Background: In recent decades, the development of the environmentally responsive systems
for drug delivery has been well regarded, with enormous potential in different applications.
Methods: These environmentally sensitive, smart, intelligent formulations have the ability to alter their
physical properties in response to small changes in physical or chemical conditions, such as temperature,
glucose, pH, ultrasound, light, electric field and redox potential with a huge potential in drug delivery
systems. The use of formulations containing smart materials enables to carry the drug to the target
tissue, cells and release in a triggered way. Consequently, they have demonstrated several advantages
like decreased dose frequency, ease of preparation and administration, prolonged release with
reduced side effects, as well as, reduced costs when compared to conventional processes for industrial
applications. In this sense, many patents have deposited, displaying different pharmaceutical devices
using responsive systems.
Results: There are more than twenty-five patents deposited about thermoresponsive systems. Furthermore,
a few number of patents within glucose responsive, ultrasound responsive and light responsive
deposited. There also are about eight patents that are pH-responsive, four as electric-field responsive.
Most of them cover more than one type of stimuli.
Conclusion: Therefore, in this review, since 1975 to 2016, we have categorized, reviewed and discussed
the patents, applications, pharmaceutical dosage forms, the importance and perspectives of this
environmentally responsive approach as potentially useful therapeutic modality.