A Soluplus/Poloxamer 407-based self-nanoemulsifying drug delivery system for the weakly basic drug carvedilol to improve its bioavailability.

Carvedilol (CAR), a β-adrenoceptor and α1-receptor blocker, has pH-dependent solubility, which greatly limits its oral bioavailability. In this work, a precipitation inhibitor-based self-nanoemulsifying drug delivery system (PI-SNEDDS) was developed by employing Soluplus and Poloxamer 407 to improve drug dissolution and to inhibit drug precipitation in the gastrointestinal tract. In vitro phase distribution and in vivo dissolution studies indicated that PI-SNEDDS significantly increased drug content in the oil phase of the nanoemulsions in the stomach and greatly inhibited the subsequent precipitation of CAR in the intestine compared with the carvedilol self-nanoemulsifying drug delivery system (CAR SNEDDS) and the carvedilol tablets. Moreover, a 1.56-fold increase in the relative bioavailability of CAR was observed for the CAR PI-SNEDDS (397.41%) compared to a CAR SNEDDS (254.09%) with commercial capsules as a reference. Therefore, our developed PI-SNEDDS is a promising vehicle for improving the dissolution and bioavailability of poorly soluble drugs with pH-dependent solubility.