Diagram illustrating the difference between conventional tables and SDD-based tablets carrying an oil-soluble drug
Conventional Tablet
Drug in
crystaline
solid form
Drug in
solution
in highly
dispersed oil aphrons
SDD Tablet
SDD is a drug delivery system that is particularly suited to poorly water-soluble drugs needing to be delivered in tablet or capsule form. This technology consists of trapping aphrons (containing the drug in solution) in a dry, free-flowing powder produced by a spray-drying methodology. SDD powder can be made into tablets or filled into hard gelatine capsules for oral drug delivery. It can also be used as the basis of a fine powder for inhalation (pulmonary or nasal drug delivery).
SDD-based tablets contain a solution of the drug in oil in the form of aphrons. When the tablet dissolves, the aphrons and the drug they contain are released in a water-dispersible form. In the case of tablets made from conventional materials, oil soluble drugs are included as crystalline solids (since oils disrupt the tablet-forming process). When the tablet disintegrates, the active is released as a solid.
The main advantage of SDD based tablets is the improved absorption (and therefore bioavailability) of the oil soluble drug in solution rather than its release in the form of a solid.
The solid form of the drug, when released from conventional tablets, finds itself in an aqueous environment in which it cannot dissolve. As a consequence it may pass through the GI tract with comparatively little absorption. In the form of water-dispersible aphrons, the drug can be absorbed from a lipid solution through the intestinal epithelium much more easily.
SDD-based tablets are free from competing patents.
