In the case of the majority of studied drugs , an increased absorption rate was observed early after RYGBP .
The effect on systemic exposure allows for a low degree of extrapolation , including between drugs subjected to the same major metabolic and transporter pathways .
Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery .
This review systematic ally examines the effects of bariatric surgery on drug pharmacokinetics , focusing especially on the mechanisms involved in restricting oral bioavailability .
Drug disposition and modelling before and after gastric bypass: immediate and controlled-release metoprolol formulations.
AIMS The aim of the present study was to evaluate the disposition of metoprolol after oral administration of an immediate and controlled-release formulation before and after Roux-en-Y gastric bypass ( RYGB ) surgery in the same individuals and to vali date a physiologically based pharmacokinetic ( PBPK ) model for predicting oral bioavailability following RYGB . METHODS A single-dose pharmacokinetic study of metoprolol tartrate 200 mg immediate release and controlled release was performed in 14 volunteers before and 6 - 8 months after RYGB . The observed data were compared with predicted results from the PBPK modelling and simulation of metoprolol tartrate immediate and controlled-release formulation before and after RYGB . RESULTS After administration of metoprolol immediate and controlled release , no statistically significant difference in the observed area under the curve ( AUC(0 - 24 h ) ) was shown , although a tendency towards an increased oral exposure could be observed as the AUC(0 - 24 h ) was 32.4 % [ 95 % confidence interval ( CI ) 1.36 , 63.5 ] and 55.9 % ( 95 % CI 5.73 , 106 ) higher following RYGB for the immediate and controlled-release formulation , respectively . This could be explained by surgery-related weight loss and a reduced presystemic biotransformation in the proximal gastrointestinal tract . The PBPK values predicted by modelling and simulation were similar to the observed data , confirming its validity . CONCLUSIONS The disposition of metoprolol from an immediate-release and a controlled-release formulation was not significantly altered after RYGB ; there was a tendency to an increase , which was also predicted by PBPK modelling and simulation
In the case of the majority of studied drugs , an increased absorption rate was observed early after RYGBP .
The effect on systemic exposure allows for a low degree of extrapolation , including between drugs subjected to the same major metabolic and transporter pathways .
Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery .
This review systematic ally examines the effects of bariatric surgery on drug pharmacokinetics , focusing especially on the mechanisms involved in restricting oral bioavailability .