Bromocriptine tablet of self-microemulsifying system adsorbed onto porous carrier to stimulate lipoproteins secretion for brain cellular uptake.

Abstract Both low solubility and high hepatic metabolism cause low oral bioavailability of bromocriptine mesylate (BM) leading to very low drug amount in brain. Self-microemulsion (SME) tablets were developed to improve solubility, stimulate lipoprotein synthesis to promote lymphatic transport, avoid hepatic metabolism and target drug to brain. SME liquid containing castor oil, Tween ® 80 and Cremophor ® EL was prepared and then adsorbed onto solid carries, Aerosil ® 200, Aeroperl ® 300 or NeusilinUS2 ® , yielding SME powders. The optimal ratios of SME liquid to carriers determined from flowability and scanning electron photomicrographs before tableting were 1.5:1, 2:1 and 2.5:1 for Aerosil ® 200, Aeroperl ® 300 and NeusilinUS2 ® , respectively. Only Aeroperl ® 300 SME tablet had comparable dissolution to BM commercial tablet. From in vitro study in Caco-2 cells, fluorescein loaded SME tablet showed higher uptake than fluorescein loaded in either oil or surfactant. Although significantly lower amount of drug was permeated from SME tablet than from commercial tablet, higher drug uptake was obviously observed ( P P