Mechanistic time scales in adhesive mixing investigated by dry particle sizing.

This study exploits the mechanisms governing blending of adhesive mixtures, i.e. random mixing, de-agglomeration and adhesion, and their relative importance to achieve mixing homogeneity.

Fundamental mechanisms for tablet dissolution: simulation of particle deaggregation via Brownian dynamics.

For disintegrating tablet formulations, deaggregation of small particles is sometimes one of the rate-limiting processes for drug release. Because the tablets contain particles that are in the colloidal size range, it may be assumed that the deaggregation process, at least qualitatively, is governed by Brownian motion and electrostatic and van der Waals interactions, where the latter two can be described by a Derjaguin-Landau-Verwey-Overbeek interaction potential. On the basis of this hypothesis, the present work investigates the applicability of Brownian dynamics (BD) simulations as a tool to understand the deaggregation mechanism on a fundamental level.

μPIV methodology using model systems for flow studies in heterogeneous biopolymer gel microstructures.

A methodology for studying flow in heterogeneous soft microstructures has been developed. The methodology includes: (1) model fractal or random heterogeneous microstructures fabricated in PDMS and characterised using CLSM; (2) μPIV measurements; (3) Lattice-Boltzmann simulations of flow. It has been found that the flow behaviour in these model materials is highly dependent on pore size as well as on the connectivity and occurrence of dead ends.

Applying spectral peak area analysis in near-infrared spectroscopy moisture assays.

Spectral peak area analysis has in this study been shown to be a viable method in near-infrared spectroscopy (NIRS) moisture assays. The study also shows that the required number of calibration samples can be minimized, and the method is, therefore, especially suitable for moisture assays in early formulation development and in-situ process monitoring. Diffuse NIRS was utilized in the development of moisture assays for the model compounds polyvinylpyrrolidone and hydroxypropyl-beta-cyclodextrin and also for a lyophilized formulation.

In-situ near-infrared spectroscopy monitoring of the lyophilization process.

Purpose: The purpose of this work was to demonstrate the feasibility of using near-infrared spectroscopy (NIRS) to monitor the freeze-drying process in-situ.

Methods: The experiment was performed in a pilot-scale freeze-dryer, in which the NIRS probe was interfaced using a lead-through to the lyophilizer. Special equipment for the sample presentation was developed.