be applicable in many areas.

Aim: To study the interactions of insulin with dipalmitoylphosphatidylcholine liposomes., Methods: The liposomes were prepared by reverse-phase evaporation vesicle method. The entrapped efficiency, size and distribution of the liposomes were determined, and the influences of insulin on entrapped efficiency, size and distribution of the liposomes were investigated. The influences of liposomes on the fluorescence emission spectra of insulin and the calcein leakage from the liposomes entrapped calcein induced by insulin were measured., Results: Insulin has little influence on the size and distribution of the liposomes while the sizes of the liposomes were about 170-190 nm. The insertion of tyrosine of insulin into dipalmitoylphosphatidylcholine liposomes membrane was not deep. The insulin disturbed the liposomes membrane, induced the calcein leakage from the calcein-loaded liposomes., Conclusion: Amphiphilic, example insulin, may disturb the intact membrane of liposome through the interaction either hydrophobic or hydrophilic. The attention should be paid to the entrapment process of peptides into liposomes.

The effects of soybean-derived sterylglucoside (SG) on the fluidity of liposomal membrane composed of dipalmitoylphosphatidylcholine (DPPC) were investigated compared with those of soybean-derived sterol (SS) and cholesterol (Ch) using an electron spin resonance spectrometer. Three kinds of liposomes were prepared in the molar ratio of DPPC/X=7/4, where X is SS, Ch or SG. The fluidity close to the polar head groups increased with an increase of temperature in the DPPC membrane containing SS, Ch and SG in the range 35 to 45 degrees C. Those near the hydrophobic end changed with an increase in temperature in liposomes containing SS, Ch and SG, which had a fluidizing effect on the DPPC membrane below the transition temperature (Tm, 41.9 degrees C) and a condensing effect over the Tm. The fluidizing effects of these compounds around 37 degrees C near the polar head group and the hydrophobic end increased in the following order: Ch < SG < or = SS and SS < Ch < SG, respectively. SG increased the fluidity of liposomal membrane dramatically above the Tm (35.4 degrees C). These results suggest that the high fluidity close to the hydrophobic end of the liposomal membranes around 37 degrees C, the decrease of Tm, and the sigmoidal nature of fluidity vs. temperature are important factors in the effectiveness of liposomes containing SG as a carrier of drugs.

Remote loading of insulin and bovine serum albumin (BSA) into neutral or positively-charged liposomes by incubation under a transmembrane pH gradient or non-pH gradient was investigated. Trapping efficiencies in several incubation conditions were compared with those of the conventional reverse-phase evaporation vesicle method (c-REV method). For neutral liposomes, insulin could not be effectively loaded into the liposomes by incubation, regardless of the incubation conditions. The trapping efficiency of insulin into positively-charged liposomes was higher than that of neutral liposomes, especially by the pH-gradient method. Insulin could be loaded into positively-charged liposomes about twofold more efficiently than by the pH-gradient method, compared with the c-REV method. Insulin distributed more on the surface of liposomes by the pH-gradient method than by the c-REV method. BSA showed significantly higher affinity to positively-charged liposomes than to neutral ones by various methods. However, the transmembrane pH-gradient method did not increase BSA loading into liposomes, compared with the c-REV and the non-pH-gradient methods. Our results suggest that the pH-gradient method, combining electrostatic interactions, may be useful for preparation of liposomal insulin and that the high hydrophobicity of BSA may not increase the remote loading of BSA into liposomes by the pH-gradient method.

The relationship between the rigidity of the liposomal membrane and the absorption of insulin after nasal administration of liposomes modified with an enhancer containing insulin was investigated for the nasal delivery of peptide drugs in rabbits. The rigid liposomal membrane makes liposomes stable, protecting insulin from enzymatic degradation. Soybean-derived sterol (SS) or its sterylglucoside (SG) was used as an enhancer. Dipalmitoylphosphatidylcholine (DPPC) liposomes modified with SG had increased fluidity of the hydrophobic group of the liposome bilayer compared with the liposomes modified with cholesterol (Ch) or SS, as shown by measurements of the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5,-hexatriene (DPH); however, the fluidity of the polar group of the liposome bilayer was decreased according to measurements of steady-state fluorescence anisotropy of dansylhexadecylamine (DSHA) at 37 degrees C. These findings suggest that the fluidity of the hydrophobic group of the liposome bilayer is responsible for the increase of liposomal leakage and instability of the liposomes. When insulin was administered nasally to rabbits as a solution, no hypoglycemic effect was observed. The administration of insulin contained in DPPC/SG (7/4, mole) liposomes with high fluidity caused a high glucose reduction of long duration (8 hr). DPPC/SS and DPPC/Ch (7/4) liposomes with low fluidity caused low glucose reductions. These results demonstrated that liposomes modified with SG can be useful as carriers of insulin administered nasally.

The effects of shikonnin (SK) and its optical isomer alkannin (AK) on the hydroxyl radical (HO.) generation system including iron ions were evaluated using the spin trap method by ESR spectroscopy. 5,5-Dimethyl-1-pyrroline-1-oxide (DMPO) was used as a spin trap agent and HO. was generated by a reaction between an iron ion and hydrogen peroxide, which is called Fenton reaction system. SK inhibited the HO. spin adduct (DMPO-OH) yielded in a dose-dependent manner. In this effect no difference was observed between SK and AK. When different concentrations of DMPO were used for the confirmation of its competitive reaction, no difference was also observed in the concentration of SK required to reduce the amount of the DMPO-OH by 50% (ID50). These findings suggested that the inhibitory effect of SK against the thus yielded DMPO-OH was not generated by the scavenging for HO., but by the inhibition on the Fenton reaction system. The mechanism of the inhibition on this system may be based on the formation of a complex between SK and the iron ion. The molar ratio of SK to the iron ion in the complex was considered 2 to 1 (2:1), because the concentrations of the observed ID50 and the used iron ion exhibited the same value. In addition, the same result was also obtained from the study using spectroscopic analysis.

The effect of shikonin (SK) on granulation tissue formation was biochemically evaluated and the biological effect of SK on cotton pellet induced granulation tissue formation and the induction of hind paw edema was compared with that of lambda-carrageenan (carrageenan) in rats. The dry weight of granulation tissue formed was increased by SK. The amounts of hemoglobin and hydroxyproline in granulation tissue were also increased by SK. These results suggest that SK has an enhancing effect on the formation of granulation tissue, accompanied by the proliferation of capillaries and the increased production of collagen in rats. SK showed mild stimulation toward swelling when injected into the hind paws of rats, as did carrageenan, while it showed a marked enhancing effect on granulation tissue formation compared with carrageenan. These results suggest that the mechanism underlying the biological effect of SK on granulation tissue formation is different from that of carrageenan, though the mild stimulation by SK might still contribute in part to the enhancing effect on granulation tissue formation.

The effect of a soybean-derived sterol mixture (SS) and a steryl glucoside mixture (SG) as enhancers of the nasal absorption of insulin in rabbits was investigated. SS consists of beta-sitosterol (Sit), campesterol (Camp), stigmasterol (Stig) and brassicasterol (Bras), and SG is a mixture of their monoglucosides. For each component of SS tested for efficacy in promoting the systemic absorption of nasally administered insulin, the following order was observed: Sit> or =Camp>Stig. This finding was in agreement with the order of the enhancers' lipophilicity. In the case of SG, the effect of beta-sitosterol beta-D-glucoside (Sit-G) was significantly greater than that of SG. The pharmacological bioavailability was 6.7% for SG and 11.3% for Sit-G in the suspension dosage forms. SG showed a greater degree of enhancement of insulin permeation through the nasal mucosa than SS. To elucidate the contribution of SG to the enhanced absorption, insulin permeation through an artificial membrane and the nasal mucosa was investigated in vitro, and the results were compared with those for SS. The findings suggest that SG and SS have some effect on nasal mucosa lipids.

A soybean-derived sterylglucoside mixture (SG) is a potential enhancer of the nasal absorption of insulin. The aim of the study was to examine the absorption of insulin given as the powder dosage form with SG and excipient and to determine the subchronic effects of SG on the morphology of rabbit nasal epithelium. The insulin powder dosage form with SG was administered to the rabbit nasal cavity for five successive days. The average bioavailability and the average pharmacological bioavailability of insulin were about 25.0 and 61.6%, respectively. The nasal mucosa was taken from the nasal cavity and side-effects were investigated using an optiphoto light microscope. The insulin powder dosage form with SG produced no signs of inflammation, erosion or squamous metaplasia. These findings indicate that SG can be considered as a safe and effective enhancer and excipient in the nasal insulin powder dosage form.

Dipalmitoylphosphatidylcholine (DPPC) and cholesterol (Ch) liposomes containing a soybean-derived sterylglucoside mixture (SG) (SG-liposomes) are effective for targeting hepatocytes in mice. We investigated uptake of SG-liposomes to hepatocytes compared with that via the galactose receptor. The association of SG-liposomes entrapping calcein was examined at 4 degrees C or 37 degrees C, changing incubation time and the SG concentration of the liposomes, and using the inhibitor on the galactose receptor in rat primary cultured hepatocytes. The amount of liposomes recovered with hepatocytes was determined by measuring the concentration of calcein and imaged with confocal laser scanning microscopy in the cultured cells. The association of SG-liposomes at 4 degrees C was significantly decreased compared with that at 37 degrees C as that of liposomes containing lactosylceramide (LC) (LC-liposomes) that were already known to be taken up by hepatocytes via the asialoglycoprotein receptor. While the association of SG-liposomes at both 4 degrees C and 37 degrees C increased with the increase of incubation time, the association of SG-liposomes at 37 degrees C was almost saturated after 1 h. The association of SG-liposomes pretreated with concanavalin A was significantly decreased (to about 40% of that without pretreatment at 37 degrees C) and was at the same level as the association of SG-liposomes and non-SG-liposomes at 4 degrees C. The association of the SG-liposomes by hepatocytes incubated for I h at 37 degrees C was almost saturated at about 2.0 nmol SG/mg protein. The association of the SG-liposomes with hepatocytes was not inhibited in the presence of LC-liposomes. The affinity of the galactose residue for hepatocytes appeared to be similar to that of the glucose residue in the liposomes, because the amount of sugar residue and the association of SG-liposomes and LC-liposomes were almost the same values. These results suggest that SG-liposomes may be associated with hepatocytes not by a galactose receptor-mediated endocytosis.

The blood clearance, tissue uptake and antitumor efficacy against liver metastasis of M5076 reticulosarcoma in mice and against primary liver cancer in rats of doxorubicin (DOX) encapsulated in two types of liposomes, with and without a soYbean-derived sterylglucoside mixture (SG), were examined. Liposomes entrapping DOX were composed of dipalmitoylphosphatidylcholine (DPPC), SG and cholesterol (Ch) at a molar ratio of 6:1:3, (SG-liposomes) and 6:0:4 (non-SG-liposomes). Pharmacokinetic analysis of drug disposition was based on the area under the curve (AUC) for liposomes up to 24 h following i.v. injection. SG-liposomes showed lower DOX concentrations in blood and higher concentrations in liver compared with non-SG-liposomes. The highest AUC of SG-liposomes in tissue was in liver, 2.4 times higher than that of the free drug. The antitumor efficacy of SG-liposomes was compared with that of free DOX and non-SG-liposomes at a dose of 5 mg DOX/kg. SG-liposomes displayed stronger antitumor activity than the free drug and non-SG-liposomes in murine reticulosarcoma M5076 tumor models and primary liver cancer models reflecting accumulation in hepatocytes. The antitumor activity of SG-liposomes in rats with primary liver cancer was significantly higher compared with free DOX and non-SG-liposomes (ILS: 92.7%).

Purpose: Recombinant human erythropoietin (Epo) is used frequently through intravenous (i.v.) and subcutaneous (s.c.) administration for the clinical treatment of the last stage of renal anemia. We encapsulated Epo in liposomes to develop an alternative administration route. The purpose of our study was to evaluate the pharmacokinetics and the pharmacological effects of liposomal Epo in comparison with the Epo after i.v. and s.c. administration to rats., Methods: Epo was encapsulated in liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and soybean-derived sterol mixture (SS) prepared by the reversed-phase evaporation vesicle method. After filtration through a 0.1 micron polycarbonate membrane, liposomes were gel filtered (Epo/liposomes)., Results: Epo/liposomes showed higher pharmacological activity than Epo/liposomes before gel filtration after i.v. administration to rats. Non-encapsulated Epo lost its activity, whereas encapsulated Epo in liposomes retained it. The pharmacological effects of Epo/liposomes were greater than those of Epo after i.v. administration. Epo/liposomes afforded 3-9 times higher AUC, lower clearance and lower steady-state volume of distribution than Epo after both i.v. and s.c. administrations. Epo/liposomes had an improved pharmacokinetics profile compared with Epo. S.c. administration of Epo/liposomes at 7 h may penetrate primarily (40% of dose) through the blood as a liposome and partly (7% of dose) in lymph. CONCLUSIONS. Epo/liposomes may reduce the frequency of injections required for a certain reticulocyte effect in comparison to Epo. The lower clearance of Epo/liposomes may increase the plasma concentrations of Epo, which increases the efficacy.

In this study, we investigated a liposomal formulation of dipalmitoylphosphatidylcholine (DPPC) with a soybean-derived sterylglucoside mixture (SG) and cholesterol (Ch) for targeting the liver in mice. We found two distribution profiles of liposomes (reverse-phase evaporation vesicles, REV) in the liver depending on the concentration of Ch and SG in vivo; Ch tends to enhance liposomes containing 10 mol% SG accumulation in the liver, but to decrease those containing 20 mol% SG, and it prolongs the circulation in blood. Dicetylphosphate did not enhance liver targeting by liposomes with SG and Ch. More DPPC/SG/Ch-liposomes (6:1:3) were significantly taken up by cultivated hepatocytes than DPPC/SG/Ch-liposomes (6:0:4), suggesting a glucose residue. The optimal composition for the maximal liver targeting was a mixture of 0.2 micron DPPC/SG/Ch-liposomes (REV) at a molar ratio of 6:1:3. This composition of liposomes was distributed 3 times greater in hepatocytes than non-parenchymal cells 1 h after intravenous injection.

With a rapid demand to decrease the side effect of drug, a variety of drug delivery systems have been developed. This review will focus on the development of liposomes with soybean-derived sterols and their glucosides for drug carriers. Current status and further perspectives in this research field are reviewed mainly based on the results obtained in our laboratory. First we studied the different physicochemical properties of dipalmitoylphos-phatidylcholine (DPPC) liposomes with soybean-derived sterols (SS) and their glucosides (SG). SS rigidifies the liposomal membrane but SG fluidizes it. SS stabilizes liposomes more than cholesterol that is conventionally used as stabilizing agents in liposomes. On the basis of this information, we developed liposomes with SS and SG for a drug carrier. Secondly we studied the stability of liposomes in the blood and biodistribution and found that liposomes with SS were stable as expected in vitro results. In particular, DPPC: SS (7:4, molar ratio) size 0.2 micron showed long circulation. Thirdly successful targeting of the drugs to the liver was achieved by liposomes with SG. Finally, we succeeded in developing liposomal erythropoietin and doxorubicin using liposomes with SS for sustained release of drugs. Liposomal drugs increased the pharmacological effect compared with free drugs, suggesting a decrease of side effect and long circulation. The attempt for oral administration using liposomes of peptide drugs was carried out successfully. We have established that the study of physicochemical properties of liposomes is needed rationally as the distribution of drugs in liposomes and the rigidity of liposomal membrane, prior to the development of the drug carrier of liposomes. SS is useful to stabilize liposomes and SG to targeting to the liver parenchymal cells. This information can be useful and practical for the development of liposomes for drug carriers.

Dipalmitoylphosphatidylcholine (DPPC) liposomes with a soybean-derived sterol mixture (SS) or cholesterol (Ch) were examined as a carrier for the oral administration of insulin in rats. Four kinds of liposomes were prepared: liposomes containing SS or Ch (molar ratio of DPPC/X = 7:2 or 7:4, X = SS or Ch), respectively. The pharmacological availability was greater and the lag time for the glucose reduction was later in the order of DPPC/SS (7:4) > DPPC/SS (7:2) > DPPC/Ch (7:4) > > DPPC/Ch (7:2)-liposomes. This order appears to correspond well with that of the rigidity of the liposomal membrane. In particular, DPPC/SS (7:4)-liposomes reduced blood glucose levels for up to 21 h in rats after oral administration. The highest absolute pharmacological availability was 31.6% at a dose of 20.0 IU/kg of DPPC/SS (7:4)-liposomes among the liposomes in comparison to intravenous administration.

Previously, we reported that dipalmitoylphosphatidylcholine liposomes (DPPC-liposomes) containing soybean-derived steryl glucoside mixtures (SG) (DPPC/SG-liposomes) accumulated in the liver, especially in parenchymal cells. DPPC/SG-liposomes and a mixture of DPPC and SG (DPPC/SG mixture) were compared by means of differential scanning calorimetry, Fourier transform infrared (FT-IR), and enzymatic assays. The results suggested that the maximum molar mixing ratios of DPPC and SG in a powder was DPPC:SG = 7:2.2. Enzymatic assays indicated that the glucose group of SG projected outward from the liposomal surface and that the amount of SG on the liposomal surface was limited, the maximum mole fraction of SG in DPPC/SG-liposomes being 0.27 (DPPC: SG = 7:2.6). FT-IR spectra indicated that the glucose group of SG interacts with the phosphate group of DPPC on the surface of liposomes, since the phosphate symmetric and asymmetric stretching bands of DPPC/ SG-liposomes were shifted to lower frequencies with increasing SG. These results suggested that the glucose group of SG projecting outward from the liposomal membrane contributes to the hepatic cellular distribution of DPPC/SG-liposomes.

Intestinal absorption of recombinant human erythropoietin (Epo) encapsulated in liposomes (Epo/liposomes) was examined by measuring the pharmacological effects of Epo after oral administration in rats. Circulating reticulocyte counts after oral administration of Epo/liposomes showed a profile different from that after intravenous administration. Epo/liposomes 0.1 micron in diameter were absorbed more effectively than those 0.2 micron in diameter. In the 0.1 micron Epo/liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and soybean-derived sterols (SS), cholesterol (Ch), or soybean-derived sterylglucosides (SG), DPPC/SS (in molar ratio 7/2) and DPPC/Ch (7/2) showed higher efficiency in intestinal absorption than DPPC/Ch (7/4) and DPPC/SG (7/2) at a low dose by the sysmex method. Pharmacological availabilities for oral administration of Epo/liposomes were 0.74-31% and 3.3-30% as evaluated by circulating reticulocyte counts and percentage circulating reticulocytes of erythrocytes, respectively, in comparison to those for intravenous administration of the same dose.

The mechanism of l-menthol, oleic acid and lauricidin as enhancers on percutaneous absorption was examined using diclofenac (DH) as a hydrophobic drug and sodium diclofenac (DNa) as a hydrophilic drug in in vitro diffusion experiments with two kinds of membranes: ethanol-treated and untreated silicone membranes; these were models for the lipid and pore pathways of skin. A 20% w/w ethanol-aqueous solution decreased the flux of DH but increased the flux of DNa significantly across the treated membrane compared with those fluxes across the untreated membrane, suggesting that DH penetrated by the lipid pathway and DNa by the pore pathway. The permeability of DNa through the pore pathway decreased significantly across the treated membrane with the addition of oleic acid and lauricidin. l-Menthol increased the permeability coefficients of DH and DNa more in a treated membrane than in an untreated one, showing the same tendency as in rat skin. Thus, while oleic acid and lauricidin did not increase the permeation of DNa by the pore pathway, l-menthol appeared to enhance the permeation of the drug by both the lipid and pore pathways.

We investigated multilamellar vesicle (MLV) liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and a soybean-derived sterylglucoside mixture (SG) (DPPC/SG-liposomes) for targeting liver parenchymal cells after administration via the tail vein in mice, using liposome-entrapping calcein. The accumulation of DPPC/SG(7:2, mole ratio, DPPC:SG = 7:2)-liposomes in the liver was the highest among DPPC/SG-liposomes. About 80% and 40% of the dose of DPPC/SG(7:2)-liposomes accumulated in the liver at 15 min and 2 h, respectively, but about 20% of DPPC/SG(7:3.5, 7:7)-liposomes accumulated at 2 h after an intravenous administration. However, the uptake of DPPC/SG(7:2, 7:3.5, 7:7)-liposomes by liver parenchymal cells was about 7 times greater than that in non-parenchymal cells irrespective of the SG concentration in liposomes. The uptake of DPPC/SG(7:2)-liposomes in liver was almost the same level as that by liposomes containing lactocylceramide (LC) (LC-liposomes) that were already known to be taken up in liver parenchymal cells by the asialoglycoprotein receptor. DPPC/SG(7:2)-liposomes effectively targeted liver, having optimal stability and SG.

The effects on Wistar rat body weight were examined after a single subcutaneous (s.c.) or oral (p.o.) administration of dipalmitoylphosphatidylcholine (DPPC) liposomes composed of soybean-derived sterols (SS) and their glucosides (SG) with or without entrapping recombinant human erythropoietin (Epo) for 1 week. Body weight increased significantly after both types of administration compared with the control groups irrespective of the existence of Epo. The neutral lipid concentration in plasma increased with the increase in body weight whereas the total contents of cholesterol and high density lipoprotein cholesterol in the plasma did not change significantly. The SS and SG suspensions following p.o. administration, however, did not alter the body weight. These findings suggest that liposomal SS and SG may be absorbed through the intestinal membrane and induce a change in the uptake of lipid, in contrast to the suspension state. SS in liposomes significantly increased body weight more than SG after p.o. administration.

Soybean-derived sterylglucoside mixture (SG) is a potentially effective absorption enhancer for the nasal absorption of insulin. Insulin is a peanut oil suspension dosage form and in a powder dosage form with SG were administered into the rabbit nasal cavity. After 0.5 or 1 h, nasal mucosa was taken from the nasal cavity and side effects were examined by an optiphoto light microscope. The insulin in the peanut oil suspension produced a histological change in the nasal epithelium mucosae, as well as mucodermal phlogistic cellular infiltration. The peanut oil suspension with SG showed side effects slightly stronger than without SG. SG alone and the insulin powder dosage form with SG produced no signs of inflammation, erosion or squamous metaplasia. The results from this study indicate that SG can be considered safe.

The effects of dose, pH and osmolarity on the intranasal absorption of a recombinant human erythropoietin (rEPO) solution were studied in male Wistar rats. The intranasal administration of rEPO was evaluated by measuring percentage circulating reticulocytes of red blood cells on a stained blood smear (smear method), and also by measuring residual circulating reticulocyte counts using a microcell counter (sysmex method). Both results suggest that rEPO solution was absorbed through the nasal mucosa of rats without enhancers after a single intranasal administration. The pharmacological availabilities of rEPO after intranasal administration compared with intravenous administration were about 7% and 4%, when estimated by smear method and sysmex method, respectively. The pharmacological activity was enhanced in low pH and hypotonic mannitol solution.

We encapsulated erythropoietin (Epo) in dipalmitoylphosphatidylcholine (DPPC) liposomes with soybean-derived sterols (SS-liposomes) and its glucoside (SG-liposomes) by reverse-phase evaporation vesicle method, and evaluated them by subcutaneous administration in rats. With 4 min of sonication, the damage to Epo activity was observed mainly in the non-encapsulated Epo in the liposomes. This study indicated that the bilayer of liposomes had the ability to protect the Epo activity, by reducing the aggregation that was caused by interaction between Epo molecules. The SG-liposomes had a higher retention of the Epo activity the SS-liposomes. 25.3% or 33.6% of activity was retained by SS-liposomes under the conditions of 4 min or 1 min of sonication, while 53.3% or 58.3% of the activity was retained by SG-liposomes under the same conditions. Shorter sonication was available to minimize the loss of the Epo activity. Epo in SG-liposomes appeared to increase the activity.

The systemic degradation and the reticuloendothelial system (RES) uptake of calcein entrapped in dipalmitoylphosphatidylcholine (DPPC) liposomes with soybean-derived sterols (SS) were examined after intravenous administration to mice by measuring the free and liposomal calcein levels in the blood. The results indicate that the rates of systemic degradation and the RES uptake of liposomes decrease with the addition of SS in DPPC liposomes since the SS has the ability to stabilize the liposomes. The rate of uptake by RES is larger than the rate of systemic degradation. The rate of leakage of calcein from liposomes by incubation in plasma in vitro is almost the same as that of systemic degradation in vivo.

The objectives of this study were to evaluate the size of the diclofenac ion and the electrical behavior of diclofenac salts (DM; M = Li, Na, or K) in ethanol/water mixtures. The molar conductance of DM in aqueous solution was measured in a dilute concentration range of < 10 mol.m-3 at 25 degrees C. The Fuoss-Onsager conductance equation for unassociated electrolytes was used to determine the limiting molar conductance (lambda degrees) of DM. The molar conductivity of DM at a finite concentration was, however, larger than the value calculated by the Fuoss-Onsager limiting law. To correct the difference in the experimental data, two equations were employed to fit the experimental molar conductance of DM. The size of the diclofenac ion was calculated from the limiting molar conductance and compared with the values obtained by the Fedors method and the apparent ionization constant (pKa) of sodium diclofenac in ethanol/water mixture. The Walden products of DM increased up to 20% (w/w) ethanol, but above this concentration of ethanol they decreased. Specific interactions between the ions and solvent are discussed.

The cohesion parameters of diclofenac and propranolol were determined experimentally. The theoretical partition coefficient (Ps,v) was calculated from the activity coefficient (gamma) and the cohesion parameters of the solvent (delta 1 = delta v), solute (delta 2), and skin (delta s). By using the extended Hildebrand solubility equation, the potential energy of solute-solvent interaction in a given solution was considered to have the gamma value derived from solubility data of diclofenac and propranolol in ethanol-aqueous buffer. Values for experimental permeability coefficients (Kp), which were determined from flux and solubility, were compared with values for the respective Ps,v. For a solvent that consists of ethanol-aqueous buffer exhibiting cohesion parameters in the range of delta v = 18-24 (cal/cm3)1/2, the fluxes increased and the Kp decreased because of the similarity in cohesion parameters of these solvents to the solute. The difference between Ps,v and experimental Kp suggests that ethanol in the solvent affects the membrane and diclofenac and propranolol penetrate through the membrane, possibly solvated by ethanol.

The promoting effect of d-limonene and l-menthol on the percutaneous absorption of nonionized and ionized diclofenac (DF) was investigated employing a pretreatment method. After the pretreatment of hairless rat skin with an ethanol buffer solution containing terpenes, the permeation study was performed in vitro. The permeability coefficients of nonionized (Pn) and ionized diclofenac (Pi) were calculated under the assumption that the total flux was composed of individual fluxes of nonionized and ionized DF. In the case of pretreatment with d-limonene, both Pn and Pi values were increased dramatically. However, the promoting magnitude was not affected by an extension of the pretreatment period. In contrast, when the skin was pretreated with l-menthol, the Pn and Pi values increased gradually as the pretreatment period increased. Based on the measurement of the solubility of terpenes in the pretreatment solution, the difference in promoting efficiency could arise from the difference in thermodynamic activity of the terpenes.

The permeability of liposome entrapping insulin through the nasal mucosa of rabbit has been studied and compared with the permeability of insulin solution with or without pretreatment by sodium glycocholate (GC). Insulin entrapped in liposome was not detected in the receiver cell using the diffusion cells with the nasal mucosa. On the other hand, permeability of insulin entrapped in liposome increased after the pretreatment of GC. The phospholipids which result from liposomes, were not observed in the receiver. Also, the GC remaining in the nasal mucosa was measured. Considering the mechanism of permeation of insulin entrapped in liposome through the nasal mucosa, the GC remaining in the nasal mucosa may cause the lysis of liposomes.

In previous studies on the nasal administration of human fibroblast interferon (HuIFN-beta), only rabbits have been used. Therefore, this route was investigated in mice, rats, rabbits and dogs. HuIFN-beta could be delivered across the nasal mucosa in mice, rats, rabbits and dogs, when it was mixed with sodium glycocholate as an absorption promoter. However, the pattern of the plasma HuIFN-beta concentration-time curve was different from that in rabbits. Rabbits gave the highest value of the maximum plasma HuIFN-beta concentration (Cmax), but plasma HuIFN-beta declined rapidly thereafter, upon nasal administration of the powder dosage form (8.45 x 10(2) IU/g). In rats and dogs, Cmax was lower than in rabbits, but plasma HuIFN-beta declined slowly after nasal administration of the powder or liquid dosage form (4-6 x 10(2) IU/g). These differences might be attributed to differences of absorption rate constant.

beta-Interferon (IFN) administered intranasally in solution or as a powder without surfactants was not absorbed in rabbits. However, absorption occurred after the addition of surfactants (non-ionic, anionic and amphoteric). Maximum concentrations of IFN in plasma were dependent on the surfactant used, sodium glycocholate being the most effective. Total absorption of IFN following nasal administration with sodium glycocholate was 2.2% of that following intravenous administration.

Rabbits were given single doses (2 x 10(6) IU) of human fibroblast interferon (HuIFN-beta) by the following routes of administration: (a) intravenous injection, (b) dropwise intranasal administration of a liquid dosage form, and (c) spraywise intranasal administration of a powder dosage form. Following the intravenous injection, plasma HuIFN-beta concentrations declined rapidly in a biphasic manner in agreement with a two-compartment model, whilst concentrations following the intranasal administrations conformed to a one-compartment model. Maximum plasma levels and the areas under the plasma concentration-time curve (AUC) in response to dose were studied in the case of the spray administration, and found to be proportional to dose. The systemic bioavailability of HuIFN-beta (administered with sodium glycocholate and excipients) via the nasal routes was about 3% of that via the intravenous route. The elimination half-lives did not differ significantly between these two routes of administration.

The utility of the absorption promoters, sodium glycocholate (GC-Na), ethylenediamine dihydrochloride (EDTA-2Na), sodium caprylate (Cap-Na) and sodium salicylate (Sal-Na), in the intranasal administration of human fibroblast interferon-beta (HuIFN-beta) in rabbits was investigated. The optimal amount of added EDTA-2Na, Cap-Na and Sal-Na with respect to HuIFN-beta was examined for nasal absorption in the powder dosage form. Formulations of HuIFN-beta with GC-Na showed greatly enhanced intranasal HuIFN-beta absorption, as compared to the other absorption promoters. The results of a stability study on HuIFN-beta in homogenates of nasal mucosa suggested that GC-Na behaved as a hydrolysis inhibitor in the nasal mucosa and maintained the activity of HuIFN-beta.