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Introduction: Cannabinoids including cannabidiol (CBD) have attracted enormous interest as bioactive ingredients for various dermatological and/or cosmeceutical uses. However, topical applications of cannabinoids might be limited without a fundamental understanding of their skin permeability. Herein, we aimed to evaluate the skin permeability of CBD and its topical formulations using artificial skin membrane assays. The solubility and stability of CBD in various surfactants that are commonly used in topical applications were also evaluated. Methods: CBD and two CBD-incorporated topical formulations (cream and gel) were prepared for this study. Computational predictions (SwissADME and DERMWIN™) and the parallel artificial membrane permeability assay (PAMPA) were used to evaluate the skin permeability of CBD isolate. The Franz cell diffusion (in vitro release testing) assay was used to evaluate the skin permeability of CBD formulations. The solubility and stability of CBD in surfactants were assessed by high-performance liquid chromatography and mass spectrometry analysis. Results: CBD isolate showed favorable skin permeability in the SwissADME and DERMWIN™ predictions (−Log Kp of 3.6 and 5.7 cm/s, respectively) and PAMPA (−LogPe value of 5.0 at pH of 6.5 and 7.4). In addition, CBD had higher solubility (378.4 μg/mL) in surfactant Tween 20 as compared to its solubility in polyisobutene. In an acidic environment (pH 5 and 6), Tween 20 maintained the CBD content at 81% and 70% over 30 days, respectively. CBD in the formulations of cream and gel also had moderate skin permeability in the Franz cell diffusion assay. Conclusion: Data from artificial membrane-based assays support that CBD is a skin permeable cannabinoid and the permeability and stability of its formulations may be influenced by several factors such as surfactant and pH environment. Findings from our study suggest that CBD may have suitable skin permeability for the development of dermatological and/or cosmeceutical applications but further studies using in vivo models are warranted to confirm this.

Parallel Artificial Membrane Permeability Assay (PAMPA) is an in vitro laboratory method for screening the transmembrane permeability of chemicals. Stemming from medicinal chemistry, PAMPA has the potential for use in the cost-effective high-throughput evaluation of chemicals of environmental concern. However, many chemicals of environmental concern differ substantially from pharmaceuticals in hydrophobicity and volatility. Here, we develop an in silico mass balance model to explore the impacts of chemical properties on chemical mass transfer in PAMPA and PAMPA’s applicability to hydrophobic or volatile chemicals of environmental concern. The model’s performance is evaluated by agreement between predicted and measured permeabilities of 1383 chemicals. The model predicts that the PAMPA measured permeability can be highly uncertain for hydrophobic chemicals because of considerable retention by the artificial membrane and for volatile chemicals because of substantial volatilization to the headspace. Notably, the permeabilities of hydrophobic chemicals are remarkably sensitive to specific experimental conditions, for example, the frequency of stirring and incubation time, challenging the comparison between measurements under different conditions. For hydrophobic chemicals, the PAMPA measured permeability may largely indicate the permeability of the unstirred water layer over the membrane, instead of the “intrinsic” permeability of the membrane, and therefore, may not be of interest for environmental exposure and risk assessments. The model also predicts that the time for mass transfer of highly hydrophobic chemicals to reach the steady state likely exceeds the incubation time, which violates the steady-state assumption used in calculating permeability from measured concentrations. Overall, our theoretical analysis underscores the importance to consider chemical properties when applying the current design of PAMPA to chemicals of environmental concern.

Passive permeability is one of the key features that determine absorbability and one of the most studied properties in the early phases of drug development. Newly synthesized succinimide derivatives from two different series (1‐aryl‐3‐methylsuccinimides and 1‐aryl‐3‐ethyl‐3‐methylsuccinimides) with high biological potential have been subjected to estimation of their passive permeability and their association with (a) experimentally obtained anisotropic lipophilicity, (b) in silico–calculated lipophilicity and (c) in silico–predicted permeability and absorbability. Non‐cellular‐based parallel artificial membrane permeability assay was applied for quantifying their passive permeation, expressed as logPapp. Passive permeation was governed by the lipophilicity of the analysed compounds, and anisotropic lipophilicity was related with statistically significant passive transcellular diffusion (r2 = 0.614, P < 0.001). Moreover, experimentally determined passive permeability, logPapp, was statistically significantly associated with both in silico–predicted absorption constant, ka (r2 = 0.7886, P < 0.001), and human intestinal absorption (HIA) in percentage (r2 = 0.484, P < 0.001), respectively. However, there was no statistically significant relationship between experimentally obtained permeability on non‐cellular‐based model and in silico–predicted Caco‐2 permeability based on the predictions conducted on two different software. Based on the obtained results, anisotropic systems are promising surrogates for determining lipophilicity, except for compounds with acidic functional groups that are completely ionized under (pH = 7.4). [ABSTRACT FROM AUTHOR]

Introduction: Cannabinoids including cannabidiol (CBD) have attracted enormous interest as bioactive ingredients for various dermatological and/or cosmeceutical uses. However, topical applications of cannabinoids might be limited without a fundamental understanding of their skin permeability. Herein, we aimed to evaluate the skin permeability of CBD and its topical formulations using artificial skin membrane assays. The solubility and stability of CBD in various surfactants that are commonly used in topical applications were also evaluated. Methods: CBD and two CBD-incorporated topical formulations (cream and gel) were prepared for this study. Computational predictions (SwissADME and DERMWIN™) and the parallel artificial membrane permeability assay (PAMPA) were used to evaluate the skin permeability of CBD isolate. The Franz cell diffusion (in vitro release testing) assay was used to evaluate the skin permeability of CBD formulations. The solubility and stability of CBD in surfactants were assessed by high-performance liquid chromatography and mass spectrometry analysis. Results: CBD isolate showed favorable skin permeability in the SwissADME and DERMWIN™ predictions (−Log Kp of 3.6 and 5.7 cm/s, respectively) and PAMPA (−LogPe value of 5.0 at pH of 6.5 and 7.4). In addition, CBD had higher solubility (378.4 μg/mL) in surfactant Tween 20 as compared to its solubility in polyisobutene. In an acidic environment (pH 5 and 6), Tween 20 maintained the CBD content at 81% and 70% over 30 days, respectively. CBD in the formulations of cream and gel also had moderate skin permeability in the Franz cell diffusion assay. Conclusion: Data from artificial membrane-based assays support that CBD is a skin permeable cannabinoid and the permeability and stability of its formulations may be influenced by several factors such as surfactant and pH environment. Findings from our study suggest that CBD may have suitable skin permeability for the development of dermatological and/or cosmeceutical applications but further studies using in vivo models are warranted to confirm this. [ABSTRACT FROM AUTHOR]

In this study, the effect of four xyloketals 1-4 on store-operated calcium entry (SOCE) was investigated in primary distal pulmonary arterial smooth muscle cells (PASMCs) isolated from mice. The results showed that xyloketal A (1), an unusual ketal with C-3 symmetry, exhibited strong SOCE blocking activity. Secretion of interleukin-8 (IL-8) was also inhibited by xyloketal A. The parallel artificial membrane permeability assay (PAMPA) of 1-4 suggested that these xyloketals penetrated easily through the cell membrane. Moreover, the molecular docking study of xyloketal A with activation region of the stromal interaction molecule (STIM) 1 and the calcium release-activated calcium modulator (ORAI) 1 (STIM1-ORAI1) protein complex, the key domain of SOCE, revealed that xyloketal A exhibited a noncovalent interaction with the key residue lysine 363 (LYS363) in the identified cytosolic regions in STIM1-C. These findings provided useful information about xyloketal A as a SOCE inhibitor for further evaluation.

The use of sunscreen products is widely promoted by schools, government agencies, and health-related organizations to minimize sunburn and skin damage. In this study, we developed stable solid lipid nanoparticles (SLNs) containing the chemical UV filter octyl methoxycinnamate (OMC). In parallel, we produced similar stable SLNs in which 20% of the OMC content was replaced by the botanical urucum oil. When these SLNs were applied to the skin of human volunteers, no changes in fluorescence lifetimes or redox ratios of the endogenous skin fluorophores were seen, suggesting that the formulations did not induce toxic responses in the skin. Ex vivo (skin diffusion) tests showed no significant penetration. In vitro studies showed that when 20% of the OMC was replaced by urucum oil, there was no reduction in skin protection factor (SPF), suggesting that a decrease in the amount of chemical filter may be a viable alternative for an effective sunscreen, in combination with an antioxidant-rich vegetable oil, such as urucum. There is a strong trend towards increasing safety of sun protection products through reduction in the use of chemical UV filters. This work supports this approach by producing formulations with lower concentrations of OMC, while maintaining the SPF. Further investigations of SPF in vivo are needed to assess the suitability of these formulations for human use. [ABSTRACT FROM AUTHOR]

Objectives Analysis of the biopharmaceutical properties of eremantholide C, sesquiterpene lactone with proven pharmacological activity and low toxicity, is required to evaluate its potential to become a drug. Methods Preliminary analysis of the physicochemical characteristics of eremantholide C was performed in silico. Equilibrium solubility was evaluated using the shake-flask method, at 37.0 °C, 100 rpm during 72 h in biorelevant media. The permeability was analysed using parallel artificial membrane permeability assay, at 37.0 °C, 50 rpm for 5 h. The donor compartment was composed of an eremantholide C solution in intestinal fluid simulated without enzymes, while the acceptor compartment consisted of phosphate buffer. Key findings Physicochemical characteristics predicted in silico indicated that eremantholide C has a low solubility and high permeability. In-vitro data of eremantholide C showed low solubility, with values for the dose/solubility ratio (ml): 9448.82, 10 389.61 e 15 000.00 for buffers acetate (pH 4.5), intestinal fluid simulated without enzymes (pH 6.8) and phosphate (pH 7.4), respectively. Also, it showed high permeability, with effective permeability of 30.4 × 10−6 cm/s, a higher result compared with propranolol hydrochloride (9.23 × 10−6 cm/s). Conclusions The high permeability combined with its solubility, pharmacological activity and low toxicity demonstrate the importance of eremantholide C as a potential drug candidate. [ABSTRACT FROM AUTHOR]

The blood-brain barrier accounts for the high attrition rate of the treatments of most brain disorders, which therefore remain one of the greatest health-care challenges of the twenty first century. Against this background of hindrance to brain delivery, nanomedicine takes advantage of the assembly at the nanoscale of available biomaterials to provide a delivery platform with potential to raising brain levels of either imaging or therapeutic agents. Nevertheless, to prevent later failure due to ineffective drug levels at the target site, researchers have been endeavoring to develop a battery of in vitro screening procedures that can predict earlier in the drug discovery process the ability of these cutting-edge drug delivery platforms to cross the blood-brain barrier for biomedical purposes. This review provides an in-depth analysis of the currently available in vitro blood-brain barrier models (both cell-based and non-cell-based) with the focus on their suitability for understanding the biological brain distribution of forthcoming nanomedicines. The relationship between experimental factors and underlying physiological assumptions that would ultimately lead to a more predictive capacity of their in vivo performance, and those methods already assayed for the evaluation of the brain distribution of nanomedicines are comprehensively discussed. [ABSTRACT FROM AUTHOR]

With the number of designer drugs on the streets rampantly on the rise, it's becoming more and more important to be able to rapidly characterize them in a biologically relevant way. Using a parallel artificial membrane permeability assay (PAMPA) to assess the blood brain barrier permeability has shown to be a high throughput way to compare new drugs with currently controlled substances via their effective permeability values. This combined with direct infusion electrospray ionization–mass spectrometry creates a rapid technique for characterization of new designer drugs. PAMPA has successfully determined the effective permeabilities of cocaine, methamphetamine, heroin, MDMA, and several tryptamine derivatives. [ABSTRACT FROM AUTHOR]

In drug discovery research, the compounds should not only to be potent and selective but also must possess acceptable pharmacokinetic properties such as absorption, distribution, metabolism, and excretion (ADME) to increase success rate in clinical studies. Objective: Exploration of drug-like properties of 2-(2-methylquinolin-4-ylamino)-N-phenyl acetamide, a potent antileishmanial compound by performing some in vitro ADME experiments along with validation of such studies. Materials and Methods: Experimental protocols were established and validated for stability (in PBS pH7.4, simulated gastric and intestinal fluid), solubility, permeability, distribution coefficient (Log D), plasma protein binding and metabolism by rat liver microsomes by using spectrophotometer or HPLC. Methods were considered valid if the results of the standard compounds matched with reported results or within acceptable range or with proper ranking (high-medium-low). Results: The compound was found to be stable (>95% remaining) in all stability studies and aqueous solubility was 299.7 ± 6.42 μM. The parallel artificial membrane permeability assay (PAMPA) indicated its medium permeability (Log Pe = -5.53 ± 0.01). The distribution coefficients (Log D) in octanol/PBS and cyclohexane/PBS systems were found to be 0.54 and -1.33, respectively. The plasma protein binding study by the equilibrium dialysis method was observed to be 78.82 ± 0.13% while metabolism by Phase-I enzymes for 1 hour at 37°C revealed that 36.07 ± 4.15% of the compound remained after metabolism. Conclusion: The methods were found to be very useful for day-to-day ADME studies. All the studies with the antileishmanial compound ascertained that the compound bears optimum pharmacokinetic properties to be used orally as a potential drug for the treatment of leishmaniasis. [ABSTRACT FROM AUTHOR]

Experimental PAMPA data generated for 40 low molecular weight commercial drugs is reviewed in the context of its utility in the drug discovery process. Several experimental variables that have been introduced in the literature as additions or improvements to the PAMPA were also evaluated. The relationship between PAMPA data and both calculated and measured octanol/water distribution coefficients was examined. From this assessment, it was concluded that the PAMPA yields information about the lipophilicity as measured by the octanol/water partitioning of a compound, but that this same information could be derived in a simpler manner from calculated log D values. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2886–2892, 2007 [ABSTRACT FROM AUTHOR]

• Influence of di(2-ethylhexyl) phthalate (DEHP) and mono(2-ethylhexyl) phthalate (MEHP) on lipid vesicles and planar bilayers. • Vesicle size changes after DEHP exposure. • Chitosan nanoparticles incubated with DEHP negate vesicle size change. • Mass and rigidity changes upon planar lipid bilayer exposure to DEHP and MEHP. • Interactions of small molecules with lipid bilayers are affected by DEHP and MEHP pre-treatment. Di(2-ethylhexyl) phthalate (DEHP) is one of the most abundant plasticizers in common household products. It leaches from materials, resulting in exposure associated with detrimental health effects. The main objective of this study was to investigate how DEHP and its metabolite, mono(2-ethylhexyl) phthalate (MEHP), interact with and permeate lipid structures, namely vesicles and planar bilayers. Using dynamic light scattering, we observed significant changes in the size and polydispersity of L-α-phosphatidylcholine (egg PC) vesicles when incubated with DEHP but not MEHP at the same concentrations (100 and 200 μM). We demonstrated that these effects are mitigated by pre-treatment with chitosan nanoparticles which adsorb the phthalates. Using quartz crystal microbalance with dissipation monitoring (QCM-D), we observed a concentration dependence on the interaction of DEHP with egg PC supported lipid bilayers (SLBs). QCM-D results suggested lipid removal for 5 and 100 μM DEHP, and adsorption and potential embedment in the bilayer at 50 and 200 μM DEHP. SLB mass decrease was observed for all concentrations of MEHP (5, 50, 100, and 200 μM), suggesting lipid removal. We also investigated the permeability of DEHP and MEHP as well as several small molecules across a 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) suspended lipid bilayer. We found that DEHP and MEHP both had low permeabilities, but only DEHP remained associated with the bilayer. Exposure to DEHP and MEHP influenced how several common small molecules interacted with DOPC bilayers. Ultimately, this work provides insight into mechanisms of phthalate interactions with lipid structures, having implications for human health. [ABSTRACT FROM AUTHOR]

Under different pathological conditions, aberrant induction of neuronal nitric oxide synthase (nNOS) generates overproduction of NO that can cause irreversible cell damage. The aim of this study was to develop an amidoxime prodrug of a potent nNOS inhibitor, the benzhydryl acetamidine. We synthesized the benzhydryl acetamidoxime, which was evaluated in vitro to ascertain the potential NOS inhibitory activity, as well as conducting bioconversion into the parent acetamidine. The prodrug was also profiled for in vitro physicochemical properties, by determining the lipophilicity, passive permeation through the human gastrointestinal tract and across the blood-brain barrier by PAMPA, and chemical, enzymatic, and plasma stability. The obtained data demonstrate that the amidoxime prodrug shows an improved pharmacokinetic profile with respect to the acetamidine nNOS inhibitor, thus suggesting that it could be a promising lead compound to treat all those pathological conditions in which nNOS activity is dysregulated., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

The placenta plays a key role in regulating the maternal-fetal transport but it is a difficult organ to study due to a lack of existing in vitro models. Lipid bilayers inspired by the placenta can provide a facile new in vitro tool with promise for screening molecular transport across this important organ. Here we developed lipid bilayers that mimic the composition of human placental trophoblast cells at different times during the course of pregnancy. Mass spectrometry identified five major lipid classes (phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and sphingomyelin) present at varying concentrations in trophoblasts representative of the first and third trimesters and full-term placenta. We successfully developed supported and suspended lipid bilayers mimicking these trophoblast lipid compositions and then demonstrated the utility of these synthetic placenta models for investigating molecular interactions. Specifically, we investigated the interactions with di(2-ethylhexyl) phthalate (DEHP), a common plasticizer and environmental toxicant, and amphotericin B, a common yet toxic, antifungal therapeutic. Overall, we observed that DEHP adsorbs and potentially embeds itself within all placental lipid bilayers, with varying levels of interaction. For both amphotericin B and a liposomal formulation of amphotericin B, AmBisome, we noted lower levels of permeation in transport studies with bilayers and trophoblast cells compared with DEHP, likely driven by differences in size. AmBisome interacted less with both the supported and suspended placental lipid bilayers in comparison to amphotericin B, suggesting that drug delivery carriers can vary the impact of a pharmaceutical agent on these lipid structures. We found that the apparent permeability observed in suspended bilayers was approximately an order of magnitude less than those observed for trophoblast monolayers, which is typical of lipid bilayers. Ultimately, these placenta mimetic lipid bilayers can serve as a platform for the rapid initial screening of molecular interactions with the maternal-fetal interface to better inform future testing.

The affinity indexes for phospholipids (log kW(IAM)) for 42 compounds were measured by high performance liquid chromatography (HPLC) on two different phospholipid-based stationary phases (immobilized artificial membrane, IAM), i.e., IAM.PC.MG and IAM.PC.DD2. The polar/electrostatic interaction forces between analytes and membrane phospholipids (Δlog kW(IAM)) were calculated as the differences between the experimental values of log kW(IAM) and those expected for isolipophilic neutral compounds having polar surface area (PSA) = 0. The values of passage through a porcine brain lipid extract (PBLE) artificial membrane for 36 out of the 42 compounds considered, measured by the so-called PAMPA-BBB technique, were taken from the literature (P0(PAMPA-BBB)). The values of blood-brain barrier (BBB) passage measured in situ, P0(in situ), for 38 out of the 42 compounds considered, taken from the literature, represented the permeability of the neutral forms on "efflux minimized" rodent models. The present work was aimed at verifying the soundness of Δlog kW(IAM) at describing the potential of passage through the BBB as compared to data achieved by the PAMPA-BBB technique. In a first instance, the values of log P0(PAMPA-BBB) (32 data points) were found significantly related to the n-octanol lipophilicity values of the neutral forms (log P(N)) (r(2) = 0.782) whereas no significant relationship (r(2) = 0.246) was found with lipophilicity values of the mixtures of ionized and neutral forms existing at the experimental pH 7.4 (log D(7.4)) as well as with either log kW(IAM) or Δlog kW(IAM) values. log P0(PAMPA-BBB) related moderately to log P0(in situ) values (r(2) = 0.604). The latter did not relate with either n-octanol lipophilicity indexes (log P(N) and log D(7.4)) or phospholipid affinity indexes (log kW(IAM)). In contrast, significant inverse linear relationships were observed between log P0(in situ) (38 data points) and Δlog kW(IAM) values for all the compounds but ibuprofen and chlorpromazine, which behaved as moderate outliers (r(2) = 0.656 and r(2) = 0.757 for values achieved on IAM.PC.MG and IAM.PC.DD2, respectively). Since log P0(in situ) refer to the "intrinsic permeability" of the analytes regardless their ionization degree, no correction for ionization of Δlog kW(IAM) values was needed. Furthermore, log P0(in situ) were found roughly linearly related to log BB values (i.e., the logarithm of the ratio brain concentration/blood concentration measured in vivo) for all the analytes but those predominantly present at the experimental pH 7.4 as anions. These results suggest that, at least for the data set considered, Δlog kW(IAM) parameters are more effective than log P0(PAMPA-BBB) at predicting log P0(in situ) values for all the analytes. Furthermore, ionization appears to affect differently, and much more markedly, BBB passage of acids (yielding anions) than that of the other ionizable compounds.

Introducing a sulfamide moiety to our coumarin derivatives afforded enhanced Raf/MEK inhibitory activity concomitantly with an acceptable PK profile. Novel sulfamide 17 showed potent HCT116 cell growth inhibition (IC50=8 nM) and good PK profile (bioavailability of 51% in mouse), resulting in high in vivo antitumor efficacy in the HCT116 xenograft (ED50=4.8 mg/kg). We confirmed the sulfamide moiety showed no negative impact on tests run on the compound to evaluate DMPK (PK profiles in three animal species, CYP inhibition and CYP induction) and the safety profile (hERG and AMES tests). Sulfamide 17 had favorable properties that warranted further preclinical assessment., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Protozoal diseases such as malaria are a leading world health concern. We screened a library of fractionated natural products to identify new potential therapeutic leads and discovered that jatrophone (a product of Jatropha isabelli) exerts significant activity against Plasmodium falciparum strains 3D7 and K1. A focused jatrophone-scaffold library was synthesized to evaluate jatrophone's mode of action and identify more selective analogs. Compounds 25 and 32 of this natural product-inspired compound library exhibited micromolar EC50 values against strains 3D7 and K1, thus providing a new antimalarial molecular scaffold. Our report describes an efficient derivatization approach used to evaluate the structure-activity relationship of jatrophone analogs in search of potential new antimalarial agents., (Published by Elsevier Masson SAS.)