Kuentz, Martin
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Kuentz, Martin
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- PublikationA 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
- PublikationTrends in the Assessment of Drug Supersaturation and Precipitation In Vitro Using Lipid-Based Delivery Systems(Elsevier, 2016) Stillhart, Cordula; Kuentz, Martin [in: Journal of Pharmaceutical Sciences]The generation of drug supersaturation close to the absorptive site is an important mechanism of how several formulation technologies enhance oral absorption and bioavailability. Lipid-based formulations belong to the supersaturating drug delivery systems although this is not the only mechanism of how drug absorption is promoted in vivo. Different methods to determine drug supersaturation and precipitation from lipid-based formulations are described in the literature. Experimental in vitro setups vary according to their complexity and proximity to the in vivo conditions and, therefore, some tests are used for early formulation screening, while others better qualify for a later stage of development. The present commentary discusses this rapidly evolving field of in vitro testing with a special focus on the advancements in analytical techniques and new approaches of mechanistic modeling. The importance of considering a drug absorption sink is particularly emphasized. This commentary should help formulators in the pharmaceutical industry as well as in academia to make informed decisions on how to conduct in vitro tests for lipid-based delivery systems and to decide on the implications of experimental results.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationA Systematic Study on Manufacturing of Prilled Microgels into Lipids for Oral Protein Delivery(Wiley, 10/2015) Kendall de Kruif, Jan; Varum, Felipe; Bravo, Roberto; Kuentz, Martin [in: Journal of Pharmaceutical Sciences]The development of novel systems with oral protein delivery as ultimate goal represents an important field of pharmaceutics. Prilling of protein-loaded polymeric solutions into lipid-based hardening baths could provide here an attractive formulating technology. As the obtained microgel dispersion can be directly capsule-filled, no drying step is required and thermal drug degradation is avoided. This study aims to find excipient combinations for the novel prilling process and investigate systematically diverse material and process factors. Bovine serum albumin and mono-N-carboxymethyl chitosan were selected as model protein and prilling polymer, respectively. The prilling suitability of 880 formulations was screened with 60 ternary phase diagrams comprising two co-solvents, 10 different glycerides, and three so-called complementary excipients. Preliminary capsule compatibility was tested for one month on 245 formulations in hard and soft capsules with different shell materials. Ternary phase diagrams' center points were used to evaluate morphology, encapsulation efficiency, and protein stability of the prilled microgels. As result, several formulations proved suitable for prilling and compatible for capsule filling. Statistical analysis using partial least square regression revealed significant factors regarding different quality attributes of microgel dispersions. Therefore, an improved understanding was obtained for this promising drug delivery approach.01A - Beitrag in wissenschaftlicher Zeitschrift