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

Injectable, reversibly thermoresponsive captopril-laden hydrogel for the local treatment of sensory loss in diabetic neuropathy

A major and irreversible complication of diabetes is diabetic peripheral neuropathy (DPN), which can lead to significant disability and decreased quality of life. Prior work demonstrates the peptide hormone Angiotensin II (Ang II) is released locally in neuropathy and drives inflammation and impaired endoneurial blood flow. Therefore, we proposed that by utilizing a local thermoresponsive hydrogel injection, we could deliver inhibitors of angiotensin-converting enzyme (ACE) to suppress Ang II production and reduce nerve dysfunction in DPN through local drug release. The ACE inhibitor captopril was encapsulated into a micelle, which was then embedded into a reversibly thermoresponsive pluronics-based hydrogel matrix. Drug-free and captopril-loaded hydrogels demonstrated excellent product stability and sterility. Rheology testing confirmed sol properties with low viscosity at ambient temperature and increased viscosity and gelation at 37 °C. Captopril-loaded hydrogels significantly inhibited Ang II production in comparison to drug-free hydrogels. DPN mice treated with captopril-loaded hydrogels displayed normalized mechanical sensitivity and reduced inflammation, without side-effects associated with systemic exposure. Our data demonstrate the feasibility of repurposing ACE inhibitors as locally delivered anti-inflammatories for the treatment of sensory deficits in DPN. To the best of our knowledge, this is the first example of a locally delivered ACE inhibitor for the treatment of DPN.

Nanoemulsions as a Promising Carrier for Topical Delivery of Etodolac: Formulation Development and Characterization

This research primarily focuses on the development of innovative topical nanoemulsions for etodolac, aimed at surmounting its inherent limitations. The preparation of etodolac nanoemulsions is accomplished through a combination of high shear homogenization and ultrasonication methods. The optimization of the formulation components is systematically conducted using the design of experiments methodology. The droplet size (DS), polydispersity index (PDI), and zeta potential (ZP) of the optimized formulation were assessed using the differential light scattering (DLS) technique. Surface morphology examinations were conducted using electron microscopy, while interactions between excipients and the drug were analyzed through FTIR analysis. Additionally, in vitro release and ex vivo permeability studies were carried out. Furthermore, anti-inflammatory activity was evaluated in the context of a carrageenan-induced paw edema model in rats. The DS, PDI, and ZP of the optimal formulation were 163.5 nm, 0.141, and -33.1 mV, respectively. The in vitro release profile was assessed as a sustained release by following a non-Fickian drug transport. The flux of etodolac nanoemulsions and coarse dispersions were 165.7 ± 11.7 µg/cm2 h and 59.7 ± 15.2 µg/cm2 h, respectively. Enhanced edema inhibition was observed at 13.4%, 36.5%, and 50.65% for the 6th, 8th, and 24th hours, respectively. Taken together, these results confirmed that nanoemulsions are promising carriers for the topical delivery of etodolac.

In vitro Quality Assessments of Perfluorocarbon Nanoemulsions for Near-infrared Fluorescence Imaging of Inflammation in Preclinical Models

Tracking macrophages by non-invasive molecular imaging can provide useful insights into the immunobiology of inflammatory disorders in preclinical disease models. Perfluorocarbon nanoemulsions (PFC-NEs) have been well documented in their ability to be taken up by macrophages through phagocytosis and serve as 19F magnetic resonance imaging (MRI) tracers of inflammation in vivo and ex vivo. Incorporation of near-infrared fluorescent (NIRF) dyes in PFC-NEs can help monitor the spatiotemporal distribution of macrophages in vivo during inflammatory processes, using NIRF imaging as a complementary methodology to MRI. Here, we discuss in depth how both colloidal and fluorescence stabilities of the PFC-NEs are essential for successful and reliable macrophage tracking in vivo and for their detection in excised tissues ex vivo by NIRF imaging. Furthermore, PFC-NE quality assures NIRF imaging reproducibility and reliability across preclinical studies, providing insights into inflammation progression and therapeutic response. Previous studies focused on assessments of colloidal property changes in response to stress and during storage as a means of quality control. We recently focused on the joint evaluation of both colloidal and fluorescence properties and their relationship to NIRF imaging outcomes. In this protocol, we summarize the key assessments of the fluorescent dye-labeled nanoemulsions, which include long-term particle size distribution monitoring as the measure of colloidal stability and monitoring of the fluorescence signal. Due to its simplicity and reproducibility, our protocols are easy to adopt for researchers to assess the quality of PFC-NEs for in vivo NIRF imaging applications.

A Reversibly Thermoresponsive, Theranostic Nanoemulgel for Tacrolimus Delivery to Activated Macrophages: Formulation and In Vitro Validation

Despite long-term immunosuppression, organ transplant recipients face the risk of immune rejection and graft loss. Tacrolimus (TAC, FK506, Prograf®) is an FDA-approved keystone immunosuppressant for preventing transplant rejection. However, it undergoes extensive first-pass metabolism and has a narrow therapeutic window, which leads to erratic bioavailability and toxicity. Local delivery of TAC directly into the graft, instead of systemic delivery, can improve safety, efficacy, and tolerability. Macrophages have emerged as promising therapeutic targets as their increased levels correlate with an increased risk of organ rejection and a poor prognosis post-transplantation. Here, we present a locally injectable drug delivery platform for macrophages, where TAC is incorporated into a colloidally stable nanoemulsion and then formulated as a reversibly thermoresponsive, pluronic-based nanoemulgel (NEG). This novel formulation is designed to undergo a sol-to-gel transition at physiological temperature to sustain TAC release in situ at the site of local application. We also show that TAC-NEG mitigates the release of proinflammatory cytokines and nitric oxide from lipopolysaccharide (LPS)-activated macrophages. To the best of our knowledge, this is the first TAC-loaded nanoemulgel with demonstrated anti-inflammatory effects on macrophages in vitro.

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.

Cardiovascular Molecular Imaging With Fluorine-19 MRI: The Road to the Clinic

Fluorine-19 (19F) magnetic resonance imaging is a unique quantitative molecular imaging modality that makes use of an injectable fluorine-containing tracer that generates the only visible 19F signal in the body. This hot spot imaging technique has recently been used to characterize a wide array of cardiovascular diseases and seen a broad range of technical improvements. Concurrently, its potential to be translated to the clinical setting is being explored. This review provides an overview of this emerging field and demonstrates its diagnostic potential, which shows promise for clinical translation. We will describe 19F magnetic resonance imaging hardware, pulse sequences, and tracers, followed by an overview of cardiovascular applications. Finally, the challenges on the road to clinical translation are discussed.

Quality attributes of CTVad1, a nanoemulsified adjuvant for phase I clinical trial of SpiN COVID-19 vaccine

Aim: To develop, characterize and evaluate an oil/water nanoemulsion with squalene (CTVad1) to be approved as an adjuvant for the SpiN COVID-19 vaccine clinical trials. Materials & methods: Critical process parameters (CPPs) of CTVad1 were standardized to meet the critical quality attributes (CQAs) of an adjuvant for human use. CTVad1 and the SpiN-CTVad1 vaccine were submitted to physicochemical, stability, in vitro and in vivo studies. Results & conclusion: All CQAs were met in the CTVad1 production process. SpiN- CTVad1 met CQAs and induced high levels of antibodies and specific cellular responses in in vivo studies. These results represented a critical step in the process developed to meet regulatory requirements for the SpiN COVID-19 vaccine clinical trial.

RNA-Seq Reveals Sex Differences in Gene Expression during Peripheral Neuropathic Inflammation and in Pain Relief from a COX-2 Inhibiting Theranostic Nanoemulsion

Given decades of neuroinflammatory pain research focused only on males, there is an urgent need to better understand neuroinflammatory pain in females. This, paired with the fact that currently there is no long-term effective treatment for neuropathic pain furthers the need to evaluate how neuropathic pain develops in both sexes and how it can be relieved. Here we show that chronic constriction injury of the sciatic nerve caused comparable levels of mechanical allodynia in both sexes. Using a COX-2 inhibiting theranostic nanoemulsion with increased drug loading, both sexes achieved similar reduction in mechanical hypersensitivity. Given that both sexes have improved pain behavior, we specifically explored differential gene expression between sexes in the dorsal root ganglia (DRG) during pain and relief. Total RNA from the DRG revealed a sexually dimorphic expression for injury and relief caused by COX-2 inhibition. Of note, both males and females experience increased expression of activating transcription factor 3 (Atf3), however, only the female DRG shows decreased expression following drug treatment. Alternatively, S100A8 and S100A9 expression appear to play a sex specific role in relief in males. The sex differences in RNA expression reveal that comparable behavior does not necessitate the same gene expression.

Multiple Linear Regression Predictive Modeling of Colloidal and Fluorescence Stability of Theranostic Perfluorocarbon Nanoemulsions

Perfluorocarbon nanoemulsions (PFC-NEs) are widely used as theranostic nanoformulations with fluorescent dyes commonly incorporated for tracking PFC-NEs in tissues and in cells. Here, we demonstrate that PFC-NE fluorescence can be fully stabilized by controlling their composition and colloidal properties. A quality-by-design (QbD) approach was implemented to evaluate the impact of nanoemulsion composition on colloidal and fluorescence stability. A full factorial, 12-run design of experiments was used to study the impact of hydrocarbon concentration and perfluorocarbon type on nanoemulsion colloidal and fluorescence stability. PFC-NEs were produced with four unique PFCs: perfluorooctyl bromide (PFOB), perfluorodecalin (PFD), perfluoro(polyethylene glycol dimethyl ether) oxide (PFPE), and perfluoro-15-crown-5-ether (PCE). Multiple linear regression modeling (MLR) was used to predict nanoemulsion percent diameter change, polydispersity index (PDI), and percent fluorescence signal loss as a function of PFC type and hydrocarbon content. The optimized PFC-NE was loaded with curcumin, a known natural product with wide therapeutic potential. Through MLR-supported optimization, we identified a fluorescent PFC-NE with stable fluorescence that is unaffected by curcumin, which is known to interfere with fluorescent dyes. The presented work demonstrates the utility of MLR in the development and optimization of fluorescent and theranostic PFC nanoemulsions.

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.

Optical sensor arrays designed for guided manufacture of perfluorocarbon nanoemulsions with a non-synthetic stabilizer

Hydrophobic drugs are incorporated into oil-in-water nanoemulsions (OIW) either as new formulations or repurposed for intravenous delivery. Typically, these are manufactured through stepwise processes of sonication or high-pressure homogenization (HPH). The guiding criteria for most nanoemulsion manufacture are the size and homogeneity/polydispersity of the drug-laden particles with strict requirements for clinical injectables. To date, most formulation optimization is done through trial and error with stepwise sampling during processing utilizing dynamic light scattering (DLS), light obscuration sensing (LOS) or laser particle tracking (LPT) to assess manufacturing progress. The objective of this work was to develop and implement an in-line optical turbidity/nephelometry sensor array for the longitudinal in-process monitoring of nanoemulsion manufacture. A further objective was the use of this sensor array to rapidly optimize the manufacture of a sub-120 nm oxygen carrying perfluorocarbon nanoemulsion with a non-synthetic stabilizer. During processing, samples were taken for particle size measurement and further characterization. There was a significant correlation and agreement between particle size and sensor signal as well as improved process reproducibility through sensor-guided manufacture. Given the cost associated with nanoemulsion development and scale-up manufacture, our sensor arrays could be an invaluable tool for efficient and cost-effective drug development. Sensor-guided manufacturing was used to optimize oxygen-carrying nanoemulsions. These were tested, in vitro, for their ability to improve the viability of encapsulated endocrine clusters (mouse insulinoma, Min6) and to eliminate hypoxia due to oxygen mass transfer limitations. The nanomulsions significantly improved encapsulated cluster viability and reduced hypoxia within the microcapsule environment. STATEMENT OF SIGNIFICANCE: Nanoemulsions are rapidly becoming vehicles for the controlled release delivery of both hydrophilic and hydrophobic drugs given their large surface area for exchange. As work shifts from bench to large scale manufacturing, there is a critical need for technologies that can monitor and accumulate data during processing, particularly regarding the endpoint criteria of particle size and stability. To date, no such technology has been implemented in nanoemulsion manufacture. In this paper we develop and implement an optical sensor array for in-line nanoemulsion process monitoring and then use the array to optimize the development and manufacture of novel reproducible oxygen carrying nanoemulsions lacking synthetic surfactants.

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.

An analytical "quality by design" approach in RP-HPLC method development and validation for reliable and rapid estimation of irinotecan in an injectable formulation

The objective of the present study was to develop a robust, simple, economical and sensitive HPLC-UV method using the "quality-by-design" approach for the estimation of irinotecan (IRI) in marketed formulations. RP-HPLC method was developed by applying Box-Behnken design with Hyper-Clone (Phenomenex®) C18 column (250 × 4.6 mm id, particle size 5 µm, ODS 130 Å) as a stationary phase. Acetonitrile and 20 mmol L-1 potassium phosphate buffer (pH 2.5) containing 0.1 % triethylamine in a ratio of 45:55 % (V/V) was used as a mobile phase. The sample was injected in a volume of 20 µL into the HPLC system. UV detector at 254 nm was used to estimate and quantify IRI. Isocratic elution was opted while the flow rate was maintained at 0.75 mL min-1. The retention time of IRI was found to be 4.09 min. The responses were found to be linear for concentration range of 0.5 to 18.0 µg mL-1 and the coefficient of determination value was found to be 0.9993. Percent relative standard deviation for intra- and inter-day precisions was found in the range of 0.1 to 0.4 %. LOD and LOQ values were found to be 4.87 and 14.75 ng mL-1, resp. Robustness studies confirmed that the developed method is robust with RSD of a maximum 0.1 %. The method is simple, precise, sensitive, robust and economical making it applicable to the estimation of IRI in an injectable formulation.

Poly(lactic-co-glycolic acid) nanomaterial-based treatment options for pain management: a review

Neuropathic pain is one of the most intense types of chronic pain; it constitutes a pervasive complaint throughout the public health system. With few effective treatments, it remains a significant challenge. Commercially available drugs for neuropathic pain are still limited and have disappointing efficacy. Therefore, chronic neuropathic pain imposes a tremendous burden on patients' quality of life. Recently, the introduction and application of nanotechnology in multiple fields has accelerated the development of new drugs. This review highlights the application of poly(lactic-co-glycolic acid) nanomaterial-based vehicles for drug delivery and how they improve the therapeutic outcomes for neuropathic pain treatment. Finally, future developments for pain research and effective management are presented.

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.

Systemic Design and Evaluation of Ticagrelor-Loaded Nanostructured Lipid Carriers for Enhancing Bioavailability and Antiplatelet Activity

Ticagrelor (TGL), a P2Y12 receptor antagonist, is classified as biopharmaceutics classification system (BCS) class IV drug due to its poor solubility and permeability, resulting in low oral bioavailability. Nanostructured lipid carriers (NLC) are an efficient delivery system for the improvement of bioavailability of BCS class IV drugs. Hence, we prepared TGL-loaded NLC (TGL-NLC) to enhance the oral bioavailability and antiplatelet activity of TGL with a systemic design approach. The optimized TGL-NLC with Box-Behnken design showed a small particle size of 87.6 nm and high encapsulation efficiency of 92.1%. Scanning electron microscope (SEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) were performed to investigate the characteristics of TGL-NLC. Furthermore, TGL-NLC exhibited biocompatible cytotoxicity against Caco-2 cells. Cellular uptake of TGL-NLC was 1.56-fold higher than that of raw TGL on Caco-2 cells. In pharmacokinetic study, the oral bioavailability of TGL-NLC was 254.99% higher than that of raw TGL. In addition, pharmacodynamic study demonstrated that the antiplatelet activity of TGL-NLC was superior to that of raw TGL, based on enhanced bioavailability of TGL-NLC. These results suggest that TGL-NLC can be applied for efficient oral absorption and antiplatelet activity of TGL.