Local and Sustained Baricitinib Delivery to the Skin through Injectable Hydrogels Containing Reversible Thioimidate Adducts.

Janus kinase (JAK) inhibitors are approved for many dermatologic disorders, but their use is limited by systemic toxicities including serious cardiovascular events and malignancy. To overcome these limitations, injectable hydrogels are engineered for the local and sustained delivery of baricitinib, a representative JAK inhibitor. Hydrogels are formed via disulfide crosslinking of thiolated hyaluronic acid macromers. Dynamic thioimidate bonds are introduced between the thiolated hyaluronic acid and nitrile-containing baricitinib for drug tethering, which is confirmed with 1H and 13C nuclear magnetic resonance (NMR). Release of baricitinib is tunable over six weeks in vitro and active in inhibiting JAK signaling in a cell line containing a luciferase reporter reflecting interferon signaling. For in vivo activity, baricitinib hydrogels or controls are injected intradermally into an imiquimod-induced mouse model of psoriasis. Imiquimod increases epidermal thickness in mice, which is unaffected when treated with baricitinib or hydrogel alone. Treatment with baricitinib hydrogels suppresses the increased epidermal thickness in mice treated with imiquimod, suggesting that the sustained and local release of baricitinib is important for a therapeutic outcome. This study is the first to utilize a thioimidate chemistry to deliver JAK inhibitors to the skin through injectable hydrogels, which has translational potential for treating inflammatory disorders.

Nanoformulations for dermal delivery of imiquimod: The race of "soft" against "hard".

Imiquimod (IMQ) is an immunostimulating agent used in the treatment of basal cell carcinoma and actinic keratosis. Due to its low solubility and poor skin bioavailability, the dermal formulation of IMQ remains challenging. In analogy to tyre compounds used in Formula 1 racing, we compare four types of nanosystems belonging to three groups: (i) "hard" nanoparticles in the form of IMQ nanocrystals, (ii) "intermediate" nanoparticles in the form of liposomes and lipid nanocapsules, and (iii) "soft" nanoparticles in the form of a nanoemulsion based on oleic acid. The nanoemulsion and nanocrystals were able to incorporate the highest amount of IMQ (at least 2 wt%) compared to liposomes (0.03 wt%) and lipid nanocapsules (0.08 wt%). Regarding size, liposomes, and lipid nanocapsules were rather small (around 40 nm) whereas nanocrystals and nanoemulsion were larger (around 200 nm). All developed nanoformulations showed high efficiency to deliver IMQ into the skin tissue without undesirable subsequent permeation through the skin to acceptor. Especially, the 2 wt% IMQ nanoemulsion accumulated 129 µg/g IMQ in the skin, compared to 34 µg/g of a 5 wt% commercial cream. The effects of the respective nanoparticulate systems were discussed with respect to their possible diffusion kinetics (Brownian motion vs. settling) in the aqueous phase.

Tumor immunotherapy boosted by R837 nanocrystals through combining chemotherapy and mild hyperthermia.

Melanoma is a malignant skin cancer that is prone to metastasis in the early stage and has a poor prognosis. Immunomodulatory therapy for melanoma has been a hot research topic in recent years. However, low immune cell infiltration and loss of tumor immunogenicity may occur in tumors, resulting in low response rates to immunotherapy. Thus, immunomodulatory therapy is usually used in combination with chemotherapy and radiotherapy. Development of combined therapeutic strategies with low systemic toxicity, high immune responsiveness and long-term inhibition of metastasis and recurrence of melanoma is the goal of current research. In this study, the insoluble immune adjuvant imiquimod (R837) was prepared as nanocrystals and coated with polydopamine (PDA) to form R837@PDA, which was then loaded into chitosan hydrogel (CGP) to form the drug-loaded gel system, R837@PDA@CGP (RPC), to combine immunomodulation effects, induction of immunogenic cell death (ICD) effects and immune-enhancement effects. After treatment with RPC, ICD in melanoma was induced, and the infiltration rate of cytotoxic T cells (CTLs) in melanoma was also significantly enhanced, which turned the tumor itself into an in situ vaccine and boosted the cancer-immunity cycle at the tumor site. Therefore, melanoma growth, metastasis and recurrence were notably inhibited.

Cancer cell membrane-coated nanoparticles for bimodal imaging-guided photothermal therapy and docetaxel-enhanced immunotherapy against cancer.

BACKGROUND: Mono-therapeutic modality has limitations in combating metastatic lesions with complications. Although emerging immunotherapy exhibits preliminary success, solid tumors are usually immunosuppressive, leading to ineffective antitumor immune responses and immunotherapeutic resistance. The rational combination of several therapeutic modalities may potentially become a new therapeutic strategy to effectively combat cancer. RESULTS: Poly lactic-co-glycolic acid (PLGA, 50 mg) nanospheres were constructed with photothermal transduction agents (PTAs)-Prussian blue (PB, 2.98 mg) encapsulated in the core and chemotherapeutic docetaxel (DTX, 4.18 mg)/ immune adjuvant-imiquimod (R837, 1.57 mg) loaded in the shell. Tumor cell membranes were further coated outside PLGA nanospheres (designated "M@P-PDR"), which acted as "Nano-targeted cells" to actively accumulate in tumor sites, and were guided/monitored by photoacoustic (PA)/ magnetic resonance (MR) imaging. Upon laser irradiation, photothermal effects were triggered. Combined with DTX, PTT induced in situ tumor eradication. Assisted by the immune adjuvant R837, the maturation rate of DCs increased by 4.34-fold compared with that of the control. In addition, DTX polarized M2-phenotype tumor-associated macrophages (TAMs) to M1-phenotype, relieving the immunosuppressive TME. The proportion of M2-TAMs decreased from 68.57% to 32.80%, and the proportion of M1-TAMs increased from 37.02% to 70.81%. Integrating the above processes, the infiltration of cytotoxic T lymphocytes (CTLs) increased from 17.33% (control) to 35.5%. Primary tumors and metastasis were significantly inhibited when treated with "Nano-targeted cells"-based cocktail therapy. CONCLUSION: "Nano-targeted cells"-based therapeutic cocktail therapy is a promising approach to promote tumor regression and counter metastasis/recurrence.

A Homotypic Membrane-Camouflaged Biomimetic Nanoplatform with Gold Nanocrystals for Synergistic Photothermal/Starvation/Immunotherapy.

Although photothermal therapy (PTT) has great potential for tumor inhibition, this single mode of action frequently encounters recurrence and metastasis, highlighting the urgent need for developing combination therapy. Inspired by established evidence that PTT could induce efficient immunogenic cell death (ICD), we here developed a versatile biomimetic nanoplatform (denoted as AuDRM) for the synergism of photothermal/starvation/immunotherapy against cancer. Specifically, dendritic mesoporous silica nanoparticles (NPs) were successfully constructed followed by the in situ synthesis of Au NPs in the mesopores. Afterward, a hybrid membrane was coated to facilitate the loading of R837. Upon efficient accumulation in the tumor tissue by homotypic targeting, the pH-sensitive membrane could be jettisoned to ensure the exposure of Au NPs for starvation therapy and the effective release of the immunostimulator R837 for enhancement of immunotherapy. Except for the PTT-mediated tumor ablation, the induction of ICD coupled with the release of tumor antigens could work synergistically with the immunostimulator R837 for inhibiting the primary tumor as well as the metastasis and induce a long-term immune memory effect for tumor inhibition via a vaccine-like function. Thus, this study paves the way for high-performance tumor ablation by the synergism of photothermal/starvation/immunotherapy.

Green Phellodendri Chinensis Cortex-based carbon dots for ameliorating imiquimod-induced psoriasis-like inflammation in mice.

BACKGROUND: Carbon dots (CDs) with multifaceted advantages have provided hope for development brand-new nanodrug for treating thorny diseases. This study developed a green and simple calcination method to prepare novel CDs as promising drug for psoriasis treatment. The as-prepared CDs using Phellodendri Chinensis Cortex (PCC) as sole precursor were characterized by a series of methods, mainly including electron microscopy, optical technology and X-ray photoelectron spectroscopy (XPS). RESULTS: Results displayed that fluorescence (Quantum yield = 5.63%) and nontoxic PCC-based CDs (PCC-CDs) with abundant chemical groups exhibited solubility and tiny sizes at average of (1.93 ± 0.53) nm, which may be beneficial for its inherent biological activity. Moreover, by using the typical imiquimod (IMQ)-induced psoriasis-like skin mouse model, we firstly demonstrated the pronounced anti-psoriasis activity of as-prepared PCC-CDs on ameliorating the appearance, psoriasis area and severity index (PASI) scores as well as histopathological morphology of both back skin tissues and right ears in IMQ-induced mouse. Further potential mechanisms behind the anti-psoriasis activities may be related to suppress M1 polarization and relatively promote M2 polarization of macrophage both in vitro and in vivo. CONCLUSION: These results suggested that PCC-CDs have potential to be an anti-psoriasis candidate for clinical applications to treat psoriasis, which not only provided an evidence for further broadening the biological application of CDs, but also provided a potential hope for application nanodrugs to treat thorny diseases.

Design of Chitosan Nanocapsules with Compritol 888 ATO® for Imiquimod Transdermal Administration. Evaluation of Their Skin Absorption by Raman Microscopy.

PURPOSE: Design imiquimod-loaded chitosan nanocapsules for transdermal delivery and evaluate the depth of imiquimod transdermal absorption as well as the kinetics of this absorption using Raman Microscopy, an innovative strategy to evaluate transdermal absorption. This nanovehicle included Compritol 888ATO®, a novel excipient for formulating nanosystems whose administration through the skin has not been studied until now. METHODS: Nanocapsules were made by solvent displacement method and their physicochemical properties was measured by DLS and laser-Doppler. For transdermal experiments, newborn pig skin was used. The Raman spectra were obtained using a laser excitation source at 532 nm and a 20/50X oil immersion objective. RESULTS: The designed nanocapsules, presented nanometric size (180 nm), a polydispersity index <0.2 and a zeta potential +17. The controlled release effect of Compritol was observed, with the finding that half of the drug was released at 24 h in comparison with control (p < 0.05). It was verified through Raman microscopy that imiquimod transdermal penetration is dynamic, the nanocapsules take around 50 min to penetrate the stratum corneum and 24 h after transdermal administration, the drug was in the inner layers of the skin. CONCLUSIONS: This study demonstrated the utility of Raman Microscopy to evaluate the drugs transdermal penetration of in the different layers of the skin. Graphical Abstract New imiquimod nanocapsules: evaluation of their skin absorption by Raman Microscopy and effect of the compritol 888ATO® in the imiquimod release profile.

Treating Immunologically Cold Tumors by Precise Cancer Photoimmunotherapy with an Extendable Nanoplatform.

Although immunotherapy has merged as an ideal cancer therapeutic strategy for preventing tumor growth and recurrence, effective approaches to treat immunologically cold tumors are still lacking. Herein, we reported a practical and extendable nanoplatform (HA/ZIF-8@ICG@IMQ) that facilely integrated various therapeutics and functions for boosting host antitumor immunity to treat immunologically cold tumors. The tumor-targeted and microenvironment-responsive HA/ZIF-8@ICG@IMQ facilitated the tumor-specific accumulation and release of photothermal agents and immune adjuvants. With near-infrared irradiation, the designed nanoparticles effectively enhanced the infiltration of cytotoxic T lymphocytes and helper T cells and effectively blocked the growth of primary and distant tumors. Moreover, the smart therapeutic could effectively prevent tumor rechallenge and recurrence with a long-term host immunological memory response. This method shows an effective immunologically cold tumor treatment using extendable nanotherapeutics and may have reference significance for clinical cancer therapy.

Co-Delivery of Imiquimod and Curcumin by Nanoemugel for Improved Topical Delivery and Reduced Psoriasis-Like Skin Lesions.

The current investigation aimed to improve the topical efficacy of imiquimod in combination with curcumin using the nanoemulsion-based delivery system through a combinatorial approach. Co-delivery of curcumin acts as an adjuvant therapeutic and to minimize the adverse skin reactions that are frequently associated with the topical therapy of imiquimod for the treatment of cutaneous infections and basal cell carcinomas. The low-energy emulsification method was used for the nano-encapsulation of imiquimod and curcumin in the nanodroplet oil phase, which was stabilized using Tween 20 in an aqueous dispersion system. The weak base property of imiquimod helped to increase its solubility in oleic acid compared with ethyl oleate, which indicates that fatty acids should be preferred as the oil phase for the design of imiquimod-loaded topical nanoemulsion compared with fatty acid esters. The phase diagram method was used to optimize the percentage composition of the nanoemulsion formulation. The mean droplet size of the optimized nanoemulsion was 76.93 nm, with a polydispersity index (PdI) value of 0.121 and zeta potential value of -20.5 mV. The optimized imiquimod-loaded nanoemulsion was uniformly dispersed in carbopol 934 hydrogel to develop into a nanoemulgel delivery system. The imiquimod nanoemulgel exhibited significant improvement (p<0.05) in skin permeability and deposition profile after topical application. The in vivo effectiveness of the combination of imiquimod and curcumin nanoemulgel was compared to the imiquimod nanoemulgel and imiquimod gel formulation through topical application for ten days in BALB/c mice. The combination of curcumin with imiquimod in the nanoemulgel system prevented the appearance of psoriasis-like symptoms compared with the imiquimod nanoemulgel and imiquimod gel formulation entirely. Further, the imiquimod nanoemulgel as a mono-preparation slowed and reduced the psoriasis-like skin reaction when compared with the conventional imiquimod gel, and that was contributed to by the control release property of the nano-encapsulation approach.

TLR7/8 Agonist-Loaded Nanoparticles Augment NK Cell-Mediated Antibody-Based Cancer Immunotherapy.

Activated natural killer (NK) cells can kill malignant tumor cells via granule exocytosis and secretion of IFN-γ, a key regulator of the TH1 response. Thus, mobilization of NK cells can augment cancer immunotherapy, particularly when mediated through antibody-dependent cellular cytotoxicity (ADCC). Stimulation of toll-like receptor (TLR)7/8 activity in dendritic cells promotes pro-inflammatory cytokine secretion and costimulatory molecule upregulation, both of which can potentiate NK cell activation. However, currently available TLR7/8 agonists exhibit unfavorable pharmacokinetics, limiting their in vivo efficacy. To enable efficient delivery to antigen-presenting cells, we encapsulated a novel imidazoquinoline-based TLR7/8 agonist in pH-responsive polymeric NPs. Enhanced costimulatory molecule expression on dendritic cells and a stronger pro-inflammatory cytokine response were observed with a NP-encapsulated agonist, compared to that with the soluble form. Treatment with NP-encapsulated agonists resulted in stronger in vivo cytotoxicity and prolonged activation of NK cells compared to that with a soluble agonist. In addition, TLR7/8 agonist-loaded NPs potentiated stronger NK cell degranulation, which resulted in enhanced in vitro and in vivo ADCC mediated by the epidermal growth factor receptor-targeting antibody cetuximab. TLR7/8 agonist-loaded NP treatment significantly enhanced the antitumor efficacy of cetuximab and an anti-HER2/neu antibody in mouse tumor models. Collectively, our data show that a pH-responsive NP-encapsulating TLR7/8 agonist could be used as a potent immunostimulatory adjuvant for antibody-based cancer immunotherapy by promoting NK cell activation.

Multi-functional nanocomplex codelivery of Trp2 and R837 to activate melanoma-specific immunity.

Antigen-adjuvant combination could induce a protective and long-lasting anti-tumor immune response. However, exploiting system which could co-deliver melanoma antigen peptide Trp2 (Tyrosinase-related protein 2) and Toll-like-receptor-7 (TLR7) agonists imiquimod (R837) both are poor aqueous solubility is still challenging. Our new nanocomplex was explored for specific delivery of Trp2 and R837 into antigen-presenting cells (APCs). R837 was loaded into mannosylated-ß-cyclodextrin (Man-CD) to target dendritic cells (DCs) by binding mannose receptors (MR) on DCs. A fusion peptide (WT) was constructed by incorporating the amino acid region of TAT (cell-penetrating peptide) into Trp2 to improve the TAT-mediated intracellular efficiency. Negatively charged sodium alginate (SA), a biocompatible polymer, which can induce adjuvant responses by affecting the functions of DCs, was complexed with Man-CD/R837 and WT via physical adsorption. The optimized nanocomplex promoted the cellular uptake and showed remarkable efficacy to enhance the secreting of Th1-cytokines. This multi-functional nanocomplex system may allow effective targeting-codelivery of multi-hydrophobic drugs and be a promising subunit vaccine candidate as a potential prevention action of tumor.

Imiquimod-loaded nanoarchaeosomes as a promising immunotherapy against Trypanosoma cruzi infection.

The purpose of this study was to evaluate the efficacy of imiquimod-containing nanovesicles prepared with lipids extracted from the hyperhalophile archaebacterium Halorubrum tebenquichense (nanoARC-IMQ) to induce protection against Trypanosoma cruzi infection. The therapeutic efficacy of archaeolipid nanovesicles was assessed in an experimental murine model of acute infection with T. cruzi. The administration of nanoARQ-IMQ prevented mortality as compared to infected untreated animals, reduced parasitemia levels and diminished myocardial and musculoskeletal lesions in mice infected with a lethal strain of T. cruzi. Our findings suggest that the immunotherapy with nanoARC-IMQ has potential to limit the progression of Chagas disease.

Effect of Metamorphed Keratolytic Agent on the Behavior of Imiquimod Loaded Hybrid Vesicles Containing Gel.

The cost, side effects, and patient compliance-related issues of topically effective imiquimod have prevented its widespread acceptance. The present work intends to evaluate the feasibility of overcoming the shortcomings of poorly soluble and skin-penetrating immunomodulator by using biocompatible keratolytic agent with drug-loaded hybrid vesicles. Salicylic acid was complexed with phospholipid through simple mixing and incorporated into carbopol 940 gel containing drug-loaded vesicles, prepared by thin-film hydration method. The morphology, physicochemical properties, rheological behavior, release profile, and dermatokinetics of developed gel were compared with control gel (developed gel without keratolytic agent). In ex vivo drug release studies across the rat skin, there was significant increase in the steady-state permeation flux (Jss) and skin retention of drug from developed gel in comparison with control. There was favorable change in almost every evaluated dermatokinetic parameter. The innocuous nature of control gel had not changed on addition of skin structure-altering agent. The developed gel was found to be stable at room temperature and humidity for 1 year.

Imiquimod-oleic acid prodrug-loaded cream reduced drug crystallinity and induced indistinguishable cytotoxicity and apoptosis in mice melanoma tumour.

In the present investigation, imiquimod (IMQ) was coupled to oleic acid (OLA; IMQ-OLA) to synthesise prodrug to reduce crystallinity that later amalgamated with oil-in-water (o/w) emulsion cream (IMQ-OLA cream) for the treatment of melanoma tumour. The synthesis of IMQ-OLA prodrug was verified by FT-IR, 1HNMR and mass spectroscopy. The crystalline lattice of IMQ was transformed to somewhat amorphous structure in IMQ-OLA prodrug. IMQ-OLA cream retained 35.6% of IMQ within skin, significantly (p < 0.05) higher than 22.3% and 10.6% retained by marketed IMQ cream and IMQ solution, respectively. IMQ-OLA cream suppressed the melanoma tumour to 70.3 mm3 in C57BL6J mice as compared to 72.6 mm3 tumour, reduced by marketed IMQ cream with no significant difference (p > 0.05) at day 32 over 17-day period of treatment. IMQ-OLA cream followed the multiple mechanisms of cell death. IMQ-OLA cream warrants further in depth investigations for translating in to a clinically viable topical dermal product.

Selectively targeting tumor-associated macrophages and tumor cells with polymeric micelles for enhanced cancer chemo-immunotherapy.

Tumor-associated macrophage (TAM)-related immunotherapy is a greatly promising strategy that involves altering the immunosuppressive tumor microenvironment with the immunomodulator imiquimod (R837) for enhanced cancer therapy. However, the function of R837 is seriously limited due to poor water solubility and a lack of targeting ability. Here, we developed two types of targeting polymer micelles to separately deliver R837 and the anticancer drug doxorubicin (DOX) to TAMs and tumor cells via intratumoral injection and intravenous injection, respectively, for enhanced cancer chemo-immunotherapy against breast cancer. After these micelles accumulated in the tumor tissues, the immunostimulating micelles released R837, which bound to the TLR-7 receptor on the lysosomal membrane within the TAM, stimulating the maturation of the TAM, thereby causing an antitumor immune response and relieving the immunosuppressive effect in the tumor microenvironment. Simultaneously, the chemotherapeutic micelles released DOX in the cytoplasm of the tumor cells, directly inducing cell death. As a result, a synergistic combination of chemotherapy and immunotherapy was achieved through these nanomedicines, which separately activated the antitumor immune response and inhibited tumor cell growth. Therefore, this strategy is a new avenue for the development of targeting nanomedicines for combination chemo-immunotherapy against malignant cancer.

Developing a novel sensor based on ionic liquid molecularly imprinted polymer/gold nanoparticles/graphene oxide for the selective determination of an anti-cancer drug imiquimod.

Despite its useful properties, imiquimod (IMQ), known as an anti-cancer drug, can be harmful to the skin at high concentrations. Therefore, we have developed a novel electrochemical sensor to determine IMQ, for the first time. A glassy carbon electrode (GCE) was modified by a new composite comprising of ionic liquid-based molecularly imprinted polymer (MIP) and gold nanoparticles/graphene oxide (Au/GO). The MIP/Au/GO nanocomposite was synthesized through non-covalent imprinting process in the presence of IMQ, as template molecule and characterized by SEM and FT-IR. The square wave voltammetry technique (SWV) was applied for IMQ determination in 0.1 M phosphate buffer solution (PBS) at pH 7.0. Several parameters affecting the IMQ quantification were evaluated and optimized. Under the optimized conditions, the sensor presented a linear range of 0.02-20.0 µM, a limit of quantification and detection of 0.02 µM and 0.006 µM, respectively. Low RSD values indicate the good repeatability and reproducibility of the modified electrodes in preparation and determination procedures. The satisfactory results indicated that the proposed sensor could be successfully applied for IMQ determination in real samples.

Conjugation of a Small-Molecule TLR7 Agonist to Silica Nanoshells Enhances Adjuvant Activity.

Stimulation of Toll-like receptors (TLRs) and/or NOD-like receptors on immune cells initiates and directs immune responses that are essential for vaccine adjuvants. The small-molecule TLR7 agonist, imiquimod, has been approved by the FDA as an immune response modifier but is limited to topical application due to its poor pharmacokinetics that causes undesired adverse effects. Nanoparticles are increasingly used with innate immune stimulators to mitigate side effects and enhance adjuvant efficacy. In this study, a potent small-molecule TLR7 agonist, 2-methoxyethoxy-8-oxo-9-(4-carboxybenzyl)adenine (1V209), was conjugated to hollow silica nanoshells (NS). Proinflammatory cytokine (IL-6, IL-12) release by mouse bone-marrow-derived dendritic cells and human peripheral blood mononuclear cells revealed that the potency of silica nanoshells-TLR7 conjugates (NS-TLR) depends on nanoshell size and ligand coating density. Silica nanoshells of 100 nm diameter coated with a minimum of ∼6000 1V209 ligands/particle displayed 3-fold higher potency with no observed cytotoxicity when compared to an unconjugated TLR7 agonist. NS-TLR activated the TLR7-signaling pathway, triggered caspase activity, and stimulated IL-1ß release, while neither unconjugated TLR7 ligands nor silica shells alone produced IL-1ß. An in vivo murine immunization study, using the model antigen ovalbumin, demonstrated that NS-TLR increased antigen-specific IgG antibody induction by 1000× with a Th1-biased immune response, compared to unconjugated TLR7 agonists. The results show that the TLR7 ligand conjugated to silica nanoshells is capable of activating an inflammasome pathway to enhance both innate immune-stimulatory and adjuvant potencies of the TLR7 agonist, thereby broadening applications of innate immune stimulators.

Stability Kinetics of Imiquimod: Development and Validation of an Analytical Method.

For a new immune modulator imiquimod, various liquid chromatography methods have been described in literature but all of them are deficient in one or other aspects of complete method development. The present work intends to develop and validate the stability indicating reverse phase high performance liquid chromatographic (HPLC) method. The isocratic flow of mobile phase comprising equal volume ratio of acetate buffer BP pH 3.7 and acetonitrile at the rate of 1.5 mL/min through the C-18 column at 25°C lead to elution of drug around 2.3 min when analyzed at 244 nm using UV-detector. The linear regression equation in calibration plot was y = 61632×-1224 with 0.9992 coefficient of determination (r2). The percent relative standard variation (% RSD) in peak area at low, mid and high region of linearity range was less than 5% in precision studies. The method was able to detect 0.039 µg/mL of drug but practical limit of quantitation (LOQ) was 1.5 µg/mL. The imiquimod molecule was stable in all except oxidizing conditions where it degraded into more polar molecule in hydrogen peroxide (H2O2) concentration dependent manner. Therefore, an analytical method capable of accurately and specifically estimating the drug in microgram range was successfully developed.

Co-delivery of antigen and dual agonists by programmed mannose-targeted cationic lipid-hybrid polymersomes for enhanced vaccination.

Exploiting Toll-like receptor (TLR) agonists or their certain combinations can enhance the immune potency of subunit vaccine. Nevertheless, the design of co-delivery systems which can act in a synergistic and spatio-temporal way to achieve effective and durable specific immune response is still challenging. Here we fabricated mannose-functionalized lipid-hybrid polymersomes (MAN-IMO-PS) for co-delivery of ovalbumin antigen both inside the inner core and outside the lipid layer, TLR7/8 agonist imiquimod within the hydrophobic membrane, TLR4 agonist monophosphoryl lipid A in the lipid layer as programmed nanovaccine to synergistically activate immune responses for improving vaccine efficacy. After efficiently internalized by dendritic cells via mannose targeting and TLR4 ligating, MAN-IMO-PS significantly enhanced cross-presentation and cytokine production. In addition, MAN-IMO-PS showed depot effect at the injection site and enhanced migration to draining lymph nodes. Mice immunized with MAN-IMO-PS elicited greater lymphocyte activation, CD4+ and CD8+ T cell response, effector cytokines secretion, and induced Th-1 biased humoral responses. More importantly, prophylactic vaccination by MAN-IMO-PS significantly delayed tumor occurrence, suppressed tumor growth with prolonged survival, and achieved long-term immune effect. The present study demonstrates a rationally designed nanovaccine for combining antigen, different TLR agonists, and targeting moiety in a programmed manner to induce synergistic antitumor immune response.

Design, Development, and Characterization of Imiquimod-Loaded Chitosan Films for Topical Delivery.

Aldara™ (5% w/w imiquimod) topical cream is approved by the US FDA for the treatment of superficial basal cell carcinoma. However, the cream formulation suffers from dose variability, low drug availability due to the incomplete release, and poor patient compliance. To achieve sustained and complete release of imiquimod, chitosan films were prepared by casting using propylene glycol as a plasticizer. Chitosan films had appropriate physicochemical characteristics for wound dressing and excellent content uniformity and maintained the original physical form of imiquimod. Films were capable of releasing a defined dose of imiquimod over a period of 7 days. The bioactivity of imiquimod was not affected by its entrapment in chitosan matrix as indicated by the results of in vitro growth inhibition assay. In addition, the film formulation showed significantly (p Ë‚ 0.05) higher drug accumulation in the skin when compared to commercial cream formulation.