* ** Fig. 39 Cyclone-type homogenizer mixing chamber. (From Ref. 41.) chamber. The symmetry axes of these entry ports are perpendicular to the symmetry axis of the interaction chamber. This design is presented in Fig. 40, with only four entry ports. This machine is called Novamix® (a registered name for Micro Vesicular Sys-tems). It was originally designed to process and produce nonphospholipid lamellar mi-crostructures or lipid vesicles. The lipid vesicles are composed of two immiscible aqueous and lipid phases. The lipid phase consists, generally, of solid polyoxyethylene-derived amphiphiles that form micelles in aqueous media. Under the proper mixing conditions, i.e., a combination of shear, heat, and turbulence, followed by appropriate cooling, the micelles of these types of lipids fuse to form lipid vesicles. The two phases are metered carefully and heated in separate reservoirs and finally pumped to the interaction chamber for pro-cessing. The interaction chamber and pump heads are confined in an insulated com-partment that is maintained at the required temperature for the production of the lipid vesicles. The outlet is attached to a chilling device that cools the product at the required rate [43]. The flow pattern is similar to that of a cyclone, i.e., the flow of liquid is in a vertically positioned rotating cylinder along its vertical axis. The streamlines are con-centric circles with their radii decreasing toward the center of the cylinder. The de-crease is a function of cylinder radius, flow rate of fluid (speed of rotation), and other parameters like viscosity, density, and surface tension of the formulation. In curved type of flow with changing radii, there exists a pressure gradient, i.e. dPIdr = V /r (8) where P = pressure; r = vessel (interaction chamber) radius; V = tangential linear velocity; and p= the liquid density. Since the change in pressure is positive for a positive radius change, the pressure at successive points increases from the concave to the convex side of the streamline [39]. The exact change in pressure depends on the variation in tangential linear velocity, which is proportional to the speed of the rotation and the ra-dius. The flow pattern in the interaction chamber is neither a free vortex, due to the presence of an initial momentum from the pumps, nor a forced vortex, for the stream-

DOI link for * ** Fig. 39 Cyclone-type homogenizer mixing chamber. (From Ref. 41.) chamber. The symmetry axes of these entry ports are perpendicular to the symmetry axis of the interaction chamber. This design is presented in Fig. 40, with only four entry ports. This machine is called Novamix® (a registered name for Micro Vesicular Sys-tems). It was originally designed to process and produce nonphospholipid lamellar mi-crostructures or lipid vesicles. The lipid vesicles are composed of two immiscible aqueous and lipid phases. The lipid phase consists, generally, of solid polyoxyethylene-derived amphiphiles that form micelles in aqueous media. Under the proper mixing conditions, i.e., a combination of shear, heat, and turbulence, followed by appropriate cooling, the micelles of these types of lipids fuse to form lipid vesicles. The two phases are metered carefully and heated in separate reservoirs and finally pumped to the interaction chamber for pro-cessing. The interaction chamber and pump heads are confined in an insulated com-partment that is maintained at the required temperature for the production of the lipid vesicles. The outlet is attached to a chilling device that cools the product at the required rate [43]. The flow pattern is similar to that of a cyclone, i.e., the flow of liquid is in a vertically positioned rotating cylinder along its vertical axis. The streamlines are con-centric circles with their radii decreasing toward the center of the cylinder. The de-crease is a function of cylinder radius, flow rate of fluid (speed of rotation), and other parameters like viscosity, density, and surface tension of the formulation. In curved type of flow with changing radii, there exists a pressure gradient, i.e. dPIdr = V /r (8) where P = pressure; r = vessel (interaction chamber) radius; V = tangential linear velocity; and p= the liquid density. Since the change in pressure is positive for a positive radius change, the pressure at successive points increases from the concave to the convex side of the streamline [39]. The exact change in pressure depends on the variation in tangential linear velocity, which is proportional to the speed of the rotation and the ra-dius. The flow pattern in the interaction chamber is neither a free vortex, due to the presence of an initial momentum from the pumps, nor a forced vortex, for the stream-

* ** Fig. 39 Cyclone-type homogenizer mixing chamber. (From Ref. 41.) chamber. The symmetry axes of these entry ports are perpendicular to the symmetry axis of the interaction chamber. This design is presented in Fig. 40, with only four entry ports. This machine is called Novamix® (a registered name for Micro Vesicular Sys-tems). It was originally designed to process and produce nonphospholipid lamellar mi-crostructures or lipid vesicles. The lipid vesicles are composed of two immiscible aqueous and lipid phases. The lipid phase consists, generally, of solid polyoxyethylene-derived amphiphiles that form micelles in aqueous media. Under the proper mixing conditions, i.e., a combination of shear, heat, and turbulence, followed by appropriate cooling, the micelles of these types of lipids fuse to form lipid vesicles. The two phases are metered carefully and heated in separate reservoirs and finally pumped to the interaction chamber for pro-cessing. The interaction chamber and pump heads are confined in an insulated com-partment that is maintained at the required temperature for the production of the lipid vesicles. The outlet is attached to a chilling device that cools the product at the required rate [43]. The flow pattern is similar to that of a cyclone, i.e., the flow of liquid is in a vertically positioned rotating cylinder along its vertical axis. The streamlines are con-centric circles with their radii decreasing toward the center of the cylinder. The de-crease is a function of cylinder radius, flow rate of fluid (speed of rotation), and other parameters like viscosity, density, and surface tension of the formulation. In curved type of flow with changing radii, there exists a pressure gradient, i.e. dPIdr = V /r (8) where P = pressure; r = vessel (interaction chamber) radius; V = tangential linear velocity; and p= the liquid density. Since the change in pressure is positive for a positive radius change, the pressure at successive points increases from the concave to the convex side of the streamline [39]. The exact change in pressure depends on the variation in tangential linear velocity, which is proportional to the speed of the rotation and the ra-dius. The flow pattern in the interaction chamber is neither a free vortex, due to the presence of an initial momentum from the pumps, nor a forced vortex, for the stream-