The incorporation of an imidazoline (IDZ) based switchable surfactant into the lipid membrane of a liposome produces a system that can be triggered to release its solute upon pH change. However, unlike traditional pH-triggered controlled release systems, IDZ–liposomes are capable of undergoing multiple triggering events, resulting in solute release in a pulsatile manner. Furthermore near-total release can be achieved incrementally with temporal control. A mechanism for this reversible behaviour is also proposed, and dependence on the physical properties of the surfactant is discussed.