Publications by authors named "Alexandros Kourentas"

The Biorelevant Gastrointestinal Transfer (BioGIT) system is a useful screening tool for assessing the impact of dose and/or formulation on early exposure after administration of immediate release or enabling drug products with a glass of water in the fasted state. The objective of this study was to investigate potential limitations. BioGIT experiments were performed with five low solubility active pharmaceutical ingredients with weakly alkaline characteristics: mebendazole (tablet and chewable tablet), Compound E (aqueous solutions, three doses), pazopanib-HCl (Votrient™ tablet, crushed Votrient™ tablet and aqueous suspension), Compound B-diHCl (hard gelatin capsule, three doses) and Compound C (hard gelatin capsule containing nanosized drug and hard gelatin capsule containing micronized drug).

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Physiologically based pharmacokinetic and absorption modeling has increasingly been implemented for biopharmaceutics applications to define the safe space for drug product quality attributes such as dissolution. For fevipiprant/QAW039, simulations were performed to assess the impact of in vitro dissolution on the in vivo performance of immediate-release film-coated tablets during development and scaling up to commercial scale. A fevipiprant dissolution safe space was established using observed clinical intravenous and oral PK data from bioequivalent and non-bioequivalent formulations.

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Article Synopsis
  • * Four APIs were tested, including two compounds in various forms (tablets and capsules), and the study analyzed mean plasma area under the curve (AUC) values to evaluate their effectiveness.
  • * A strong correlation (R = 0.90) was found between bioavailability estimated by BioGIT AUC values and actual plasma AUC ratios, suggesting that BioGIT can be an effective early screening method for analyzing drug exposure variations.
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The majority of drug candidates exhibit weakly basic characteristics with high lipophilicity. The risk of intraluminal compound precipitation has been studied in vivo and extensively in vitro using advanced dissolution transfer setups mimicking drug transfer from the stomach to the small intestine. The present investigation aims to evaluate the usefulness of the recently introduced Artificial Stomach-Duodenum in silico tool in the DDDPlus platform (ASD-D+) to simulate intraluminal drug behavior.

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A physiologically based pharmacokinetic (PBPK) human model for alpelisib, an oral α-specific class I phosphatidylinositol-3-kinase (PI3K) inhibitor, was established to simulate oral absorption and plasma pharmacokinetics of healthy subjects to allow model-informed drug development. The GastroPlus™ model consisted of an advanced absorption gut model, which was linked to a 2-compartmental model. Systemic clearance and volume of distribution were estimated using population pharmacokinetics (popPK).

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This paper summarizes efforts to (i) better understand the behavior of amorphous solid dispersions (ASDs) under real-life dosing conditions and (ii) evaluate the capability of in vitro methodologies to capture gastro-intestinal drug disposition. In a first part of the study, five healthy volunteers participated in a two-way crossover trial in which one Norvir® tablet (100 mg ritonavir) was dosed under fasted and fasted + PPI conditions. Gastrointestinal aspirates were collected from both the stomach and duodenum as a function of time to map the gastrointestinal drug disposition of the ritonavir ASD formulation and to evaluate the impact of reduced gastric acid secretion on formulation performance.

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The purpose of this study was to evaluate the usefulness of the in vitro biorelevant gastrointestinal transfer (BioGIT) system in assessing the impact of dose and formulation on early exposure by comparing in vitro data with previously collected human plasma data of low solubility active pharmaceutical ingredients. Eight model active pharmaceutical ingredients were tested; Lu 35-138C (salt of weak base in a HP-beta-CD solution, three doses), fenofibrate (solid dispersion, tablet, two doses), AZD2207 EQ (salt of weak base, capsule, three doses), posaconazole (Noxafil® suspension, two doses), SB705498 (weak base, tablets vs. capsules), cyclosporine A (Sandimmun® vs.

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Biorelevant Gastrointestinal Transfer system (BioGIT) has been shown to be useful in reproducing concentrations of drugs in the fasted upper small intestine after their administration in the stomach. In the present investigation, we evaluated the impact of gastrointestinal transfer on luminal performance of commercially available products of two highly lipophilic weak bases, posaconazole (Noxafil suspension) and itraconazole (Sporanox hard gelatin capsules and Sporanox oral solution) by comparing % solid fraction, concentrations and supersaturation in the duodenal compartment of BioGIT with recently reported data in the upper small intestine of healthy adults. BioGIT was useful for estimating the % solid fraction in the upper small intestine, in cases where dissolution during gastric residence was incomplete, i.

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An in vitro biorelevant gastrointestinal transfer (BioGIT) system was assessed for its ability to mimic recently reported albendazole concentrations in human upper small intestine after administration of free base suspensions to fasted adults in absence and in presence of supersaturation promoting excipients (hydroxypropylmethylcellulose and lipid self-emulsifying vehicles). The in vitro method was also used to evaluate the likely impact of using the sulfate salt on albendazole concentrations in upper small intestine. In addition, BioGIT data were compared with equilibrium solubility data of the salt and the free base in human aspirates and biorelevant media.

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Purpose: To evaluate the impact of dosage form relevant levels of a polymeric precipitation inhibitor and of lipid excipients on supersaturation of upper gastrointestinal contents with albendazole, a lipophilic weak base.

Materials And Methods: Albendazole concentrations in stomach and in duodenum were evaluated after administration of 1) a suspension in water (Susp-Control), 2) a suspension in water in which hydroxyprolylmethylcellulose E5 (HPMC E5) had been pre-dissolved (Susp-HPMC), and 3) and 4) two contrasting designs of lipid based suspensions dispersed in water (Susp-IIIA and Susp-IV), on a cross-over basis to fasted healthy adults.

Results: Limited, but statistically significant supersaturation of duodenal contents was observed after Susp-HPMC, Susp-IIIA, and Susp-IV; supersaturation was more consistent after Susp-HPMC administration.

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Purpose: Design an in vitro methodology for studying gastrointestinal transfer in the fasted state and implement the methodology in vitro by using a biorelevant gastrointestinal transfer system(BioGIT); evaluate the usefulness of BioGIT in predicting luminal concentrations of lipophilic weak bases in the fasted upper small intestine.

Methods: The methodology was designed after modeling existing luminal data. Its implementation in vitro was based on a three compartment setup.

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