Fasted State Simulated Intestinal Fluid Research Articles

Use of Poly(vinyl alcohol) in Spray-Dried Dispersions: Enhancing Solubility and Stability of Proteolysis Targeting Chimeras.

PROTACs, proteolysis targeting chimeras, are bifunctional molecules inducing protein degradation through a unique proximity-based mode of action. While offering several advantages unachievable by classical drugs, PROTACs have unfavorable physicochemical properties that pose challenges in application and formulation. In this study, we show the solubility enhancement of two PROTACs, ARV-110 and SelDeg51, using Poly(vinyl alcohol). Hereby, we apply a three-fluid nozzle spray drying set-up to generate an amorphous solid dispersion with a 30% w/w drug loading with the respective PROTACs and the hydrophilic polymer. Dissolution enhancement was achieved and demonstrated for t = 0 and t = 4 weeks at 5 °C using a phosphate buffer with a pH of 6.8. A pH shift study on ARV-110-PVA is shown, covering transfer from simulated gastric fluid (SGF) at pH 2.0 to fasted-state simulated intestinal fluid (FaSSIF) at pH 6.5. Additionally, activity studies and binding assays of the pure SelDeg51 versus the spray-dried SelDeg51-PVA indicate no difference between both samples. Our results show how modern enabling formulation technologies can partially alleviate challenging physicochemical properties, such as the poor solubility of increasingly large 'small' molecules.

Efficiency of single pharmaceutical surfactants to mimic intestinal biorelevant media solubilization and dissolution of etravirine: Comparison of intrinsic and film dissolution models

We understand that quality control dissolution media may best anticipate in vivo product performance by mimicking in vivo media, but preferably involve at most a single pharmaceutical surfactant for routine laboratory use. The objective here was to estimate the concentrations of six pharmaceutical surfactants to mimic etravirine solubility and intrinsic dissolution rate, as well as dissolution rate from a film model, in each Fed State Simulated Intestinal Fluid Version 2 (FeSSIF-V2) and Fasted State Simulated Intestinal Fluid Version 2 (FaSSIF-V2). Solubility studies and colloid sizing measurements were conducted. Results indicate that all six surfactants were more efficient than FeSSIF-V2 or FaSSIF-V2 at solubilizing drug, and also exhibited higher micelle diffusivities than FeSSIF-V2 and FaSSIF-V2 mixed-micelles. The rank-order potency (on mM basis) of the six pharmaceutical surfactants to mimic etravirine solubility in each FeSSIF-V2 and FaSSIF-V2 was: polysorbate 80 (PS80) > polysorbate 20 (PS20) > polyoxyethylene(23) lauryl ether (POE23) > POE10 > hexadecyltrimethylammonium bromide (HEX) > sodium lauryl sulfate (SLS). This rank-order potency was almost the same to mimic drug dissolution rate into each FeSSIF-V2 and FaSSIF-V2, except POE10 > POE23. For the most potent surfactant, PS80, 0.461 mM and 0.140 mM PS80 was estimated to mimic etravirine's solubility and dissolution rate into FeSSIF-V2, respectively, using the intrinsic dissolution model. The low PS80 concentration to mimic dissolution rate reflects the relatively high diffusivity of PS80 micelles, compared to FeSSIF-V2 mixed-micelle diffusivity, which was the case for all six pharmaceutical surfactants. Results are also presented in terms of a film dissolution model for surfactant-mediated dissolution, where dissolution enhancement was less than that in the intrinsic dissolution model, and the film model required lower surfactant concentration than in intrinsic dissolution model to mimic FeSSIF-V2-enhanced dissolution. Findings have promised to identify single pharmaceutical surfactant concentrations that mimic key performance attributes of biorelevant media.

Importance of Considering Fed-State Gastrointestinal Physiology in Predicting the Reabsorption of Enterohepatic Circulation of Drugs

PurposeThe purpose of this study was to develop a simulation model for the pharmacokinetics (PK) of drugs undergoing enterohepatic circulation (EHC) with consideration to the environment in the gastrointestinal tract in the fed state in humans. The investigation particularly focused on the necessity of compensating for the permeability rate constant in the reabsorption process in consideration of drug entrapment in bile micelles.MethodsMeloxicam and ezetimibe were used as model drugs. The extent of the entrapment of drugs inside bile micelles was evaluated using the solubility ratio of Fed State Simulated Intestinal Fluid version 2 (FeSSIF-V2) to Fasted State Simulated Intestinal Fluid version 2 (FaSSIF-V2). Prediction accuracy was evaluated using the Mean Absolute Percentage Error (MAPE) value, calculated from the observed and predicted oral PK profiles.ResultsThe solubilization of ezetimibe by bile micelles was clearly observed while that of meloxicam was not. Assuming that only drugs in the free fraction of micelles permeate through the intestinal membrane, PK simulation for ezetimibe was performed in both scenarios with and without compensation by the permeation rate constant. The MAPE value of Zetia® tablet, containing ezetimibe, was lower with compensation than without compensation. By contrast, Mobic® tablet, containing meloxicam, showed a relatively low MAPE value even without compensation.ConclusionFor drugs which undergo EHC and can be solubilized by bile micelles, compensating for the permeation rate constant in the reabsorption process based on the free fraction ratio appears an important factor in increasing the accuracy of PK profile prediction.

Synthesis and Biological Evaluations of Novel Human Parathyroid Hormone 1 Receptor (hPTHR1) Agonists Bearing Bicyclic Aromatic Moiety.

We have previously shown that the small molecule hPTHR1 agonist PCO371 (1) orally and dose-dependently induces PTH-like calcemic and hypophostemic activity in thyroparathyroidectomized rats. Compound 2a, bearing a bicyclic aromatic ring, was identified as a novel hPTHR1 agonist during hit to lead modification. It showed moderate PTHR1 agonistic activity with an EC20 value of 15 μM, and its metabolic stability in human liver microsome (hLM) as well as its solubility in phosphate buffer (PPb) and Fasted state simulated intestinal fluid (FaSSIF) were found to be poor. As results of the initial derivatization of 2a, we identified the indole derivatives as another scaffold. In this article, we report on the structure-activity relationship (SAR), structure-metabolism relationship (SMR), and structure-solubility relationship (SSR) of bicyclic aromatic derivatives, and the in vivo efficacy of 2j.

Drug solubility in biorelevant media in the context of an inhalation-based biopharmaceutics classification system (iBCS)

An inhalation-based Biopharmaceutics Classification System for pulmonary drugs (iBCS) holds the perspective to allow for scientifically sound prediction of differences in the in vivo performance of orally inhaled drug products (OIDPs).A set of nine drug substances were selected, that are administered via both the oral and pulmonary routes. Their solubility was determined in media representative for the oral (Fasted State Simulated Intestinal Fluid (FaSSIF)) and pulmonary (Alveofact medium and Simulated Lung Fluid (SLF)) routes of administration to confirm the need for a novel approach for inhaled drugs. The complexity of these media was then stepwise reduced with the purpose of understanding the contribution of their components to the solubilizing capacity of the media. A second reason for varying the complexity was to identify a medium that would allow robust but accurate dissolution testing. Hence, Hank’s balanced salt solution (HBSS) as a medium used in many in vitro biological tests, non-buffered saline solution, and water were included.For some drug substances (salbutamol sulfate, tobramycin, isoniazid, and tiotropium bromide), no significant differences were observed between the solubility in the media used. For other drugs, however, we observed either just small (rifampicin, budesonide, salmeterol) or unexpectedly large differences (beclomethasone dipropionate).Based on the minimum theoretical solubility required for their common pulmonary dose in 10 ml of lung lining fluid, drug solubility was classified as either high or low. Two high solubility and two low solubility compounds were then selected for refined solubility testing in pulmonary relevant media by varying their content of phospholipids, surfactant proteins and other proteins.The solubility of drug substances in simulated lung lining fluids was found to be dependent on the physicochemical properties of the drug substance and the composition of the media. While a pulmonary dissolution medium that would fit all drugs could not be established, our approach may provide guidance for finding the most suitable dissolution medium for a given drug substance and better designing in vitro tests for predicting the in vivo performance of inhalable drug products.

Green Tea Catechins Decrease Solubility of Raloxifene In Vitro and Its Systemic Exposure in Mice.

Green tea is a widely consumed beverage. A recent clinical study reported green tea decreased systemic exposure of raloxifene and its glucuronide metabolites by 34-43%. However, the underlying mechanism(s) remains unknown. This study investigated a change in raloxifene's solubility as the responsible mechanism. The effects of green tea extract, (-)-epigallocatechin gallate (EGCG), and (-)-epigallocatechin (EGC) on raloxifene's solubility were assessed in fasted state simulated intestinal fluids (FaSSIF) and fed state simulated intestinal fluids (FeSSIF). EGCG and EGC represent green tea's main bioactive constituents, flavan-3-gallate and flavan-3-ol catechins respectively, and the tested concentrations (mM) match the µg/mg of each compound in the extract. Our mouse study (n = 5/time point) evaluated the effect of green tea extract and EGCG on the systemic exposure of raloxifene. EGCG (1mM) and EGC (1.27mM) decreased raloxifene's solubility in FaSSIF by 78% and 13%, respectively. Micelle size in FaSSIF increased with increasing EGCG concentrations (> 1000% at 1mM), whereas EGC (1.27mM) did not change micelle size. We observed 3.4-fold higher raloxifene solubility in FeSSIF compared to FaSSIF, and neither green tea extract nor EGCG significantly affected raloxifene solubility or micelle size in FeSSIF. The mice study showed that green tea extract significantly decreased raloxifene Cmax by 44%, whereas EGCG had no effect. Green tea extract and EGCG did not affect the AUC0-24h of raloxifene or the metabolite-to-parent AUC ratio. This study demonstrated flavan-3-gallate catechins may decrease solubility of poorly water-soluble drugs such as raloxifene, particularly in the fasted state.

Study of in vitro poorly soluble drug solubility into fasted state simulated intestinal fluid reflective of in vivo gastrointestinal variability

Solubilityand dynamic light scattering (DLS) studies of three poorly soluble drugs(naproxen, indomethacin and phenytoin) in simulated intestinal fluid (SIF) werecarried out in order to calculate the number of drug molecules per micelle basedon the assumption of monodisperse spherical micelles. As the total amphiphileconcentration increased in the SIF the solubility of the drug also increased.The size of the micelles formed decreased with increasing amphiphileconcentration in combination with drug and the number of drug molecules permicelle decreased. Further work is planned to provide more information of theparticle size and geometry of the drug loaded micelles.

A novel formulation of ketoconazole entrapped in alginate with anionic polymer beads for solubility enhancement: Preparation and characterization

Ketoconazole has low solubility in intestinal pH, whereas drug absorption is largest in the small intestine, which can reduce the bioavailability of the drug. Alginate can be combined with a suitable polymer and cross-linked with divalent ions and another polymer to enhance the solubility of the drug. Ketoconazole could be loaded into a matrix polymer consisting of alginate and anionic polymer through hydrogen bonds formed with the N atom of the ketoconazole. The method employed to produce ketoconazole beads involved ionic gelation with CaCl2 as a cross- linking agent, and various polymer combinations were used: alginate 100:0 (AL100), alginate:pectin 75:25 (AP75) and 50:50 (AP50), alginate:gum acacia 75:25 (AG75) and 50:50 (AG50), and alginate:carrageenan 75:25 (AK75) and 50:50 (AK50). The beads were characterized by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), swelling study, in vitro drug release study, and solubility determination. The incorporation of ketoconazole into combination matrices of AL100, AG75, AP75, AP50, and AK75 resulted in significantly higher solubility in FaSSIF-2X (Fasted State Simulated Intestinal Fluid) at pH 6.5 compared to pure ketoconazole.

Cocrystals Enhance Biopharmaceutical and Antimicrobial Properties of Norfloxacin.

A solvate cocrystal of the antimicrobial norfloxacin (NFX) was formed by using isonicotinamide (INA) as a coformer with the solvent evaporation technique. The cocrystal formation was confirmed by performing solid-state characterization techniques. We evaluated the dissolution under supersaturated conditions and also the solubility at the vertex of triphasic domain of cocrystal and NFX in both water and Fasted-State Simulated Intestinal Fluid (FaSSIF). The antimicrobial activity was evaluated using the microdilution technique. The cocrystal showed 1.8 times higher dissolution than NFX in water at 60 min and 1.3 times higher in FaSSIF at 180 min in the kinetic study. The cocrystal also had an increase in solubility of 8.38 times in water and 6.41 times in FaSSIF. The biopharmaceutical properties of NFX with cocrystallization improved antimicrobial action, as shown in the results of minimum inhibitory concentration (MIC) and inhibitory concentrations of 50% (IC50%) and 90% (IC90%). This paper presents, for the first time, a more in-depth analysis of the cocrystal of NFX-INA concerning its dissolution, solubility, and antimicrobial activity. In all these criteria, the cocrystal obtained better results compared to the pure drug.

A Combined In-Vitro and GastroPlus® Modeling to Study the Effect of Intestinal Precipitation on Cinnarizine Plasma Profile in a Fasted State.

Poorly water-soluble weak base molecules such as cinnarizine often exhibit pH-dependent solubility within the gastrointestinal tract. This means that their solubility can be influenced by the pH of the surrounding environment, and this can affect their oral absorption. The differential pH solubility between the fasted-state stomach and intestine is an important consideration when studying the oral absorption of cinnarizine. Cinnarizine has moderate permeability and is known to exhibit supersaturation and precipitation in fasted-state simulated intestinal fluid (FaSSIF), which can significantly impact its oral absorption. The present work is aimed at studying the precipitation behavior of cinnarizine in FaSSIF using biorelevant in vitro tools and GastroPlus® modeling, to identify the factors contributing to the observed variability in clinical plasma profiles. The study found that cinnarizine demonstrated variable precipitation rates under different bile salt concentrations, which could impact the concentration of the drug available for absorption. The results also showed that a precipitation-integrated modeling approach accurately predicted the mean plasma profiles from the clinical studies. The study concluded that intestinal precipitation may be one of the factors contributing to the observed variability in Cmax but not the AUC of cinnarizine. The study further suggests that the integration of experimental precipitation results representing a wider range of FaSSIF conditions would increase the probability of predicting some of the observed variability in clinical results. This is important for biopharmaceutics scientists, as it can help them evaluate the risk of in vivo precipitation impacting drug and/or drug product performance.

Amphotericin B and monoacyl-phosphatidylcholine form a stable amorphous complex

Amphotericin B (AmB) is a “life-saving” medicine for the treatment of invasive fungal infections and visceral leishmaniasis. To date, all marketed AmB formulations require parenteral administration, which causes high rates of acute infusion-related side effects and dose-dependent nephrotoxicity. The development of an oral AmB formulation will entail numerous advantages including increased patient compliance, eliminated infusion-related toxicities and reduced nephrotoxicity. Unfortunately, the gastrointestinal absorption of AmB is negligible due to its extremely low solubility in both aqueous and lipid solvents, and its poor gastrointestinal permeability. Drug-phospholipid complexation is an emerging strategy for oral delivery of poorly soluble drugs. In this study, monoacyl-phosphatidylcholine (MAPC) was complexed with AmB forming an AmB-MAPC complex (APC), to enhance the dissolution rate and aqueous solubility of AmB, in order to enable oral delivery of AmB. X-ray powder diffraction demonstrated that AmB was transformed to its amorphous form following complexation with MAPC, i.e. in the APC. Fourier-transform infrared spectroscopy suggested molecular interactions between AmB and MAPC. Dynamic light scattering indicated formation of colloidal structures after aqueous dispersion of APC; Cryogenic transmission electron microscopy showed that APC formed small round, “rod-like” and “worm-like” micellar structures and Small-angle neutron scattering provided three-dimensional micellar structures formed by APC upon aqueous dispersion, which indicated that AmB was inserted into the micellar mono-layer membrane formed by MAPC. Additionally, APC showed an increased dissolution rate and a higher amount of AmB solubilized in fasted state simulated intestinal fluid, compared to AmB/MAPC physical mixtures and crystalline AmB. In conclusion, an APC exhibiting amorphous properties was developed, the APC showed improved dissolution rate and increased apparent aqueous solubility compared to AmB, indicating that the application of APC could be a promising strategy to enable the oral delivery of AmB.

Synthesis and Characterization of Ezetimibe Pharmaceutical Cocrystal: A Reaction Crystallization Method to Improve Physicochemical Properties and Hypolipemic Activity Evaluation

Ezetimibe has significant lipid-lowering activity but presents low aqueous solubility. Co-crystallization techniques can be used to overcome this limitation. However, it is not yet clear whether the solubility of the cocrystal can be maintained after oral administration. In the present study, an ezetimi-imidazole cocrystal was synthetized by the reaction crystallization method, a promising strategy in cocrystal engineering. After conducting characterization tests, we determined the solubility and thermodynamic stability of the cocrystal. Also, the solubility advantage for both water and biorelevant fasted state simulated intestinal fluid (FaSSIF) was calculated. Dissolution was determined under supersaturated conditions, and the hypolipidemic activity of the cocrystal was assessed in vivo. The cocrystal exhibited high solubility and thermodynamic stability in FaSSIF. The solubility advantage was calculated as 22.4 in water and 11.8 in FaSSIF. The dissolution of the cocrystal resulted in supersaturation levels (σmax) of 1.3 in water and 3.3 in FaSSIF and the area under the curve (AUC) increased from 478.49 (ezetimibe) to 2963.62 µg min mL-1(cocrystal) in FaSSIF. The atherogenic index of the animals that received the cocrystal was similar to that of the control group. These results demonstrate that the inherent advantages of the co-crystallization process were maintained, enabling us to elucidate the behavior of the cocrystal.

When Interactions Between Bile Salts and Cyclodextrin Cause a Negative Food Effect: Dynamic Dissolution/Permeation Studies with Itraconazole (Sporanox®) and Biomimetic Media

The marketed oral solution of itraconazole (Sporanox®) contains 40% (259.2 mM) of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The obvious role of HP-β-CD is to solubilize itraconazole and to overcome its poor aqueous solubility that restricts its absorption.In this study, we investigated the biorelevance of in vitro experiments by the influence of biomimetic media (containing bile salts and phospholipids) on the predicted itraconazole absorption from the commercial HP-β-CD-based Sporanox® solution. We performed phase-solubility studies of itraconazole and dynamic 2-step-dissolution/permeation studies using a biomimetic artificial barrier, Sporanox® solution, and fasted state simulated intestinal fluid (FaSSIF_V1).Both FaSSIF_V1 and HP-β-CD increased the apparent solubility of itraconazole when used individually. In combination, their solubility-enhancing effects were not additive probably due to the competition of bile salts with itraconazole for the hydrophobic cavity of HP-β-CD. Our combined dissolution/permeation experiments indicated the occurrence of a transient supersaturation from Sporanox® upon two-step dissolution. Through systematic variation of bile salt concentrations in the biomimetic media, it was observed that the extent and the duration of supersaturation depend on the concentrations of bile salts: supersaturation was rather stable in the absence of bile salts and phospholipids. The higher the bile salt concentration, the faster the collapse of the transient supersaturation occurred, an effect which is nicely mirrored by reduced in vitro permeation across the barrier. This is an indication of a negative food effect, which in fact correlates well with what earlier had been observed in clinical studies for Sporanox® solution.In essence, we could demonstrate that in vitro two-stage dissolution/permeation experiments using an artificial barrier and selected biomimetic media may predict the negative effects of the latter on cyclodextrin-based drug formulations like Sporanox® Oral Solution and, at the same time, provide a deeper mechanistic insight.

Oral Delivery of Niclosamide as an Amorphous Solid Dispersion That Generates Amorphous Nanoparticles during Dissolution.

Niclosamide is an FDA-approved anthelmintic that is being studied in clinical trials as a chemotherapeutic and broad-spectrum antiviral. Additionally, several other applications are currently in the preclinical stage. Unfortunately, niclosamide is a poorly water soluble molecule, with reduced oral bioavailability, which hinders its use for new indications. Moreover, niclosamide is a poor glass former; in other words, the molecule has a high tendency to recrystallize, and it is virtually impossible to generate a stable amorphous solid employing the neat molecule. Previously, our group reported the development of an amorphous solid dispersion (ASD) of niclosamide (niclosamide ASD) that generates nanoparticles during its dissolution, not only increasing niclosamide's apparent solubility from 6.6 ± 0.4 to 481.7 ± 22.2 µg/mL in fasted state simulated intestinal fluid (FaSSIF) but also its oral bioavailability 2.6-fold in Sprague-Dawley rats after being administered as a suspension. Nevertheless, niclosamide ASD undergoes recrystallization in acidic media, and an enteric oral dosage form is needed for its translation into the clinic. In this work, we further characterized the nanoparticles that generated during the dissolution of the niclosamide ASD. Cryogenic transmission electron microscopy (Cryo-TEM) and wide-angle X-ray scattering (WAXS) revealed that the nanoparticles were amorphous and had a particle size of ~150 nm. The oral dosage forms of niclosamide ASD were formulated using commercial enteric capsules (Capsuline® and EudracapTM) and as enteric-coated tablets. The enteric dosage forms were tested using pH-shift dissolution and acid-uptake tests, using the USP type II dissolution apparatus and the disintegration apparatus, respectively. The capsules exhibited a higher percentage of weight gain, and visual rupture of the Capsuline capsules was observed. Eudracap capsules protected the formulation from the acidic media, but polymer gelling and the formation of a nondispersible plug were noted during dissolution testing. In contrast, enteric-coated tablets protected the formulation from acid ingress and maintained the performance of niclosamide ASD granules during dissolution in FaSSIF media. These enteric-coated tablets were administered to beagle dogs at a niclosamide dose of 75 mg/kg, resulting in plasma concentrations of niclosamide higher than those reported in the literature using solubilized niclosamide at a higher dose (i.e., 100 mg/kg). In summary, an enteric oral dosage form of niclosamide ASD was formulated without hindering the generation of nanoparticles while maintaining the increase in the niclosamide's apparent solubility. The enteric-coated tablets successfully increased the niclosamide plasma levels in dogs when compared to a niclosamide solution prepared using organic solvents.

The effect of mucin on supersaturation of poorly water-soluble drugs with different crystallization behavior and in vitro-in vivo correlation

Drug delivery systems such as lipids, solid dispersions, or nanocrystals have been proposed to improve the absorption and bioavailability of poorly water-soluble drugs with different crystallization behavior by polymers in a spring-parachute model, which generate and stabilize the drug supersaturation. Mucins, synthesized by specialized epithelial cells, have characteristics of high molecular polymer and electrostatic or hydrophobic interactions with drugs. Our study aims to investigate the effect of mucin on supersaturation of poorly water-soluble drugs with different crystallization behavior in fasted state simulated intestinal fluid (FaSSIF) and in vitro-in vivo correlation (IVIVC). The solubility of poorly water-soluble drugs was tested. The experiment of supersaturation stability was performed by solvent-shift method. The experiment of crystallization was observed by polarized light microscope analysis. The animal pharmacokinetic experiment was conducted, and the IVIVC was analyzed by linear regression. There was no significant difference in solubility between FaSSIF without and with mucin. It showed significant differences in Tss or AUC of naproxen (nifedipine, itraconazole) between FaSSIF without and with mucin (p < 0.05, p < 0.01). There was no significant difference in Tss of ritonavir between FaSSIF without and with mucin, except for significant differences in AUC (p < 0.01). In the presence of mucin, crystallization time was prolonged in FaSSIF. The SSR of drugs in FaSSIF with mucin and Fa in rat showed a better level of IVIVC with a higher r value, compared with that between FaSSIF and rat. Mucin prolonged the supersaturation of poorly water-soluble drugs with different crystallization behavior, without the change of solubility, by inhibiting the drug nucleation (or crystal growth) or forming the mucin-drug interaction. It showed the role of mucin widely existed in poorly water-soluble drugs in vivo condition.

Solubility measurement of poorly soluble drugs in fasted state simulated intestinal fluid

Adequatedrug solubility in the gastrointestinal tract is essential for systemic therapyof orally administered medications. To carry out research on the solubility ofpoorly soluble drugs in vitro, simulated intestinal fluid (SIF) is usedin place of human intestinal fluid (HIF). However, typical SIF reflects averagecompositions of HIF rather than the full range of compositions previouslyreported. This study examines a new suite of SIF media (based on variabilityobserved in HIF) to explore the range of solubility of four poorly soluble drugs(Naproxen, Indomethacin, Phenytoin and Tadalafil) in the fasted state.

Survival of human coronavirus 229E at different temperatures on various food-contact surfaces and food and under simulated digestive conditions

The COVID-19 pandemic caused by SARS-CoV-2 has had a major impact on human health and the global economy. Various transmission possibilities of SARS-CoV-2 have been proposed, such as the surface of food in the cold chain and food packaging, as well as the fecal-oral route, although person-to-person contact via droplets and aerosols has been confirmed as the main route of transmission. This study evaluated the survivability of HCoV-229E, a SARS-CoV-2 surrogate, in suspension, on food-contact surfaces and on food at various temperatures, and in simulated digestive fluids by TCID50 assay. In suspension, HCoV-229E survived after 5 days at 20 °C with a 3.69 log reduction, after 28 days at 4 °C with a 3.07 log reduction, and after 12 weeks at –20 °C with a 1.18 log reduction. On food-contact surfaces, HCoV-229E was not detected on day 3 on stainless steel (SS), plastic (LDPE), and silicone rubber (SR) at 20 °C with a 3.28, 3.24 and 3.28 log reduction, respectively, and survived after 28 days on SS and LDPE at 4 °C with a 3.13 and 2.88 log reduction, respectively, and survived after 12 weeks on SS, LDPE, and SR at –20 °C with a 1.92, 1.32 and 1.99 log reduction, respectively. On food, HCoV-229E was not detected on day 3 on lettuce and day 4 on chicken breast and salmon at 20 °C with a 3.61, 3.26 and 3.08 log reduction, respectively, and on day 14 on lettuce and day 21 on chicken breast and salmon at 4 °C with a 3.88, 3.44 and 3.56 log reduction, respectively. The virus remained viable for 12 weeks in all foods at –20 °C with 2–2.47 log reduction. In addition, in simulated digestive fluid experiments, HCoV-229E was relatively resistant in simulated salivary fluid (SSF; pH 7, 5), fed state simulated gastric fluid (FeSSGF; pH 3, 5, 7), and fasted state simulated intestinal fluid (FaSSIF; pH 7). However, the virus was less tolerant in fasted state simulated gastric fluid (FaSSGF; pH 1.6) and fed state simulated intestinal fluid (FeSSIF; pH 5). Therefore, this study suggested that HCoV-229E remained infectious on various food-contact surfaces and foods; in particular, it survived longer at lower temperatures and survived depending on the pH of the simulated digestive fluid.

Supersaturated amorphous solid dispersions of celecoxib prepared in situ by microwave irradiation

This study investigated the ability of in situ amorphisation using microwave irradiation in order to prepare highly supersaturated ASDs, i.e. ASDs with drug loads higher than the saturation solubility in the polymer at ambient temperature. For this purpose, compacts containing the crystalline drug celecoxib (CCX) and polyvinylpyrrolidone (PVP), polyvinylpyrrolidone—vinyl acetate copolymer (PVP/VA), or polyvinyl acetate (PVAc), were prepared at drug loads between 30 and 90 % w/w. Sodium dihydrogen phosphate (NaH2PO4) monohydrate was included in all compacts, as a source of water, to facilitate the dielectric heating of the compacts upon dehydration during microwave irradiation. After processing, the samples were analysed towards their solid state using X-ray powder diffraction (XRPD) and modulated differential scanning calorimetry (mDSC). Complete amorphisation of CCX was achieved across all the investigated polymers and with a maximal drug load of 90, 80, and 50 % w/w in PVP, PVP/VA, and PVAc, respectively. These drug loads corresponded to a 2.3-, 2.4-, and 10.0-fold supersaturation in the investigated polymers at ambient temperature. However, dissolution experiments with the in situ prepared ASDs in fasted state simulated intestinal fluid (FaSSIF), showed a lower initial drug release (0–2 h) compared to equivalent physical mixtures of crystalline CCX and polymers or crystalline CCX alone. The lower drug release rate was explained by the fusion of individual drug and polymer particles during microwave irradiation and, subsequently, a lack of disintegration of the monolithic ASDs. Nevertheless, supersaturation of CCX in FaSSIF was achieved with the in situ amorphised ASDs with PVP and PVP/VA, albeit only after 3–24 h. Overall, the present study confirmed that it is feasible to prepare supersaturated ASDs in situ. However, in the current experimental setup, the monolithic nature of the resulting ASDs is considered a limiting factor in the practical applicability of this preparation method, due to limited disintegration and the associated negative effect on the drug release.

Biopredictive capability assessment of two dissolution/permeation assays, µFLUX™ and PermeaLoop™, using supersaturating formulations of Posaconazole

The majority of new drug entities exhibits poor water solubility and therefore enabling formulations are often needed to ensure sufficient in vivo bioavailability upon oral administration. Several in vitro tools have been proposed for biopredictive screening of such drug formulations to facilitate formulation development. Among these, combined dissolution/permeation (D/P) assays have gained increasing interest in recent years, since they are presumed to better predict the absorption behavior as compared to single-compartment dissolution assays. Moreover, especially for supersaturating formulations, it has been demonstrated that the presence of an absorption sink better mimics the intraluminal supersaturation performance.The present study aimed to investigate the biopredictive abilities of two in vitro D/P setups to predict intestinal supersaturation and systemic absorption of supersaturable systems. Experiments were performed with a µFLUX™ and PermeaLoop™ apparatus, respectively, which differ primarily in their volume-to-area ratios between donor compartment and membrane as well as in the type of biomimetic barrier. A two-stage dissolution protocol was adopted to mimic the transit from acidic stomach to more neutral intestinal fluids using biomimetic media. Three formulations of the weakly basic compound Posaconazole (PCZ), namely an acidified and a neutral suspension and an amorphous solid dispersion (ASD) tablet, were tested.Under the present conditions, and for the specific set of formulations studied here, PermeaLoop™ showed a better biopredictive ability for intestinal supersaturation and systemic absorption for the three formulations than the µFLUX™ D/P setup. Interestingly, minor modifications of the two-stage D/P protocol in terms of medium transfer rates from simulated gastric fluid (SGF) to fasted state simulated intestinal fluid (FaSSIF) had a substantial impact particularly on the permeation of the crystalline PCZ suspension (“acidified suspension”). The ASD tablet was less sensitive to gradual medium changes than the crystalline PCZ suspensions. The current study confirms the usefulness of D/P assays for formulation ranking of weakly basic compounds and supersaturating formulations.

Development of a Microgram Scale Video-Microscopic Method to Investigate Dissolution Behavior of Poorly Water-Soluble Drugs.

Poor aqueous solubility is a common characteristic of new drug candidates, which leads to low or inconsistent oral bioavailability. This has sparked an interest in material efficient testing of solubility and dissolution rate. The aim was to develop a microgram scale video-microscopic method to screen the dissolution rates of poorly water-soluble drugs. This method was applied to six drugs (carvedilol, diazepam, dipyridamole, felodipine, fenofibrate, and indomethacin) in fasted state simulated intestinal fluid (FaSSIF), of indomethacin in buffer with varying pH, and of diazepam and dipyridamole in customized media. An additional aim was to track phase transformations for carbamazepine in FaSSIF. The dissolution rates and particle behavior of the drugs were investigated by tracking particle surface area over time using optical video-microscopy. Applying miniaturized UV spectroscopic dissolution resulted in a similar grouping of dissolution rates and pH effects, as for the video-microscopic setup. Using customized media showed that lysophospholipid enhanced the dissolution rate of diazepam and dipyridamole. The video-microscopic setup allowed for the nucleation of transparent particles on dissolving carbamazepine particles to be tracked over time. The developed setup offers a material efficient screening approach to group drugs according to dissolution rate, where the use of optical microscopy helps to achieve a high sample throughput.