Molecular Pharmaceutics

There has been an increasing trend towards subcutaneous (SC) delivery of fusion proteins and monoclonal antibodies (mAbs) in recent years versus intravenous (IV) administration. The prediction of bioavailability is one of the major barriers in clinical translation of SC administered therapeutic proteins due to a lack of reliable in vitro and preclinical in vivo predictive models. In this study, we explored the relationships between human SC bioavailability and physicochemical or pharmacokinetic properties of 20 Fc-or albumin-fusion proteins and 98 monoclonal antibodies. An inverse linear correlation was observed between human SC bioavailability and human intravenous clearance (CL) or isoelectric point (pI). The bioavailability of fusion proteins is more correlated with pI while the bioavailability of mAbs is more correlated with CL. A mAbs with intravenous CL < 4 mL/day/kg is likely to have SC bioavailability > 60%. Multivariate regression models were developed using intravenous CL and pI of a training set (N = 59) as independent variables. The predictive models were validated with an independent test set (N = 33). A linear regression model resulted in 27 among 33 (82%) predictions within 0.8-to 1.2-fold deviations. Overall, this study demonstrated that CL- and pI-based multivariate regression models could be used to predict human SC bioavailability of fusion proteins and mAbs.

Bispecific T cell engager (TCE) is an emerging anti-cancer modality which redirects cytotoxic T cells to tumor cells expressing tumor-associated antigen (TAA) thereby forming immune synapses to exerts anti-tumor effects. Considering the protein engineering challenges in designing and optimizing size and pharmacokinetically acceptable TCEs in the context of the complexity of intercellular bridging between T cells and tumor cells, a physiologically relevant and clinically verified computational modeling framework is of crucial importance to guide the process to understand the protein engineering trade offs. In this study, we developed a quantitative, physiologically based computational framework to predict immune synapse formation for a variety of molecular format of TCEs in tumor tissue. Our model incorporated the molecular size dependent biodistribution using the two pore theory, extra-vascularization of T cells and hematologic cancer cells, mechanistic bispecific intercellular binding of TCEs and competitive inhibitory interaction by shed targets. The biodistribution of TCE was verified by positron emission tomography imaging of [89Zr]AMG211 (a carcinoembryonic antigen-targeting TCE) in patients. Parameter sensitivity analyses indicated that immune synapse formation was highly sensitive to TAA expression, degree of target shedding and binding selectivity to tumor cell surface TAA over shed target. Interestingly, the model suggested a "sweet spot" for TCEs CD3 binding affinity which balanced the trapping of TCE in T cell rich organs. The final model simulations indicated that the number of immune synapses is similar ([~]50/tumor cell) between two distinct clinical stage B cell maturation antigen (BCMA)-targeting TCEs, PF-06863135 in IgG format and AMG420 in BiTE format, at their respective efficacious dose in multiple myeloma patients, demonstrating the applicability of the developed computational modeling framework to molecular design optimization and clinical benchmarking for TCEs. This framework can be employed to other targets to provide a quantitative means to facilitate the model-informed best in class TCE discovery and development. Author summaryCytotoxic T cells play a crucial role in eliminating tumor cells. However, tumor cells develop mechanisms to evade from T cell recognition. Bispecific T cell engager (TCE) is designed to overcome this issue with bringing T cells to close proximity of tumor cells through simultaneous bivalent binding to both tumor-associated antigen and T cells. After successful regulatory approval of blinatumomab (anti-CD19 TCE), more than 40 TCEs are currently in clinical development with a variety of molecular size and protein formats. In this study, we developed a quantitative computational modeling framework for molecular design optimization and clinical benchmarking of TCEs. The model accounts for molecular size dependent biodistribution of TCEs to tumor tissue and other organs as well as following bispecific intercellular bridging of T cells and tumor cells. The model simulation highlighted the importance of binding selectivity of TCEs to tumor cell surface target over shed target. The model also demonstrated a good agreement in predicted immune synapse number for two distinct molecular formats of TCEs at their respective clinically efficacious dose levels, highlighting the usefulness of developed computational modeling framework for best in class TCE discovery and development.

This study investigated the feasibility and efficiency of neuron-targeting hybrid placental mesenchymal stromal cell-derived extracellular vesicles (PMSC-EVs), engineered by membrane fusion with Targeted Axonal Import (TAxI) peptide modified, TrkB agonist 7,8-DHF-loaded liposomes for treatment of myelomeningocele (MMC) via intra-amniotic cavity administration. The prepared TAxI modified liposomes with 7,8-DHF were used to fuse with PMSC-EVs. Different fusion approaches were investigated and freeze-thaw-extrude method was found to be the optimal. The engineered PMSC-EVs had a uniform particle size and efficiently loaded 7,8-DHF. It also had typical markers of native EVs. Freeze-thaw-extrude process did not change the release profile of 7,8-DHF from engineered EVs compared to TAxI modified, 7,8-DHF loaded liposomes. The engineered EVs could elicit TrkB phosphorylation depending on the incorporation of 7,8-DHF while native EVs did not. The engineered EVs increased neurite outgrowth of apoptotic cortical neurons induced by staurosporine, suggesting that they exhibited neuroprotective function. In a rodent model of MMC, neuron-targeting, engineered EVs became an active targeting delivery system to MMC defect sites. Pups treated with engineered EVs had the lowest density of apoptotic cells and displayed a therapeutic outcome. The study suggests the potential use of engineered hybrid, active neuron-targeting EVs for the in utero treatment of MMC.

Antibody-based therapeutics have revolutionized disease treatment, and recent advances in messenger RNA (mRNA) technologies have opened new opportunities for their intracellular production. In particular, in vitro-transcribed mRNA encapsulated in lipid nanoparticles (LNPs) enables targeted delivery to specific cells, where it can enable the synthesis of therapeutic antibodies with prolonged half-lives in a cost-effective manner. Despite rapidly growing experimental data, a modeling framework that integrates mRNA delivery, intracellular expression kinetics, and whole-body antibody disposition remains unavailable. To address this gap, we extended a Physiologically Based Pharmacokinetic model with a novel multiscale layer describing mRNA trafficking, cellular uptake, translation, and degradation. The integrated model was calibrated and validated using five datasets of mRNA-based cancer therapeutics, demonstrating strong predictive performance for the biodistribution of mRNA-encoded antibodies. The newly introduced mRNA layer, while minimally parameterized, effectively represents complex intracellular and systemic processes, enabling quantitative investigation of antibody biodistribution, optimization of dose scheduling, and providing an initial framework for future exploration of how LNP-mRNA formulation influences delivery and pharmacokinetics.

Synthetic high-density lipoprotein (sHDL) constituted of apolipoprotein A-I (apoA-I) mimetic peptides and phospholipids are nanometer-scale particles designed to recreate biological functions of HDL particles in the context of cardiovascular disease. Particularly, the therapeutic efficacy of sHDL particles is attributed to their ability to promote reverse cholesterol transport (RCT), a process where accumulated cholesterol is transported from peripheral tissues to the liver for elimination. Here, we designed two novel apoA-I mimetic peptides (22A-F and 22A-P-18A) by modifying the sequence of the well-studied apoA-I mimetic peptide 22A. These modifications were intended to improve cholesterol efflux from macrophages in vitro and structural stability of sHDL particles in human plasma while preserving their ability to activate lecithin-cholesterol acyltransferase (LCAT). We performed a systematic examination of the potency of sHDL particles made with these peptides in cellular cholesterol efflux, activation of LCAT, plasma HDL remodeling and proteolytic stability. Our study highlights that these modifications improve cholesterol efflux and, in the case of 22A-P-18A, also cholesterol esterification rate by LCAT but they do not appear to influence HDL remodeling in human plasma. Nonetheless, the LCAT activity assay conducted in human plasma suggest that intact sHDL particles are present and are likely the primary contributors to the increased cholesterol esterification rate, rather than the pre-{beta} HDL fraction generated through HDL remodeling. These findings offer new mechanistic insights into how specific peptide modifications affect key steps in RCT, laying the groundwork for future studies to explore their functional relevance in atherosclerosis and HDL-based drug delivery applications.

Effective blood-brain barrier (BBB) penetration is a significant challenge for antisense oligonucleotide (ASO) therapies targeting neurodegenerative diseases. We utilized a peptide (ApoB11) mediated transport delivery of an ASO to the CNS following systemic delivery to reduce expression of targeted transcripts for neurodegenerative diseases. This study evaluates the pharmacokinetics, CNS penetration, and therapeutic efficacy of ApoB11:2-OMe ASO--Syn, an ASO for -synuclein (-Syn) suppression in synucleinopathies. After a single intraperitoneal (IP) injection (2 mg/kg) in C57BL/6 mice, ApoB11:ASO--Syn showed robust brain penetration, reaching peak concentrations (Cmax = 0.14 nMol/mg) at 1.5 hours and an extended brain half-life (t1/2 = 646.2 hours), indicating prolonged CNS retention. Immunofluorescence confirmed widespread uptake in neurons and endothelial cells. The ASO also accumulated in the liver (Cmax = 419.5 nMol/mg, t1/2 = 104.9 hours), consistent with receptor-mediated uptake. Acute and subacute toxicity studies revealed no systemic toxicity at the highest non-lethal dose (32 mg/kg). In a mouse model of dementia with lewy body (DLB) mice overexpressing human -Syn, ApoB11:ASO--Syn reduced -Syn mRNA and protein levels in the hippocampus and cortex by [~]50% at 16 mg/kg. These results demonstrate that ApoB11 is an effective ASO carrier for CNS delivery, supporting its potential as a therapeutic strategy for synucleinopathies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=154 SRC="FIGDIR/small/651722v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@f73353org.highwire.dtl.DTLVardef@14ababforg.highwire.dtl.DTLVardef@12a92e3org.highwire.dtl.DTLVardef@1176b4_HPS_FORMAT_FIGEXP M_FIG C_FIG

Effective delivery of therapeutics to the brain is restricted by the blood-brain barrier (BBB). A strategy to overcome this limitation involves taking advantage of receptor-mediated transcytosis pathways, such as those mediated by transferrin receptor 1 (TfR1), which is highly expressed on brain endothelial cells and naturally transports iron-bound transferrin across the BBB. To exploit this mechanism, we immunized camelids with human TfR1 and cloned 470 VHH nanobody sequences from their B cells. From this repertoire, 24 nanobodies (TfR1b-Nbs) were identified that bind human TfR1 on the cell membrane. These nanobodies were screened for binding to human TfR1, lack of interference with transferrin binding and TfR1-mediated iron uptake, and the ability to cross the BBB via human TfR1-mediated transcytosis in newly generated humanized Tfr1h knock-in rats. To improve developability and reduce potential immunogenicity, selected TfR1b-Nbs were humanized and optimized with computational and artificial intelligence (AI) algorithms, enhancing humanness, solubility, and VHH-nativeness. Eight optimized TfR1b-Nbs retained BBB permeability and were fused to humanized anti-TNF nanobody inhibitors (TNFI- or TNFI-{beta}), generating 16 heterodimers. Fusion to these TNFIs served as a functional readout, confirming that TfR1b-Nbs can shuttle biologically active, BBB-impermeable payloads into the central nervous system (CNS). All heterodimers demonstrated CNS delivery after intravenous administration, and selected constructs also reached the brain via subcutaneous injection, maintaining high serum and cerebrospinal fluid (CSF) levels for up to 72 hours. A pilot study with one heterodimer showed that chronic administration in rats humanized for both transferrin and TfR1 caused no hematological toxicity or signs of anemia - a key safety concern when targeting TfR1. These results establish humanized TfR1b-Nbs - designated NewroBus - as promising BBB shuttles for the safe and effective therapeutic delivery of biologics to the brain.

Neuroendocrine (NE) cancers include a diverse spectrum of hormone-secreting neoplasms that arise from the endocrine and nervous systems. Current chemo- and radio- therapies have marginal curative benefits. This study aimed to develop an innovative antibody-drug conjugate (ADC) to effectively treat NE tumors (NETs). We first confirmed that somatostatin receptor 2 (SSTR2) is an ideal surface target by analyzing 38 patient-derived NET tissues, 33 normal organs, and 3 NET cell lines. We then developed a new monoclonal antibody (mAb, IgG1 and kappa) to target two extracellular domains of SSTR2, which showed strong and specific surface binding to NETs. The ADC was constructed by conjugating the anti-SSTR2 mAb and antimitotic monomethyl auristatin E. In vitro evaluations indicated that the ADC can effectively bind, internalize, release payload, and kill NET cells effectively. Finally, the ADC was evaluated in vivo using a NET xenografted mouse model to determine cancer targeting, maximal tolerated dosage, pharmacokinetics, and anti-cancer efficacy. The anti-SSTR2 ADC was able to exclusively target and kill NETs with minimal toxicity and high stability in vivo. This study demonstrates that the anti-SSTR2 mAb-based ADC has high therapeutic values for NET therapy.

Antenatal depression, or depression during pregnancy, is a common psychiatric disorder and poses significant risks to both the mother and the fetus. Despite these risks, it is frequently left untreated due to fears of side effects caused by antidepressant medications which cross through the placental barrier. It is therefore desirable to develop formulation strategies to mitigate systemic exposure to relevant drug molecules while maintaining their psychotropic efficacy. In this work, we develop formulations of sertraline, a common antidepressant, to target delivery to the brain through intranasal administration. Formulation engineering enables successful solubilization of sertraline at high concentrations and our lead formulation remains stable at room temperature for months. Using mice, we compare sertraline biodistribution following intranasal administration and standard oral administration. Intranasal administration of our drug product candidate provides comparable brain exposure at half the dose compared to oral treatment and lowers the maximum plasma exposure. These findings suggest that intranasal administration may provide selectivity for drug exposure in the central nervous system over systemic exposure.

BackgroundComirnaty, Pfizer-BioNTechs polyethylene-glycol (PEG)-containing Covid-19 vaccine, can cause hypersensitivity reactions (HSRs) in a small fraction of immunized people which can, very rarely, culminate in life-threatening anaphylaxis. A role of anti-PEG antibodies (Abs) has been proposed, but causality has not yet been proven in an animal model. This study aimed to provide such evidence using anti-PEG hyperimmune pigs (i.e., pigs displaying very high levels of anti-PEG Abs). We also sought to find evidence for the role of complement (C) activation and thromboxane A2 (TXA2) release in blood as contributing effects to anaphylaxis. MethodsPigs (n=6) were immunized with 0.1 mg/kg PEGylated liposome (Doxebo) i.v. the rise of anti-PEG IgG and IgM was measured in serial blood samples with ELISA. After 2-3 weeks, during the height of seroconversion, the animals were injected i.v. with 1/3 human vaccine dose (HVD) of Comirnaty, and the hemodynamic (PAP, SAP), cardiopulmonary (HR, EtCO2,), hematological parameters (WBC, granulocyte, lymphocyte, and platelet counts) and blood immune mediators (anti-PEG IgM and IgG Abs, C3a and TXA2) were measured as endpoints of HSRs. ResultsA week after immunization of 6 pigs with Doxebo, the level of anti-PEG IgM and IgG rose 5-10-thousands-fold in all animals, and they all developed anaphylactic shock to i.v. injection of 1/3 HVD of Comirnaty. The reaction, starting within 1 min, led to the abrupt decline of SAP along with maximal pulmonary hypertension, decreased pulse pressure amplitude, tachycardia, granulo- and thrombocytopenia, and paralleling rises of plasma C3a and TXB2 levels. These vaccine effects were not observed in non-immunized pigs. ConclusionsConsistent with previous studies with PEGylated nano-liposomes, these data show a causal role of anti-PEG Abs in the anaphylaxis to Comirnaty. The reaction involves C activation, and, hence, it represents C activation-related pseudo-allergy (CARPA). The setup provides the first large-animal model for mRNA-vaccine-induced anaphylaxis in humans.

Native and engineered extracellular vesicles (EVs) generated from human megakaryocytes (huMkEVs) or from the human megakaryocytic cell line CHRF (CHEVs) interact with tropism delivering their cargo to both human and murine hematopoietic stem and progenitor cells (HSPCs). 24 hours after intravenous infusion of huMkMPs into NOD-scid IL2R{gamma}null (NSG) mice, they induced a nearly 50% increase in murine platelet counts relative to saline control, thus demonstrating the potential of these EVs, which can be stored frozen, for treating thrombocytopenias. PKH26-labeled huMkMPs or CHEVs localized to the HSPC-rich bone marrow preferentially interacting with murine HSPCs. Using engineered huMkEVs or CHEVs, their receptor-mediated tropism for HSPCs was explored to functionally deliver synthetic cargo, notably plasmid DNA coding for a fluorescent reporter, to murine HSPCs both in vitro and in vivo. These data demonstrate the potential of these EVs as a non-viral, HSPC-specific cargo vehicle for gene therapy applications to treat hematological diseases. Native and engineered human megakaryocytic extracellular vesicles for targeted non-viral cargo delivery to blood stem cells (Table of Contents): O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/536479v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@664768org.highwire.dtl.DTLVardef@d9fe13org.highwire.dtl.DTLVardef@1b795eforg.highwire.dtl.DTLVardef@1d48e2d_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical Overview: Native and engineered human megakaryocytic extracellular vesicles (huMkEVs) for provide targeted non-viral cargo delivery to blood stem cells. We demonstrate that huMkEVs as a transformational cargo-delivery system to blood stem cells (hematopoietic stem and progenitor cells, HSPCs) in NOD-scid IL2R{gamma}null (NSG) mice. Intravenous delivery of native huMkEVs enhances de novo platelet biogenesis by inducing megakaryocytic differentiation of murine HSPCs, thus demonstrating the desirable strong tropism of huMkEVs for murine HSPCs. Based on this tropism, we demonstrate that engineered huMkEVs can deliver functional plasmid-DNA cargo specifically to HSPCs.

SlpB from Levilactobacillus brevis offers a solution to stabilise liposome in gastrointestinal tract, and to target intestinal APCs in Peyers patches, rendering it a powerful tool for oral delivery of drugs, and to yield the benefits provided by oral delivery. However, the stability of SlpB-coated liposome (SlpB-LP) and its distribution in tissues were not characterized. In this study, we have demonstrated that SlpB-coating could improve the stability of liposome in gastrointestinal tract, and facilitate specific uptake of liposome into Peyers patches, but not intestinal, nor intestinal mucosa. Furthermore, we have shown that uptake of SlpB-LP into Peyers patches enhanced bioavailability of drugs, which have resulted in 427.65-fold increase in bioavailability and at least 2.41-fold decrease in retention of fluorophore in liver where drug metabolism takes places, to a degree which approximate control group. In conclusion, this study shows that SlpB could increase stability of liposome in gastrointestinal tract, increase specific uptake of liposome into Peyers patches, and improve bioavailability. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/533723v1_ufig1.gif" ALT="Figure 1"> View larger version (69K): org.highwire.dtl.DTLVardef@ed508aorg.highwire.dtl.DTLVardef@42cef8org.highwire.dtl.DTLVardef@2219a9org.highwire.dtl.DTLVardef@c2e3dd_HPS_FORMAT_FIGEXP M_FIG C_FIG

Steady-state volume of distribution (Vss) can be predicted using tissue-to-plasma partition coefficients (Kp) and tissue volumes. Kp values are important components of physiologically based pharmacokinetic (PBPK) models, allowing for estimation of distribution kinetics and simulation of concentration-time profiles. Many in silico approaches have been developed to predict tissue Kp values based on physicochemical processes that govern drug distribution. However, these methods frequently over- or under-predict tissue Kp values, highlighting the need to consider additional mechanisms that can impact drug distribution kinetics. Many drugs have been shown to bind to rat and human fatty acid binding proteins (FABPs) in vitro but the impact of this binding to drug distribution has not been incorporated into Kp predictions. We hypothesized that incorporating intracellular protein binding into tissue Kp predictions will improve Kp prediction accuracy. Using liver as a model organ, four physiologically based dynamic liver distribution models (LDMs) were developed to assess the role of distribution processes in Kp predictions. The developed LDMs incorporated known distribution mechanisms and intracellular drug binding to liver FABP (FABP1). The liver Kp values for drugs that bind to FABP1 were accurately predicted using the LDM that incorporates lipid partitioning, albumin distribution, and FABP1 binding but not using LDMs without FABP1 binding. Human FABP1 expression was quantified in 61 human livers and the interindividual variability in tissue FABP1 binding was incorporated into tissue Kp predictions. These simulations showed that intracellular FABP1 binding can cause interindividual variability in Kp values and result in concentration dependent tissue distribution. Significance StatementThis study shows that incorporating intracellular protein binding such as binding to FABP1 into tissue Kp predictions improves accuracy of the predictions. The novel dynamic LDM can be extrapolated to other organs of interest and integrated into full-body PBPK models to predict drug distribution kinetics. With dynamic and saturable distribution mechanisms incorporated into a PBPK model, nonlinear distribution kinetics can be simulated for various drugs.

The wide-scale use of liposomal delivery systems is hampered by difficulties in obtaining potent liposomal suspensions. Passive and active loading strategies have been proposed to formulate drug encapsulated liposomes, but are limited by low efficiencies (passive) or high drug specificities (active). Here, we present an efficient and universal loading strategy for synthesizing therapeutic liposomes. Integrating a thermal equilibration technique with our unique liposome synthesis approach, co-loaded targeting liposomes can be engineered in an efficient and scalable manner with potencies 200-fold higher than typical passive encapsulation techniques. We demonstrate this capability through simultaneous co-loading of hydrophilic and hydrophobic small molecules and through targeted delivery of liposomal Doxorubicin to a metastatic breast cancer cell line MDA-MB-231. Molecular dynamic simulations are used to explain interactions between Doxorubicin and liposome membrane during thermal equilibration. By addressing the existing challenges, we have developed an unparalleled approach that will facilitate the formulation of novel theranostic and pharmaceutical strategies.

VIAN-c4551 is a cyclic antiangiogenic peptide that stands as a potent and stable inhibitor of vascular endothelial cell growth factor (VEGF), the major vasopermeability and angiogenic factor in diabetic macular edema and diabetic retinopathy. Intravitreal injections of inhibitors of VEGF are a first-line therapy, but the invasiveness, risk, and low adherence of frequent intravitreal injections interfere with the needed long-term treatments and successful outcomes. Eye drops are non-invasive and favor compliance. Here, we evaluated the preclinical efficacy, permeability, and ocular pharmacokinetics of VIAN-c4551 delivered in eye drops. VIAN-c4551 demonstrated high potency (IC50 = 137 pM) to inhibit the permeability of human umbilical vein endothelial cell monolayers induced by VEGF. VIAN-c4551 eye drops potently (0.005% minimum effective dose) prevented the retinal vascular leakage induced by VEGF injected intravitreally for up to 24 hours and reversed the increase in retinal vascular permeability due to streptozotocin-induced diabetes in rats and mice. VIAN-c4551 exhibited high permeability across MDCK epithelium and, after a single topical ocular instillation in rabbits, reached the retina-choroid in micromolar concentrations several orders of magnitude above its IC50 (Cmax= 51 {micro}M at 6 hours) that lasted at least 24 hours. In conclusion, VIAN-c4551 eye drops reach the back of the eye at therapeutic concentrations, providing a potential, once-a-day, non-invasive intervention for preventing and reversing retinal vascular leakage in diabetic macular edema, diabetic retinopathy, and other vascular retinopathies and preserving sight.

2019-nCoV, which is a novel coronavirus emerged in Wuhan, China, at the end of 2019, has caused at least infected 11,844 as of Feb 1, 2020. However, there is no specific antiviral treatment or vaccine currently. Very recently report had suggested that novel CoV would use the same cell entry receptor, ACE2, as the SARS-CoV. In this report, we generated a novel recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. An ACE2 mutant with low catalytic activity was also used in the study. The fusion proteins were then characterized. Both fusion proteins has high affinity binding to the receptor-binding domain (RBD) of SARS-CoV and 2019-nCoV and exerted desired pharmacological properties. Moreover, fusion proteins potently neutralized SARS-CoV and 2019-nCoV in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they could have potential applications for diagnosis, prophylaxis, and treatment of 2019-nCoV.

Computational chemistry and machine learning are used in drug discovery to predict target-specific and pharmacokinetic properties of molecules. Multiparameter optimization (MPO) functions are used to summarize multiple properties into a single score, aiding compound prioritization. However, over-reliance on subjective MPO functions risks reinforcing human bias. Mechanistic modeling approaches based on physiological relevance can be adapted to meet different potential key objectives of the project (e.g. minimizing dose, maximizing safety margins and/or minimized drug-drug interaction risk) while retaining the same underlying model structure. The current work incorporates recent approaches to predict in vivo PK properties and validates in vitro to in vivo correlation analysis to support mechanistic PK MPO. Examples of use and impact in small molecule drug discovery projects are provided. Overall, the mechanistic MPO identifies 83% of the compounds considered as short-listed for clinical experiments in the top 2nd percentile, and 100% in the top 10th percentile, resulting in an area under the receiver operating characteristic curve (AUCROC) > 0.95. In addition, the MPO score successfully recapitulates the chronological progression of the optimization process across different scaffolds. Finally, the MPO scores for compounds characterized in pharmacokinetics experiments are markedly higher compared to the rest of the compounds synthesized, highlighting the potential of this tool to reduce the reliance on in vivo testing for compound screening.

A stable lyophilized formulation for a cancer vaccine containing quadrivalent frameshift neo antigen peptides TAFB(-1), AIM2(-1), HT001(-1) and TGFBR2(-1), was obtained through an iterative screening process. To develop a lyophilized formulation, the screening included evaluation of pH, stabilizers, bulking agents, and surfactants. The screening resulted in a scalable formulation and lyophilization process that co-formulated four peptides with 100 {micro}g/ml each peptide in10 mM Histidine at pH 5.5, 260 mM trehalose, and 0.02% polysorbate 20 as a clinical formulation. Based on peptide content and peptide purity from a three-month stability study, the lyophilized formulation is estimated to be stable at ambient temperatures for 18 months.

Extracellular vehicles (EVs) are an emerging class of drug carriers and are primarily reported to be internalized into recipient cells via a combination of endocytic routes such as clathrin-mediated, caveolae-mediated and macropinocytosis pathways. In this work, (1) we investigated potential effects of homotypic vs. heterotypic interactions by studying the cellular uptake of homologous EVs (EV donor cells and recipient cells of the same type) vs. heterologous EVs (EV donor cells and recipient cells of different types) and (2) determined the route of EV internalization into low pinocytic/hard-to-deliver cell models such as brain endothelial cells (BECs). We used BECs and macrophages as low-pinocytic and phagocytic cell models, respectively, to study the effect of homotypic vs. heterotypic interactions on EV uptake in the recipient cells. Homotypic interactions led to a greater extent of uptake into the recipient BECs compared to heterotypic interactions. However, we did not see a complete reduction in EV uptake into recipient BECs when endocytic pathways were blocked using pharmacological inhibitors. Our results suggest that EVs primarily use membrane fusion to enter low-pinocytic recipient BECs instead of relying on endocytosis. Lipophilic PKH67 dye-labeled EVs but not intravesicular esterase-activated calcein ester-labeled EVs severely reduced particle uptake into BECs while phagocytic macrophages internalized both types of EV-labeled particles to comparable extents. Our results also highlight the importance of carefully choosing labeling dye chemistry to study EV uptake, especially in the case of low pinocytic cells such as BECs. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=171 HEIGHT=200 SRC="FIGDIR/small/563628v2_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@d5cb50org.highwire.dtl.DTLVardef@172d1dorg.highwire.dtl.DTLVardef@192caf6org.highwire.dtl.DTLVardef@4b16ba_HPS_FORMAT_FIGEXP M_FIG C_FIG

This study delves into the optimization of niosome production for biological applications, focusing on their emerging role as amphiphilic nanoparticles derived from nonionic surfactants, poised at the forefront of biomedical research. We aimed to formulate and characterize a diverse array of niosomal nanoparticles, with particular emphasis on process-related parameters and physicochemical characteristics. Critical thresholds for size, polydispersity, and zeta potential were established to identify parameters crucial for optimal niosomal formulations through a comprehensive investigation of concentrations, sonication times, ingredient ratios, and surfactant types. Leveraging MODDE(R) software, we generated ten optimized formulations from preliminary parameter screening. The proposed experimental model design by the software exhibited acceptable similarity to the obtained experimental results (F-score:0.83). The criteria for selection of the predicted experimental model formed based on targeted physicochemical considerations. To enhance half-life and penetration, especially in higher electrostatic regions like the Central Nervous System (CNS), we proposed a neutralized surface charge (-10 to 10 mV) while maintaining size within 100-200 nm and polydispersity below 0.5. Extended stability screening revealed periodic and extended Gaussian distributions for size and zeta potential to minimize flocculation and coagulation caused by neutralized surface charge. Notably, the cellular response performance of optimized niosomes was assessed via cellular binding, uptake, and viability in comparison to liposomes. Glioblastoma cell line (U-87) and granulocyte colony-stimulating factor (G-CSF) containing lymphoblastic leukemia cell line (NFS-60) were chosen to represent tumors developed in the CNS region and white blood cells, respectively, enabling a comprehensive comparative analysis with liposomes. The meticulous comparison between niosomes and liposomes revealed comparable cellular viability profiles on both U-87 and NFS-60 cell lines, highlighting their similarities in cellular interactions. Moreover, selected niosomal formulations demonstrated exceptional cellular uptake, either equaling or surpassing observed liposomal uptake. One of the most promising niosomes was selected and optimized to evaluate drug encapsulation performance of niosomes for further drug delivery adaptations by one of chemotherapy drugs, Paclitaxel (PTX). Cytotoxicity study was established with the most efficiently encapsulated niosome condition with human-derived fibroblasts (HDFs) and U-87 as the representation of healthy and cancerous cell lines. Results demonstrated 1:100 diluted PTX-loaded niosome in the certain concentration demonstrated favourable toxicity in U-87 than original PTX at the same concentration while not disturbing healthy HDFs. These findings underscore the potential of niosomes for reliable drug delivery, challenging the dominance of liposomal vehicles and presenting economically viable nanocarriers with significant implications for advancing biomedical research.