Pharmaceutical powders in experiment and simulation : towards a fundamental understanding

(cont.) The DEM simulation was used to simulate the relative importance of cohesion and friction. For angle of repose simulations, increasing the cohesion increased the final angle in a consistent, linear fashion. Increasing the interparticle friction coefficient increased the final angle up to a critical friction coefficient. For the range of two dimensional simulations with the particles shaped as discs, this critical friction coefficient was about 0.30. Above this threshold, increasing the interparticle friction had no impact on the angle of repose. This suggests that for most pharmaceutical powders, the cohesion and shape are the most important particle properties. Case studies relating interparticle adhesion to labscale powder performance (flow and blends) were completed with two active pharmaceutical ingredients and a number of excipients. In all of the flow cases, the rank order of interparticle or intermaterial adhesion forces measured with AFM was exactly predictive of the rank order of ease of flow. Similarly, in all of the blending case studies, the rank order of adhesion force between the active pharmaceutical ingredient and the excipient was exactly predictive of the rank order stability of blends of the materials. The blend stability was quantified using an on-line, nondestructive, noninvasive light induced fluorescence (LIF) instrument. Separately, the LIF instrument was used to estimate the content of fluorescent drugs (caffeine and triamterene) in tablets by measuring the surface fluorescence. A theoretical description of the accuracy of the surface measurement to correctly estimate the total content in a tablet ...

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Domike, Reuben Dumont, 1979-

Advisor dc:contributor.advisor

• Charles L. Cooney.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/28659

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28659