Solid lipid nanoparticles for enhanced oral absorption: A review

Recent trends in nanoparticles-based oral therapy have led to a proliferation of studies to enhance solubility, permeability and chemical stability of many drugs. One of the significant current discussions is achieving high bioavailability of drugs poorly absorbed with an impairing coincidence of oral degradation. Solid lipid nanoparticles (SLNs), absorbed and trafficked via transcellular and paracellular pathways, are one of the utmost innovative promising nanocarriers to overwhelm drawbacks of the poorly absorbed drugs. The central topic of this review is focusing on providing brief updates on SLNs for improving drug oral absorption with their evolutions in curing numerous ailments. In order to create a new paradigm of therapeutic formulations, we also highlight the transversal mechanisms of SLNs across the gastrointestinal hurdles and a series of novel researches regarding in vitro protocols to uncover the investigations of the transmembrane absorption and transport kinetics of SLNs. The current challenges and future perspectives of SLNs for oral drug delivery are refined and forecasted. Several questions remain unanswered and it is recommended to pay a close attention to the most sophisticated in vivo-like culture practices which open new avenues to thoroughly elucidate how SLNs interact with intestinal mucosa at cellular and molecular levels. Additionally, further studies are needed to concentrate on the factors influencing the absorption efficiency, proportion of SLNs in gastrointestinal tract as well as their correlation with their loaded drug bioavailability.