Thickness-dependent humidity sensing by poly(vinyl alcohol) stabilized Au-Ag and Ag-Au core-shell bimetallic nanomorph resistors.

We herein report a simple chemical route to prepare Au-Ag and Ag-Au core-shell bimetallic nanostructures by reduction of two kinds of noble metal ions in the presence of a water-soluble polymer such as poly(vinyl alcohol) (PVA). PVA was intentionally chosen as it can play a dual role of a supporting matrix as well as stabilizer. The simultaneous reduction of metal ions leads to an alloy type of structure. Ag(c)-Au(s) core-shell structures display tendency to form prismatic nanostructures in conjunction with nanocubes while Au(c)-Ag(s) core-shell structures show formation of merely nanocubes. Although UV-visible spectroscopy and X-ray photoelectron spectroscopy analyses of the samples typically suggest the formation of both Ag(c)-Au(s) and Au(c)-Ag(s) bimetallic nanostructures, the definitive evidence comes from high-resolution transmission electron microscopy-high-angle annular dark field elemental mapping in the case of Au(c)-Ag(s) nanomorphs only. The resultant nanocomposite materials are used to fabricate resistors on ceramic rods having two electrodes by drop casting technique. These resistors are examined for their relative humidity (RH) response in the range (2-93% RH) and both the bimetallic nanocomposite materials offer optimized sensitivity of about 20 Kohm/% RH and 300 ohm/% RH at low and higher humidity conditions, respectively, which is better than that of individual nanoparticles.

Tumor-suppressing miR-141 gene complex-loaded tissue-adhesive glue for the locoregional treatment of hepatocellular carcinoma.

microRNAs (miRNAs) regulate gene expression post-transcriptionally and have been extensively tested as therapeutic molecules against several human diseases. In vivo delivery of miRNAs needs to satisfy the following conditions: safety, efficiency, and long-term therapeutic effectiveness. To satisfy these conditions, we developed a tissue-adhesive nucleotide-polymer complex (NPX-glue) for in vivo delivery of miRNAs to treat hepatocellular carcinoma (HCC). Methods: Polyallylamine (PAA), a cationic polymer, was mixed with tumor-suppressing miR-141 to form NPX and then mixed with partially oxidized alginate (OA) to form NPX-glue. Delivery efficiency of miR-141:NPX-glue was determined in cultured HCC cells and in an implanted HCC tumor model. In vivo tumor-suppressive effects of miR-141 on HCC were examined in mice upon intratumoral injection of miR-141:NPX-glue. Result: NPX-glue was generated by mixing of NPX with OA, which eliminated the inherent cytotoxic effect of NPX. NPX-glue led to the efficient delivery of miR-141 and plasmid to cultured cells and solid tumors in mice, where their expression was maintained for up to 30 days. Upon intratumoral injection of miR-141:NPX-glue, the growth of the tumors was dramatically retarded in comparison with the negative control, NCmiR:NPX-glue, (p < 0.05). Molecular examination proved miR-141:NPX-glue efficiently regulated the target genes including MAP4K4, TM4SF1, KEAP1, HDGF, and TIAM1 and finally induced apoptosis of cancer tissues. Conclusion: Here, we show that NPX-glue delivers therapeutic miR-141 to solid tumors in a safe, stable, and long-term manner and prove that locoregional treatment of HCC is possible using the NPX-glue system.

Fluorescence-based immunosensor using three-dimensional CNT network structure for sensitive and reproducible detection of oral squamous cell carcinoma biomarker.

A hierarchical three-dimensional network of carbon nanotubes on Si pillar substrate (3DN-CNTs) was developed for the accurate detection of oral squamous cell carcinoma (OSCC) in clinical saliva samples. The 3DN-CNTs were uniformly coated with a layer of aluminum oxides to enhance structural stability during biomarker detection. Cytokeratin-19 antigen (Cyfra 21-1) was utilized as a model biomarker of OSCC for fluorescence-based immunosensor using 3DN-CNTs (3DN-CNTs sensor). The 3DN-CNTs sensor enhances the sensitivity of Cyfra 21-1 detection by increasing the density of immobilized antibody through high surface area of 3DN-CNTs and enhancing the accessibility of biomolecules through the ordered pathway of hierarchical structure. The reliable detection limit for sensing of Cyfra 21-1 was estimated as in the level of 0.5 ng/mL and the quantitative estimation of Cyfra 21-1 was analyzed by 4-parameter logistic (4-PL) model for curve-fitting analysis. Clinical applicability of 3DN-CNTs sensor was evaluated through correlation with the commercially available electrochemiluminescence (ECL) detection system in the hospital. The assay results of the two systems for clinical saliva samples showed a good linear correlation. The 3DN-CNTs sensor offers great potential for accurate diagnosis of OSCC using Cyfra 21-1 biomarker in clinical fluids.

Designing Ecofriendly Bionanocomposite Assembly with Improved Antimicrobial and Potent on-site Zika Virus Vector Larvicidal Activities with its Mode of Action.

Dialyzed natural polymer, fibroin, from Bombyx mori was used to synthesize biocompatible silver and gold nanoparticles in-situ in dispersion form. The films of pure fibroin (PF), fibroin-silver nanocomposite (FSNC) and fibroin-gold nanocomposite (FGNC) were fabricated by drop casting method. The characterization of the resultant dispersion and films was performed by visual color change, UV-Vis spectroscopy and atomic force microscopy. The dispersions of PF, FSNC and FGNC were tested for antibacterial activity against E. coli NCIM 2065, S. aureus NCIM 5021, K. pneumoniae NCIM 2957, P. aeruginosa ATCC 9027 and antifungal activity against A. fumigatus NCIM 902. FSNC dispersion exhibited an effective antimicrobial action against all the tested microbes as compared to FGNC dispersion. The mechanism of action for FSNC and FGNC against these microorganisms is proposed. Additionally, the larvicidal activity of the films was investigated against the larvae of Aedes aegypti. The films of FSNC exhibited 100% mortality while the films of FGNC revealed 86-98% mortality against all the larval instars and pupae of A. aegypti. The phytotoxicity study of the nanocomposite films was also carried out to confirm the reusability of water. This is first noble metal nanocomposite based report on larvicidal activity of zika virus vector.

A label-free electrochemical immunosensor for the detection of cardiac marker using graphene quantum dots (GQDs).

A label-free immunosensor based on electrochemical impedance spectroscopy has been developed for the sensitive detection of a cardiac biomarker myoglobin (cMyo). Hydrothermally synthesized graphene quantum dots (GQDs) have been used as an immobilized template on screen printed electrodes for the construction of an impedimetric sensor platform. The GQDs-modified electrode was conjugated with highly specific anti-myoglobin antibodies to develop the desired immunosensor. The values of charge transfer resistance (Rct) were monitored as a function of varying antigen concentration. The Rct value of the immunosensor showed a linear increase (from 0.20 to 0.31kΩ) in the range of 0.01-100ng/mL cMyo. The specific detection of cMyo was also made in the presence of other competing proteins. The limit of detection for the proposed immunosensor was estimated as 0.01ng/mL which is comparable to the standard ELISA techniques.

Poloxamer-based solid dispersions for oral delivery of docetaxel: Differential effects of F68 and P85 on oral docetaxel bioavailability.

Development of an oral docetaxel formulation has been hindered mainly due to its poor solubility and oral bioavailability. The aim of this study was to develop poloxamer F68/P85-based solid dispersions (SDs) for the oral delivery of docetaxel and investigate their in vivo pharmacokinetic impacts on the systemic absorption of docetaxel given orally, in comparison with a SD based on F68 alone. The F68 and/or P85-based docetaxel SDs were prepared with varying the contents of poloxamers and then evaluated in terms of morphology, crystallinity, solubility, dissolution, permeation across rat intestinal segments, and oral pharmacokinetics in rats. As a result, the SDs successfully changed the crystalline properties of docetaxel and enhanced the drug solubility and dissolution. The SD prepared with F68 alone significantly enhanced the dissolution but not intestinal permeation of docetaxel, leading to only limited enhancement of oral bioavailability (1.39-fold increase). Notably, however, the F68/P85-based SD significantly enhanced both the dissolution and intestinal permeation of docetaxel, achieving a markedly improved oral bioavailability (2.97-fold increase). Therefore, the present results suggest that the intestinal permeation factor should be taken into account when designing SD formulations for the oral delivery of BCS class IV drugs including docetaxel, and that P85 could serve as a potential formulation excipient for enhancing the intestinal permeation of docetaxel.

Ceramide and N,N,N-Trimethylphytosphingosine-Iodide (TMP-I)-Based Lipid Nanoparticles for Cancer Therapy.

PURPOSE: To evaluate the anti-tumor effect of ceramide or trimethylphytosphingosine-iodide (TMP-I) containing solid lipid nanoparticles (SLNs) prepared using trymyristin, phosphatidylcholine (PC), and Pluronic P85 (P85) for intravenous delivery of docetaxel. METHODS: Docetaxel-loaded SLNs using ceramide or TMP-I at 3.22% (w/w) with a mean diameter of 89-137 nm were successfully prepared by high pressure homogenization. The prepared nanoparticles were characterized by particle size, zeta potential, drug content, and TEM analysis. Cellular uptake and cytotoxicity were studied using adriamycin-resistant breast cancer (MCF-7/ADR) cells. The optimized formulation's dissolution profile, pharmacokinetics, and antitumor effect in mice tumor model were compared with that of control (Taxotere(®)). RESULTS: The drug release rate of docetaxel from SLNs was lower than that of control (Taxotere(®)). The prepared SLNs showed higher cellular uptake of docetaxel compared to that of Taxotere(®) in MCF-7/ADR cell lines, which was further confirmed by the confocal laser scanning microscopy (CLSM) study using coumarin 6 (C6). Prepared SLNs exhibited significantly increased antitumor efficacy, compared to Taxotere(®), in MCF-7/ADR cells. In vivo pharmacokinetic study in rats (at 10 mg/kg dose) showed that the SLNs significantly reduced in vivo clearance of drug than Taxotere(®). Interestingly, ceramide and TMP-I SLNs efficiently inhibited the tumor growth compared to Taxotere(®) in MCF-7/ADR tumor xenografted mouse model. CONCLUSION: This work showed that TMP-I and ceramide SLNs not only significantly enhanced systemic exposure of drug, but also increased antitumor efficacy compared to Taxotere(®) and control SLN.

Development and validation of a highly sensitive LC-MS/MS method for the determination of acacetin in human plasma and its application to a protein binding study.

A highly sensitive bioanalytical method for the quantification of acacetin in human plasma was developed and comprehensively validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A minimal volume of human plasma sample (20 µL) was prepared by simple deproteinization with 80 µL of acetonitrile. Chromatographic separation was performed using Kinetex C18 column with an isocratic mobile phase consisting of water and acetonitrile (20:80, v/v) containing 0.1 % formic acid at a flow rate of 0.3 mL/min over a total run time of 2.0 min. Mass spectrometric detection was performed using multiple reaction-monitoring modes at the mass/charge transitions m/z 285.22 â†’ 242.17 for acacetin and m/z 277.59 â†’ 175.04 for chlorpropamide (internal standard). The calibration curve was linear over the range of 0.1-500 ng/mL with a lower limit of quantitation of 0.1 ng/mL. The coefficients of variation for both intra- and inter-day validation were less than 11.9 %, and the intra- and inter-day accuracy ranged from 96.8 to 108 %. Mean recovery of acacetin in human plasma was within the range of 91.5-95.6 %. This validated LC-MS/MS method was successfully applied to a human plasma protein binding study that indicated extensive and concentration-independent protein binding of acacetin in human plasma.

Nanomemulsion of megestrol acetate for improved oral bioavailability and reduced food effect.

Megestrol acetate (MGA) belongs to the BCS class II drugs with low solubility and high permeability, and its oral absorption in conventional dosage form MGA microcrystal suspension (MGA MS) is very limited and greatly affected by food. In this study, MGA nanoemulsion (MGA NE) was formulated based on solubility, phase-diagram and release studies. Then oral bioavailability of MGA NE and MGA MS was evaluated. A randomized two-way crossover trial was conducted on six male dogs under fed and fasting conditions. Blood concentrations of MGA were analyzed using LC-MS/MS. MGA NE yielded 5.00-fold higher oral bioavailability in fasting conditions and displayed more stable absorption profiles after food intake compared with MGA MS.

Carbopol-incorporated thermoreversible gel for intranasal drug delivery.

The present study describes the preparation and evaluation of a poloxamer 407 (P407)-based thermoreversible gel using Carbopol 934P (C934P) as a mucoadhesive polymer and hydroxypropyl-ß-cyclodextrin (HP-ß-CD) for enhancing the aqueous solubility and intranasal absorption of fexofenadine hydrochloride (FXD HCl). The prepared gels were characterized by gelation temperature, viscoelasticity, and drug release profile. Thermoreversibility of P407/C934P gel was demonstrated by rheological studies. The incorporation of carbopol into P407 gel also reduced the amounts of drug released from the gel formulations (p < 0.05). In vivo pharmacokinetic results of the prepared gel formulations in rabbits (at 0.5 mg/kg dose) showed that the relative bioavailability of drug from P407/C934P gel was 11.3 and 2.7-fold higher than those of drug solution and P407 gel group, respectively. These findings suggested that developed thermoreversible gels could be used as promising dosage forms to improve intranasal drug absorption.

AAPE proliposomes for topical atopic dermatitis treatment.

CONTEXT: Anti-inflammatory effect of advanced adipose stem cell derived protein extract (AAPE) could be improved by minimising protein degradation. OBJECTIVE: To develop a proliposomal formulation of AAPE for the treatment of topical atopic dermatitis. MATERIALS AND METHODS: Proliposomal powder was manufactured by evaporating a solution of soy phosphatidyl choline, AAPE and Poloxamer 407 in ethanol under vacuum on sorbitol powder. Characterisation of proliposomes (zeta potential, diameter, stability and flowability) as well as in vivo efficacy in a dermatitis mouse model was investigated. RESULTS AND DISCUSSION: Reconstitution of the proliposomal powder formed liposomes of 589 ± 3.6 nm diameter with zeta potential of -51.33 ± 0.36 mV. Protein stability was maintained up to 90 days at 25 °C as proliposomes. In vivo studies on atopic dermatitis mouse model showed a significant reduction in IgE levels after topical AAPE proliposome treatment. CONCLUSION: AAPE proliposomes maintained protein stability and showed promising results for atopic dermatitis treatment.

Inclusion complex effect on the bioavailability of clotrimazole from poloxamer-based solid suppository.

To study the effect of ß-cyclodextrin (ßCD) inclusion complex on the bioavailability of clotrimazole from poloxamer-based suppository, formulations composed of P 188, propylene glycol and different molar ratio of clotrimazole-ßCD inclusion complex were prepared. Clotrimazole (1%) has been formulated in a suppository using the thermo sensitive polymer P188 (70%) together with propylene glycol (30%). To increase its aqueous solubility, clotrimazole was incorporated as its inclusion complex at various molar ratios with ßCD (1:0.25, 1:0.5, 1:1, and 1:2). The inclusion complex was characterized by differential scanning calorimetry (DSC), XRD and phase solubility studies. It was observed that the complexation with ßCD, particularly at high molar ratio (F3 (1:1) and F4 (1:2)) decreased the release profile of clotrimazole considerably. However, suppositories containing inclusion complex at low molar ratio (F1 (1:0.25) and F2 (1:0.5)) showed excellent release profile compared to control formulation. In vivo study in rats at 15 mg/Kg dose showed that the F1 and F2 (82.39 ± 15.40 and 67.05 ± 8.79, respectively) significantly increased the AUC compared to that of F3 (41.48 ± 11.51), F4 (23.34 ± 8.37) and control (46.7 ± 7.87) suppositories. Thus, the suppositories containing inclusion complexes prepared at low drug to ßCD molar ratio (F1) could be a potential suppository formulation to increase the bioavailability of hydrophobic drugs such as clotrimazole.

In vitro and in vivo evaluation of N,N,N-trimethylphytosphingosine-iodide (TMP) in liposomes for the treatment of angiogenesis and metastasis.

Phytosphingosine and methyl derivatives are important mediators on cellular processes, and are associated with cell growth and death. The antitumor activity of N,N,N-trimethylphytosphingosine-iodide (TMP) as a novel potent inhibitor of angiogenesis and metastasis was evaluated in B16F10 murine melanoma cells. The results indicated that TMP itself effectively inhibited in vitro cell migration, tube formation, and the expression of angiogenic factors as well as in vivo lung metastasis. However, TMP slightly suppressed in vivo experimental tumor metastasis in its free form and induced side effects including hemolysis and local side effects. Therefore, in an attempt to reduce the toxicity and the undesirable side effects of TMP, a liposomal formulation was prepared and tested for its effectiveness. TMP liposomes retained the effectiveness of TMP in vitro while side effects were reduced, and both in vivo experimental and spontaneous tumor metastasis were significantly suppressed. These results support the conclusion that TMP effectively inhibits in vitro angiogenesis as well as in vivo metastasis, and a liposomal formulation is more efficient delivery system for TMP treatment than solution.

A novel vesicular carrier, transethosome, for enhanced skin delivery of voriconazole: characterization and in vitro/in vivo evaluation.

This study describes a novel carrier, transethosome, for enhanced skin delivery of voriconazole. Transethosomes (TELs) are composed of phospholipid, ethanol, water and edge activator (surfactants) or permeation enhancer (oleic acid). Characterization of the TELs was based on results from recovery, particle size, transmission electron microscopy (TEM), zeta potential and elasticity studies. In addition, skin permeation profile was obtained using static vertical diffusion Franz cells and hairless mouse skin treated with TELs containing 0.3% (w/w) voriconazole, and compared with those of ethosomes (ELs), deformable liposomes (DLs), conventional liposomes (CLs) and control (polyethylene glycol, PG) solutions. The recovery of the studied vesicles was above 90% in all vesicles, as all of them contained ethanol (7-30%). There was no significant difference in the particles size of all vesicles. The TEM study revealed that the TELs were in irregular spherical shape, implying higher fluidity due to perturbed lipid bilayer compared to that of other vesicles which were of spherical shape. The zeta potential of vesicles containing sodium taurocholate or oleic acid showed higher negative value compared to other vesicles. The elasticities of ELs and TELs were much higher than that of CLs and DLs. Moreover, TELs dramatically enhanced the skin permeation of voriconazole compared to the control and other vesicles (p<0.05). Moreover, the TELs enhanced both in vitro and in vivo skin deposition of voriconazole in the dermis/epidermis region compared to DLs, CLs and control. Therefore, based on the current study, the novel carrier TELs could serve as an effective dermal delivery for voriconazole.

Enhanced in vitro cellular uptake of P-gp substrate by poloxamer-modified liposomes (PMLs) in MDR cancer cells.

Poloxamer-modified liposomes (PMLs) were prepared using poloxamers (P85 and F68) by the thin-film hydration method for overcoming the multidrug resistance and thereby enhancing the intracellular uptake of specific substrates of P-gp, rhodamine 123 (R123). The prepared liposomes, plain liposomes (PLs) and PMLs, were characterized by particle size, zeta potential and drug entrapment efficiency, and assessed by in vitro cellular uptake using KB and KBV20C (P-gp over-expression cell line) cells. The transmission electron microscopy study revealed the spherical shape of the prepared liposomes. No significant difference was observed between the PMLs and liposome without poloxamer (PLs) in the particle size (∼160 nm) and zeta potential (∼-5 mV). The in vitro cellular uptake study showed that P85-modified liposomes (PML-P85) significantly increased the internalization of R123 in MDR tumour cells. Our results showed that PML-P85 could be an effective carrier for anticancer drugs in MDR cancer therapy.

Disaccharide-modified liposomes and their in vitro intracellular uptake.

Sterically stabilized liposomes (SSL) were known to be accumulated passively in cancer due to the effect of enhanced permeability and retention (EPR). However, drug delivery via SSL to cancer seemed to show an insufficient improvement of chemotherapeutic efficacy. Herein, carbohydrate-binding proteins (lectins) of cell surface, which express on the plasmic membrane of many malignant cells, can be a good model of surface-modified liposomes. In this study, we investigated the in vitro characteristics of liposomes of which the surface was modified with a disaccharide molecule, sucrose or maltose. The disaccharide-modified lipids such as sucrose-modified lipid and maltose-modified lipid, in which the disaccharide was conjugated to the one end of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-(polyethylene glycol)-2000 (DSPE-PEG2000), was synthesized. The disaccharide-modified liposomes were prepared by thin film-hydration method and then doxorubicin (DOX), an anticancer drug, was loaded to the prepared liposomes by the remote loading method with ammonium ion gradient. Flow cytometry and confocal microscopy analyses showed that the disaccharide-modified liposomes enhanced the intracellular uptake of liposomes into various cancer cell lines via lectin-mediated endocytosis. The disaccharide-modified liposomes in which DOX was loaded inside of liposomes exhibited higher cytotoxicity against various cancer cells than DOX-loaded SSL did. These results suggest that disaccharide-modified liposomes may be promising cancer targeting carriers which can enhance intracellular uptake and cytotoxicity of the drug-loaded liposomes via lectin-mediated endocytosis.

Physicochemical characterization and skin permeation of liposome formulations containing clindamycin phosphate.

This study was undertaken to evaluate the physicochemical properties and skin permeation of liposome formulations containing clindamycin phosphate (CP), especially when charge was imparted to the liposome. Five different liposome formulations were prepared using Phospholipon 85G (PL) and cholesterol (CH) by conventional lipid film hydration technique. Molar ratio of CH to PL was varied in the range of 0.16-1.0. Charged liposomes were prepared in the same way with addition of 1,2-dioleoyl-3-trimethylammonium-propane chloride salt (DOTAP) and 1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt (DMPA) as charge carrier lipid for cationic or anionic charge of the liposome, respectively. Fresh full-thickness mice skin was taken and used for skin permeation study using Keshary-Chien diffusion cell with 1.77 cm(2) diffusion area at 37 degrees C. All liposome formulations prepared showed homogeneous size distribution with mean particle size of about 1 mum or less. Among the five liposome formulations prepared, formulation with the molar ratio of 0.5 showed the best result in the physicochemical properties such as polydispersity index, entrapment efficiency, size evolution, and ability of the liposome to retain CP as of entrapped in the vesicles. Charge-impartation of the formulation with cationic charge carrier lipid resulted in additional benefit in terms of inhibition of size evolution, the ability of the liposome to retain CP in the vesicles, and skin permeation. Steady state flux of the drug through the mice skin in the cationic liposome vesicles was 0.75 +/- 0.01 microg/cm(2)h while that in the control (dissolved into mixed alcohol solution) was 0.17 microg/cm(2)h. One half molar ratio of CH to PL was optimal in terms of physicochemical properties of the liposome formulation containing CP, and incorporation of cationic charge carrier lipid appeared to provide additional benefits for the stability of the liposome formulation and skin permeation of the drug.

Synergistic anti-tumor activity of paclitaxel-incorporated conjugated linoleic acid-coupled poloxamer thermosensitive hydrogel in vitro and in vivo.

Local delivery of anti-tumor drugs provides a high local concentration and decreases the incidence of side effects commonly observed with systemic therapy. Hydrogel systems are commonly used as a local drug delivery system. In this study, we prepared a novel thermosensitive conjugated linoleic acid (CLA)-coupled poloxamer hydrogel for local delivery of paclitaxel (PTX) to gain the benefits of the pro-drug activity of the CLA-coupled poloxamer and enhanced PTX solubility due to the micellar property of the CLA-coupled poloxamer. To evaluate the anti-tumor activity of the PTX-incorporated CLA-coupled poloxamer hydrogel in vivo, formulations were injected subcutaneously into tumor-bearing mice. Cell cycle and apoptosis markers were examined to determine the mechanism of the anti-tumor activity of PTX. The PTX-incorporated CLA-coupled poloxamer thermosensitive hydrogel showed excellent anti-tumor activity in vivo inducing stronger cell cycle arrest and apoptosis in tumor tissue than the PTX-incorporated poloxamer hydrogel. These results were attributed to the synergistic effect of the anti-tumor property of PTX with released CLA from the CLA-coupled poloxamer as the pro-drug and the enhanced solubility of PTX resulting from the micellar property of the CLA-coupled poloxamer. The CLA-coupled poloxamer designed in this study has great potential as an effective injectable carrier of PTX.

Skin penetration and retention of L-ascorbic acid 2-phosphate using multilamellar vesicles.

Transdermal formulation of L-ascorbic acid 2-phosphate magnesium salt (A2P) was prepared using multilamellar vesicles (MLV). A2P was either physically mixed with or entrapped into three different MLVs of neutral, cationic, and anionic liposome vesicles. For the preparation of neutral MLVs, phosphatidylcholine (PC) and cholesterol (CH) were used. For cationic and anionic MLVs, dioleoyl-trimethylammonium-propane and dimyristoyl glycerophosphate were added as surface charge inducers, respectively, in addition to PC and CH. Particle size of the three A2P-loaded MLVs was submicron, and polydispersity index revealed homogenous distribution of the prepared MLVs except neutral ones. Skin penetration study with hairless mouse skin showed that both physical mixtures of A2P with empty MLVs and A2P-loaded MLVs increased penetration of the drug compared to aqueous A2P solution. During the penetration, however, significant amount of the drug was metabolized into L-ascorbic acid, which has no beneficial effect on stimulation of hair growth. Out of the physical mixtures and A2P-loaded MLVs tested, physical mixture of A2P with empty cationic MLV resulted in the greatest skin penetration and retention in hairless mouse skin.

A chitosan hydrogel-based cancer drug delivery system exhibits synergistic antitumor effects by combining with a vaccinia viral vaccine.

Cancer treatment combining chemotherapy and immunotherapy has been vigorously exploited to further improve cancer therapeutic efficacy. This study investigated a new chemoimmunotherapy approach utilizing hydrogel as a local anti-cancer drug delivery system. Chitosan hydrogel containing doxorubicin (CH-DOX) and vaccinia virus vaccine expressing Sig/E7/LAMP-1 (Vac-Sig/E7/LAMP-1) were used as chemoimmunotherapeutic agents. It was found that intratumoral injection of CH-DOX effectively inhibited tumor growth itself and, in addition, exhibited a synergistic antitumor effect in combination with a vaccinia virus-based vaccine. This combination did not decrease but rather increased the number of tumor-specific CD8(+) T cells primed by vaccinia virus-mediated vaccination; the resulting antitumor effects were further improved up to 60 days as compared with monotherapy after tumor challenge, and the survival of tumor-bearing mice was dramatically prolonged. This study is a pioneer report that demonstrates the use of a biodegradable hydrogel system as an anti-cancer drug delivery system for successful chemoimmunotherapy. It is hoped that, this study can provide a foundation for a rational approach to improve antitumor efficacy of chemoimmunotherapy.