Papp Values Research Articles

Preformulation Studies of Novel Menthol Prodrugs with Antiparasitic Activity: Chemical Stability, In Silico, and In Vitro Permeability Assays

Based on the demonstrated and reported trypanocidal, leishmanicidal, and antiplasmodial activities of two menthol prodrugs, it was decided to proceed with preformulation studies, which are of key relevance in the drug discovery process. The aim of this study is to examine the stability and permeability of two new menthol prodrugs with antiparasitic activity. To determine the stability of menthol and its prodrugs, the corresponding studies were carried out in buffered solutions at pH values of 1.2, 5.8, and 7.4 at 37 °C. In silico permeability studies were performed using the free PerMM software and then in vitro permeability studies were performed using a biomimetic artificial membrane (BAM). Permeability studies conducted in silico predicted that both menthol and its prodrugs would pass through biological membranes via flip-flop movement. This prediction was subsequently confirmed by in vitro BAM permeability studies, where it was observed that the menthol prodrugs (1c and 1g) exhibited the highest Papp (apparent permeability) value compared to the parent compound. The study reveals that menthol prodrugs exhibit stability at a pH of 5.8 and possess sufficient in vitro permeability values as preformulation parameters.

In vitro blood[sbnd]brain barrier permeability study of four main active ingredients from Alpiniae oxyphyllae fructus

The fruits of Alpinia oxyphylla Miq., a broadly utilized traditional Chinese medicine, have a number of effects on the central nervous system (CNS). The main active constituents of Alpiniae oxyphyllae fructus (AOF) were nootkatone, tectochrysin, chrysin and protocatechuic acid. An immortalized human brain microvascular endothelial cell (hCMEC/D3) and astrocyte (HA1800) coculture model was used to investigate the permeability of the blood-brain barrier (BBB). The validation of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) methods for the four compounds was conducted following industry guidelines. Calibration curves were generated with mean coefficients (R2) better than 0.99. The inter-day and intra-day precisions were less than 8.53% and 7.12%, respectively. The accuracies were lower than ± 11.57%, and recoveries were greater than 86.07%. The samples of the transport experiment were examined, and the apparent permeability coefficients (Papp) were calculated. The efflux ratios of the four compounds are all less than 2. The Papp values of protocatechuic acid, chrysin, nootkatone, tectochrysin were at the level of 10−5, 10−6, 10−6, and 10−7 cm/s, respectively. All four compounds crossed the BBB by passive diffusion, with protocatechuic acid having high permeability, and tectochrysin having poor permeability. This research indicated the permeability of protocatechuic acid, chrysin, nootkatone and tectochrysin through the BBB and offered a foundation for related research on AOF in the treatment of CNS illnesses.

Transepithelial transport characteristics of Hydroxysafflor yellow A across cellular monolayers and the effects of the influx and efflux transporters

Hydroxysafflor yellow A (HSYA), the major biologically active constituent distributed in the florets of Carthamus tinctorius L. (safflower), is concerned with potential health-promoting functions against cardiovascular diseases. However, little information on clarifying the intestinal absorption characteristics of HSYA has been reported, which has limited its widespread application in the medical and healthcare fields. The intention of this research was to systematically characterize the transepithelial transport of HSYA using in vitro cell monolayer models (Caco-2, mucus-producing Caco-2/HT29-MTX-E12, MDCKⅡ and P-gp overexpressed MDCKⅡ-MDR1 cell monolayers). The apparent permeability coefficient (Papp) from the apical to the basolateral side of HSYA is approximately (4.30 ± 0.22) × 10⁻⁸ cm/s, suggesting that HSYA is poorly absorbed across the intestinal epithelium. The transport and uptake of HSYA depends on time, concentration, pH and temperature, and the Papp values increase with ethylene diamine tetraacetic acid pretreatment, indicating that the transport mechanisms of HSYA include passive diffusion (transcellular and paracellular pathways) and carrier-mediated transport. Meanwhile, transporter inhibitors were added in transport and uptake experiments, the results showed that carrier-mediated efflux and influx transport of HSYA is relevant to P-glycoprotein and H⁺ correlative transporters (e.g., peptide transporter 1, monocarboxylic acid transporter). In addition, the mucus layer acts as a barrier to HSYA absorption, as evidenced by a decrease in Papp (22–47%) and cellular uptake (18%) in the coculture model compared to the Caco-2 cell model. Detailed knowledge on the transepithelial transport of HSYA would provide insights to improve the pharmacological activities of HSYA and expand its application in food and healthcare fields.

Impact of dietary plant flavonoids on 7,8-dihydroxyflavone transepithelial transport in human intestinal Caco-2 cells.

7,8-dihydroxyflavone (7,8-DHF) is a biologically active flavone with various physiological activities, including neuroprotection, anti-inflammation, and weight loss. Previous studies have found that the efflux protein P-glycoprotein (P-gp) significantly affects the transepithelial transport of 7,8-DHF in the intestine, resulting in its low oral bioavailability. Based on this, in this study, a Caco-2 monolayer cell model was used to investigate 14 dietary plant flavonoids as potential P-gp inhibitors, and their effects on the transepithelial transport and in vitro digestion of 7,8-DHF were explored. The results showed that among the 14 plant flavonoids, hesperetin, epigallocatechin gallate, fisetin, kaempferol, quercetin, and isoorientin increased and the apparent permeability coefficients (P app) of 7,8-DHF at AP → BL direction and lowered P app value at BL → AP direction to varying degrees, reducing the efflux ratio of 7,8-DHF less than 1.5. In particular, kaempferol and quercetin exhibited the best effect on promoting the transepithelial transport of 7,8-DHF, especially when used at molar concentration ratios of 1:1 and 1:2 with 7,8-DHF. This is beneficial for improving the oral bioavailability of 7,8-DHF. Meanwhile, 7,8-DHF was found to maintain structural stability in simulated saliva, gastric juice, and intestinal juice, and its stability was not affected by the coexistence of quercetin and kaempferol. Overall, this study provided a theoretical basis for seeking natural and safe P-gp inhibitors to improve the oral absorption of natural products.

Plasma non-transferrin-bound iron uptake by the small intestine leads to intestinal injury and intestinal flora dysbiosis in an iron overload mouse model and Caco-2 cells.

Iron overload often occurs during blood transfusion and iron supplementation, resulting in the presence of non-transferrin-bound iron (NTBI) in host plasma and damage to multiple organs, but effects on the intestine have rarely been reported. In this study, an iron overload mouse model with plasma NTBI was established by intraperitoneal injection of iron dextran. We found that plasma NTBI damaged intestinal morphology, caused intestinal oxidative stress injury and reactive oxygen species (ROS) accumulation, and induced intestinal epithelial cell apoptosis. In addition, plasma NTBI increased the relative abundance of Ileibacterium and Desulfovibrio in the cecum, while the relative abundance of Faecalibaculum and Romboutsia was reduced. Ileibacterium may be a potential microbial biomarker of plasma NTBI. Based on the function prediction analysis, plasma NTBI led to the weakening of intestinal microbiota function, significantly reducing the function of the extracellular structure. Further investigation into the mechanism of injury showed that iron absorption in the small intestine significantly increased in the iron group. Caco-2 cell monolayers were used as a model of the intestinal epithelium to study the mechanism of iron transport. By adding ferric ammonium citrate (FAC, plasma NTBI in physiological form) to the basolateral side, the apparent permeability coefficient (Papp) values from the basolateral to the apical side were greater than 3×10-6 cm s-1. Intracellular ferritin level and apical iron concentration significantly increased, and SLC39A8 (ZIP8) and SLC39A14 (ZIP14) were highly expressed in the FAC group. Short hairpin RNA (shRNA) was used to knock down ZIP8 and ZIP14 in Caco-2 cells. Transfection with ZIP14-specific shRNA decreased intracellular ferritin level and inhibited iron uptake. These results revealed that plasma NTBI may cause intestinal injury and intestinal flora dysbiosis due to the uptake of plasma NTBI from the basolateral side into the small intestine, which is probably mediated by ZIP14.

Methylprednisolone 100 mg tablet formulation with pea protein: experimental approaches over intestinal permeability and cytotoxicity

Objective This study was carried out to transform the hydrolyzed pea protein into a pharmaceutical tablet form by masking methylprednisolone. Significance This study provides some crucial contributions in showing how functional excipients such as pea protein, which are generally used in food industries, can be used in pharmaceutical product formulations and their effects. Methods Methylprednisolone was formulated using spray drying technology. Design Expert Software (Version 13) was used for the statistical analysis. The in vitro cytotoxic effects for NIH/3T3 mouse fibroblast cells were investigated by XTT cell viability assay. HPLC was used to analyze the Caco-2 permeability studies and dissolution tests. Results The optimum formulation was evaluated against the reference product by performing cytotoxicity and cell permeability studies. According to our test results, Papp (apparent permeability) values of Methylprednisolone were measured around 3 × 10-6 cm/s and Fa (fraction absorbed) values around 30%. These data indicate that Methylprednisolone HCl has ‘moderate permeability’ and our study confirmed that it could have belonged to BCS Class II-IV since both low solubility and moderate permeability. Conclusion The findings offer valuable information to guide and inform the use of pea protein in pharmaceutical formulations. Significant effects on methylprednisolone tablet formulation designed with the philosophy of quality by design (QbD) of pea protein have been demonstrated by both in vitro and cell studies.

Comparison of Ussing Chamber and Caco-2 Model in Evaluation of Intestinal Absorption Mechanism of Compounds from Different BCS Classifications.

Oral bioavailability (F), which is evaluated by permeability and solubility, is one of the key parameters in drug discovery. Currently, Caco-2 and Ussing chamber are both used in the study of intestinal permeability of drugs at different stages of drug development. However, comparative research between the Ussing chamber and Caco-2 for predicting the intestinal availability data (Fa×Fg) in humans has not been reported. In the present study, we evaluated the permeability of 22 drugs in rat intestines by Ussing chamber and compared them with the reported permeability data from Caco-2. In addition, the active transport of gabapentin was evaluated by Ussing Chamber. Intestine segments were selected by corresponding absorption site for Ussing chamber analysis. BCS Class I and II compounds were more absorbed in the duodenum and jejunum, and Class III and IV compounds were more absorbed in the ileum. Papp values in the Caco-2 model were moderately correlated with human Fa×Fg (R2=0.722), and the Papp of the rat in the Ussing chamber revealed a better correlation with human Fa×Fg (R2=0.952). In addition, we also used the Ussing chamber to identify the transporter of gabapentin, and the results showed that the active absorption of gabapentin was related to LAT1. Ussing chamber combined with rat intestinal tissue would be a significant tool for predicting the intestinal absorption and metabolism of compounds with diverse physiochemical characteristics.

Novel Casein-Derived Peptide-Zinc Chelate: Zinc Chelation and Transepithelial Transport Characteristics

Casein-derived peptides are recognized as promising candidates for improving zinc bioavailability through the form of a peptide-zinc chelate. In the present work, a novel 11-residue peptide TEDELQDKIHP identified from casein hydrolysate in our previous study was synthesized to investigate the zinc chelation characteristics. Meanwhile, the digestion stability and transepithelial transport of TEDELQDKIHP-Zn were also investigated. The obtained results indicated that the carboxyl groups (from Asp and Glu), amino groups (from Lys and His), pyrrole nitrogen group of Pro, and imidazole nitrogen group of His were responsible for zinc chelation. The complexation with zinc resulted in a more ordered structure of TEDELQDKIHP-Zn. In terms of digestion stability, the chelate of TEDELQDKIHP-Zn could remain stable to a large extent after gastric (78.54 ± 0.14%) and intestinal digestion (70.18 ± 0.17%). Moreover, TEDELQDKIHP-Zn was proven to be a well-absorbed biological particle with a Papp value higher than 1 × 10-6 cm/s, and it could be transported across the intestine epithelium through transcytosis. TEDELQDKIHP-Zn exhibited more bioavailable effects on zinc absorption and ALP activity than inorganic zinc sulfate.

Differences in tissue distribution ability of evodiamine and dehydroevodiamine are due to the dihedral angle of the molecule stereo-structure.

Introduction: This researcher focused at the evodiamine and dehydroevodiamine tissue distribution and structure-pharmacokinetics (PK) relationship after intravenous injection in mice. Methods: Using a transmembrane transport experiment, the permeability of evodiamine and dehydroevodiamine on Caco-2 cells was evaluated. The tissue distribution and pharmacokinetics (PK) of evodiamine and dehydroevodiamine in mice were studied. To comprehend the connection between structure and tissue distribution, physicochemical property evaluations and molecular electrostatic potential (MEP) calculations were performed. Results: Dehydroevodiamine's Papp values in vitro were 10-5cm/s, whereas evodiamine's were 10-6cm/s. At a dose of 5mg/kg, the brain concentration of dehydroevodiamine was 6.44 times more than that of evodiamine. By MEP or physicochemical measures, the permeability difference between evodiamine and dehydroevodiamine is unaffected. The dihedral angle of the stereo-structure appears to be the main cause of the difference in tissue distribution ability between evodiamine and dehydroevodiamine. Discussion: Dehydroevodiamine has a dihedral angle of 3.71° compared to 82.34° for evodiamine. Dehydroevodiamine can more easily pass through the phospholipid bilayer than evodiamine because it has a more planar stereo-structure. Dehydroevodiamine is therefore more likely to pass cross the blood-brain barrier and enter the brain in a tissue-specific manner.

CRBN ligand expansion for hematopoietic prostaglandin D2 synthase (H-PGDS) targeting PROTAC design and their in vitro ADME profiles

An increasing number of research reports are describing modifications of the E3 ligand, in particular, cereblon (CRBN) ligands, to improve the chemical and metabolic stabilities as well as the physical properties of PROTACs. In this study, phenyl-glutarimide (PG) and 6-fluoropomalidomide (6-F-POM), recently used as CRBN ligands for PROTAC design, were applied to hematopoietic prostaglandin D2 synthase (H-PGDS)-targeted PROTACs. Both PROTAC-5 containing PG and PROTAC-6 containing 6-F-POM were found to have potent activities to induce H-PGDS degradation. Furthermore, we obtained in vitro ADME data on the newly designed PROTACS as well as our previously reported PROTACs(H-PGDS) series. Although all PROTACs(H-PGDS) are relatively stable toward metabolism, they had poor PAMPA values. Nevertheless, PROTAC-5 showed Papp values similar to TAS-205, which is in Phase 3 clinical trials, and is expected to be the key to improving the pharmacokinetics of PROTACs.

Generation of Caco-2 cells with predictable metabolism by CYP3A4, UGT1A1 and CES using the PITCh system

Caco-2 cells are widely used as an in vitro intestinal model. However, the expression levels of the drug-metabolizing enzymes CYP3A4 and UGT1A1 are lower in these cells than in intestinal cells. Furthermore, the majority of prodrugs in use today are ester-containing, and carboxylesterase (CES) 1 and CES2 are among the enzymes that process the prodrugs into drugs. In the human small intestine, CES1 is hardly expressed while CES2 is highly expressed, but the CES expression pattern in Caco-2 cells is the opposite. In this study, we generated CYP3A4-POR-UGT1A1-CES2 knock-in (KI) and CES1 knock-out (KO) Caco-2 (genome-edited Caco-2) cells using a PITCh system. Genome-edited Caco-2 cells were shown to express functional CYP3A4, POR, UGT1A1 and CES2 while the expression of the CES1 protein was completely knocked out. We performed transport assays using temocapril. The Papp value of temocapril in genome-edited Caco-2 cells was higher than that in WT Caco-2 cells. Interestingly, the amount of temocaprilat on the apical side in genome-edited Caco-2 cells was lower than that in WT Caco-2 cells. These results suggest that genome-edited Caco-2 cells are more suitable than WT Caco-2 cells as a model for predicting intestinal drug absorption and metabolism.

Polyols Permeability on Caco-2 Cells and Their Effects on Transport of Low-Permeability Drugs

Some pharmaceutical excipients are able to modify intestinal permeability, thus influencing drug absorption and bioavailability. The effect of four polyols (mannitol, maltitol, sorbitol and xylitol) on the permeability of seven active pharmaceutical ingredients (API), representing different BCS classes (furosemide, amiloride, atenolol, ranitidine, nadolol, L-thyroxine and acyclovir), was investigated using the Caco-2 cell permeability model. Analytical methods for the sensitive polyol and API quantification were developed using Ultra High Performance Liquid Chromatography coupled to triple-quadrupole Mass Spectrometry (UHPLC-QqQ). Apparent permeability coefficients (Papp) were calculated from the measured concentrations in the apical and basolateral compartments. The cell monolayer remained intact throughout the experiment in all trials, neither significant Lucifer Yellow (LY) passage, nor modification of the electrical resistance was detected, demonstrating that no active principle or excipient (or combinations thereof) modulated the paracellular transport. The Papp values for apical to basolateral and basolateral to apical directions of drug + excipient combinations were compared with the Papp values for the drug substance alone. Our results show that mannitol, maltitol, sorbitol and xylitol did not modify the permeability of furosemide, amiloride, atenolol, ranitidine, nadolol, acyclovir and L-thyroxine APIs. Moreover, the presence of polyols did not alter the efflux of the active principle (basolateral to apical).

Comparison of barrier properties of outer blood-retinal barrier models – Human stem cell-based models as a novel tool for ocular drug discovery

The retinal pigment epithelial (RPE) cell monolayer forms the outer blood–retinal barrier and has a crucial role in ocular pharmacokinetics. Although several RPE cell models are available, there have been no systematic comparisons of their barrier properties with respect to drug permeability. We compared the barrier properties of RPE secondary cell lines (ARPE19, and ARPE19mel) and both primary (hfRPE) and stem-cell derived RPE (hESC-RPE) cells by investigating the permeability of nine drugs (aztreonam, ciprofloxacin, dexamethasone, fluconazole, ganciclovir, ketorolac, methotrexate, voriconazole, and quinidine) across cell monolayers. ARPE19, ARPE19mel, and hfRPE cells displayed a narrow Papp value range, with relatively high permeation rates (5.2–26 × 10−6 cm/s). In contrast, hESC-RPE cells efficiently restricted the drug flux, and displayed even lower Papp values than those reported for bovine RPE-choroid, with the range of 0.4–32 cm−6/s. Therefore, ARPE19, ARPE19mel, and hfRPE cells failed to form a tight barrier, whereas hESC-RPE cells restricted the drug flux to a similar extent as bovine RPE-choroid. Therefore, hESC-RPE cells are valuable tools in ocular drug discovery.

Assessment of the Permeability of 3,4-Methylenedioxypyrovalerone (MDPV) across the Caco-2 Monolayer for Estimation of Intestinal Absorption and Enantioselectivity.

3,4-Methylenedioxypyrovalerone (MDPV) is a widely studied synthetic cathinone heterocycle mainly concerning its psychoactive effects. It is a chiral molecule and one of the most abused new psychoactive substances worldwide. Enantioselectivity studies for MDPV are still scarce and the extent to which it crosses the intestinal membrane is still unknown. Herein, an in vitro permeability study was performed to evaluate the passage of the enantiomers of MDPV across the Caco-2 monolayer. To detect and quantify MDPV, a UHPLC-UV method was developed and validated. Acceptable values within the recommended limits were obtained for all evaluated parameters (specificity, linearity, accuracy, limit of detection (LOD), limit of quantification (LOQ) and precision). The enantiomers of MDPV were found to be highly permeable across the Caco-2 monolayer, which can indicate a high intestinal permeability. Enantioselectivity was observed for the Papp values in the basolateral (BL) to apical (AP) direction. Furthermore, efflux ratios are indicative of efflux through a facilitated diffusion mechanism. To the best of our knowledge, determination of the permeability of MDPV across the intestinal epithelial cell monolayer is presented here for the first time.

Citrus, Milk Thistle, and Propolis Extracts Improved the Intestinal Permeability of Curcuminoids from Turmeric Extract─ an In Silico and In Vitro Permeability Caco-2 Cells Approach

Curcumin has been traditionally used in food recipes for biological health benefits. However, these properties are compromised due to its very low bioavailability. Thus, this work assessed the impact of using natural potential bioenhancers to improve intestinal permeability and understanding the interaction of flavonoids with curcuminoids through molecular dynamic simulation. The intestinal permeability (Papp) was measured on the human colon carcinoma cell line (Caco-2). The Papp values measured on Caco-2 cell monolayers provided information regarding the increased permeability of curcumin across the intestinal barrier specially caused by the presence of citrus (100.45%), and milk thistle extracts (81.70%) at level +1 showed the higher Papp increase (%) compared to level 0. With respect to the soft standardized green propolis EPP-AF extract, the Papp increase was higher at level 0 (26.34%). Molecular dynamic (MD) simulations of curcumin with naringin and silybin B confirmed this increase of permeability of curcumin at higher concentrations through non-covalent interactions. These results suggest the prominent importance of the association of natural flavonoids as bioenhancers to increase curcumin bioavailability and health benefits.

Intestinal absorption of DHA microcapsules with different formulations based on ex vivo rat intestine and in vitro dialysis models.

Intestinal permeability is a key factor affecting the bioavailability and physiological efficacy of docosahexaenoic acid (DHA) encapsulated in microcapsules. However, how the DHA microcapsules are transformed and the components absorbed across the small intestinal membrane has seldom been examined previously. In this study, an ex vivo absorption model based on the permeability of the rat small intestine was established to evaluate the intestinal absorption of DHA microcapsules with five formulations after gastrointestinal digestion in vitro. For pure glucose solutions, the apparent permeability coefficient (Papp) increased from 5.70 ± 0.60 × 10-6 cm s-1 at 5 mg mL-1 to 20.25 ± 0.88 × 10-6 cm s-1 at 30 mg mL-1 and decreased to 15.73 ± 0.91 × 10-6 cm s-1 at 100 mg mL-1. The Papp values obtained using the ex vivo model are comparable to those reported in the human jejunum. For algal oil DHA microcapsules with whey protein as the wall material (A-WP-DHA) after in vitro digestion, the Papp of glucose released was 3.81 × 10-6 cm s-1 with an absorption ratio of 59.55% in the ex vivo model, significantly lower than that from the in vitro porcine casing model. The Papp and absorption ratio varied little among the in vitro dialysis models with different molecular weight cut-off values. A similar trend was observed for the absorption of amino acids. However, the absorption ratio (26.6%) was the highest in the ex vivo model for free fatty acids (FFAs) released from the microcapsules due to the rapid accumulation of compounds on the inner wall of the intestinal sac. In addition, the DHA microcapsules with algal oil as the DHA source (36.40%) exhibited a higher absorption ratio of FFAs than that from tuna oil (14.26%) in the ex vivo model. The wall material compositions seemed to have little effect on FFA absorption. The present study is practically meaningful for the future formulation of DHA microcapsules with enhanced absorption.

Assessment of hydrophobic-ion paired insulin incorporated SMEDDS for the treatment of diabetes mellitus

To overcome the low oral bioavailability of insulin, we hypothesized that the insulin-hydrophobic ion pairing (HIP) complex incorporated self-microemulsifying drug delivery system (SMEDDS) would be beneficial. In the present study, an oral insulin delivery system was developed and estimated using the HIP technique and SMEDDS. Further insulin-HIP complexes were characterized using various spectroscopical techniques. Additionally, insulin-HIP complexes were subjected to analysis of complexes' conformational stability in the real physiological solution using computational approaches. On the other hand, in vitro, and in vivo studies were carried out to investigate the permeability and hypoglycemic effect. Subsequently, in an in vitro non-everted gut sac study, the apparent permeability coefficient (Papp) was approximately 8-fold higher in the colon than in the jejunum, and the HIP-incorporated SMEDDS showed an approximately 3-fold higher Papp value than the insulin solution. The hypoglycemic effect after in situ colon instillation, the HIP complex between insulin and sodium docusate-incorporated SMEDDS showed a pharmacological availability of 2.52 ± 0.33 % compared to the subcutaneously administered insulin solution. Thus, based on these outcomes, it can be concluded that the selection of appropriate counterions is important in developing HIP-incorporated SMEDDS, wherein this system shows promise as a tool for oral peptide delivery systems.

Computational prediction of Calu-3-based in vitro pulmonary permeability of chemicals

Pulmonary is a potential route for drug delivery and exposure to toxic chemicals. The human bronchial epithelial cell line Calu-3 is generally considered to be a useful in vitro model of pulmonary permeability by calculating the apparent permeability coefficient (Papp) values. Since in vitro experiments are time-consuming and labor-intensive, computational models for pulmonary permeability are desirable for accelerating drug design and toxic chemical assessment. This study presents the first attempt for developing quantitative structure-activity relationship (QSAR) models for addressing this goal. A total of 57 chemicals with Papp values based on Calu-3 experiments was first curated from literature for model development and testing. Subsequently, eleven descriptors were identified by a sequential forward feature selection algorithm to maximize the cross-validation performance of a voting regression model integrating linear regression and nonlinear random forest algorithms. With applicability domain adjustment, the developed model achieved high performance with correlation coefficient values of 0.935 and 0.824 for cross-validation and independent test, respectively. The preliminary results showed that computational models could be helpful for predicting Calu-3-based in vitro pulmonary permeability of chemicals. Future works include the collection of more data for further validating and improving the model.

Development of Paeonol Liposomes: Design, Optimization, in vitro and in vivo Evaluation.

BackgroundUlcerative colitis (UC) is one of the intractable diseases recognized by the World Health Organization, and paeonol has been proven to have therapeutic effects. However, the low solubility of paeonol limits its clinical application. To prepare and optimize paeonol liposome, study its absorption mechanism and the anti-inflammatory activity in vitro and in vivo, in order to provide experimental basis for the further development of paeonol into an anti-inflammatory drug in the future.MethodsPaeonol loaded liposomes were prepared and optimized by thin film dispersion-ultrasonic method. The absorption mechanism of paeonol-loaded liposomes was studied by pharmacokinetics, in situ single-pass intestinal perfusion and Caco-2 cell monolayer model, the anti-inflammatory activity was studied in a mouse ulcerative model.ResultsBox-Behnken response surface methodology permits to screen the best formulations. The structural and morphological characterization showed that paeonol was entrapped inside the bilayer in liposomes. Pharmacokinetic studies found that the AUC0-t of Pae-Lips was 2.78 times than that of paeonol suspension, indicating that Pae-Lips significantly improved the absorption of paeonol. In situ single intestinal perfusion and Caco-2 monolayer cell model results showed that paeonol was passively transported and absorbed, and was the substrate of P-gp, MRP2 and BCRP, and the Papp value of Pae-Lips was significantly higher than that of paeonol. In vitro and in vivo anti-inflammatory experiments showed that compared with paeonol, Pae-Lips exhibited excellent anti-inflammatory activity.ConclusionIn this study, Pae-Lips were successfully prepared to improve the oral absorption of paeonol. Absorption may involve passive diffusion and efflux transporters. Moreover, Pae-Lips have excellent anti-inflammatory activity in vitro and in vivo, which preliminarily clarifies the feasibility of further development of Pae-Lips into oral anti-inflammatory drugs.

Chlorpyrifos, permethrin and cyfluthrin effect on cell survival, permeability, and tight junction in an in-vitro model of the human blood-brain barrier (BBB)

The blood-brain barrier (BBB) is a structural and functional interface between the plasma and the human brain. Predictive BBB in-vitro models like immortalized human capillary microvascular endothelial cells (HCMEC/D3) can be used to explore the BBB disruption potential of daily exposed chemicals. The present study was focused on investigating the human BBB permeation potential of one organophosphate pesticide, chlorpyrifos (CPF), and two pyrethroids, permethrin (PMT) and cyfluthrin (CFT). HCMEC/D3 cells were exposed to the chemical and the time-dependent pass across BBB along with permeation coefficient (Papp) was calculated. Transendothelial electrical resistance (TEER) was measured for the cells to check the monolayer formation and later to check the reduction in integrity after chemical exposure. Real time PCR was conducted to investigate the effect of chemicals on the expression BBB´s tight and adherens junction proteins. Calculated Papp value for three chemicals was in the following order: CPF>CFT>PMT, where CPF showed the highest permeation coefficient. TEER calculation showed that the integrity decreased after CPF exposure which was in concordance with Papp value whereas for other chemicals, no change in TEER after exposure was observed. In addition, the transwell study showed a higher efflux ratio (ER) (>2) of CFT indicating that CFT could be a substrate for active transport. For CPF and PMT, ER was less than 2, so no active transport seems to be involved. The evaluation of the mRNA expression analysis revealed a statistically significant decrease in Occludin (OCLN) gene expression for CPF, VE-Cadherin (CDH5) for PMT and Zonula Occludens (ZO1) expression for CFT. Our study showed that CPF has the highest potential for inducing cell death, higher permeation, and capability to induce BBB dysfunction than among the above-mentioned chemicals. Additionally, the results of the permeation study could be useful to build a human PBPK model using in vitro-to-in vivo extrapolation approach.