Transmembrane helix interactions regulate oligomerization of the receptor tyrosine kinase EphA2.

The transmembrane helices of receptor tyrosine kinases (RTKs) have been proposed to switch between two different dimeric conformations, one associated with the inactive RTK and the other with the active RTK. Furthermore, recent work has demonstrated that some full-length RTKs are associated into oligomers that are larger than dimers, raising questions about the roles of the TM helices in the assembly and function of these oligomers. Here we probe the roles of the TM helices in the assembly of EphA2 RTK oligomers in the plasma membrane. We employ mutagenesis to evaluate the relevance of a published NMR dimeric structure of the isolated EphA2 TM helix in the context of the full-length EphA2 in the plasma membrane. We use two fluorescence methods, Förster Resonance Energy Transfer and Fluorescence Intensity Fluctuations spectrometry, which yield complementary information about the EphA2 oligomerization process. These studies reveal that the TM helix mutations affect the stability, structure, and size of EphA2 oligomers. However, the effects are multifaceted and point to a more complex role of the TM helix than the one expected from the "TM dimer switch" model.

Concentration of clarified pool by single-pass tangential flow filtration to improve productivity of protein A capture step: Impact of clarification strategies.

Protein A capture chromatography remains a high-cost and relatively low-productivity step for downstream processing of monoclonal antibodies. As bioprocessing transitions toward intensified processes, maximizing the efficiency of individual steps is key to achieving economic targets. This study was performed to assess the impact of inline concentration of clarified cell culture fluid (CCF), using single-pass tangential flow filtration, on protein A chromatography purification productivity. CCF with varying levels of impurities and turbidity were obtained dependent upon the clarification method. These CCFs were concentrated and processed over a protein A capture step. Productivity increases of 1.8- to 2.6-fold were achieved as compared to a protein A capture step with no CCF concentration. Achieving such targeted improvements requires careful consideration of the multiple components in the clarification strategy before implementation.

Quantitative Investigation of Intestinal Drug Absorption Enhancement by Drug-Rich Nanodroplets Generated via Liquid-Liquid Phase Separation.

Drug-rich droplets formed through liquid-liquid phase separation (LLPS) have the potential to enhance the oral absorption of drugs. This can be attributed to the diffusion of these droplets into the unstirred water layer (UWL) of the gastrointestinal tract and their reservoir effects on maintaining drug supersaturation. However, a quantitative understanding of the effect of drug-rich droplets on intestinal drug absorption is still lacking. In this study, the enhancement of intestinal drug absorption through the formation of drug-rich droplets was quantitatively evaluated on a mechanistic basis. To obtain fenofibrate (FFB)-rich droplets, an amorphous solid dispersion (ASD) of FFB/hypromellose (HPMC) was dispersed in an aqueous medium. Physicochemical characterization confirmed the presence of nanosized FFB-rich droplets in the supercooled liquid state within the FFB/HPMC ASD dispersion. An in situ single-pass intestinal perfusion (SPIP) assay in rats demonstrated that increased quantities of FFB-rich nanodroplets enhanced the intestinal absorption of FFB. The effective diffusion of FFB-rich nanodroplets through UWL would partially contribute to the improved FFB absorption. Additionally, confocal laser scanning microscopy (CLSM) of cross sections of the rat intestine after the administration of fluorescently labeled FFB-rich nanodroplets showed that these nanodroplets were directly taken up by small intestinal epithelial cells. Therefore, the direct uptake of drug-rich nanodroplets by the small intestine is a potential mechanism for improving FFB absorption in the intestine. To quantitatively evaluate the impact of FFB-rich droplets on the FFB absorption enhancement, we determined the apparent permeabilities of the FFB-rich nanodroplets and dissolved FFB based on the SPIP results. The apparent permeability of the FFB-rich nanodroplets was 110-130 times lower than that of dissolved FFB. However, when the FFB-rich nanodroplet concentration was several hundred times higher than that of dissolved FFB, the FFB-rich nanodroplets contributed significantly to FFB absorption improvement. The present study highlights that drug-rich nanodroplets play a direct role in enhancing drug absorption in the gastrointestinal tract, indicating their potential for further improvement of oral absorption from ASD formulations.

Studies on pharmacokinetic properties and intestinal absorption mechanism of sanguinarine chloride: in vivo and in situ.

Sanguinarine (SAN) is an alkaloid with multiple biological activities, mainly extracted from Sanguinaria canadensis or Macleaya cordata. The low bioavailability of SAN limits its utilization. At present, the nature and mechanism of SAN intestinal absorption are still unclear. The pharmacokinetics, single-pass intestinal perfusion test (SPIP), and equilibrium solubility test of SAN in rats were studied. The absorption of SAN at 20, 40, and 80 mg/L in different intestinal segments was investigated, and verapamil hydrochloride (P-gp inhibitor), celecoxib (MPR2 inhibitor), and ko143 (BCRP inhibitor) were further used to determine the effect of efflux transporter proteins on SAN absorption. The equilibrium solubility of SAN in three buffer solutions (pH 1.2, 4.5 and 6.8) was investigated. The oral pharmacokinetic results in rats showed that SAN was rapidly absorbed (Tmax=0.5 h), widely distributed (Vz/F = 134 L/kg), rapidly metabolized (CL = 30 L/h/kg), and had bimodal phenomena. SPIP experiments showed that P-gp protein could significantly affect the effective permeability coefficient (Peff) and apparent absorption rate constant (Ka) of SAN. Equilibrium solubility test results show that SAN has the best solubility at pH 4.5. In conclusion, SAN is a substrate of P-gp, and its transport modes include efflux protein transport, passive transport and active transport.

[Preparation and intestinal absorption mechanism of self-assembled nanoparticles of Herpetospermum caudigerum].

In this experiment, the micro-precipitation method was used to prepare self-assembled nanoparticles of Herpetospermum caudigerum Wall.(MP-SAN). The process was optimized using average particle size and polydispersity index(PDI)as evaluation indexes. The mean particle size, PDI,zeta potential, and microstructure of MP-SAN were characterized. The intestinal absorption mechanism of dehydrodiconiferyl alcohol(DA)and herpetrione(Her)in MP-SAN was investigated through single-pass intestinal perfusion in rats. The optimized process parameters for producing MP-SAN were a stirring speed of 800 r·min~(-1),stirring time of 5 min, and rotary evaporation temperature of 40℃. The resulting MP-SAN exhibited a spherical-like structure and uniform morphology, with a mean particle size of(267.63±13.27) nm, a PDI of 0.062 0±0.043 9,and a zeta potential of(-46.18±3.66) mV. The absorption rate constant(K_a)and apparent permeability coefficient(P_(app))of DA in the ileal segment were significantly higher than those in the jejunal segment(P<0.05). However, there was no significant difference in the absorption of Her between the ileal and jejunal segments. Intestinal absorption parameters of DA and Her tended to increase with increasing drug concentration. Specifically, the K_a and P_(app) of DA in MP-SAN in the high-concentration group were significantly higher than those in the low-concentration group(P<0.01). The addition of verapamil, a P-glycoprotein inhibitor, did not significantly affect the intestinal absorption of DA and Her. However, the absorption of both DA and Her in MP-SAN was significantly increased by the addition of indomethacin(P<0.05),suggesting that DA and Her may be substrates for multidrug resistance-associated protein 2.

Trilayer Polymer Electrolytes Enable Carbon-Efficient CO2 to Multicarbon Product Conversion in Alkaline Electrolyzers.

The electrochemical CO2 reduction reaction (CO2RR) is an appealing method for carbon utilization. Alkaline CO2 electrolyzers exhibit high CO2RR activity, low full-cell voltages, and cost-effectiveness. However, the issue of CO2 loss caused by (bi)carbonate formation leads to excessive energy consumption, rendering the process economically impractical. In this study, we propose a trilayer polymer electrolyte (TPE) comprising a perforated anion exchange membrane (PAEM) and a bipolar membrane (BPM) to facilitate alkaline CO2RR. This TPE enables the coexistence of high alkalinity near the catalyst surface and the H+ flux at the interface between the PAEM and the cation exchange layer (CEL) of the BPM, conditions favoring both CO2 reduction to multicarbon products and (bi)carbonate removal in KOH-fed membrane electrode assembly (MEA) reactors. As a result, we achieve a Faradaic efficiency (FE) of approximately 46 % for C2H4, corresponding to a C2+ FE of 64 % at 260 mA cm-2, with a CO2-to-C2H4 single-pass conversion (SPC) of approximately 32 % at 140 mA cm-2-nearly 1.3 times the limiting SPC in conventional AEM-MEA electrolyzers. Furthermore, coupling CO2 reduction with formaldehyde oxidation reaction (FOR) in the TPE-MEA electrolyzer reduces the full-cell voltage to 2.3 V at 100 mA cm-2 without compromising the C2H4 FE.

Hypotonicity-Induced Increase in Duodenal Mucosal Permeability Is Regulated by Cholinergic Receptors in Rats.

BACKGROUND: The role of cholinergic receptors in the regulation of duodenal mucosal permeability in vivo is currently not fully described. AIMS: To elucidate the impact of nicotinic and muscarinic acetylcholine receptor signaling in response to luminal hypotonicity (50 mM NaCl) in the proximal small intestine of rat. METHODS: The effect on duodenal blood-to-lumen clearance of 51Cr-EDTA (i.e., mucosal permeability) and motility was studied in the absence and presence of nicotinic and muscarinic receptor agonists and antagonists, a sodium channel blocker (tetrodotoxin), and after bilateral cervical vagotomy. RESULTS: Rats with duodenal contractions responded to luminal hypotonicity by substantial increase in intestinal permeability. This response was absent in animals given a non-selective nicotinic receptor antagonist (mecamylamine) or agonist (epibatidine). Pretreatment with tetrodotoxin reduced the increase in mucosal permeability in response to luminal hypotonicity. Further, the non-selective muscarinic receptor antagonist (atropine) and agonist (bethanechol) reduced the hypotonicity-induced increase in mucosal permeability, while vagotomy was without an effect, suggesting that local enteric reflexes dominate. Finally, neither stimulating nor blocking the α7-nicotinic receptor had any significant effects on duodenal permeability in response to luminal hypotonicity, suggesting that this receptor is not involved in regulation of duodenal permeability. The effect of the different drugs on mucosal permeability was similar to the effect observed for duodenal motility. CONCLUSIONS: A complex enteric intramural excitatory neural reflex involving both nicotinic and muscarinic receptor subtypes mediates an increase in mucosal permeability induced by luminal hypotonicity.

A Novel Oral Drugs Delivery System for Borneol Based on HiCap®100 and Maltodextrin: Preparation, Characterization, and the Investigation as an Intestinal Absorption Enhancer.

The objective of this study was to create a new method for delivering oral borneol (BN) drug that would improve stability. This was accomplished through microencapsulation using HiCap®100 and maltodextrin (MD), resulting in HiCap®100/MD/BN microcapsules (MCs). The HiCap®100/MD/BN MCs were evaluated in terms of encapsulation efficiency (EE%), drug loading (DL%), morphological observations, particle size distribution, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermal analysis, drug degradation rate studies, and in vitro release behavior. The effect of MCs on intestinal permeability in a rat model was assessed using the model drug "florfenicol" (FF) in single-pass intestinal perfusion (SPIP) study. The relationship between MCs and P-glycoprotein (P-gp) was further investigated in comparison with verapamil (Ver). The irritation of MCs was assessed by histological analysis. The MCs in a spherical structure with micron-scale dimensions were obtained. The EE% and DL% were (86.71 ± 0.96)% and (6.03 ± 0.32)%, respectively. MCs played a significantly protective role in drug degradation rate studies. In vitro release studies indicated that the release behavior of MCs was significantly better than BN at the three-release media, and the cumulative release rate exceeded 90% in 15 min. The SPIP studies showed that MCs significantly enhanced the absorption of FF in rats. Compared with Ver, MCs were not promoted by a single inhibition of P-gp. Hematoxylin-eosin (HE)-stained images showed that MCs had no obvious irritation and toxic effects on the intestines of rats. Thus, the preparation of HiCap®100/MD/BN MCs improves the stability of BN, which has certain scientific value for the development and application of BN, and provides unique perspectives for future BN-related researches.

Ni2+ Catalyzed Cleavage of TrpLE-Fused Small Transmembrane Peptides.

In addition to a membrane anchor, the transmembrane domain (TMD) of single-pass transmembrane proteins (SPTMPs) recently has shown essential roles in the cross-membrane activity or receptor assembly/clustering. However, these small TMD peptides are generally hydrophobic and dynamic, difficult to be expressed and purified. Here, we have integrated the power of TrpLE fusion protein and a sequence-specific nickel-assisted cleavage (SNAC)-tag to produce small TMD peptides in a highly efficient way under mild conditions, which uses Ni2+ as the cleavage reagent, avoiding the usage of toxic cyanogen bromide (CNBr). Furthermore, this method simplifies the downstream protein purification and reconstitution. Two representative TMDs, including the Spike-TMD from severe acute respiratory syndrome coronavirus 2 (SARS2), were successfully produced with high-quality nuclear magnetic resonance (NMR) spectra. Therefore, our study provides a more efficient and practical approach for general structural characterization of the small TM proteins.

The rapid transformation of triclosan in the liver reduces its effectiveness as inhibitor of hepatic energy metabolism.

Triclosan (5-chloro-2'-[2,4-dichlorophenoxi]-phenol) is a polychlorinated biphenolic antimicrobial, utilized as antiseptic and preservative in hygiene products and medical equipment. Triclosan causes mitochondrial dysfunction (uncoupling, inhibition of electron flow), as demonstrated in isolated rat liver mitochondria. These actions in the mitochondria could compromise energy-dependent metabolic fluxes in the liver. For this reason, the present work aimed at investigating how these effects on isolated mitochondria translate to the whole and intact hepatocyte. For accomplishing this, the isolated perfused rat liver was utilized, a system that preserves both microcirculation and the cell-to-cell interactions. In addition, the single-pass triclosan hepatic transformation was also evaluated by HPLC as well as the direct action of triclosan on gluconeogenic enzymes. The results revealed that triclosan decreased anabolic processes (e.g., gluconeogenesis) and increased catabolic processes (e.g., glycolysis, ammonia output) in the liver, generally with a complex pattern of concentration dependences. Unlike the effects on isolated mitochondria, which occur in the micromolar range, the effects on intact liver required the 10-5 to 10-4 M range. The most probable cause for this behavior is the very high single-pass transformation of triclosan, which was superior to 95% at the portal concentration of 100 µM. The concentration gradient along the sinusoidal bed is, thus, very pronounced and the response of the liver reflects mainly that of the periportal cells. The high rates of hepatic biotransformation may be a probable explanation for the low acute toxicity of triclosan upon oral ingestion.

Exploring the Predictive Power of the In Situ Perfusion Technique towards Drug Absorption: Theory, Practice, and Applications.

Considering the broad applications and popularity, the in situ perfusion technique is an established and interesting approach to evaluate the absorption mechanisms of drug molecules in specific regions of the intestinal tract. Compared to perfusion studies in humans, this surrogate model shows several familiar characteristics making it interesting to apply this technique in rats in the non-clinical stage of drug product development. The differences in gastrointestinal (GI) anatomy and physiology between rats and humans are thoroughly discussed in the present review. Moreover, an in-depth overview of the Doluisio (i.e., closed-loop) versus the single-pass intestinal perfusion (i.e., open-loop) technique is shown. Finally, applications and future perspectives of the technique are presented.

Evaluation of Single-Pass Disinfection Performance of Far-UVC Light on Airborne Microorganisms in Duct Flows.

Far-UVC irradiation (222 nm) is considered an emerging and sustainable solution for future infection and pandemic challenges. We examined the disinfection performance of a krypton-chloride lamp, with a quasi-monochromatic UVC peak at 222 nm, for inactivating airborne microorganisms in a full-scale ventilation duct system. Single-pass disinfection efficacy of far-UVC was determined and compared with that of a conventional mercury-type UVC (254 nm) lamp. Four bacteria, Escherichia coli (E. coli), Pseudomonas alcaligenes (P. alcaligenes), Serratia marcescens (S. marcescens), and Staphylococcus epidermidis (S. epidermidis), as well as bacteriophage P22, were tested under UV exposure with different velocities of duct flows. The data revealed that as the air velocity increased from 0.7 to 4 m/s, the far-UVC disinfection efficacies would decrease by 42, 47, 35, 39, and 33% for these five microorganisms, respectively. The inactivation rate constants to far-UVC light were 4.9, 7.5, 3.3, 6.3, and 3.0 cm2/mJ for aerosolized E. coli, P. alcaligenes, S. marcescens, S. epidermidis, and bacteriophage P22, respectively. Far-UVC irradiation showed a comparable disinfection ability on airborne microorganisms compared with the 254 nm UV irradiation. This first study of far-UVC in real duct applications provides a better understanding of the disinfection performance of this solution in bioaerosol inactivation. It offers a valuable database in the sizing and design of excimer lamps for novel portable air purifiers or in-duct disinfection units.

Extracorporeal Albumin Dialysis in Liver Failure with MARS and SPAD: A Randomized Crossover Trial.

INTRODUCTION: Liver failure is associated with hepatic and extrahepatic organ failure leading to a high short-term mortality rate. Extracorporeal albumin dialysis (ECAD) aims to reduce albumin-bound toxins accumulated during liver failure. ECAD detoxifies blood using albumin dialysis through an artificial semipermeable membrane with recirculation (molecular adsorbent recirculating system, MARS) or without (single-pass albumin dialysis, SPAD). METHODS: We performed a randomized crossover open trial in a surgical intensive care unit. The primary outcome of the study was total bilirubin reduction during MARS and during SPAD therapies. The secondary outcomes were conjugated bilirubin and bile acid level reduction during MARS and SPAD sessions and tolerance of dialysis system devices. Inclusion criteria were adult patients presenting liver failure with factor V activity <50% associated with bilirubin ≥250 µmol/L and a complication (either hepatic encephalopathy, severe pruritus, or hepatorenal syndrome). For MARS and SPAD, the dialysis flow rate was equal to 1,000 mL/h. RESULTS: Twenty crossovers have been performed. Baseline biochemical characteristics (bilirubin, ammonia, bile acids, creatinine, and urea) were not statistically different between MARS and SPAD. Both ECAD have led to a significant reduction in total bilirubin (-83 ± 67 µmol/L after MARS; -122 ± 118 µmol/L after SPAD session), conjugated bilirubin (-82 ± 61 µmol/L after MARS; -105 ± 96 µmol/L after SPAD session), and bile acid levels (-64 ± 75 µmol/L after MARS; -56 ± 56 µmol/L after SPAD session), all nondifferent comparing MARS to SPAD. CONCLUSION: A simple-to-perform SPAD therapy with equal to MARS dialysate flow parameters provides the same efficacy in bilirubin and bile acid removal. However, clinically relevant endpoints have to be evaluated in randomized trials to compare MARS and SPAD therapies and to define the place of SPAD in the liver failure care program.

Single-pass albumin dialysis and hemoadsorption for bilirubin and bile acids removal for a child with hyperbilirubinemia after ventricular assist device implantation.

We report the successful management of hyperbilirubinemia using two different modalities of extracorporeal bilirubin removal therapy for a pediatric patient. A 13-year-old boy with dilated cardiomyopathy requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO) developed acute kidney injury and was dependent on continuous renal replacement therapy. He developed hyperbilirubinemia with a peak total bilirubin level of 786 µmol/L after implantation of biventricular assist device (BiVAD). Extracorporeal bilirubin and bile acids removal using single-pass albumin dialysis (SPAD) with 4% albumin as dialysate brought down the bilirubin level to 672 µmol/L after 21 h of therapy. Subsequently, he was started on two sessions of hemoadsorption using the Cytosorb® column which further lowered the total bilirubin level to 306 µmol/ in 24 h and 173 µmol/ after the treatment. No complication was encountered. Our case illustrated that both SPAD and hemoadsorption can effectively and safely reduce the serum bilirubin and bile acid levels in pediatric patients with BiVAD implantation. The ease of set-up, faster rate of bilirubin decline and capability of cytokine removal make hemoadsorption a favorable alternative to albumin dialysis.

Protective Effects of Melatonin and Misoprostol against Experimentally Induced Increases in Intestinal Permeability in Rats.

Intestinal mucosal barrier dysfunction caused by disease and/or chemotherapy lacks an effective treatment, which highlights a strong medical need. Our group has previously demonstrated the potential of melatonin and misoprostol to treat increases in intestinal mucosal permeability induced by 15-min luminal exposure to a surfactant, sodium dodecyl sulfate (SDS). However, it is not known which luminal melatonin and misoprostol concentrations are effective, and whether they are effective for a longer SDS exposure time. The objective of this single-pass intestinal perfusion study in rats was to investigate the concentration-dependent effect of melatonin and misoprostol on an increase in intestinal permeability induced by 60-min luminal SDS exposure. The cytoprotective effect was investigated by evaluating the intestinal clearance of 51Cr-labeled EDTA in response to luminal SDS as well as a histological evaluation of the exposed tissue. Melatonin at both 10 and 100 µM reduced SDS-induced increase in permeability by 50%. Misoprostol at 1 and 10 µM reduced the permeability by 50 and 75%, respectively. Combination of the two drugs at their respective highest concentrations had no additive protective effect. These in vivo results support further investigations of melatonin and misoprostol for oral treatments of a dysfunctional intestinal barrier.

Nomogram for single-pass automated microkeratome graft preparation for ultrathin Descemet stripping automated endothelial keratoplasty.

PURPOSE: To create a nomogram including the translational speed of the microkeratome blade, microkeratome head size and precut tissue thickness to predict the postcut thickness for Descemet stripping automated endothelial keratoplasty to obtain the thinnest possible graft. METHODS: This prospective study incorporated 48 grafts for DSAEK from March 2017 to June 2020. Corneal tissue for DSAEK was prepared by 3 experienced physicians using the Moria Evolution 3E (Moria Inc, Antony, France) microkeratome with 400, 450 and 500 µm head sizes. Precut central corneal thickness was measured with a DGH 550 handheld pachymeter (Pachette 2), taking an average of 3 readings. The microkeratome head was selected according to precut tissue thickness. The selected microkeratome head size was 150 µm less than the donor cornea thickness. Two translational speeds were used for the microkeratome cuts. One month after surgery, the central lenticular thickness was measured with a Visante® Optical Coherence Tomography caliper (Carl Zeiss Meditec Inc, Germany). A descriptive analysis was performed. RESULTS: Forty-eight donor grafts were prepared. Mean graft thickness was 97.58 ± 29.84 µm (range 39-176 µm). Of the 48 samples, central graft thickness was < 120 µm (81.3%) in 39, < 100 µm (58.3%) in 28 and < 80 µm (37.5%) in 18 at 1-month follow-up. There were no statically significant differences between translational speeds. CONCLUSIONS: A nomogram with an automated microkeratome to obtain thin grafts for DSAEK provided good graft thickness results without donor waste.

The Longer Route can be Better: Electrosynthesis in Extended Path Flow Cells.

This personal account provides an overview of work conducted in my research group, and through collaborations with other chemists and engineers, to develop flow electrolysis cells and apply these cells in organic electrosynthesis. First, a brief summary of my training and background in organic synthesis is provided, leading in to the start of flow electrosynthesis in my lab in collaboration with Derek Pletcher. Our work on the development of extended path electrolysis flow reactors is described from a synthetic organic chemist's perspective, including laboratory scale-up to give several moles of an anodic methoxylation product in one day. The importance of cell design is emphasised with regards to achieving good performance in laboratory electrosynthesis with productivities from hundreds of mg h-1 to many g h-1 , at high conversion in a selective fashion. A simple design of recycle flow cell that can be readily constructed in a small University workshop is also discussed, including simple modifications to improve cell performance. Some examples of flow electrosyntheses are provided, including Shono-type oxidation, anodic cleavage of protecting groups, Hofer-Moest reaction of cubane carboxylic acids, oxidative esterification and amidation of aldehydes, and reduction of aryl halides.

Glycyrrhizic acid-based self-assembled micelles for improving oral bioavailability of paeoniflorin.

BACKGROUND: Paeoniflorin (Pae), a water-soluble monoterpene glucoside, has high potential clinical value in autoimmune and inflammatory diseases. However, the extremely low oral bioavailability of Pae (approximately 3%-4%) limits its formulation development and clinical application. This study aimed to develop micelles using the glycyrrhizic acid (GL) as the carrier to improve the oral absorption of Pae. METHODS: Pae-loaded GL micelles were prepared by the ultrasonic dispersion method and its formulation was optimized by single-factor tests. Characterizations of Pae-loaded GL micelles including particle size, zeta potential, entrapment efficiency (EE), drug loading (DL), morphology, and drug release in vitro were carried out. The single-pass intestinal perfusion and pharmacokinetic studies of Pae-loaded GL micelles were also evaluated in rats and compared with Pae solution and the mixed solution of Pae and GL. RESULTS: The optimized Pae-loaded GL micelles had EE of (42.21 ± 0.89)%, particle size of (58.89 ± 4.24) nm with PDI of (0.194 ± 0.010), zeta potential of (-24.40 ± 1.90) mV. Pae-loaded GL micelles showed a nearly spherical shape under TEM. Drug release of micelles demonstrated a delayed drug release compared to Pae solution. The single-pass intestinal perfusion study showed a significantly higher permeability of Pae in duodenum (p < 0.05), jejunum (p < 0.05), ileum (p < 0.01) and colon (p < 0.01) intestine after perfusion of Pae-loaded GL micelles as compared to Pae solution. The in vivo pharmacokinetics demonstrated that the Cmax and AUC0-t values of Pae-loaded GL micelles were approximately 2.18- and 3.64-fold superior than the Pae solution. CONCLUSION: These results suggested GL could be a potential carrier for the oral delivery of Pae.

Melatonin-Activated Receptor Signaling Pathways Mediate Protective Effects on Surfactant-Induced Increase in Jejunal Mucosal Permeability in Rats.

A well-functional intestinal mucosal barrier can be compromised as a result of various diseases, chemotherapy, radiation, and chemical exposures including surfactants. Currently, there are no approved drugs targeting a dysfunctional intestinal barrier, which emphasizes a significant medical need. One candidate drug reported to regulate intestinal mucosal permeability is melatonin. However, it is still unclear if its effect is primarily receptor mediated or antioxidative, and if it is associated with enteric neural pathways. The aim of this rat intestinal perfusion study was to investigate the mechanisms of melatonin and nicotinic acetylcholine receptors on the increase in intestinal mucosal clearance of 51Cr-labeled ethylenediaminetetraacetate induced by 15 min luminal exposure to the anionic surfactant, sodium dodecyl sulfate. Our results show that melatonin abolished the surfactant-induced increase in intestinal permeability and that this effect was inhibited by luzindole, a melatonin receptor antagonist. In addition, mecamylamine, an antagonist of nicotinic acetylcholine receptors, reduced the surfactant-induced increase in mucosal permeability, using a signaling pathway not influenced by melatonin receptor activation. In conclusion, our results support melatonin as a potentially potent candidate for the oral treatment of a compromised intestinal mucosal barrier, and that its protective effect is primarily receptor-mediated.

Physicochemical Characterization and Biopharmaceutical Evaluation of ZWF: A Novel Anticancer Drug for the Treatment of Non-small Cell Lung Cancer.

The orally available novel small molecule drug ZWF is under preclinical development for an anticancer purpose. The present study aimed to assess the viability of developing ZWF as a form of oral formulation for clinical application based on the principles of biopharmaceutics and pharmacokinetics. The crucial physicochemical properties of ZWF were determined by in vitro assays. The in situ gastrointestinal absorption characteristics and in vivo pharmacokinetic behaviors of ZWF in rats were characterized. The solubility of ZWF showed a highly pH-dependent profile, decreasing from 25,392.89 to 20.48 µg/mL as the solution pH increased from 1.0 to 5.8. In PBS with a pH of 1.0 to 5.8, the LogP value of ZWF ranged from -2.35 to 2.20 and was gradually increased as the pH value increased. ZWF was partially absorbed in the stomach, and the favorable absorption sites were the duodenum, jejunum, and ileum. Pharmacokinetic studies showed that the AUC(0-t) and Cmax values of ZWF after its oral administration as a suspension prepared with 0.5% CMC-Na were increased by 18.97% and 40% than that with normal saline, providing a model oral formulation of ZWF with ideal bioavailability and system exposure in rats. From the perspective of oral absorption, ZWF possessed appealing qualities as a drug candidate and could be prepared as an oral preparation for clinical application. The present study has established a fundamental foundation for the development and quality evaluation of the ZWF oral formulations.