The Induction of Combined Hyperthermal Ablation Effect of Irreversible Electroporation with Polydopamine Nanoparticle-Coated Electrodes.

Irreversible electroporation (IRE) is a prominent non-thermal ablation method widely employed in clinical settings for the focal ablation therapy of solid tumors. Utilizing high-voltage, short-duration electric pulses, IRE induces perforation defects in the cell membrane, leading to apoptotic cell death. Despite the promise of irreversible electroporation (IRE) in clinical applications, it faces challenges concerning the coverage of target tissues for ablation, particularly when compared to other thermal ablation therapies such as radiofrequency ablation, microwave ablation, and cryoablation. This study aims to investigate the induced hyperthermal effect of IRE by applying a polydopamine nanoparticle (Dopa NP) coating on the electrode. We hypothesize that the induced hyperthermal effect enhances the therapeutic efficacy of IRE for cancer ablation. First, we observed the hyperthermal effect of IRE using Dopa NP-coated electrodes in hydrogel phantom models and then moved to in vivo models. In particular, in in vivo animal studies, the IRE treatment of rabbit hepatic lobes with Dopa NP-coated electrodes exhibited a two-fold higher increase in temperature (ΔT) compared to non-coated electrodes. Through a comprehensive analysis, we found that IRE treatment with Dopa NP-coated electrodes displayed the typical histological signatures of hyperthermal ablation, including the disruption of the hepatic cord and lobular structure, as well as the infiltration of erythrocytes. These findings unequivocally highlight the combined efficacy of IRE with Dopa NPs for electroporation and the hyperthermal ablation of target cancer tissues.

Assessment of Hepatic Lesions After non-Thermal Tumor Ablation by Irreversible Electroporation in a Pig Model.

Irreversible electroporation (IRE) is a non-thermal and minimal invasive modality to ablate pathologic lesions such as hepatic tumors. Histological analysis of the initial lesions after IRE can help predict ablation efficacy. We aimed to investigate the histological characteristics of early hepatic lesions after IRE application using animal models. IRE (1500 V/cm, a pulse length of 100 µs, 60 or 90 pulses) was applied to the liver of miniature pigs. H&E and TUNEL staining were performed and analyzed. Ablated zones of pig liver were discolored and separated from the normal zone after IRE. Histologic characteristics of ablation zones included preserved hepatic lobular architecture with a unique hexagonal-like structure. Apoptotic cells were detected, and sinusoidal dilatation and blood congestion were observed, but hepatic arteries and bile ducts were intact around the ablation zones. The early lesions obtained by delivering monophasic square wave pulses through needle electrodes reflected typical histological changes induced by IRE. Therefore, it was found that the histological assessment of the early hepatic lesion after IRE can be utilized to predict the IRE ablation effect.

Pheophorbide A and SN38 conjugated hyaluronan nanoparticles for photodynamic- and cascadic chemotherapy of cancer stem-like ovarian cancer.

In this study, we designed photo-triggered reactive oxygen species (ROS)-generating pheophorbide A and ROS-cleavable thioketal-SN38 conjugated hyaluronan-cholesterol nanoparticles (PheoA-SN38-HC NPs). And we observed the combined therapeutic effects of PheoA-SN38-HC NPs against HEY-T30 human ovarian cancer (OC) model. Clinical Proteomic Tumor Analysis Consortium (CPTAC) data showed that the expression of cancer stem cell (CSC) markers (CD44, ALDH1A1, and CD117) is highly associated with poor clinical outcomes in OC patients. We proved that HEY-T30 cells overexpress CSC markers and much more invasive than other cancer cells. Flow cytometry (FACS) and microscopic analysis revealed the active targeting property of PheoA-SN38-HC NPs to CD44+ HEY-T30 cells. Moreover, the combination therapeutic effect of PheoA-SN38-HC NPs was clearly demonstrated against in vitro HEY-T30 cells and an in vivo xenograft mouse model. In particular, the paracrine cytotoxic effect of SN38 probably compensates the locoregional therapeutic limitation of photodynamic therapy.

Enhanced thermodynamic, pharmacokinetic and theranostic properties of polymeric micelles via hydrophobic core-clustering of superparamagnetic iron oxide nanoparticles.

BACKGROUND: Superparamagnetic iron oxide nanoparticles (SPIO) have been applied for decades to design theranostic polymeric micelles for targeted cancer therapy and diagnostic MR imaging. However, the effects of SPIO on the physicochemical, and biological properties of polymeric micelles have not yet been fully elucidated. Therefore, we investigated potential effect of SPIO on the physical and biological properties of theranostic polymeric micelles using representative cancer drug (doxorubicin; Doxo) and polymer carrier (i.e., poly (ethylene glycol)-co-poly(D,L-lactide), PEG-PLA). METHODS: SPIO were synthesized from Fe(acetyl acetonate)3 in an aryl ether. SPIO and Doxo were loaded into the polymeric micelles by a solvent-evaporation method. We observed the effect of SPIO-clustering on drug loading, micelle size, thermodynamic stability, and theranostic property of PEG-PLA polymeric micelles. In addition, cellular uptake behaviors, pharmacokinetic and biodistribution study were performed. RESULTS: SPIO formed hydrophobic geometric cavity in the micelle core and significantly affected the integrity of micelles in terms of micelle size, Doxo loading, critical micelle concentration (CMC) and in vitro dissociation. In vivo pharmacokinetic studies also showed the enhanced Area Under Curve (AUC) and elongated the half-life of Doxo. CONCLUSIONS: Clustered SPIO in micelles largely affects not only MR imaging properties but also biological and physical properties of polymeric micelles.

T1-Positive Mn2+-Doped Multi-Stimuli Responsive poly(L-DOPA) Nanoparticles for Photothermal and Photodynamic Combination Cancer Therapy.

In this study, we designed near-infrared (NIR)-responsive Mn2+-doped melanin-like poly(L-DOPA) nanoparticles (MNPs), which act as multifunctional nano-platforms for cancer therapy. MNPs, exhibited favorable π-π stacking, drug loading, dual stimuli (NIR and glutathione) responsive drug release, photothermal and photodynamic therapeutic activities, and T1-positive contrast for magnetic resonance imaging (MRI). First, MNPs were fabricated via KMnO4 oxidation, where the embedded Mn2+ acted as a T1-weighted contrast agent. MNPs were then modified using a photosensitizer, Pheophorbide A, via a reducible disulfide linker for glutathione-responsive intracellular release, and then loaded with doxorubicin through π-π stacking and hydrogen bonding. The therapeutic potential of MNPs was further explored via targeted design. MNPs were conjugated with folic acid (FA) and loaded with SN38, thereby demonstrating their ability to bind to different anti-cancer drugs and their potential as a versatile platform, integrating targeted cancer therapy and MRI-guided photothermal and chemotherapeutic therapy. The multimodal therapeutic functions of MNPs were investigated in terms of T1-MR contrast phantom study, photothermal and photodynamic activity, stimuli-responsive drug release, enhanced cellular uptake, and in vivo tumor ablation studies.

Doxycycline-Eluting Core-Shell Type Nanofiber-Covered Trachea Stent for Inhibition of Cellular Metalloproteinase and Its Related Fibrotic Stenosis.

In this study, we fabricated a doxycycline (doxy)-eluting nanofiber-covered endotracheal stent for the prevention of stent intubation-related tissue fibrosis and re-stenosis. The nanofiber was deposited directly on the outer surface of the stent using a coaxial electrospinning method to form a doxy-eluting cover sleeve. Poly(d,l-lactide) was used as the shell-forming polymer and dedicated drug release-control membrane. Polyurethane was selected as the drug-loading core polymer. The compositional ratio of the core to shell was adjusted to 1:0, 1:2, and 1:4 by changing the electro-spray rate of each polymeric solution and microscopic observation of nanofibers using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the fluorescence microscopy proved core-shell structure of nanofibers. The in vitro release study suggested that the release of doxy could be controlled by increasing the compositional ratio of the shell. The growth of HT1080 fibrosarcoma cells was inhibited by the 10% doxy-containing nanofiber. The real-time polymerase chain reaction (PCR) in HT1080 cells and xenografted tissue models indicated that the doxy-releasing nanofiber inhibited mRNA expression of metalloproteinases (MT1-MMP, MMP-2, and MMP-9). Overall, our study demonstrates that a doxy-eluting core-shell nanofiber stent can be successfully fabricated using coaxial electrospinning and displays the potential to prevent fibrotic re-stenosis, which is the most problematic clinical complication of tracheal stent intubation.

NIR-responsive ROS generating core and ROS-triggered 5'-Deoxy-5-fluorocytidine releasing shell structured water-swelling microgel for locoregional combination cancer therapy.

Combination chemotherapy now becomes the most standard cancer treatment protocol. Here, we present a core-shell type polymeric microgel (CSPM) which combines photodynamic and chemo therapeutic modalities in one-pot system. CSPM localizes in the malignant lesion after intratumoral injection, releases reactive oxygen species (ROS) and anticancer drug (5'-deoxy-5-fluorocytidine; DFCR) under the near-infrared (NIR) laser treatment. Pheophorbide A (PheoA)-linked poly(hydroxyethyl methacrylate) (poly-HEMA) was designated to a ROS-generating core, and chemically covered with a chitosan shell. In addition, phenylboronic acid was employed in chitosan shells and linked to DFCR to form an ROS cleavable boronic ester. The core-shell structure of CSPM was determined by transmission electron microscopy. NIR-responsive photodynamic ROS generation was confirmed by the oxidative reduction of 9,10-dimethylanthracene (a fluorescent dye), and the cascadic release of DFCR by ROS was confirmed by a release study and a live and dead cell imaging study. Typically, poly-HEMA cored microgel increased its volume by 48.9-fold after absorption of body fluid. This swelling property ensured CSPM was retained in tumor tissues after subtumoral injection and the suitability of CSPM for locoregional phototherapy. The therapeutic effect of CSPM was attributed to the combined, cascadic deliveries of cytotoxic ROS and DFCR and confirmed by growth inhibition studies in in vitro pancreatic cancer cells and in vivo colon cancer mouse model.

MT1-MMP Responsive Doxorubicin Conjugated Poly(lactic-co-glycolic Acid)/Poly(styrene-alt-maleic Anhydride) Core/Shell Microparticles for Intrahepatic Arterial Chemotherapy of Hepatic Cancer.

In this study, we demonstrated that the MT1-MMP-responsive peptide (sequence: GPLPLRSWGLK) and doxorubicin-conjugated poly(lactic-co-glycolic acid/poly(styrene-alt-maleic anhydride) core/shell microparticles (PLGA/pSMA MPs) can be applied for intrahepatic arterial injection for hepatocellular carcinoma (HCC). PLGA/pSMA MPs were prepared with a capillary-focused microfluidic device. The particle size, observed by scanning electron microscopy (SEM), was around 22 ± 3 µm. MT1-MMP-responsive peptide and doxorubicin (DOX) were chemically conjugated with pSMA segments on the shell of MPs to form a PLGA/pSMA-peptide-DOX complex, resulting in high encapsulation efficiency (91.1%) and loading content (2.9%). DOX was released from PLGA/pSMA-peptide-DOX MPs in a pH-dependent manner (∼25% at pH 5.4 and ∼8% at pH 7.4) and accumulated significantly in an MT1-MMP-overexpressing Hep3B cell line. An in vivo intrahepatic injection study showed localization of MPs on the hepatic vessels and hepatic lobes up to 24 h after the injection without any shunting to the lung. Moreover, MPs efficiently inhibited tumor growth of Hep3B hepatic tumor xenografted mouse models. We expect that PLGA/pSMA-peptide-DOX MPs can be utilized as an effective intrahepatic drug delivery system for the treatment of HCC.

Combined delivery of the adiponectin gene and rosiglitazone using cationic lipid emulsions.

For the combined delivery of an insulin-sensitizing adipokine; i.e., the ADN gene, and the potent PPARγ agonist rosiglitazone, cationic lipid emulsions were formulated using the cationic lipid DOTAP, helper lipid DOPE, castor oil, Tween 20 and Tween 80. The effect of drug loading on the physicochemical characteristics of the cationic emulsion/DNA complexes was investigated. Complex formation between the cationic emulsion and negatively charged plasmid DNA was confirmed and protection from DNase was observed. The in vitro transfection efficiency and cytotoxicity were evaluated in HepG2 cells. The particle sizes of the cationic emulsion/DNA complex were in the range 230-540 nm and those of the rosiglitazone-loaded cationic emulsion/DNA complex were in the range 220-340 nm. Gel retardation of the complexes was observed when the complexation weight ratios of the cationic lipid to plasmid DNA exceeded 4:1 for both the drug-free and rosiglitazone-loaded complexes. Both complexes stabilized plasmid DNA against DNase. The ADN expression level increased dose-dependently when cells were transfected with the cationic emulsion/DNA complexes. The rosiglitazone-loaded cationic emulsion/DNA complexes showed higher cellular uptake in HepG2 cells depending on the rosiglitazone loading, but not depending on the type of plasmid DNA type such as pVAX/ADN, pCAG/ADN, or pVAX. The drug-loaded cationic emulsion/plasmid DNA complexes were less cytotoxic than free rosiglitazone. Therefore, a cationic emulsion could potentially serve as a co-delivery system for rosiglitazone and the adiponectin gene.

Thermosensitive and mucoadhesive sol-gel composites of paclitaxel/dimethyl-ß-cyclodextrin for buccal delivery.

The purpose of this study was to develop a buccal paclitaxel delivery system using the thermosensitive polymer Pluronic F127 (PF127) and the mucoadhesive polymer polyethylene oxide (PEO). The anticancer agent paclitaxel is usually used to treat ovarian, breast, and non-small-cell lung cancer. To improve its aqueous solubility, paclitaxel was incorporated into an inclusion complex with (2,6-di-O-methyl)-ß-cyclodextrin (DMßCD). The formation of the paclitaxel inclusion complex was evaluated using various techniques, including x-ray diffractometry (XRD), Fourier-transform infrared (FT-IR) spectrophotometry, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Hydrogels were prepared using a cold method. Concentrations of 18, 20, and 23% (w/v) PF127 were dissolved in distilled water including paclitaxel and stored overnight in a refrigerator at 4 °C. PEO was added at concentrations of 0.1, 0.2, 0.4, 0.8, and 1% (w/v). Each formulation included paclitaxel (0.5 mg/mL). The sol-gel transition temperature of the hydrogels was measured using the tube-inverting method. Drug release from the hydrogels was measured using a Franz diffusion cell containing pH 7.4 phosphate-buffered solution (PBS) buffer at 37 °C. The cytotoxicity of each formulation was measured using the MTT assay with a human oral cancer cell (KB cell). The sol-gel transition temperature of the hydrogel decreased when PF127 was present and varied according to the presence of mucoadhesive polymers. The in vitro release was sustained and the release rate was slowed by the addition of the mucoadhesive polymer. The cytotoxicity of the blank formulation was low, although the drug-loaded hydrogel showed acceptable cytotoxicity. The results of our study suggest that the combination of a PF 127-based mucoadhesive hydrogel formulation and inclusion complexes improves the in vitro release and cytotoxic effect of paclitaxel.

Topical treatment of the buccal mucosa and wounded skin in rats with a triamcinolone acetonide-loaded hydrogel prepared using an electron beam.

In this study, a triamcinolone acetonide-loaded hydrogel was prepared by electron beam irradiation and evaluated for use as a buccal mucoadhesive drug delivery system. A poloxamer was modified to have vinyl end groups for preparation of the hydrogel via an irradiation cross-linking reaction. Carbopol was introduced to improve the mucoadhesive properties of the hydrogel. The in vitro release of triamcinolone acetonide from the hydrogel was examined at 37 °C. To investigate the topical therapeutic effect of triamcinolone acetonide on wounded rat skin and buccal mucosa, the appearance and histological changes were evaluated for 15 days after treatment with saline, triamcinolone acetonide solution, triamcinolone acetonide hydrogel, and blank hydrogel, respectively. Triamcinolone acetonide was released constantly from the gel formulation at 37 °C and reach 100% at about 48 h. After 15 days, in the skin of the group treated with the triamcinolone acetonide-loaded hydrogel, the wound was almost completely free of crust and a number of skin appendages, including hair follicles, had formed at the margins of the tissue. Moreover, the inflammatory response in the buccal mucosa was milder than that in the other groups, and the wound surface was completely covered with regenerating, hyperkeratotic, thickened epithelial cells. Our results indicate that the triamcinolone-acetonide hydrogel showed sustained drug release behavior, while causing no significant histopathological changes in buccal and skin tissues. Therefore, this hydrogel system may be a powerful means of drug delivery for buccal administration with controlled release and no tissue irritation.

Preparation and irradiation of Pluronic F127-based thermoreversible and mucoadhesive hydrogel for local delivery of naproxen.

To improve physical properties and modulate the mucoadhesive hydrogel formulation via cross-linking by radiation, hydrogels were prepared using thermoreversible polymer Pluronic F127 (PF127) and mucoadhesive polymer carbopol 934P (C934P). As a model drug, naproxen was loaded in the hydrogel formulation. Sol-gel transition temperatures of hydrogels were measured by the tube-inversion method. The mucoadhesive potential of each formulation was determined by measuring the force required to detach the formulation from oral mucosal tissue. To strengthen the mechanical properties, the formulations were irradiated using an electronic beam. Drug release from the hydrogels and the cytotoxicity of each formulation were investigated. Sol-gel transition temperatures of the formulations were decreased by the addition of carbopol and were close to body temperature. The mucoadhesive force of the PF127 formulation was increased by addition of carbopol. In vitro release was sustained and the release rate was reduced by the addition of carbopol. After irradiation, the mucoadhesive force was increased about five-fold especially in the case of PF127 23% (9.7 kPa) and in vitro release was not sustained further. In conclusion, the use of a PF127 formulation incorporating a mucoadhesive polymer could effectively and safely improve oral residence time and absorption of naproxen. Irradiated formulations showed permanent cross-linking and improved properties.

Formulation parameters influencing the physicochemical characteristics of rosiglitazone-loaded cationic lipid emulsion.

To enhance the solubility of rosiglitazone, rosiglitazone-loaded cationic lipid emulsion was formulated using cationic lipid DOTAP, DOPE, castor oil, tween 20, and tween 80. The formulation parameters in terms of droplet size were optimized focused on the effect of the cationic lipid emulsion composition ratio on drug encapsulating efficiency, in vitro drug release, and cellular uptake of the rosiglitazone-loaded emulsion. Droplet sizes of a blank cationic emulsion and a rosiglitazone-loaded cationic emulsion ranged between 195-230 nm and 210-290 nm, respectively. The encapsulation efficiency of the rosiglitazone-loaded emulsion was more than 90%. The rosiglitazone-loaded cationic emulsion improved in vitro drug release over the drug alone and showed a much higher cellular uptake than rosiglitazone alone. Moreover, drug loading in cationic emulsions increased cellular uptake of rosiglitazone in insulin-resistant HepG2 cells more than the normal HepG2 cells. Taken together, these results indicate that cationic lipid emulsions could be a potential delivery system for rosiglitazone and could enhance its cellular uptake efficiency into target cells.

Encapsulation enhancement and stabilization of insulin in cationic liposomes.

The purpose of this study was to enhance encapsulation efficiency and sustained-release delivery for parenteral administration of a protein drug. To reduce the administration frequency of protein drugs, it is necessary to develop sustained delivery systems. In this study, protein drug-loaded cationic liposomes were formulated with dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), dioleoyl-3-trimethylammonium-propane (DOTAP), and cholesterol (CH) at a molar ratio of DOPE/DOTAP/CH of 2/1.5/2. Five mol% of distearoylphosphatidyl ethanolamine polyethylene glycol (DSPE-PEG) was added prior to encapsulation of the drug into liposomes. Insulin was chosen as a model protein drug and encapsulation efficiency was evaluated in various liposomes with and without DSPE-PEG. Scanning electron microscopy was used to examine the insulin-loaded cationic liposomes. Structural analysis was performed using spectropolarimetry. Additionally, the stability and cytotoxicity of insulin-loaded cationic liposomes were evaluated. Liposomes coated with DSPE-PEG showed higher insulin encapsulation efficiency than did those without DSPE-PEG, but not significantly. Moreover, among the liposomes coated with DSPE-PEG, those hydrated with 10% sucrose showed higher encapsulation efficiency than did liposomes hydrated in either phosphate-buffered saline or 5% dextrose. In vitro release of insulin was prolonged by cationic liposomes. Our findings suggest that cationic liposomes may be a potential sustained-release delivery system for parenteral administration of protein and peptide drugs to prolong efficacy and improve bioavailability.

A thermosensitive vaginal gel formulation with HPgammaCD for the pH-dependent release and solubilization of amphotericin B.

To achieve better therapeutic efficacy and patient compliance in the treatment for Candida vaginitis, the antifungal agent amphotericin B (AmB) was formulated in a vaginal gel using Pluronic-based multiblock copolymers (MBCP-2). To increase its aqueous solubility, the drug was incorporated as its inclusion complex with hydroxypropyl-gamma-cyclodextrin (HPgammaCD). The formation of the AmB inclusion complex was characterized using different techniques including XRD, FT-IR spectrophotometry, DSC, and SEM. The sol-gel transition diagrams were determined by the inversion method at temperature intervals of 2 degrees C. Moreover, a histopathology study was performed to determine whether vaginal tissue damage was caused by repeated doses. The inclusion complex between AmB and HPgammaCD was completely formed, and the aqueous solubility of AmB was improved by the formation of the inclusion complex. The sol-gel transition diagrams showed that the aqueous solutions of MBCP-2 gelled at body temperature, and the gelation temperature of the polymer solutions was dependent on polymer concentration. In vitro drug release results indicated that MBCP-2 exhibited a sustained release of AmB in pH 7.4 and pH 9.0 buffers, whereas at pH 5.0, it presented a constant release that was completed within 3 days. There was no visible sign of inflammation or necrosis in vaginal tissues after repetitive intravaginal application. In conclusion, the thermosensitive vaginal gel might be useful in the delivery of an antifungal agent for local treatment.

Enhanced siRNA delivery using cationic liposomes with new polyarginine-conjugated PEG-lipid.

Gene therapy based on small interfering RNA (siRNA) has emerged as an exciting new therapeutic approach. However, insufficient cellular uptake and poor stability have limited its usefulness. Here, we report efficient delivery of siRNA via the use of cationic liposomes that contain a new PEG-lipid. The new lipid, poly-l-arginine-conjugated polyethylene glycol (PLR-PEG), was synthesized. To confirm the synthesis of the amino acid-conjugated PEG-lipid, (1)H NMR and gel permeation chromatography (GPC) were performed. Cationic liposomes as non-viral vectors were formulated using the cationic lipids 1,2-dioleoyl-3-trimethylammonium propane (DOTAP), 1,2-dioleoyl-sn-glycero-3-phosphoethanolaminepropane (DOPE), cholesterol (Chol) and PLR-PEG. Physicochemical properties of cationic liposomes were investigated. A GFP siRNA was used as a model siRNA to test the efficiency of cationic liposome-mediated siRNA delivery. The liposomes could enhance delivery efficiency and decrease cytotoxicity at an optimized lipid composition. The new cationic liposome formulation using a new PEG-lipid (PLR-PEG) showed not only enhanced intracellular delivery of siRNA but also decreased cytotoxicity in H4II-E and HepG2 cell lines. The GFP siRNA delivered by new cationic liposomes using PLR-PEG was effective in reducing the GFP protein expression levels of the gene. These results suggest that the new cationic liposomes could be used for efficient delivery of siRNA therapeutics.

A new vaginal delivery system of amphotericin B: a dispersion of cationic liposomes in a thermosensitive gel.

Amphotericin B (AmB) is used in the treatment of fungal infections; however, its clinical use is limited by its toxic side effects. In this study, AmB-loaded cationic liposome gels were formulated with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), and cholesterol (CH) at a molar ratio of DOPE:DOTAP:CH = 4:5:1 in thermosensitive gel composed of poloxamer 407 (P407) and poloxamer 188 (P188). To enhance the solubility of AmB, 6 mol% of distearoyl phosphatidyl ethanolamine-polyethylene glycol was added prior to encapsulation of the drug into liposomes. Scanning electron microscopy was used to observe the AmB encapsulated cationic liposome gels. In vitro release, stability and cytotoxicity of AmB in cationic liposome gels were evaluated. The particle size and zeta potential of AmB-loaded liposomes were in the range of 400-500 nm and 40-60 mV, respectively. The thermosensitive gel at the ratio of P407:P188 = 15:15 (w/w) gelled at 37 degrees C, approximating body temperature. Encapsulation efficiency of AmB was approximately 50-60%, which was influenced by the ratio of AmB to lipid. Moreover, AmB-loaded cationic liposome gels were more stable and less toxic than free AmB. From these results, cationic liposome gel formulations may be useful for vaginal delivery of AmB.