In vitro investigation on the impact of the surface‐active excipients Cremophor EL, Tween 80 and Solutol HS 15 on the metabolism of midazolam

Abstract

The impact of the surface-active formulation ingredients Cremophor EL, Tween 80 and Solutol HS 15 on the intrinsic clearance (Clint) of midazolam (MDZ) was investigated in rat hepatocytes and microsomes. In rat hepatocytes with 0.003%, 0.03% and 0.3% (w/v) Solutol HS 15 already present in the incubation medium, the Clint was significantly reduced in a dose-dependent manner by about 25%, 30% and 50%, respectively. In the presence of Cremophor EL and Tween 80 a significant reduction in Clint by about 30% and 25%, respectively, was observed at 0.03% surfactant concentration. At 0.3% of Cremophor EL and Tween 80, Clint was reduced by about 50% and 20%, respectively. A reduction in Clint was also observed in experiments with rat liver microsomes. At surfactant concentrations up to 0.03%, cytotoxicity assays (lactate dehydrogenase release, adenosine triphosphate content) as well as light microscope investigations did not reveal any cytotoxic impact of the surfactants on the hepatocyte monolayer. A potential interaction of the surfactants with biological membranes was determined using phosphatidylcholine-cholesterol liposomes loaded with self-quenching concentrations of carboxyfluorescein. No marked release of carboxyfluorescein from the liposomes (that would be an indication for a surfactant-dependent disruption of membrane integrity) was observed up to concentrations of 0.03% of the different surfactants. It is concluded that cytochrome P450 3A mediated metabolism of MDZ seems to be prevented by all surfactants at concentrations above 0.03%. In our experiments the surfactants did not show toxic effects at concentrations that resulted in a decreased Clint of MDZ. Thus, a direct inhibition of the metabolizing enzymes, a molecular interaction with the microsomes as well as an alteration of membrane properties that did not yet result in a release of LDH have to be taken into consideration as reasons for the observed changes in the metabolism of MDZ.

Comparison of tetrahydrofuran, fetal calf serum, and Tween 40 for the delivery of astaxanthin and canthaxanthin to HepG2 cells

“…This discrepancy may be due to the use of a different cell line (derived from a colon carcinoma instead of a liver carcinoma) and the fact that lower maximum concentrations of Tween in the cell culture medium (0.1%) were employed (O'Sullivan et al 2004;During and Harrison 2007). Similarly, the viability of freshly prepared primary rat hepatocytes was not impaired by incubation for 1, 4 or 24 h with B0.03% Tween 80, but significantly reduced when 0.3% Tween 80 were used (Bravo Gonzalez et al 2004). Interestingly, the extent of the cytotoxic effect of Tween 40 was slightly reduced upon addition of AX or CX (Fig.…”

Physiological Modeling to Understand the Impact of Enzymes and Transporters on Drug and Metabolite Data and Bioavailability Estimates

“…N-Trimethyl chitosan chloride acts as a potential absorption enhancer by opening tight junctions of intestinal epithelial cells to allow increased transport of hydrophilic compounds through the paracellular transport pathway (23,24). In other instances, excipients are found to reduce hepatocyte uptake (25,26) and/or the activity of enzymes and decrease the metabolic intrinsic clearance (27,28). Therefore, important components of pharmaceutical formulations that affect improvement of formulation characteristics can reduce the effectiveness of some preparations and result in variations in BA and BE with use of different excipients.…”

In vitro metabolic stability of moisture-sensitive rabeprazole in human liver microsomes and its modulation by pharmaceutical excipients

“…Numerous efforts have been made to explain the inhibition of microsomal enzyme activity by common pharmaceutical excipients. The inhibitory effects of pharmaceutical excipients appear to involve micelle formation and/or direct disruption of enzyme activities, and are also influenced by the characteristics of individual drugs and excipients (Johnson et al, 2002;Bravo Gonzalez et al, 2004;da Silva and Meirelles, 2004). However, another important factor is that pharmaceutical excipients can interact with the drug and/or serve as matrices that affect the critical attributes of the drug, resulting in the enhancement of the drug's stability in a nonenzymatic system (VillalobosHernandez and Villafuerte-Robles, 2001;Yang and Macdonald, 2004;Ren et al, 2007).…”