Stimuli-sensitive crosslinked hydrogels as drug delivery systems: Impact of the drug on the responsiveness

Publication date: Available online 17 February 2020Source: International Journal of PharmaceuticsAuthor(s): Carmen Alvarez-Lorenzo, Valerij Y. Grinberg, Tatiana V. Burova, Angel ConcheiroAbstractResponsiveness of drug delivery systems (DDS) against internal and external stimuli attracts wide interest as a mechanism that can provide both site-specific release at the target place and feedback regulated release rate. Biological environment is quite complex and the effects that the intricate medium may have on the effectiveness of the stimulus have received certain attention. Differently, the impact that the drug loaded may have itself on the responsiveness of the DDS has been underestimated. Most drugs are not merely trapped in the polymer network, but they effectively interact with some polymer moieties. Nearly all drugs, including therapeutic proteins, are ionizable amphiphilic molecules, and thus ionic, hydrogen bonding and hydrophobic interactions are commonly exploited to increase the loading yield. If the moiety involved in drug binding is also responsible for (or at least partially involved in) the stimuli responsiveness, a strong impact of the drug on the behavior of the DDS can be expected. This review gathers relevant examples of how the drug may modify the sensitiveness (stimulus threshold) and the responsiveness (actuation) of the DDS to therapeutically relevant stimulus, and aims to shed light on the different drug binding modes of the swollen and collapsed states, ...
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research