Significant pain decrease in children with non-systemic Juvenile Idiopathic Arthritis treated to target:results over 24 months of follow up

Background: The aim of this study was to compare pain-scores in three targeted treatment-strategies in JIA-patients and to identify characteristics predicting persistent pain. Methods: In the BeSt-for-Kids-study 92 DMARD-naïve JIA-patients were randomized in 3 treatment-strategies: 1) initial sequential DMARD-monotherapy 2) initial methotrexate (MTX)/prednisolone-bridging or 3) initial MTX/etanercept. Potential differences in VAS pain scores (0-100 mm) over time between treatment-strategies were compared using linear mixed models with visits clustered within patients. A multivariable model was used to assess the ability of baseline characteristics to predict the chance of high pain-scores during follow-up. Results: Pain-scores over time reduced from mean 55.3 (SD 21.7) to 19.5 (SD 25.3) mm after 24 months. On average, pain-scores decreased significantly with β -1.37 mm (95% CI -1.726; -1.022) per month. No significant difference was found between treatment-strategies (interaction term treatment arm*time (months) β (95% CI) arm 1: 0.13 (-0.36; 0.62) and arm 2: 0.37 (-0.12; 0.86) compared to arm 3). Correction for sex and symptom duration yielded similar results. Several baseline characteristics were predictive for pain over time. Higher VAS pain [β 0.44 (95% CI 0.25; 0.65)] and higher active joint count [0.77 (0.19; 1.34)] were predictive of higher pain over time, whereas, low VAS physician [-0.34 (-0.55; -0.06)], CHQ Physical [-0.42 (-0.72; -0.11)] and Psychosocial summary Score [-0.42 (-0.77; -0.06)] were predictive of lower pain. Conclusions: Treatment-to-target seems effective in pain-reduction in non-systemic JIA-patients irrespective of initial treatment-strategy. Several baseline-predictors for pain over time were found, which could help to identify patients with a high risk for development of chronic pain. Trial registration: Dutch Trial Registry number 1574.</p

Caco-2 Cell Conditions Enabling Studies of Drug Absorption from Digestible Lipid-Based Formulations

Purpose To identify conditions allowing the use of cell-based models for studies of drug absorption during in vitro lipolysis of lipid-based formulations (LBFs). Methods Caco-2 was selected as the cell-based model system. Monolayer integrity was evaluated by measuring mannitol permeability after incubating Caco-2 cells in the presence of components available during lipolysis. Pure excipients and formulations representing the lipid formulation classification system (LFCS) were evaluated before and after digestion. Porcine mucin was evaluated for its capacity to protect the cell monolayer. Results Most undigested formulations were compatible with the cells (II-LC, IIIB-LC, and IV) although some needed mucin to protect against damaging effects (II-MC, IIIB-MC, LC, and IIIA-LC). The pancreatic extract commonly used in digestion studies was incompatible with the cells but the Caco-2 monolayers could withstand immobilized recombinant lipase. Upon digestion, long chain formulations caused more damage to Caco-2 cells than their undigested counterparts whereas medium chain formulations showed better tolerability after digestion. Conclusions Most LBFs and components thereof (undigested and digested) are compatible with Caco-2 cells. Pancreatic enzyme is not tolerated by the cells but immobilized lipase can be used in combination with the cell monolayer. Mucin is beneficial for critical formulations and digestion products

Primary Hepatocytes in Sandwich Culture

Hepatocytes in sandwich configuration constitute of primary hepatocytes cultured between two layers of extracellular matrix. Sandwich-cultured hepatocytes maintain expression of liver-specific proteins and gradually form intact bile canaliculi with functional biliary excretion of endogenous compounds and xenobiotics. Both freshly isolated and cryopreserved hepatocytes can be used to establish sandwich cultures. Therefore, this preclinical model has become an invaluable in vitro tool to evaluate hepatobiliary drug transport, metabolism, hepatotoxicity, and drug interactions. In this chapter, commonly used procedures to cultivate primary hepatocytes from human and rat in sandwich configuration are described.edition: 1ststatus: publishe

Lipolysis-Permeation Setup for Simultaneous Study of Digestion and Absorption in Vitro

Lipid-based formulations (LBFs) are a delivery strategy to enhance intestinal absorption of poorly water-soluble drugs. LBF performance is typically evaluated by in vitro lipolysis studies, but these do not accurately predict the in vivo performance. One possible reason is the absence of an absorptive membrane driving sink conditions in the serosal compartment. To explore the impact of absorption under sink conditions on the performance evaluation, we developed a lipolysis-permeation setup that allows simultaneous investigation of intestinal digestion of an LBF and drug absorption. The setup consists of two chambers, an upper one for digestion (luminal), and a lower, receiving one (serosal), separated by a Caco-2 monolayer. Digestions were performed with immobilized lipase, instead of the pancreatic extract typically used during lipolysis, since the latter has proven incompatible with Caco-2 cells. Danazol-loaded LBFs were used to develop the setup, and fenofibrate-loaded LBFs were used to establish an in vitro in vivo correlation. As in regular lipolysis studies, our setup allows for the evaluation of (i) the extent of digestion and (ii) drug distribution in different phases present during lipolysis of drug-loaded LBFs (i.e., oil, aqueous, and solid phase). In addition, our setup can determine drug permeation across Caco-2 monolayers and hence, the absorptive flux of the compound. The presence of the absorptive monolayer and sink conditions tended to reduce aqueous drug concentrations and supersaturation in the digestion chamber. The drug transfer across the Caco-2 membrane accurately reflected in vivo drug exposure upon administration of three different LBFs loaded with fenofibrate, where the traditional lipolysis setup failed to predict in vivo performance. As the new setup reflects the dynamic processes occurring in the gastrointestinal tract, it is a valuable tool that can be used in the development of LBFs prior to in vivo studies

Does the Intake of Ethanol Affect Oral Absorption of Poorly Soluble Drugs?

The presence of ethanol in gastrointestinal (GI) fluids may increase the solubility of poorly water-soluble drugs. This suggests that intake of ethanol with such compounds could result in increased drug absorption in the stomach and duodenum because of the greater concentration gradient present. To test this hypothesis, in vitro dissolution of 2 poorly soluble compounds (indomethacin and felodipine) was studied in simulated GI rat fluids in the presence or absence of ethanol. Results were used to predict plasma exposure of the compounds using the software PK-Sim. Finally, in vivo plasma exposure in rats was investigated after oral dosing followed by immediate administration of water or ethanol. Despite increased solubility in GI fluids in the presence of ethanol, simulations predicted a negligible effect on absorption. This was confirmed in the rat study where oral intake of indomethacin or felodipine with ethanol did not increase in vivo plasma exposure. A possible explanation for the lack of an effect may be that dilution, absorption, and transfer of ethanol upon arrival in the stomach resulted in intragastric and intraduodenal ethanol concentrations that did not reach the levels required to affect local solubility

Comparison of cellular monolayers and an artificial membrane as absorptive membranes in the in vitro lipolysis-permeation assay

Permeation across Caco-2 cells in lipolysis-permeation setups can predict the rank order of in vivo drug exposure obtained with lipid-based formulations (LBFs). However, Caco-2 cells require a long differentiation period and do not capture all characteristics of the human small intestine. We therefore evaluated two in vitro assays with artificial lecithin-in-dodecane (LiDo) membranes and MDCK cells as absorptive membranes in the lipolysis-permeation setup. Fenofibrate-loaded LBFs were used and the results from the two assays compared to literature plasma concentrations in landrace pigs administered orally with the same formulations. Aqueous drug concentrations, supersaturation, and precipitation were determined in the digestion chamber and drug permeation in the receiver chamber. Auxiliary in vitro parameters were assessed, such as permeation of the taurocholate, present in the simulated intestinal fluid used in the assay, and size of colloidal structures in the digestion medium over time. The LiDo membrane gave a similar drug distribution as the Caco-2 cells and accurately reproduced the equivalent rank-order of fenofibrate exposure in plasma. Permeation of fenofibrate across MDCK monolayers did not, however, reflect the in vivo exposure rankings. Taurocholate flux was negligible through either membrane. This process was therefore not considered to significantly affect the in vitro distribution of fenofibrate. We conclude that the artificial LiDo membrane is a promising tool for lipolysis–permeation assays to evaluate LBF performance

Modeling of telmisartan disposition in sandwich-cultured rat hepatocytes. Does cryopreservation change disposition kinetics?

status: accepte

An in vitro dissolution–digestion–permeation assay for the study of advanced drug delivery systems

Advanced drug delivery systems (ADDS) are widely explored to overcome poor aqueous solubility of orally administered drugs. However, the prediction of their in vivo performance is challenging, as in vitro models typically do not capture the interplay between processes occurring in the gut. In additions, different models are used to evaluate the different systems. We therefore present a method that allows monitoring of luminal processing (dissolution, digestion) and its interplay with permeation to better inform on the absorption of felodipine formulated as ADDS. Experiments were performed in a µFLUX-apparatus, consisting of two chambers, representing the intestinal and serosal compartment, separated by Caco-2 monolayers. During dissolution–digestion–permeation experiments, ADDS were added to the donor compartment containing simulated intestinal fluid and immobilized lipase. Dissolution and permeation in both compartments were monitored using in situ UV-probes or, when turbidity interfered the measurements, with HPLC analysis. The method showed that all ADDS increased donor and receiver concentrations compared to the condition using crystalline felodipine. A poor correlation between the compartments indicated the need for an serosal compartment to evaluate drug absorption from ADDS. The method enables medium-throughput assessment of: (i) dynamic processes occurring in the small intestine, and (ii) drug concentrations in real-time

Extra collagen overlay prolongs the differentiated phenotype in sandwich-cultured rat hepatocytes

INTRODUCTION: Sandwich-cultured rat hepatocytes (SCRH) have become an invaluable in vitro model to study hepatic drug disposition. SCRH are maintained between two layers of extracellular matrix. In this configuration, culture periods of 4days are typically applicable. The aim of the present study was to modify conventional SCRH by applying an additional collagen overlay to prolong the hepatic phenotype in SCRH and thus to extend the applicability of the model. METHODS: The cultures receiving an extra top layer ('SCRH-plus' cultures) were compared with the conventional SCRH by testing the morphology, cell functionality, metabolic capacity and Mrp2-activity. RESULTS: In the SCRH-plus cultures, cell functionality, evaluated by measuring urea production, was increased from day 5 onwards, compared to conventional cultures. Furthermore, these cells retained the appearance of typical hepatocytes, in contrast with conventional sandwich cultures which showed rapid dedifferentiation. SCRH-plus exhibited significantly improved metabolic clearance mediated by cytochrome P450 3A compared to conventional SCRH whereas UDP-glucuronosyltransferase-mediated metabolism was unaffected. Both conventional SCRH and SCRH-plus showed extensive biliary networks at day 4 of culture. However, from day 4 onwards, a decline in biliary excretion index (BEI) was observed in the conventional SCRH, while BEI values in SCRH-plus cultures did not decrease until day 7. DISCUSSION: The application of an extra top layer of collagen on the SCRH prolongs their useful life-span to 7days. Therefore, SCRH-plus cultures will broaden the applications of SCRH in terms of long-term toxicity evaluation and when determining metabolism of low turnover compounds.status: publishe

Impact of Drug Physicochemical Properties on Lipolysis-Triggered Drug Supersaturation and Precipitation from Lipid-Based Formulations

In this study we investigated lipolysis-triggered supersaturation and precipitation of a set of model compounds formulated in lipid-based formulations (LBFs). The purpose was to explore the relationship between precipitated solid form and inherent physicochemical properties of the drug. Eight drugs were studied after formulation in three LBFs, representing lipid-rich (extensively digestible) to surfactant-rich (less digestible) formulations. In vitro lipolysis of drug-loaded LBFs were conducted, and the amount of dissolved and precipitated drug was quantified. Solid form of the precipitated drug was characterized with polarized light microscopy (PLM) and Raman spectroscopy. A significant solubility increase for the weak bases in the presence of digestion products was observed, in contrast to the neutral and acidic compounds for which the solubility decreased. The fold-increase in solubility was linked to the degree of ionization of the weak bases and thus their attraction to free fatty acids. A high level of supersaturation was needed to cause precipitation. For the weak bases, the dose number indicated that precipitation would not occur during lipolysis; hence, these compounds were not included in further studies. The solid state analysis proved that danazol and griseofulvin precipitated in a crystalline form, while niclosamide precipitated as a hydrate. Felodipine and indomethacin crystals were visible in the PLM, whereas the Raman spectra showed presence of amorphous drug, indicating amorphous precipitation that quickly crystallized. The solid state analysis was combined with literature data to allow analysis of the relationship between solid form and the physicochemical properties of the drug. It was found that low molecular weight and high melting temperature increases the probability of crystalline precipitation, whereas precipitation in an amorphous form was favored by high molecular weight, low melting temperature, and positive charge