A novel tool to standardize rheology testing of molten polymers for pharmaceutical applications

Treffer, Daniel Franz; Troiß, Alexander; Khinast, Johannes G.

doi:10.1016/j.ijpharm.2015.09.001

Cited by 38 publications

(25 citation statements)

References 24 publications

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“…The rheological behaviour of viscous liquids is relevant in the food 1–4 , pharmaceutical 5–9 and cosmetic 10–12 industries, as well as technical chemistry 13–15 and production engineering 16 . Several devices have been developed to measure the viscous, viscoelastic and elastic properties of liquids and solids 17–19 .…”

Section: Introductionmentioning

confidence: 99%

Contact-free determination of viscosity in multiple parallel samples

Sieben

Hanke

Büchs

2019

Sci Rep

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Viscosity is an inherent characteristic of fluids and is therefore an important parameter in many different processes. Current methods to measure viscosity involve direct contact with the liquid sample, which is often undesirable. Here we present a simple, precise and robust contact-free method to determine viscosity, using a single drive motor, inexpensive components and disposable sample vessels. The measurement principle involves the detection of viscosity-dependent angular positions in a rotating liquid relative to the direction of centrifugal acceleration in an orbitally shaken vessel. The signal can be detected using different optical methods, as shown here using fluorescence and transmitted light. The sensitivity of the system can be adjusted over a wide range by varying the sample volume or the shaking diameter, and multiple samples can be analysed in parallel. This novel viscometer is also applicable to characterize non-Newtonian shear rate-dependent fluids.

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Section: Introductionmentioning

confidence: 99%

Contact-free determination of viscosity in multiple parallel samples

Sieben

Hanke

Büchs

2019

Sci Rep

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“…Melt rheology is an efficient tool 30 which provides insight into material properties that are important for the HME-manufacturing process and can provide guidance for the process design. 33 Temperature and screw speed are among the most important factors affecting both the HME processing and final ASD products through the distributive mixing and solubilization of APIs. 34 Screening of various compositions can be performed effectively with the rheological study of drug: polymer physical mixtures (PMs).…”

Section: Methods Of Asd Characterization (Molecular Mobility)mentioning

confidence: 99%

Applications of Dynamic Mechanical Analysis in the Engineering of Amorphous Solid Dispersions

Ojo

Lee

2020

Pharmaceutical Fronts

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AbstractDynamic mechanical analysis (DMA) offers several advantages over prevailing methods in the characterization of amorphous solid dispersions (ASDs) typically used for improving the delivery of poorly water-soluble drugs. This method of analysis, though underutilized in the study of pharmaceutical systems, is particularly attuned to rheological investigations of thermal and mechanical properties of solids such as ASDs. Its ability to determine the viscoelastic properties of systems across a wide range of temperatures and shear conditions provides useful insight for the development and processing of ASDs. The response of materials to an imposed stress, captured by DMA, can help identify proper conditions for preparing homogenous extrudates of the polymer and active pharmaceutical ingredient through hot melt extrusion (HME). As HME continues to gain utility within the pharmaceutical industry, the ability to tailor process conditions will become increasingly important for the efficient design and production of ASD products for poorly water-soluble drugs. Furthermore, DMA can be used to probe molecular mobility and its link to physical stability of ASDs. Establishing the link between molecular mobility and crystallization kinetics is central to predicting the physical stability of ASDs. Therefore, increasing the understanding of material properties through DMA will enable the successful development of more stable amorphous drug products. This review summarizes current characterization tools for ASDs and discusses the potential of utilizing DMA as a robust alternative to traditional methods.

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“…S+ is a powdery material in delivery conditions. Homogeneous solid specimens were produced via vacuum compression molding (VCM Tool, MeltPrep GmbH, Austria), resulting in cylindrical discs with a diameter of 25 mm and a thickness of approximately 2.5 mm as described in a previous publication . The sample discs were manually placed onto the rheometer's ground plate, temperature controlled and molten by the rheometer's internal heating.…”

Section: Methodsmentioning

confidence: 99%

Why hot melts do not stick to cold surfaces

Treffer

Khinast

2016

Polymer Engineering & Sci

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Many industrial polymer processing operations (e.g., extrusion, injection molding, etc.) include solid-to-liquid or liquid-to-solid phase changes at non-isothermal interfaces. Stickiness (tack) can occur depending on the process conditions. However, prediction of tack formation is not trivial. This work presents a hypothesis for tack formation between molten polymers and solids under non-isothermal conditions. Our hypothesis states that strong adhesion requires wetting (and thus surface creation) at the interface upon contact and, consequently, contact temperatures above the polymer's solidification point. Lower contact temperatures result in a solid-solid interface with negligible adhesion. It was suggested that the contact temperature determines the existence or non-existence of surface sticking. The hypothesis was supported by non-isothermal tack experiments, which showed that the change from stickiness to non-stickiness was surprisingly pronounced with changing surface temperature of the solid material. From a practical perspective, the work may be useful both for professionals (e.g., designing new processing equipment and performing process troubleshooting) and home users (e.g., working with hot melt glue or 3d printers).

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A novel tool to standardize rheology testing of molten polymers for pharmaceutical applications

Cited by 38 publications

References 24 publications

Contact-free determination of viscosity in multiple parallel samples

Contact-free determination of viscosity in multiple parallel samples

Applications of Dynamic Mechanical Analysis in the Engineering of Amorphous Solid Dispersions

Why hot melts do not stick to cold surfaces

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