Combination of PEGylation and Cationization on Phospholipid-Coated Cyclosporine Nanosuspensions for Enhanced Ocular Drug Delivery.

Strong precorneal clearance mechanisms including reflex blink, constant tear drainage, and rapid mucus turnover constitute great challenges for eye drops for effective drug delivery to the ocular epithelium. In this study, cyclosporine A (CsA) for the treatment of dry eye disease (DED) was selected as the model drug. Two strategies, PEGylation for mucus penetration and cationization for potent cellular uptake, were combined to construct a novel CsA nanosuspension (NS@lipid-PEG/CKC) by coating nanoscale drug particles with a mixture of lipids, DSPE-PEG2000, and a cationic surfactant, cetalkonium chloride (CKC). NS@lipid-PEG/CKC with the mean size ∼173 nm and positive zeta potential ∼+40 mV showed promoted mucus penetration, good cytocompatibility, more cellular uptake, and prolonged precorneal retention without obvious ocular irritation. More importantly, NS@lipid-PEG/CKC recovered tear production and goblet cell density more efficiently than the commercial cationic nanoemulsion on a dry eye disease rat model. All results indicated that a combination of PEGylation and cationization might provide a promising strategy to coordinate mucus penetration and cellular uptake for enhanced drug delivery to the ocular epithelium for nanomedicine-based eye drops.

All-stage targeted red blood cell membrane-coated docetaxel nanocrystals for glioma treatment.

Challenges for glioma treatment with nanomedicines include physio-anatomical barriers (the blood-brain barrier and blood-brain tumor barrier), low drug loading capacity, and limited circulation time. Here, a red blood cell membrane-coated docetaxel drug nanocrystal (pV-RBCm-NC(DTX)), modified with pHA-VAP (pV) for all-stage targeting of glioma, was designed. The NC(DTX) core exhibited a high drug loading capacity but low in vivo stability, and the RBCm coating significantly enhanced the stability and prolonged in vivo circulation. Moreover, the Y-shaped targeting ligand pV was modified by a mild avidin-biotin interaction, which endowed RBCm-NC(DTX) with superior barrier-crossing ability and therapeutic efficacy. The integration of nanocrystal technology, cell membrane coating, and the avidin-biotin insertion method into this active targeting biomimetic formulation represents a promising drug delivery strategy for glioma.

A novel peptide-drug conjugate for glioma-targeted drug delivery.

The existence of the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB) greatly limits the application of chemotherapy in glioma. To address this challenge, an optimal drug delivery system must efficiently cross the BBB/BBTB and specifically deliver therapeutic drugs into glioma cells while minimizing systemic toxicity. Here we demonstrated that glucose-regulated protein 78 (GRP78) and dopamine receptor D2 were highly expressed in patient-derived glioma tissues, and dopamine receptors were highly expressed on the BBB. Subsequently, we synthesized a novel "Y"-shaped peptide and compared the effects of different linkers on the receptor affinity and targeting ability of the peptide. A peptide-drug conjugate (pHA-AOHX-VAP-doxorubicin conjugate, pHA-AOHX-VAP-DOX) with a better affinity for glioma cells and higher solubility was derived for glioma treatment. pHA-AOHX-VAP-DOX could cross both BBB and BBTB via dopamine receptor and GRP78 receptor, and finally target glioma cells, significantly prolonging the survival time of nude mice bearing intracranial glioma. Furthermore, pHA-AOHX-VAP-DOX significantly reduced the toxicity of DOX and increased the maximum tolerated dose (MTD). Collectively, this work paves a new avenue for overcoming multiple barriers and effectively delivering chemotherapeutic agents to glioma cells while providing key evidence to identify potential receptors for glioma-targeted drug delivery.

Cryo-Milled ß-Glucan Nanoparticles for Oral Drug Delivery.

Gemcitabine is a nucleoside analog effective against a number of cancers. However, it has an oral bioavailability of less than 10%, due to its high hydrophilicity and low permeability through the intestinal epithelium. Therefore, the aim of this project was to develop a novel nanoparticulate drug delivery system for the oral delivery of gemcitabine to improve its oral bioavailability. In this study, gemcitabine-loaded ß-glucan NPs were fabricated using a film-casting method followed by a freezer-milling technique. As a result, the NPs showed a small particle size of 447.6 ± 14.2 nm, and a high drug entrapment efficiency of 64.3 ± 2.1%. By encapsulating gemcitabine into ß-glucan NPs, a sustained drug release profile was obtained, and the anomalous diffusion release mechanism was analyzed, indicating that the drug release was governed by diffusion through the NP matrix as well as matrix erosion. The drug-loaded NPs had a greater ex vivo drug permeation through the porcine intestinal epithelial membrane compared to the plain drug solution. Cytotoxicity studies showed a safety profile of the ß-glucan polymers, and the IC50s of drug solution and drug-loaded ß-glucan NPs were calculated as 228.8 ± 31.2 ng·mL-1 and 306.1 ± 46.3 ng·mL-1, respectively. Additionally, the LD50 of BALB/c nude mice was determined as 204.17 mg/kg in the acute toxicity studies. Notably, pharmacokinetic studies showed that drug-loaded ß-glucan NPs could achieve a 7.4-fold longer T1/2 and a 5.1-fold increase in oral bioavailability compared with plain drug solution. Finally, in vivo pharmacodynamic studies showed the promising capability of gemcitabine-loaded ß-glucan NPs to inhibit the 4T1 breast tumor growth, with a 3.04- and 1.74-fold reduction compared to the untreated control and drug solution groups, respectively. In conclusion, the presented freezer-milled ß-glucan NP system is a suitable drug delivery method for the oral delivery of gemcitabine and demonstrates a promising potential platform for oral chemotherapy.

Recent advances in nanocrystal-based technologies applied for ocular drug delivery.

INTRODUCTION: The intricate physiological barriers of the eye and the limited volume of eye drops impede efficient delivery of poorly water-soluble drugs. In the last decade, nanocrystals have emerged as versatile drug delivery systems in various administration routes from bench to bedside. The unique superiorities of nanocrystals, mainly embodied in high drug-loading capacity, good mucosal adhesion and penetration, and greatly improved drug solubility, reveal a promising prospect for ocular delivery of poorly water-soluble drugs. AREAS COVERED: This article focuses on the ophthalmic nanocrystal technologies and products that are in the literature, clinical trials, and even on the market. The recent research progress in the preparation, ocular application, and absorption of nanocrystals are highlighted, and the pros and cons of nanocrystals in overcoming the physiological barriers of the eye are also summarized. EXPERT OPINION: Nanocrystals have demonstrated success as glucocorticoid eye drops in the treatment of anterior segment diseases. However, the thermodynamic stability of nanocrystals remains the major challenge in product development. New technologies for efficiently optimizing stabilizers and sterilization processes are still expected. Strategies to confer more diverse functions via surface modification are also worth exploration to improve the potential of nanocrystals in delivering poorly water-soluble drugs to posterior segment of the eye.

Intranasal G5-BGG/pDNA Vaccine Elicits Protective Systemic and Mucosal Immunity against SARS-CoV-2 by Transfecting Mucosal Dendritic Cells.

Infectious disease pandemics, including the coronavirus disease 2019 pandemic, have heightened the demand for vaccines. Although parenteral vaccines induce robust systemic immunity, their effectiveness in respiratory mucosae is limited. Considering the crucial role of nasal-associated lymphoid tissue (NALT) in mucosal immune responses, in this study, the intranasal complex composed of G5-BGG and antigen-expressing plasmid DNA (pSP), named G5-BGG/pSP complex, is developed to activate NALT and to promote both systemic and mucosal immune defense. G5-BGG/pSP could traverse mucosal barriers and deliver DNA to the target cells because of its superior nasal retention and permeability characteristics. The intranasal G5-BGG/pSP complex elicits robust antigen-specific immune responses, such as the notable production of IgG antibody against several virus variants. More importantly, it induces elevated levels of antigen-specific IgA antibody and a significant expansion of the lung-resident T lymphocyte population. Notably, the intranasal G5-BGG/pSP complex results in antigen expression and maturation of dendritic cells in nasal mucosae. These findings exhibit the potential of G5-BGG, a novel cationic material, as an effective gene carrier for intranasal vaccines to obtain robust systemic and mucosal immunity.

Erratum: Author correction to 'Amino-functionalized poloxamer 407 with both mucoadhesive and thermosensitive properties: Preparation, characterization and application in vaginal drug delivery system' [Acta Pharm Sin B 7 (2017) 593-602].

[This corrects the article DOI: 10.1016/j.apsb.2017.03.002.].

Correction: Ci et al. Enhanced Delivery of Imatinib into Vaginal Mucosa via a New Positively Charged Nanocrystal-Loaded in Situ Hydrogel Formulation for Treatment of Cervical Cancer. Pharmaceutics 2019, 11, 15.

In the original publication [...].

Advance in Nanomedicine for Improving Mucosal Penetration and Effective Therapy of Cervical Cancer.

Insufficient intratumor drug distribution and serious adverse effects are often associated with systemic chemotherapy for cervical cancer. Considering the location of cervical cancer, access to the cervix through the vagina may provide an alternative administration route for high drug amounts at the tumor site, minimal systemic exposure as well as convenience of non-invasive self-medication. Enormous progress has been made in nanomedicine to improve mucosal penetration and enhance the effectiveness of therapy for cervical cancer. This review article first introduce the physiological state of cervicovaginal cavity and the characteristics of intravaginal environment in cervical cancers. Based on introduction to the physiological state of cervicovaginal cavity and the characteristics of intravaginal environment in cervical cancers, both "first mucus-adhering then mucosal penetration" and "first mucus-penetrating then mucosal penetration" strategies are discussed with respect to mechanism, application condition, and examples. Finally, existing challenges and future directions are envisioned in the rational design, facile synthesis, and comprehensive utilization of nanomedicine for local therapy of cervical cancer. This review is expected to provide useful reference information for future research on nanomedicine for intravaginally administered formulations for topical treatment of cervical cancer.

Ocular therapies with biomacromolecules: From local injection to eyedrop and emerging noninvasive delivery strategies.

The last two decades have witnessed a continuously increasing number of biomacromolecules approved for the treatment of ocular diseases. The eye possesses multiple protective mechanisms to resist the invasion of exogenous substances, but meanwhile these physiological defense systems also act as strong barriers, impeding absorption of most biomacromolecules into the eye. As a result, local injections play predominant roles for posterior ocular delivery of biomacromolecules in clinical practice. To achieve safe and convenient application of biomacromolecules, alternative strategies to realize noninvasive intraocular delivery are necessary. Various nanocarriers, novel penetration enhancers and physical strategies have been explored to facilitate delivery of biomacromolecules to both anterior and posterior ocular segments but still suffered difficulties in clinical translation. This review compares the anatomical and physiological characteristics of the eyes from those frequently adopted experimental species and profiles the well-established animal models of ocular diseases. We also summarize the ophthalmic biomacromolecules launched on the market and put emphasis on emerging noninvasive intraocular delivery strategies of peptides, proteins and genes.

Biological evaluation of a novel stable peptide PET molecular probe [18F]AlF-NOTA-DVAP targeting to tumor cell surface GRP78.

BACKGROUNDS: Glucose-Regulated Protein 78 (GRP78) is an attractive anticancer target for its selective anchoring on the surface of tumor cells and cancer endothelial cells rather than normal cells. Cell-surface GRP78 overexpression of tumor indicates that GRP78 is a crucial target for relative tumor imaging and clinical treatment. Herein, we report the design and preclinical evaluation of a new D peptide ligand [18F]AlF-NOTA-DVAP recognizing GRP78 expressed on the cell surface of breast cancer. METHODS: Radiochemical synthesis of [18F]AlF-NOTA-DVAP was achieved via a one-pot labeling process by heating NOTA-DVAP in the presence of in situ prepared [18F]AlF for 15 min at 110 °C and purified through HPLC. RESULTS: The radiotracer showed high in vitro stability in rat serum at 37 °C over 3 h. Both biodistribution studies and in vivo micro-PET/CT imaging studies in BALB/c mice bearing 4 T1 tumor showed [18F]AlF-NOTA-DVAP had a rapid and high uptake in tumor, as well as a long residence time. The high hydrophilicity of the radiotracer enables its fast clearance from most normal tissues and thus improves the tumor-to-normal tissue ratios (4.40 at 60 min) which is better than [18F]FDG (1.31 at 60 min). Pharmacokinetic studies showed the average in vivo mean residence time of the radiotracer was just 0.6432 h and indicated that this hydrophilic radiotracer was quickly eliminated from the body to reduce the distribution of non-target tissues. CONCLUSIONS: These results suggest that [18F]AlF-NOTA-DVAP is a very promising PET probe for tumor-specific imaging of cell-surface GRP78-positive tumor.

Targeting cerebral diseases with enhanced delivery of therapeutic proteins across the blood-brain barrier.

INTRODUCTION: Cerebral diseases have been threatening public physical and psychological health in the recent years. With the existence of the blood-brain barrier (BBB), it is particularly hard for therapeutic proteins like peptides, enzymes, antibodies, etc. to enter the central nervous system (CNS) and function in diagnosis and treatment in cerebral diseases. Fortunately, the past decade has witnessed some emerging strategies of delivering macromolecular therapeutic proteins across the BBB. AREAS COVERED: Based on the structure, functions, and substances transport mechanisms, various enhanced delivery strategies of therapeutic proteins were reviewed, categorized by molecule-mediated delivery strategies, carrier-mediated delivery strategies, and other delivery strategies. EXPERT OPINION: As for molecule-mediated delivery strategies, development of genetic engineering technology, optimization of protein expression and purification techniques, and mature of quality control systems all help to realize large-scale production of recombinant antibodies, making it possible to apply to the clinical practice. In terms of carrier-mediated delivery strategies and others, although nano-carriers/adeno-associated virus (AAV) are also promising candidates for delivering therapeutic proteins or genes across the BBB, some issues still remain to be further investigated, including safety concerns related to applied materials, large-scale production costs, quality control standards, combination therapies with auxiliary delivery strategies like focused ultrasound, etc.

Intraocular siRNA Delivery Mediated by Penetratin Derivative to Silence Orthotopic Retinoblastoma Gene.

Gene therapy brings a ray of hope for inherited ocular diseases that may cause severe vision loss and even blindness. However, due to the dynamic and static absorption barriers, it is challenging to deliver genes to the posterior segment of the eye by topical instillation. To circumvent this limitation, we developed a penetratin derivative (89WP)-modified polyamidoamine polyplex to deliver small interference RNA (siRNA) via eye drops to achieve effective gene silencing in orthotopic retinoblastoma. The polyplex could be spontaneously assembled through electrostatic and hydrophobic interactions, as demonstrated by isothermal titration calorimetry, and enter cells intactly. In vitro cellular internalization revealed that the polyplex possessed higher permeability and safety than the lipoplex composed of commercial cationic liposomes. After the polyplex was instilled in the conjunctival sac of the mice, the distribution of siRNA in the fundus oculi was significantly increased, and the bioluminescence from orthotopic retinoblastoma was effectively inhibited. In this work, an evolved cell-penetrating peptide was employed to modify the siRNA vector in a simple and effective way, and the formed polyplex interfered with intraocular protein expression successfully via noninvasive administration, which showed a promising prospect for gene therapy for inherited ocular diseases.

All-stage targeted therapy for the brain metastasis from triple-negative breast cancer.

Brain metastasis is a common and serious complication of breast cancer, which is commonly associated with poor survival and prognosis. In particular, the treatment of brain metastasis from triple-negative breast cancer (BM-TNBC) has to face the distinct therapeutic challenges from tumor heterogeneity, circulating tumor cells (CTCs), blood-brain barrier (BBB) and blood-tumor barrier (BTB), which is in unmet clinical needs. Herein, combining with the advantages of synthetic and natural targeting moieties, we develop a "Y-shaped" peptide pVAP-decorated platelet-hybrid liposome drug delivery system to address the all-stage targeted drug delivery for the whole progression of BM-TNBC. Inherited from the activated platelet, the hybrid liposomes still retain the native affinity toward CTCs. Further, the peptide-mediated targeting to breast cancer cells and transport across BBB/BTB are demonstrated in vitro and in vivo. The resultant delivery platform significantly improves the drug accumulation both in orthotopic breast tumors and brain metastatic lesions, and eventually exhibits an outperformance in the inhibition of BM-TNBC compared with the free drug. Overall, this work provides a promising prospect for the comprehensive treatment of BM-TNBC, which could be generalized to other cell types or used in imaging platforms in the future.

Influence of lung cancer model characteristics on tumor targeting behavior of nanodrugs.

Evidence is mounting that there is a significant gap between the antitumor efficacy of nanodrugs in preclinical mouse tumor models and in clinical human tumors, and that differences in tumor models are likely to be responsible for this gap. Herein, we investigated the enhanced permeability and retention (EPR) effect in mouse lung cancer models with different tumor growth rates, volumes and locations, and analyzed the nanodrug tumor targeting behaviors limited by tumor vascular pathophysiological characteristics in various tumor models. The results showed that the fast-growing tumors were characterized by lower vascular tight junctions, leading to higher vascular paracellular transport activity and nanodrug tumor accumulation. The paracellular transport activity increased with the growth of tumor, but the vascular density and transcellular transport activity decreased, and as a result, the average tumor accumulation of passive targeting nanodrugs decreased. Orthotopic tumors were rich in blood vessels, but had low vascular transcellular and paracellular transport activities, making it difficult for nanodrug accumulation in orthotopic tumors via passive targeting strategies. The antitumor efficacy of passive targeting nanodrugs in various lung cancer-bearing mice validated the aforementioned nanodrug accumulation behavior, and nanodrugs based on the angiogenesis-tumor sequential targeting strategy achieved obviously improved efficacy in orthotopic lung cancer-bearing mice. These results suggest that the EPR effect varies in different tumor models and should not be used as a universal targeting strategy for antitumor nanodrugs. Besides, attention should be paid to the animal tumor models in the evaluation of nanodrugs so as to avoid exaggerating the antitumor efficacy.

Correction to "Folic acid-conjugated liposomal vincristine for multidrug resistant cancer therapy".

[This corrects the article DOI: 10.1016/j.ajps.2013.07.015.].

Engineered platelets-based drug delivery platform for targeted thrombolysis.

Thrombolytic agents have thus far yielded limited therapeutic benefits in the treatment of thrombotic disease due to their short half-life, low targeting ability, and association with serious adverse reactions, such as bleeding complications. Inspired by the natural roles of platelets during thrombus formation, we fabricated a platelet-based delivery system (NO@uPA/PLTs) comprising urokinase (uPA) and arginine (Arg) for targeted thrombolysis and inhibition of re-embolism. The anchoring of uPA to the platelet surface by lipid insertion increased the thrombotic targeting and in vivo circulation duration of uPA without disturbing platelet functions. Nitric oxide (NO) generated by the loaded Arg inhibited platelet aggregation and activation at the damaged blood vessel, thereby inhibiting re-embolism. NO@uPA/PLTs effectively accumulated at the thrombi in pulmonary embolism and carotid artery thrombosis model mice and exerted superior thrombolytic efficacy. In addition, the platelet delivery system showed excellent thrombus recurrence prevention ability in a mouse model of secondary carotid artery injury. The coagulation indicators in vivo showed that the platelet-based uPA and NO co-delivery system possessed a low hemorrhagic risk, providing a promising tool for rapid thrombolysis and efficient inhibition of posttreatment re-embolism.

Drug Nanocrystals for Active Tumor-Targeted Drug Delivery.

Drug nanocrystals, which are comprised of active pharmaceutical ingredients and only a small amount of essential stabilizers, have the ability to improve the solubility, dissolution and bioavailability of poorly water-soluble drugs; in turn, drug nanocrystal technology can be utilized to develop novel formulations of chemotherapeutic drugs. Compared with passive targeting strategy, active tumor-targeted drug delivery, typically enabled by specific targeting ligands or molecules modified onto the surface of nanomedicines, circumvents the weak and heterogeneous enhanced permeability and retention (EPR) effect in human tumors and overcomes the disadvantages of nonspecific drug distribution, high administration dosage and undesired side effects, thereby contributing to improving the efficacy and safety of conventional nanomedicines for chemotherapy. Continuous efforts have been made in the development of active tumor-targeted drug nanocrystals delivery systems in recent years, most of which are encouraging and also enlightening for further investigation and clinical translation.

Topical instillation of cell-penetrating peptide-conjugated melphalan blocks metastases of retinoblastoma.

Retinoblastoma is the most common primary intraocular malignancy in infancy with a metastases-related death risk. However, a safe and convenient treatment without enucleation is still an unmet clinical need. In this work, a cell-penetrating peptide, 89WP, was conjugated with melphalan (89WP-Mel), which achieved high tumor inhibition effects as intravitreally injected melphalan via topical instillation for the first time. Notably, the "outside-in" diffusion of instilled 89WP-Mel created a protective shield surrounding the eye, efficiently preventing tumor metastases, while the mice treated with intravitreally injected melphalan suffered more brain metastases related death. The ocular absorption of 89WP-conjugated melphalan and other small molecules, both hydrophobic and hydrophilic, occurred via non-corneal pathway with high safety and a prolonged residence duration in retina up to 24 h. The present work paves a new avenue for simultaneous intraocular tumor inhibition and extraocular metastases prevention in a safe and convenient way via topical instillation.

In vivo self-assembled drug nanocrystals for metastatic breast cancer all-stage targeted therapy.

Chemotherapy is still the mainstay treatment for metastatic triple-negative breast cancers (TNBC) currently in clinical practice. The unmet needs of chemotherapy for metastatic TNBC are mainly from the insufficient drug delivery and unavailable targeting strategy that thwart the whole progression of metastatic TNBC. The in vivo ligands-mediated active targeting efficiency is usually affected by protein corona. While, the protein corona-bridged natural targeting, in turn, provides a new way for specific drug delivery. Herein, we develop a novel metastatic progression-oriented in vivo self-assembled Cabazitaxel nanocrystals (CNC) delivery system (PC/CNC) through the CNC automatically absorbing functional plasma proteins (transferrin, apolipoprotein A-IV and apolipoprotein E) in vivo, aiming to achieve the simultaneously targeted delivery to primary tumors, circulating tumor cells and metastatic lesions. With the unique advantages of superhigh drug-loading and protein corona empowered active targeting properties to tumor cells, HUVECs, active-platelets and blood-brain barrier/blood-tumor barrier, the PC/CNC exhibits a significantly improved therapeutic effect in metastatic TNBC therapy compared with free drug and CNC-loaded liposomes.