The First Scale-Up Production of Theranostic Nanoemulsions

Novel Therapeutic Hybrid Systems Using Hydrogels and Nanotechnology: A Focus on Nanoemulgels for the Treatment of Skin Diseases

Topical and transdermal drug delivery are advantageous administration routes, especially when treating diseases and conditions with a skin etiology. Nevertheless, conventional dosage forms often lead to low therapeutic efficacy, safety issues, and patient noncompliance. To tackle these issues, novel topical and transdermal platforms involving nanotechnology have been developed. This review focuses on the latest advances regarding the development of nanoemulgels for skin application, encapsulating a wide variety of molecules, including already marketed drugs (miconazole, ketoconazole, fusidic acid, imiquimod, meloxicam), repurposed marketed drugs (atorvastatin, omeprazole, leflunomide), natural-derived compounds (eucalyptol, naringenin, thymoquinone, curcumin, chrysin, brucine, capsaicin), and other synthetic molecules (ebselen, tocotrienols, retinyl palmitate), for wound healing, skin and skin appendage infections, skin inflammatory diseases, skin cancer, neuropathy, or anti-aging purposes. Developed formulations revealed adequate droplet size, PDI, viscosity, spreadability, pH, stability, drug release, and drug permeation and/or retention capacity, having more advantageous characteristics than current marketed formulations. In vitro and/or in vivo studies established the safety and efficacy of the developed formulations, confirming their therapeutic potential, and making them promising platforms for the replacement of current therapies, or as possible adjuvant treatments, which might someday effectively reach the market to help fight highly incident skin or systemic diseases and conditions.

Folate-conjugated near-infrared fluorescent perfluorocarbon nanoemulsions as theranostics for activated macrophage COX-2 inhibition

Activated macrophages play a critical role in the orchestration of inflammation and inflammatory pain in several chronic diseases. We present here the first perfluorocarbon nanoemulsion (PFC NE) that is designed to preferentially target activated macrophages and can deliver up to three payloads (two fluorescent dyes and a COX-2 inhibitor). Folate receptors are overexpressed on activated macrophages. Therefore, we introduced a folate-PEG-cholesterol conjugate into the formulation. The incorporation of folate conjugate did not require changes in processing parameters and did not change the droplet size or fluorescent properties of the PFC NE. The uptake of folate-conjugated PFC NE was higher in activated macrophages than in resting macrophages. Flow cytometry showed that the uptake of folate-conjugated PFC NE occurred by both phagocytosis and receptor-mediated endocytosis. Furthermore, folate-conjugated PFC NE inhibited the release of proinflammatory cytokines (TNF-α and IL-6) more effectively than nonmodified PFC NE, while drug loading and COX-2 inhibition were comparable. The PFC NEs reported here were successfully produced on multiple scales, from 25 to 200 mL, and by using two distinct processors (microfluidizers: M110S and LM20). Therefore, folate-conjugated PFC NEs are viable anti-inflammatory theranostic nanosystems for macrophage drug delivery and imaging.

Targeting Neuroimmune Interactions in Diabetic Neuropathy with Nanomedicine

Significance: Diabetes is a major source of neuropathy and neuropathic pain that is set to continue growing in prevalence. Diabetic peripheral neuropathy (DPN) and pain associated with diabetes are not adequately managed by current treatment regimens. Perhaps the greatest difficulty in treating DPN is the complex pathophysiology, which involves aspects of metabolic disruption and neurotrophic deficits, along with neuroimmune interactions. There is, therefore, an urgent need to pursue novel therapeutic options targeting the key cellular and molecular players. Recent Advances: To that end, cellular targeting becomes an increasingly compelling drug delivery option as our knowledge of neuroimmune interactions continues to mount. These nanomedicine-based approaches afford a potentially unparalleled specificity and longevity of drug targeting, using novel or established compounds, all while minimizing off-target effects. Critical Issues: The DPN therapeutics directly targeted at the nervous system make up the bulk of currently available treatment options. However, there are significant opportunities based on the targeting of non-neuronal cells and neuroimmune interactions in DPN. Future Directions: Nanomedicine-based agents represent an exciting opportunity for the treatment of DPN with the goals of improving the efficacy and safety profile of analgesia, as well as restoring peripheral neuroregenerative capacity. Antioxid. Redox Signal. 36, 122-143.

Quality by Design Methodology Applied to Process Optimization and Scale up of Curcumin Nanoemulsions Produced by Catastrophic Phase Inversion

In the presented study, we report development of a stable, scalable, and high-quality curcumin-loaded oil/water (o/w) nanoemulsion manufactured by concentration-mediated catastrophic phase inversion as a low energy nanoemulsification strategy. A design of experiments (DoE) was constructed to determine the effects of process parameters on the mechanical input required to facilitate the transition from the gel phase to the final o/w nanoemulsion and the long-term effects of the process parameters on product quality. A multiple linear regression (MLR) model was constructed to predict nanoemulsion diameter as a function of nanoemulsion processing parameters. The DoE and subsequent MLR model results showed that the manufacturing process with the lowest temperature (25 °C), highest titration rate (9 g/minute), and lowest stir rate (100 rpm) produced the highest quality nanoemulsion. Both scales of CUR-loaded nanoemulsions (100 g and 500 g) were comparable to the drug-free optimal formulation with 148.7 nm and 155.1 nm diameter, 0.22 and 0.25 PDI, and 96.29 ± 0.76% and 95.60 ± 0.88% drug loading for the 100 g and 500 g scales, respectively. Photostability assessments indicated modest loss of drug (<10%) upon UV exposure of 24 h, which is appropriate for intended transdermal applications, with expected reapplication of every 6-8 h.

Quality by design approach identifies critical parameters driving oxygen delivery performance in vitro for perfluorocarbon based artificial oxygen carriers

Perfluorocarbons (PFCs) exhibiting high solubility for oxygen are attractive materials as artificial oxygen carriers (AOC), an alternative to whole blood or Haemoglobin-based oxygen carriers (HBOCs). PFC-based AOCs, however, met clinical translation roadblocks due to product quality control challenges. To overcome these issues, we present an adaptation of Quality by Design (QbD) practices to optimization of PFC nanoemulsions (PFC-NEs) as AOCs. QbD elements including quality risk management, design of experiments (DoE), and multivariate data analysis facilitated the identification of composition and process parameters that strongly impacted PFC colloidal stability and oxygen transport function. Resulting quantitative relationships indicated a composition-driven tradeoff between stability and oxygen transport. It was found that PFC content was most predictive of in vitro oxygen release, but the PFC type (perfluoro-15-crown-5-ether, PCE or perfluorooctyl bromide, PFOB) had no effect on oxygen release. Furthermore, we found, under constant processing conditions, all PFC-NEs, comprised of varied PFC and hydrocarbon content, exhibited narrow droplet size range (100–150 nm) and narrow size distribution. Representative PFOB-NE maintained colloidal attributes upon manufacturing on larger scale (100 mL). QbD approach offers unique insights into PFC AOC performance, which will overcome current product development challenges and accelerate clinical translation.

Therapeutic Nanoemulsion: Concept to Delivery

Nanoemulsions (NEs) or nanometric-scaled emulsions are transparent or translucent, optically isotropic and kinetically stable heterogeneous system of two different immiscible liquids namely, water and oil stabilized with an amphiphilic surfactant having droplet size ranges up to 100 nm. They offer a variety of potential interests for certain applications: improved deep-rooted stability; excellent optical clarity; and, enhanced bioavailability due to its nanoscale of particles. Though there is still comparatively narrow insight apropos design, development, and optimization of NEs, which mainly stems from the fact that conventional characteristics of emulsion development and stabilization only partly apply to NEs. The contemporary article focuses on the nanoemulsion dosage form journey from concept to key application in drug delivery. In addition, industrial scalability of the nanoemulsion, as well as its presence in commercial and clinical practice, are also addressed.

Design of Thermoresponsive Polyamine Cross-Linked Perfluoropolyether Hydrogels for Imaging and Delivery Applications

Perfluorocarbons are versatile compounds with applications in ¹⁹F magnetic resonance imaging (MRI) and chemical conjugation to drugs and pH sensors. We present a novel thermoresponsive perfluorocarbon emulsion hydrogel that can be detected by ¹⁹F MRI. The developed hydrogel contains perfluoro(polyethylene glycol dimethyl ether) (PFPE) emulsion droplets that are stabilized through ionic cross-linking with polyethylenimine (PEI). Specifically, PFPE ester undergoes hydrolysis upon contact with aqueous PEI solution, resulting in an ionic bond between the PFPE acid and charged PEI amino groups. Due to the ionic nature of the PFPE/PEI bond, potassium buffer is required to preserve the hydrogel's pH and rheological and emulsion droplet stability. The presence of the surface cross-linked PFPE droplets does not affect the hydrogel's rheological behavior, drug loading, or drug release, and the hydrogel is nontoxic. We propose that the presented hydrogel can be adapted to a broad range of biomedical imaging and delivery applications.

Theranostic application of nanoemulsions in chemotherapy

Theranostics has the potential to revolutionize the diagnosis, treatment, and prognosis of cancer, where novel drug delivery systems could be used to detect the disease at an early stage with instantaneous treatment. Various preclinical approaches of nanoemulsions with entrapped contrast and chemotherapeutic agents have been documented to act specifically on the tumor microenvironment (TME) for both diagnostic and therapeutic purposes. However, bringing these theranostic nanoemulsions through preclinical trials to patients requires several fundamental hurdles to be overcome, including the in vivo behavior of the delivery tool, degradation, and clearance from the system, as well as long-term toxicities. Here, we discuss recent advances in the application of nanoemulsions in molecular imaging with simultaneous therapeutic efficacy in a single delivery system.

Pharmaceutical design and development of perfluorocarbon nanocolloids for oxygen delivery in regenerative medicine

Perfluorocarbons (PFCs) have been investigated as oxygen carriers for several decades in varied biomedical applications. PFCs are chemically and biologically inert, temperature and storage stable, pose low to no infectious risk, can be commercially manufactured, and have well established gas transport properties. In this review, we highlight design and development strategies for their successful application in regenerative medicine, transplantation and organ preservation. Effective tissue preservation strategies are key to improving outcomes of extremity salvage and organ transplantation. Maintaining tissue integrity requires adequate oxygenation to support aerobic metabolism. The use of whole blood for oxygen delivery is fraught with limitations of poor shelf stability, infectious risk, religious exclusions and product shortages. Other agents also face clinical challenges in their implementation. As a solution, we discuss new ways of designing and developing PFC-based artificial oxygen carriers by implementing modern pharmaceutical quality by design and scale up manufacturing methodologies.

Nanomedicine-driven neuropathic pain relief in a rat model is associated with macrophage polarity and mast cell activation

We explored the immune neuropathology underlying multi-day relief from neuropathic pain in a rat model initiated at the sciatic nerve, by using a nanoemulsion-based nanomedicine as a biological probe. The nanomedicine is theranostic: both therapeutic (containing celecoxib drug) and diagnostic (containing near-infrared fluorescent (NIRF) dye) and is small enough to be phagocytosed by circulating monocytes. We show that pain-like behavior reaches a plateau of maximum hypersensitivity 8 days post-surgery, and is the rationale for intravenous delivery at this time-point. Pain relief is evident within 24 h, lasting approximately 6 days. The ipsilateral sciatic nerve and associated L4 and L5 dorsal root ganglia (DRG) tissue of both nanomedicine and control (nanoemulsion without drug) treated animals was investigated by immunofluorescence and confocal microscopy at the peak of pain relief (day-12 post-surgery), and when pain-like hypersensitivity returns (day-18 post-surgery). At day-12, a significant reduction of infiltrating macrophages, mast cells and mast cell degranulation was observed at the sciatic nerve following treatment. In the DRG, there was no effect of treatment at both day-12 and day-18. Conversely, at the DRG, there is a significant increase in macrophage infiltration and mast cell degranulation at day-18. The treatment effect on immune pathology in the sciatic nerve was investigated further by assessing the expression of macrophage cyclooxygenase-2 (COX-2)-the drug target-and extracellular prostaglandin E2 (PGE2), as well as the proportion of M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages. At day-12, there is a significant reduction of COX-2 positive macrophages, extracellular PGE2, and a striking reversal of macrophage polarity. At day-18, these measures revert to levels observed in control-treated animals. Here we present a new paradigm of immune neuropathology research, by employing a nanomedicine to target a mechanism of neuropathic pain-resulting in long-lasting pain relief--whilst revealing novel immune pathology at the injured nerve and associated DRG.

Multiple linear regression applied to predicting droplet size of complex perfluorocarbon nanoemulsions for biomedical applications

Multiple linear regression (MLR) modeling as a novel methodological advancement for design, development, and optimization of perfluorocarbon nanoemulsions (PFC NEs) is presented. The goal of the presented work is to develop MLR methods applicable to design, development, and optimization of PFC NEs in broad range of biomedical uses. Depending on the intended use of PFC NEs as either therapeutics or diagnostics, NE composition differs in respect to specific applications (e.g. magnetic resonance imaging, drug delivery, etc). PFC NE composition can significantly impact on PFC NE droplet size which impacts the NE performance and quality. We demonstrated earlier that microfluidization combined with sonication produces stable emulsions with high level of reproducibility. The goal of the presented work was to establish correlation between droplet size and composition in complex PFC-in-oil-in-water NEs while manufacturing process parameters are kept constant. Under these conditions, we demonstrate that MLR model can predict droplet size based on formulation variables such as amount and type of PFC oil and hydrocarbon oil. To the best of our knowledge, this is the first report where PFC NE composition was directly related to its colloidal properties and MLR used to predict colloidal properties from composition variables.

Perfluorocarbon nanodroplets can reoxygenate hypoxic tumors in vivo without carbogen breathing

Nanoscale perfluorocarbon (PFC) droplets have enormous potential as clinical theranostic agents. They are biocompatible and are currently used in vivo as contrast agents for a variety of medical imaging modalities, including ultrasound, computed tomography, photoacoustic and 19F-magnetic resonance imaging. PFC nanodroplets can also carry molecular and nanoparticulate drugs and be activated in situ by ultrasound or light for targeted therapy. Recently, there has been renewed interest in using PFC nanodroplets for hypoxic tumor reoxygenation towards radiosensitization based on the high oxygen solubility of PFCs. Previous studies showed that tumor oxygenation using PFC agents only occurs in combination with enhanced oxygen breathing. However, recent studies suggest that PFC agents that accumulate in solid tumors can contribute to radiosensitization, presumably due to tumor reoxygenation without enhanced oxygen breathing. In this study, we quantify the impact of oxygenation due to PFC nanodroplet accumulation in tumors alone in comparison with other reoxygenation methodologies, in particular, carbogen breathing. Methods: Lipid-stabilized, PFC (i.e., perfluorooctyl bromide, CF3(CF2)7Br, PFOB) nanoscale droplets were synthesized and evaluated in xenograft prostate (DU145) tumors in male mice. Biodistribution assessment of the nanodroplets was achieved using a fluorescent lipophilic indocarbocyanine dye label (i.e., DiI dye) on the lipid shell in combination with fluorescence imaging in mice (n≥3 per group). Hypoxia reduction in tumors was measured using PET imaging and a known hypoxia radiotracer, [18F]FAZA (n≥ 3 per group). Results: Lipid-stabilized nanoscale PFOB emulsions (mean diameter of ~250 nm), accumulated in the xenograft prostate tumors in mice 24 hours post-injection. In vivo PET imaging with [18F]FAZA showed that the accumulation of the PFOB nanodroplets in the tumor tissues alone significantly reduced tumor hypoxia, without enhanced oxygen (i.e., carbogen) breathing. This reoxygenation effect was found to be comparable with carbogen breathing alone. Conclusion: Accumulation of nanoscale PFOB agents in solid tumors alone successfully reoxygenated hypoxic tumors to levels comparable with carbogen breathing alone, an established tumor oxygenation method. This study confirms that PFC agents can be used to reoxygenate hypoxic tumors in addition to their current applications as multifunctional theranostic agents.

Development of Theranostic Perfluorocarbon Nanoemulsions as a Model Non-Opioid Pain Nanomedicine Using a Quality by Design (QbD) Approach

Pain nanomedicine is an emerging field in response to current needs of addressing the opioid crisis in the USA and around the world. Our group has focused on the development of macrophage-targeted perfluorocarbon nanoemulsions as inflammatory pain nanomedicines over the past several years. We present here, for the first time, a quality by design approach used to design pain nanomedicine. Specifically, we used failure mode, effects, and criticality analysis (FMECA) which identified the process and composition parameters that were most likely to impact nanoemulsion critical quality attributes (CQAs). From here, we applied a unique combination approach that compared multiple linear regression, boosted decision tree regression, and partial least squares regression methods in combination with correlation plots. The presented combination approach allowed for in-depth analyses of which formulation steps in the nanoemulsification processes control nanoemulsion droplet diameter, stability, and drug loading. We identified that increase in solubilizer (transcutol) content increased drug loading and decreased nanoemulsion stability. This was mitigated by inclusion of perfluorocarbon oil in the internal phase. We observed negative correlation (R² = 0.4357, p value 0.0054) between the amount of PCE and the percent diameter increase (destabilization), and no correlation between processing parameters and percent diameter increase over time. Further, we identified that increased sonication time decreases nanoemulsion drug loading but does not significantly impact droplet diameter or stability. We believe the methods presented here can be useful in the development of various nanomedicines to produce higher-quality products with enhanced manufacturing and design control.

Low-dose NSAIDs reduce pain via macrophage targeted nanoemulsion delivery to neuroinflammation of the sciatic nerve in rat

Neuroinflammation involving macrophages elevates Prostaglandin E₂, associated with neuropathic pain. Treatment with non-steroidal anti-inflammatory drugs (NSAIDs) inhibits cyclooxygenase, reducing PGE₂. However, NSAIDs cause physiological complications. We developed nanoemulsions incorporating celecoxib and near infrared dye. Intravenous injected nanoemulsion is incorporated into monocytes that accumulate at the injury; revealed in live animals by fluorescence. A single dose (celecoxib 0.24 mg/kg) provides targeted delivery in chronic constriction injury rats, resulting in significant reduction in the visualized inflammation, infiltration of macrophages, COX-2 and PGE₂. Animals exhibit relief from hypersensitivity persisting at least four-days. The total body burden of drug is reduced by >2000 fold over oral drug delivery.

Nanoemulsion: Concepts, development and applications in drug delivery

Nanoemulsions are biphasic dispersion of two immiscible liquids: either water in oil (W/O) or oil in water (O/W) droplets stabilized by an amphiphilic surfactant. These come across as ultrafine dispersions whose differential drug loading; viscoelastic as well as visual properties can cater to a wide range of functionalities including drug delivery. However there is still relatively narrow insight regarding development, manufacturing, fabrication and manipulation of nanoemulsions which primarily stems from the fact that conventional aspects of emulsion formation and stabilization only partially apply to nanoemulsions. This general deficiency sets up the premise for current review. We attempt to explore varying intricacies, excipients, manufacturing techniques and their underlying principles, production conditions, structural dynamics, prevalent destabilization mechanisms, and drug delivery applications of nanoemulsions to spike interest of those contemplating a foray in this field.

Development and characterization of resveratrol nanoemulsions carrying dual-imaging agents

AIM

Delivery of the natural anti-inflammatory compound resveratrol with nanoemulsions can dramatically improve its tissue targeting, bioavailability and efficacy. Current assessment of resveratrol delivery efficacy is limited to indirect pharmacological measures. Molecular imaging solves this problem. Results/methodology: Nanoemulsions containing two complementary imaging agents, near-infrared dye and perfluoropolyether (PFPE), were developed and evaluated. Nanoemulsion effects on macrophage uptake, toxicity and NO production were also evaluated. The presence of PFPE did not affect nanoemulsion size, zeta potential, colloidal stability, drug loading or drug release.

CONCLUSION

PFPE nanoemulsions can be used in future studies to evaluate nanoemulsion biodistribution without interfering with resveratrol delivery and pharmacological outcomes. Developed nanoemulsions show promise as a versatile treatment strategy for cancer and other inflammatory diseases. [Formula: see text].