Advances in orally-delivered pH-sensitive nanocarrier systems; an optimistic approach for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is the inflammation of the gastrointestinal tract (GIT) affecting the colon and ileum in particular. Increasing IBD prevalence worldwide is alarming, and needs to be resolved. Due to the limited therapeutic efficacy, accompanying adverse effects, dependence, and pharmacokinetics issues of the available therapy, IBD patients have compromised quality of life. Meanwhile, conventional drug delivery systems (DDS) for IBD face many obstacles en-route to the colon, such as physiological and pathophysiological barriers, genetic variability, disease severity, and nutrition status. Therefore, the pH-dependent nanocarrier DDS is a recent advancement that fulfills the need for a more tolerable and effective remedy for IBD. It facilitates localized and targeted action, eliminating systemic adverse effects and unnecessary flushing of the drug from the inflamed colon tissues. The integration of a pH-sensitive polymer as a nanocarrier provides protection in drug transport to the lower region of the GIT. In this review, we will briefly explain IBD pathophysiology, the pros and cons of pH-dependent conventional DDS, and highlight a novel pH-dependent nanocarrier system for treating the disease.