An oral-controlled release drug delivery system for liquid and semisolid drug formulations.

A novel oral drug delivery system for the controlled release of liquid drugs, drug solutions, and semisolid drug preparations is presented that is utilizing the constant vapor pressure of liquefied gas. The system is equipped with a capillary as an element determining the drug delivery rate and contains a liquefied propellant with a suitable boiling point below human body temperature. In the dissolution studies, polyacrylate gels of different viscosities containing paracetamol as model drug were used. Zero-order release kinetics was obtained. The release rates were dependent on the gel viscosity. Besides, by gel viscosity, the drug release rates could also be modified by changing the propellant type and the capillary parameters such as length or diameter. Accordingly, the new system enables a wide range of drug delivery kinetics which can be modified in a case-by-case basis in order to match the desired drug delivery characteristics.