Kuentz, Martin

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Kuentz, Martin

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  • Vorschaubild nicht verfügbar
    Publikation
    From Quantum Chemistry to Prediction of Drug Solubility in Glycerides
    (American Chemical Society, 04.11.2019) Alsenz, Jochem; Kuentz, Martin [in: Molecular Pharmaceutics]
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Combining biorelevant in vitro and in silico tools to simulate and better understand the in vivo performance of a nano-sized formulation of aprepitant in the fasted and fed states
    (Elsevier, 01.10.2019) Litou, Chara; Kuentz, Martin [in: European Journal of Pharmaceutical Sciences]
    INTRODUCTION: When developing bio-enabling formulations, innovative tools are required to understand and predict in vivo performance and may facilitate approval by regulatory authorities. EMEND® is an example of such a formulation, in which the active pharmaceutical ingredient, aprepitant, is nano-sized. The aims of this study were 1) to characterize the 80 mg and 125 mg EMEND® capsules in vitro using biorelevant tools, 2) to develop and parameterize a physiologically based pharmacokinetic (PBPK) model to simulate and better understand the in vivo performance of EMEND® capsules and 3) to assess which parameters primarily influence the in vivo performance of this formulation across the therapeutic dose range. METHODS: Solubility, dissolution and transfer experiments were performed in various biorelevant media simulating the fasted and fed state environment in the gastrointestinal tract. An in silico PBPK model for healthy volunteers was developed in the Simcyp Simulator, informed by the in vitro results and data available from the literature. RESULTS: In vitro experiments indicated a large effect of native surfactants on the solubility of aprepitant. Coupling the in vitro results with the PBPK model led to an appropriate simulation of aprepitant plasma concentrations after administration of 80 mg and 125 mg EMEND® capsules in both the fasted and fed states. Parameter Sensitivity Analysis (PSA) was conducted to investigate the effect of several parameters on the in vivo performance of EMEND®. While nano-sizing aprepitant improves its in vivo performance, intestinal solubility remains a barrier to its bioavailability and thus aprepitant should be classified as DCS IIb. CONCLUSIONS: The present study underlines the importance of combining in vitro and in silico biopharmaceutical tools to understand and predict the absorption of this poorly soluble compound from an enabling formulation. The approach can be applied to other poorly soluble compounds to support rational formulation design and to facilitate regulatory assessment of the bio-performance of enabling formulations.
    01A - Beitrag in wissenschaftlicher Zeitschrift
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    Publikation
    Ultra-sub-stoichiometric “Dynamic” Bioconjugation Reduces Viscosity by Disrupting Immunoglobulin Oligomerization
    (American Chemical Society, 09.09.2019) Gong, Yuhui; Niederquell, Andreas; Kuentz, Martin [in: Biomacromolecules]
    Monoclonal antibodies (mAb) are a major focus of the pharmaceutical industry, and polyclonal immunoglobulin G (IgG) therapy is used to treat a wide variety of health conditions. As some individuals require mAb/IgG therapy their entire life, there is currently a great desire to formulate antibodies for bolus injection rather than infusion. However, to achieve the required doses, very concentrated antibody solutions may be required. Unfortunately, mAb/IgG self-assembly at high concentration can produce an unacceptably high viscosity for injection. To address this challenge, this study expands the concept of "dynamic covalent chemistry" to "dynamic bioconjugation" in order to reduce viscosity by interfering with antibody-antibody interactions. Ultra-sub-stoichiometric amounts of dynamic PEGylation agents (down to the nanomolar) significantly reduced the viscosity of concentrated antibody solutions by interfering with oligomerization.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Benefits of Fractal Approaches in Solid Dosage Form Development
    (Springer, 06.09.2019) Abreu-Villela, Renata; Kuentz, Martin [in: Pharmaceutical Research]
    Pharmaceutical formulations are complex systems consisting of active pharmaceutical ingredient(s) and a number of excipients selected to provide the intended performance of the product. The understanding of materials' properties and technological processes is a requirement for building quality into pharmaceutical products. Such understanding is gained mostly from empirical correlations of material and process factors with quality attributes of the final product. However, it seems also important to gain knowledge based on mechanistic considerations. Promising is here to study morphological and/or topological characteristics of particles and their aggregates. These geometric aspects must be taken into account to better understand how product attributes emerge from raw materials, which includes, for example, mechanical tablet properties, disintegration or dissolution behavior. Regulatory agencies worldwide are promoting the use of physical models in pharmaceutics to design quality into a final product. This review deals with pharmaceutical applications of theoretical models, focusing on percolation theory, fractal, and multifractal geometry. The use of these so-called fractal approaches improves the understanding of different aspects in the development of solid dosage forms, for example by identifying critical drug and excipient concentrations, as well as to study effects of heterogeneity on dosage form performance. The aim is to link micro- and macrostructure to the emerging quality attributes of the pharmaceutical solid dosage forms as a strategy to enhance mechanistic understanding and to advance pharmaceutical development and manufacturing processes.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Successful oral delivery of poorly water-soluble drugs both depends on the intraluminal behavior of drugs and of appropriate advanced drug delivery systems
    (Elsevier, 01.09.2019) Boyd, Ben J.; Kuentz, Martin [in: European Journal of Pharmaceutical Sciences]
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    Predicting the Angle of Internal Friction from Simple Dynamic Consolidation Using Lactose Grades as Model
    (Springer, 28.03.2019) Trpělková, Žofie; Kuentz, Martin [in: Journal of Pharmaceutical Innovation]
    Powder flow and packing behavior are among other factors determined by particle friction, which is traditionally measured in shear cells as the angle of internal friction (AIF). Considering that an AIF at a normal stress should be comparable to friction during tapping consolidation, this work aims at whether dynamic consolidation under gravity can be used to estimate an AIF.
    01A - Beitrag in wissenschaftlicher Zeitschrift
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    Publikation
    Calculation of drug-polymer mixing enthalpy as a new screening method of precipitation inhibitors for supersaturating pharmaceutical formulations
    (Elsevier, 12.03.2019) Kuentz, Martin [in: European Journal of Pharmaceutical Sciences]
    Supersaturating formulations are widely used to improve the oral bioavailability of poorly soluble drugs. However, supersaturated solutions are thermodynamically unstable and such formulations often must include a precipitation inhibitor (PI) to sustain the increased concentrations to ensure that sufficient absorption will take place from the gastrointestinal tract. Recent advances in understanding the importance of drug-polymer interaction for successful precipitation inhibition have been encouraging. However, there still exists a gap in how this newfound understanding can be applied to improve the efficiency of PI screening and selection, which is still largely carried out with trial and error-based approaches. The aim of this study was to demonstrate how drug-polymer mixing enthalpy, calculated with the Conductor like Screening Model for Real Solvents (COSMO-RS), can be used as a parameter to select the most efficient precipitation inhibitors, and thus realize the most successful supersaturating formulations. This approach was tested for three different Biopharmaceutical Classification System (BCS) II compounds: dipyridamole, fenofibrate and glibenclamide, formulated with the supersaturating formulation, mesoporous silica. For all three compounds, precipitation was evident in mesoporous silica formulations without a precipitation inhibitor. Of the nine precipitation inhibitors studied, there was a strong positive correlation between the drug-polymer mixing enthalpy and the overall formulation performance, as measured by the area under the concentration-time curve in in vitro dissolution experiments. The data suggest that a rank-order based approach using calculated drug-polymer mixing enthalpy can be reliably used to select precipitation inhibitors for a more focused screening. Such an approach improves efficiency of precipitation inhibitor selection, whilst also improving the likelihood that the most optimal formulation will be realized.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    New Insights into Using Lipid Based Suspensions for 'Brick Dust' Molecules: Case Study of Nilotinib
    (Springer, 22.02.2019) Koehl, Niklas; Kuentz, Martin [in: Pharmaceutical Research]
    PurposeLipid suspensions have been shown to be a suitablebio-enabling formulation approach for highly lipophilic or‘grease ball’drug molecules, but studies on‘brick dust’drugsare lacking. This study explored the utility of lipid suspensionsfor enhancing oral bioavailability of the rather hydrophobicdrug nilotinibin vivoin rats.MethodsFour lipid suspensions were developed containinglong chain triglycerides, medium chain triglyceride, longchain monoglycerides and medium chain monoglyceridesandin vivobioavailability was compared to an aqueous suspen-sion. Additionally,in vitrolipolysis and wettability tests wereconducted.ResultsNilotinib lipid suspensions did not show a bioavail-ability increase compared to an aqueous suspension. The bio-availability was lower for triglyceride suspensions, relative toboth monoglyceride and an aqueous suspension. The longchain monoglyceride displayed a significantly higher bioavail-ability relative to triglycerides.In vitrolipolysis results suggestedentrapment of nilotinib crystals within poorly dispersible tri-glycerides, leading to slower nilotinib release and absorption.This was further supported by higher wettability of nilotinibby lipids.ConclusionMonoglycerides improved oral bioavailability ofnilotinib in rats, relative to triglycerides. For‘brick dust’drugsformulated as lipid suspensions, poorly dispersible formula-tions may delay the release of drug crystals from the formula-tion leading to reduced absorption.
    01A - Beitrag in wissenschaftlicher Zeitschrift
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    Publikation
    Partial Solvation Parameters of Drugs as a New Thermodynamic Tool for Pharmaceutics
    (Elsevier, 04.01.2019) Niederquell, Andreas; Kuentz, Martin [in: Pharmaceutics]
    Partial solvation parameters (PSP) have much in common with the Hansen solubility parameter or with a linear solvation energy relationship (LSER), but there are advantages based on the sound thermodynamic basis. It is, therefore, surprising that PSP has so far not been harnessed in pharmaceutics for the selection of excipients or property estimation of formulations and their components. This work introduces PSP calculation for drugs, where the raw data were obtained from inverse gas chromatography. It was shown that only a few probe gases were needed to get reasonable estimates of the drug PSPs. Interestingly, an alternative calculation of LSER parameters in silico did not reflect the experimentally obtained activity coefficients for all probe gases as well, which was attributed to the complexity of the drug structures. The experimental PSPs were proven to be helpful in predicting drug solubility in various solvents and the PSP framework allowed calculation of the different surface energy contributions. A specific benefit of PSP is that parameters can be readily converted to either classical solubility or LSER parameters. Therefore, PSP is not just about a new definition of solvatochromic parameters, but the underlying thermodynamics provides a unified approach, which holds much promise for broad applications in pharmaceutics.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild nicht verfügbar
    Publikation
    A Relative Permittivity Approach for Fast Drug Solubility Screening of Solvents and Excipients in Lipid-Based Delivery
    (Elsevier, 2019) Niederquell, Andreas; Kuentz, Martin [in: Journal of Pharmaceutical Sciences]
    Drug solubility screening in solvents and lipids is central for the development of lipid-based formulations (LBFs), and any guidance to reduce the experimental workload would be highly desirable. Solubility parameters are interesting as they can be predicted in silico for a drug but they are hardly predictable for complex lipids. This paper uses a new approach to convert an in silico drug solubility parameter to an estimated relative permittivity, εr. Diverse solvents and lipid-based excipients were then experimentally tested for εr and solubility using fenofibrate as model. The typical excipients and solvents used in LBFs showed an εr range of about 2-24, and good solubility of fenofibrate was indeed evidenced in vicinity of its estimated relative permittivity 13.2 ± 2.7. Mixtures of promising excipients were studied subsequently, and the obtained εr was predictable based on the known values of the individual components. The novel permittivity approach has demonstrated its usefulness, it has much potential in early development for ranking of suitable excipients, and it gives an initial orientation to design formulations. Future research may clarify further opportunities and limits of the novel approach for LBFs.
    01A - Beitrag in wissenschaftlicher Zeitschrift