Robert W Snow

US Patent:

6604698, Aug 12, 2003

Filed:

May 10, 2001

Appl. No.:

09/852054

Inventors:

Frank H. Verhoff - Cincinnati OH
Robert A. Snow - West Chester PA
Gary W. Pace - Raleigh NC

Assignee:

SkyePharma Canada, Inc. - Montreal

International Classification:

B02C 1716

US Classification:

241 21, 214184

Abstract:

This invention describes a process for preparing a dispersion of solid particles of a milled substrate in a fluid carrier comprising the steps of (a) providing a plurality of large size milling media to the milling chamber of a media mill and forming a depth filter therefrom on an exit screen or separator in the milling chamber; (b) adding to said milling chamber a plurality of small size milling media optionally containing additional large size milling media, a conglomerate of a solid substance comprising a substrate to be milled and optionally one or more than one surface active substance, and a fluid carrier; (c) milling said conglomerate in said milling chamber to produce very small milled substrate product particles; and (d) separating said milled substrate particles suspended in said fluid carrier from the media through said depth filter; wherein the exit screen comprises openings of size S ; the large size media have a size distribution S of which all are larger than S ; the small size media have a size distribution S which are smaller than S ; the very small milled substrate particles have a size distribution S and are smaller than all of the small media; and the large size media and the small size media are essentially retained in the milling chamber.

US Patent:

6634576, Oct 21, 2003

Filed:

Aug 29, 2001

Appl. No.:

09/940864

Inventors:

Frank Verhoff - Cincinnati OH
Gary W. Pace - Winchester MA
Robert A. Snow - West Chester PA
Fay Millar - Ladson SC

Assignee:

RTP Pharma Inc. - Durham NC

International Classification:

B02C 1214

US Classification:

241 21, 241184

Abstract:

A process for milling a solid substrate in the milling chamber of a dispersion or media mill in the presence of a two or more compositions of milling media bodies is disclosed wherein all milling media bodies contribute to the grinding of the solid substrate and wherein at least one composition of media bodies provides fragments of milling media bodies that are retained with the milled solid substrate particles in the form of a synergetic commixture produced in the milling process. More specifically, a process is disclosed for preparing a synergetic commixture comprising small particles of a solid substrate and small particulates of a first material of a desired size comprising the steps of (a) providing to the milling chamber of a media mill a contents comprising a pre-mix of a solid substrate, a fluid carrier, a plurality of milling bodies of a first material having a fracture toughness K , and a plurality of milling bodies of a second material having a fracture toughness K ; (b) operating the media mill to grind the solid substrate and degrade at least a portion of the milling bodies of first material to produce a dispersion in the fluid carrier comprising a synergetic commixture of small particulates of the first material and small particles of the solid substrate having a desired size equal to or less than a size Sp; (c) separating the dispersion from any milling bodies and solid substrate particles having a size larger than S ; and (d) optionally removing the fluid carrier from the dispersion to form a synergetic commixture free of fluid and comprising the particles and the small particulates, wherein K is greater than K.