Biomimetic nanodecoys deliver cholesterol-modified heteroduplex oligonucleotide to target dopaminergic neurons for the treatment of Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the accumulation of α-synuclein (α-syn) aggregates called Lewy bodies leading to the gradual loss of dopaminergic (DA) neurons in the substantia nigra. Although α-syn expression can be attenuated by antisense oligonucleotides (ASOs) and heteroduplex oligonucleotide (HDO) by intracerebroventricular (ICV) injection, the challenge to peripheral targeted delivery of oligonucleotide safely and effectively into DA neurons remains unresolved. Here, we designed a new DNA/DNA double-stranded (complementary DNA, coDNA) molecule with cholesterol conjugation (Chol-HDO (coDNA)) based on an α-syn-ASO sequence and evaluated its silence efficiency. Further, Chol-HDO@LMNPs, Chol-HDO-loaded, cerebrovascular endothelial cell membrane with DSPE-PEG2000-levodopa modification (L-DOPA-CECm)-coated nanoparticles (NPs), were developed for the targeted treatment of PD by tail intravenous injection. CECm facilitated the blood-brain barrier (BBB) penetration of NPs, together with cholesterol escaped from reticuloendothelial system uptake, as well as L-DOPA was decarboxylated into dopamine which promoted the NPs toward the PD site for DA neuron regeneration. The behavioral tests demonstrated that the nanodecoys improved the efficacy of HDO on PD mice. These findings provide insights into the development of biomimetic nanodecoys loading HDO for precise therapy of PD. STATEMENT OF SIGNIFICANCE: The accumulation of α-synuclein (α-syn) aggregates is a hallmark of PD. Our previous study designed a specific antisense oligonucleotide (ASO) targeting human SNCA, but the traumatic intracerebroventricular (ICV) is not conducive to clinical application. Here, we further optimize the ASO by creating a DNA/DNA double-stranded molecule with cholesterol-conjugated, named Chol-HDO (coDNA), and develop a DA-targeted biomimetic nanodecoy Chol-HDO@LMNPs by engineering cerebrovascular endothelial cells membranes (CECm) with DSPE-PEG2000 and L-DOPA. The in vivo results demonstrated that tail vein injection of Chol-HDO@LMNPs could target DA neurons in the brain and ameliorate motor deficits in a PD mouse model. This investigation provides a promising peripheral delivery platform of L-DOPA-CECm nanodecoy loaded with a new Chol-HDO (coDNA) targeting DA neurons in PD therapy.

Nonviral delivery systems for antisense oligonucleotide therapeutics.

Antisense oligonucleotides (ASOs) are an important tool for the treatment of many genetic disorders. However, similar to other gene drugs, vectors are often required to protect them from degradation and clearance, and to accomplish their transport in vivo. Compared with viral vectors, artificial nonviral nanoparticles have a variety of design, synthesis, and formulation possibilities that can be selected to accomplish protection and delivery for specific applications, and they have served critical therapeutic purposes in animal model research and clinical applications, allowing safe and efficient gene delivery processes into the target cells. We believe that as new ASO drugs develop, the exploration for corresponding nonviral vectors is inevitable. Intensive development of nonviral vectors with improved delivery strategies based on specific targets can continue to expand the value of ASO therapeutic approaches. Here, we provide an overview of current nonviral delivery strategies, including ASOs modifications, action mechanisms, and multi-carrier methods, which aim to address the irreplaceable role of nonviral vectors in the progressive development of ASOs delivery.

Apoptotic bodies for advanced drug delivery and therapy.

Extracellular vesicles (EVs) have emerged as promising candidates for multiple biomedical applications. Major types of EVs include exosomes, microvesicles, and apoptotic bodies (ABs). ABs are conferred most properties from parent cells in the final stages of apoptosis. A wide variety of sources and stable morphological features are endowed to ABs by the rigorous apoptotic program. ABs accommodate more functional biomolecules by relying on the larger volume and maintaining their naturalness in circulation. The predominant body surface ratio of ABs facilitates their recognition by recipient cells and is advantageous for interactions with microenvironments. ABs can modulate and alleviate symptoms of numerous diseases for their origins, circulation, and high biocompatibility. In addition, ABs have been emerging in disease diagnosis, immunotherapy, regenerative therapy, and drug delivery. Here, we aim to present a thorough discussion on current knowledge about ABs. Of particular interest, we will summarize the application of AB-based strategies for diagnosis and disease therapy. Perspectives for the development of ABs in biomedical applications are highlighted.

Hybrid Cell Membrane-Functionalized Biomimetic Nanoparticles for Targeted Therapy of Osteosarcoma.

PURPOSE: In order to prepare a biomimetic nano-carrier which has inflammatory chemotaxis, homologous targeting and reduce immune clearance, for targeted chemotherapy of osteosarcoma, we fabricated the paclitaxel-loaded poly(lactic-co-glycolic) acid (PLGA) nanoparticles coated with 143B-RAW hybrid membrane (PTX-PLGA@[143B-RAW] NPs) and evaluate its anti-cancer efficacy in vitro and vivo. METHODS: PTX-PLGA@[143B-RAW] NPs were prepared by the ultrasonic method and were characterized by size, zeta potential, polymer dispersion index (PDI), Coomassie bright blue staining, transmission electron microscopy (TEM) and high performance liquid chromatography (HPLC). Cellular uptake, cell viability assay, flow cytometry and chemotactic effect of PTX-PLGA@[143B-RAW] NPs were evaluated in vitro. Biodistribution, anti-cancer therapeutic efficacy and safety of PTX-PLGA@[143B-RAW] NPs were evaluated in 143B osteosarcoma xenograft mice. RESULTS: The hybrid membrane successfully coated onto the surface of PLGA nanoparticles. PTX-PLGA@[143B-RAW] NPs had a drug loading capacity of 4.24 ± 0.02% and showed targeting ability to osteosarcoma. PTX-PLGA@[143B-RAW] NPs showed high cellular uptake and improved anti-cancer efficacy against 143B cells. More importantly, PTX-PLGA@[143B-RAW] NPs treatment suppressed tumor growth in tumor-bearing mice with minimal damage to normal tissues. CONCLUSION: PTX-PLGA@[143B-RAW] NPs could be used for targeted drug delivery and osteosarcoma therapy.

Recent progress of macrophage vesicle-based drug delivery systems.

Nanoparticle drug delivery systems (NDDSs) are promising platforms for efficient delivery of drugs. In the past decades, many nanomedicines have received clinical approval and completed translation. With the rapid advance of nanobiotechnology, natural vectors are emerging as novel strategies to carry and delivery nanoparticles and drugs for biomedical applications. Among diverse types of cells, macrophage is of great interest for their essential roles in inflammatory and immune responses. Macrophage-derived vesicles (MVs), including exosomes, microvesicles, and those from reconstructed membranes, may inherit the chemotactic migration ability and high biocompatibility. The unique properties of MVs make them competing candidates as novel drug delivery systems for precision nanomedicine. In this review, the advantages and disadvantages of existing NDDSs and MV-based drug delivery systems (MVDDSs) were compared. Then, we summarized the potential applications of MVDDSs and discuss future perspectives. The development of MVDDS may provide avenues for the treatment of diseases involving an inflammatory process.

Multifunctional exosome-mimetics for targeted anti-glioblastoma therapy by manipulating protein corona.

Targeted drug delivery to the glioblastoma (GBM) overcoming blood-brain barrier (BBB) has been challenging. Exosomes are promising vehicles for brain tumor drug delivery, but the production and purification hinder its application for nanomedicine. Besides, the formation of protein corona (PC) may affect the behaviour of nanocarriers. Here, multifunctional exosomes-mimetics (EM) are developed and decorated with angiopep-2 (Ang) for enhancing GBM drug delivery by manipulating PC. Docetaxel (DTX)-loaded EM with Ang modification (DTX@Ang-EM) show less absorption of serum proteins and phagocytosis by macrophages. Ang-EM show enhanced BBB penetration ability and targeting ability to the GBM. Ang-EM-mediated delivery increase the concentration of DTX in the tumor area. The multifunctional DTX@Ang-EM exhibits significant inhibition effects on orthotopic GBM growth with reduced side effects of the chemotherapeutic. Findings from this study indicate that the developed DTX@Ang-EM provide a new strategy for targeted brain drug delivery and GBM therapy.

Artificial exosomes for translational nanomedicine.

Exosomes are lipid bilayer membrane vesicles and are emerging as competent nanocarriers for drug delivery. The clinical translation of exosomes faces many challenges such as massive production, standard isolation, drug loading, stability and quality control. In recent years, artificial exosomes are emerging based on nanobiotechnology to overcome the limitations of natural exosomes. Major types of artificial exosomes include 'nanovesicles (NVs)', 'exosome-mimetic (EM)' and 'hybrid exosomes (HEs)', which are obtained by top-down, bottom-up and biohybrid strategies, respectively. Artificial exosomes are powerful alternatives to natural exosomes for drug delivery. Here, we outline recent advances in artificial exosomes through nanobiotechnology and discuss their strengths, limitations and future perspectives. The development of artificial exosomes holds great values for translational nanomedicine.

Exosomes and biomimetic nanovesicles-mediated anti-glioblastoma therapy: A head-to-head comparison.

Exosomes (Exos) are promising vehicles for brain drug delivery due to nanosize and the ability to breach the blood-brain barrier (BBB). But the low yield of natural exosomes limits its application for nanomedicine. The generation of bioinspired nanovesicles (BNVs) that mimicking Exos is attractive, but there is a lack of comparative evaluation of Exos and BNVs. Here, we perform the first head-to-head comparison study of Exos and BNVs for brain tumor drug delivery. We show that BNVs derived from brain-derived endothelial cells are competent alternative nanocarrier to natural exosomes. The drug-loading capacity of Exos and BNVs are similar, but the yield of BNVs is substantially higher (500-fold) than Exos. Doxorubicin (DOX)-loaded BNVs (BNV/DOX) and DOX-loaded Exos (Exo/DOX) showed similar pharmacokinetic profiles and prolonged circulation od DOX. Despite inconsistent mechanisms, BNV/DOX can across the BBB, and exhibit suppression effects similar to Exo/DOX on the progress of glioblastoma (GBM) in zebrafish and in vivo subcutaneous and orthotopic xenografts mice models, with minimal systemic toxicity. Findings from this head-to-head comparison study indicate that autologous BNVs is a effective alternative of Exos for brain tumor nanomedicine.

From blood to brain: blood cell-based biomimetic drug delivery systems.

Brain drug delivery remains a major difficulty for several challenges including the blood-brain barrier, lesion spot targeting, and stability during circulation. Blood cells including erythrocytes, platelets, and various subpopulations of leukocytes have distinct features such as long-circulation, natural targeting, and chemotaxis. The development of biomimetic drug delivery systems based on blood cells for brain drug delivery is growing fast by using living cells, membrane coating nanotechnology, or cell membrane-derived nanovesicles. Blood cell-based vehicles are superior delivery systems for their engineering feasibility and versatile delivery ability of chemicals, proteins, and all kinds of nanoparticles. Here, we focus on advances of blood cell-based biomimetic carriers for from blood to brain drug delivery and discuss their translational challenges in the future.

Biomimetic Liposome with Surface-Bound Elastase for Enhanced Tumor Penetration and Chemo-Immumotherapy.

Dense extracellular matrix (ECM) in the tumor stroma has been a challenge for drug penetration and cytotoxic T lymphocyte (CTL) infiltration. Neutrophil elastase (NE), in surface-bound form, can destruct ECM rapidly, may be used for remodeling tumor ECM, and overcoming tumor stromal barrier. Focusing on elastosis in triple-negative breast tumor, biomimetic liposomes with chimeric cell membrane proteins (LMP) are developed and for the first time, it is demonstrated that LMP with surface-bound elastase (NE-LMP) can target and degrade ECM effectively in tumor stroma, with minimal toxicity to normal tissues. The pretreatment of NE-LMP increases the accumulation of chemotherapeutics at the tumor site and enhances antitumor effects. Also, NE-LMP facilitates CTL infiltration in tumors and exhibits enhanced chemo-immunotherapy in combination of PD-1 immune checkpoint blockade treatment in orthotopic 4T1 tumor-bearing mice, with significantly prolonged survival. Moreover, the remodeling of the tumor ECM by NE-LMP shows inhibiting effects on metastasis in the lung. Findings from this study suggest that NE-LMP holds promise for enhancing deep penetration of drug and infiltration of CTL in desmoplastic tumor by effective degrading ECM in the tumor stroma.

Comparative evaluation of methods for isolating small extracellular vesicles derived from pancreatic cancer cells.

BACKGROUND: Small extracellular vesicles (sEVs) are nanosized vesicles involved in cell-to-cell communication. sEVs have been widely studied for clinical applications such as early detection of diseases and as therapeutics. Various methods for sEVs isolation are been using, but different methods may result in different qualities of sEVs and impact downstream analysis and applications. Here, we compared current isolation methods and performed a comparative analysis of sEVs from supernatant of cultured pancreatic cancer cells. METHODS: Ultracentrifugation, ultrafiltration and co-precipitation as concentration methods were firstly evaluated for yield, size, morphology and protein level of pellets. Then, isolate sEVs obtained by four different purification methods: size exclusion chromatography, density gradient ultracentrifugation, ultracentrifugation, and immunoaffinity capturing, were analysed and compared. RESULTS: For the concentration process, ultracentrifugation method obtained high quality and high concentration of pellets. For the purification process, immunoaffinity capturing method obtained the purest sEVs with less contaminants, while density gradient ultracentrifugation-based method obtained sEVs with the smallest size. Proteomic analysis revealed distinct protein contents of purified sEVs from different methods. CONCLUSIONS: For isolating sEVs derived from supernatant of cultured pancreatic cancer cell line, ultracentrifugation-based method is recommended for concentration of sEVs, density gradient ultracentrifugation-based method may be applied for obtaining purified sEVs with controlled size, immunoaffinity capturing may be suitable for studies requiring sEVs with high purity but may loss subtypes of sEVs without specific protein marker.

Preservation of small extracellular vesicles for functional analysis and therapeutic applications: a comparative evaluation of storage conditions.

Extracellular vesicles (EVs) are nanovesicles involved in multiple biological functions. Small EVs (sEVs) are emerging as therapeutics and drug delivery systems for their contents, natural carrier properties, and nanoscale size. Despite various clinical application potentials, little is known about the effects of storage conditions on sEVs for functional analysis and therapeutic use. In this study, we evaluated the stability of sEVs stored at 4 °C, -20 °C, and -80 °C up to 28 days and compared them to fresh sEVs. Also, the effect of freeze-thawing circles on the quantity of sEVs was assessed. We found that different storage temperatures, along with shelf life, impact the stability of sEVs when compared to freshly isolated sEVs. Storage changes the size distribution, decreases quantity and contents, and impacts cellular uptake and biodistribution of sEVs. For functional studies, isolated sEVs are suggested to be analyzed freshly or stored at 4 °C or -20 °C for short-term preservation depending on study design; but -80 °C condition would be more preferable for long-term preservation of sEVs for therapeutic application.

3,5,4'-Trimethoxy-trans-stilbene loaded microemulsion for cutaneous melanoma therapy by transdermal drug delivery.

For therapy of skin cancer, transdermal administration has been a potential way to enhance chemotherapy. However, the drug delivery efficacy remained unsatisfactory because of the physiological barriers from the skin to the tumor, which hindered the effect of 3,5,4'-trimethoxy-trans-stilbene (BTM), a drug that has toxicity to cancer. Herein, we prepared an oil-in-water (O/W) microemulsion to load BTM (BTM-ME) for transdermal therapy of melanoma. BTM-ME was characterized by size, zeta potential, and polymer disperse index (PDI). B16F10 melanoma cell line was used for cell experiments and animal models. And cell uptake, viability assay, and flow cytometry were to test the cell internalization and the ability of BTM-ME to induce cancer cell apoptosis. Skin penetration testing was to detect its penetration efficiency to the skin. And tumor-bearing mice were used to prove the improvement of anti-cancer efficacy of BTM-ME with the combination of Taxol. BTM was successfully loaded in O/W microemulsion, with a drug loading capacity of 24.82 mg/mL. BTM-ME can penetrate the skin and increase the retention of BTM in the epidermis. And the combination of Taxol and BTM-ME effectively suppressed tumor growth and has lower toxicity to normal organs. BTM-ME provides adjuvant therapy to cutaneous melanoma and the combination of Taxol and BTM-ME has the clinical potential for skin cancer therapy. Graphical abstract.

Emerging strategies for labeling and tracking of extracellular vesicles.

Extracellular vesicles (EVs) are cell-derived lipid bilayer-enclosed nanovesicles. EVs are emerging as keys for identifying molecular mechanisms by mediating intercellular communication. EVs allow the exchange of various components with neighboring and distant cells through the extracellular environment, thereby involving in various biological processes in both physiological and pathological conditions such as wound healing, immune response, and tumorigenesis. EVs are also growing rapidly as cargo carrier for their natural delivery properties. Development of bioinspired delivery nanoplatforms based on exosomes-like mimetics also showed potentials to overcome limitations of synthetic nanoparticles. EVs offer a window to multicomponent diagnosis and a tool for design therapeutics. However, for successful clinical translation of EVs, the understanding of in vivo behavior is essential. Advancements in molecular imaging enabled high-resolution in vivo tracking of EVs, providing valuable information regarding trafficking, biodistribution, cellular uptake and molecular mechanism of EVs. Recent studies have explored various methods for visualizing EVs, each imaging technique has certain strengths and limitations. Highly specific, sensitive and biocompatible labeling and tracking strategies still in demand in EV visualization. In this review, we summarized methods for labeling and tracking of EVs and discussed benefits and drawbacks for each method. Future novel imaging modalities and combined strategies will provide avenues for understanding EV behavior and accelerate their clinical translation.

Emerging nanomedicine-based strategies for preventing metastasis of pancreatic cancer.

Pancreatic cancer is highly metastatic with very short survival and increasing mortality rates. Recent advances in therapeutic regimes and other adjuvant therapies improved slightly overall survival of pancreatic cancer, but fighting metastasis has been challenging and is necessary for achieving cure. Nanomedicine, not limited to drug delivery, offers opportunities for targeting cancer metastasis. Research regarding the prevention of metastasis of this malignancy is highly demanded. Herein, we focus on advances of nanomedicine-based strategies for targeting different stages of metastasis, including cancer stem cells, tumor microenvironment, circulating tumor cells and tumor exosomes. A greater emphasis on targeting metastasis of pancreatic cancer using nanomedicine-based strategies provides avenues for improving pancreatic cancer treatment outcomes in the future.

Gemcitabine loaded autologous exosomes for effective and safe chemotherapy of pancreatic cancer.

Pancreatic cancer remains one of the most highly lethal diseases with very poor prognosis. Gemcitabine (GEM) is the first-line chemotherapeutic drug for pancreatic cancer treatment but is associated with significant side effects when administered systemically. Exosomes have emerged as attractive candidates for drug delivery for their high delivery efficiency and biocompatibility. Here, GEM was loaded into autologous exosomes to formulate ExoGEM for targeted chemotherapy of pancreatic cancer. Autologous exosomes facilitate cellular uptake of GEM and contributed to significantly increased cytotoxic effect of GEM, while heterologous cellular uptake showed less efficiency. Autologous exosomes showed targeting ability to pancreatic cancer in biodistribution study, and GEM concentration in tumor site was increased via ExoGEM delivery. ExoGEM treatment, in tumor-bearing mice, significantly suppressed tumor growth, with prolonged survival in a dose-response manner, but caused minimal damage to normal tissues. More importantly, tumors in several mice treated with ExoGEM were disappeared without recurrence. Autologous exosomes are safe and effective vehicles for targeted delivery of GEM against pancreatic cancer. This delivery strategy may have implications for personalized chemotherapy of pancreatic cancer. STATEMENT OF SIGNIFICANCE: Exosomes are efficient delivery vehicles in intracellular communication. Moreover, potential tropism of autologous exosomes to the tumor microenvironment make them competitive delivery vehicles. The use of cancer-derived exosomes for drug delivery and superior targeting efficacy and enhanced anticancer efficacy of therapeutics have been evidenced. Gemcitabine is a mainstay for pancreatic treatment. However, poor cellular uptake and low targeting effects of gemcitabine often lead to severe systemic toxicity. Therefore, to overcome this limitation, we herein loaded gemcitabine into autologous pancreatic cancer-derived exosomes for the targeted chemotherapy of pancreatic cancer.

Micelles Loaded With Puerarin And Modified With Triphenylphosphonium Cation Possess Mitochondrial Targeting And Demonstrate Enhanced Protective Effect Against Isoprenaline-Induced H9c2 Cells Apoptosis.

BACKGROUND: The protective role of puerarin (PUE) against myocardial infarction is closely related to its regulation on mitochondria. However, free PUE can hardly reach the mitochondria of ischemic cardiomyocytes due to the lack of mitochondrial targeting of PUE. Here PUE was loaded into mitochondria-targeted micelles (PUE@TPP/PEG-PE) for precisely delivering PUE into mitochondria with the aim of enhancing the anti-apoptosis effect. METHODS: The mitochondriotropic polymer TPP-PEG-PE was synthesized for the preparation of PUE@TPP/PEG-PE micelles modified with triphenylphosphonium (TPP) cation. The physicochemical properties and anti-apoptosis effect of PUE@TPP/PEG-PE micelles were investigated. The coumarin 6 (C6)-labeled TPP/PEG-PE (C6@TPP/PEG-PE) micelles were used to observe the enhanced cellular uptake, mitochondrial targeting and lysosomes escape. Moreover, in vivo and ex vivo biodistribution of lipophilic near-infrared dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR)-labeled PUE@TPP/PEG-PE (DiR@TPP/PEG-PE) micelles were detected through fluorescence imaging. RESULTS: The successful synthesis of TPP-PEG-PE conjugate was confirmed. PUE@TPP/PEG-PE micelles had a particle size of 17.1 nm, a zeta potential of -6.2 mV, and a sustained-release behavior. The in vitro results showed that the intracellular uptake of C6@TPP/PEG-PE micelles was significantly enhanced in H9c2 cells. C6@TPP/PEG-PE micelles could deliver C6 to mitochondria and reduce the capture of lysosomes. In addition, compared with the PUE@PEG-PE micelles and free PUE, the PUE@TPP/PEG-PE micelles exerted an enhanced protective effect against isoprenaline-induced H9c2 cell apoptosis, as evident by the decreased percentage of apoptotic cells, Caspase-3 activity, ROS level, Bax expression, and increased Bcl-2 expression. The in vivo detecting results of the targeting effect using DiR probe also indicated that TPP/PEG-PE micelles could accumulate and retain in the ischemic myocardium. CONCLUSION: The results of this study demonstrate the promising potential of applying PUE@TPP/PEG-PE micelles in mitochondria-targeted drug delivery to achieve maximum therapeutic effects of PUE.

3,5,4'-trimethoxy-trans-stilbene loaded PEG-PE micelles for the treatment of colon cancer.

BACKGROUND: 3,5,4'-trimethoxy-trans-stilbene (BTM) is a methylated derivative of resveratrol. To improve the pharmaceutical properties of BTM, BTM loaded PEG-PE micelles (BTM@PEG-PE) were fabricated and its anti-cancer efficacy against colon cancer was evaluated. METHODS: BTM@PEG-PE micelles were prepared by the solvent evaporation method and were characterized by nuclear magnetic resonance (NMR), size, zeta potential, polymer disperse index (PDI) and transmission electron microscopy (TEM). Cellular uptake, cell viability assay, caspase-3 activity assay and flow cytometry were performed to evaluate the cell internalization and anti-cancer efficacy of BTM@PEG-PE micelles in vitro. Pharmacokinetic profiles of BTM and BTM@PEG-PE micelles were compared and in vivo anti-cancer therapeutic efficacy and safety of BTM@PEG-PE micelles on CT26 xenograft mice were evaluated. RESULTS: BTM was successfully embedded in the core of PEG-PE micelles, with a drug loading capacity of 5.62±0.80%. PEG-PE micelles facilitated BTM entering to the CT26 cells and BTM@PEG-PE micelles exerted enhanced anti-cancer efficacy against CT26 cells. BTM@PEG-PE micelles showed prolonged half-life and increased bioavailability. More importantly, BTM@PEG-PE micelles treatment suppressed tumor growth in tumor-bearing mice and prolonged survival with minimal damage to normal tissues. CONCLUSION: Altogether, the BTM@PEG-PE micelles might be a promising strategy to enhance the pharmacokinetic and pharmacodynamic potentials of BTM for colon cancer therapy.

Phospholipid complex based nanoemulsion system for oral insulin delivery: preparation, in vitro, and in vivo evaluations.

Purpose: The aim of this research was to develop a phospholipid complex based nanoemulsion system for oral insulin delivery. Methods: Insulin-phospholipid complex (IPC) was firstly prepared by an anhydrous co-solvent lyophilization method, and then encapsulated into the oil phase of nanoemulsion to obtain the IPC-based nanoemulsion (IPC-NE). Both water-in-oil (W/O) IPC-NE and oil-in-water (O/W) IPC-NE were formulated and evaluated for comparison. Results: The obtained W/O IPC-NE and O/W IPC-NE were both spherical in shape with a mean particle size of 18.6±0.79 nm and 27.3±1.25 nm, respectively. While both IPC-NEs exhibited enhanced Caco-2 cell monolayers permeability than IPC and insulin solution, W/O IPC-NE showed relatively greater protective effects against enzymatic degradation than O/W IPC-NE. Moreover, oral administration of W/O IPC-NE exhibited significant hypoglycemic effects, with 12.4-fold and 1.5-fold higher oral bioavailability compared with insulin solution and O/W IPC-NE, respectively. Conclusion: IPC-NEs, especially the W/O IPC-NE showed promising efficiency in vitro and in vivo, thus could be a potential strategy for oral insulin delivery.

Microemulsions vs chitosan derivative-coated microemulsions for dermal delivery of 8-methoxypsoralen.

BACKGROUND: 8-methoxypsoralen (8-MOP) is one of the most commonly utilized drugs in psoralen-ultraviolet A therapy for treatment of vitiligo. However, poor skin retention and systemic side effects limit the clinical application of 8-MOP. METHODS: Microemulsions (MEs) and chitosan derivative-coated 8-MOP MEs were developed and compared for dermal delivery of 8-MOP. Ex vivo skin retention/permeation study was performed to select the ME formulation with the highest retention:permeation ratio. Four different chitosan-coated MEs were prepared and compared with the ME formulation for their ability to distribute 8-MOP in the skin. RESULTS: Among various ME formulations developed, a formulation containing 2.9% ethyl oleate, 17.2% Cromophor EL35, 8.6% ethanol and 71.3% water showed the highest ex vivo skin retention:permeation ratio (1.98). Of four chitosan-coated MEs prepared, carboxymethyl chitosan-coated MEs (CC-MEs) and hydroxypropyl chitosan-coated MEs (HC-MEs) showed higher ex vivo skin retention:permeation ratio (1.46 and 1.84). and were selected for in vivo pharmacokinetic study. AUCskin (0-12 h) for 8-MOP MEs (4578.56 h·ng·mL-1) was higher than HC-MEs (3422.47 h·ng·mL-1), CC-MEs (2808.51 h·ng·mL-1) and tincture (1500.16 h·ng·mL-1). Also, AUCplasma (0-12 h) for MEs (39.35±13.90 h·ng·mL-1) was significantly lower than HC-MEs (66.32 h·ng·mL-1), CC-MEs (59.70 h·ng·mL-1) and tincture (73.02 h·ng·mL-1). CONCLUSION: These combined results suggested that the MEs developed could be a promising and safe alternative for targeted skin delivery of 8-MOP.