Administration of an alginate based gastric reflux suppressant on the bioavailability of omeprazole.
OBJECTIVE
Omeprazole treats gastro-oesophageal reflux disease (GORD) by inhibition of acid secretion whereas alginate based reflux suppressants work by forming a low density raft of near neutral pH which floats on the stomach contents and physically impedes gastro-oesophageal reflux. There is limited pharmacokinetic information regarding possible drug interaction between these two types of products, although these may be frequently co-prescribed to improve symptom control in GORD patients. This study was designed to determine whether the administration of a 10 per cent w/v liquid alginate suspension affected the pharmacokinetic profile of omeprazole.


METHODS
This was a randomized, two-treatment, two-sequence, two-period crossover study in 26 volunteers. Each treatment was dosed for 3 consecutive days with a washout period of 7 days between dosing periods. Blood samples for pharmacokinetic analysis were taken over the 24 h period following the final dose of omeprazole.


RESULTS
Geometric means and ratios were as follows: C(max) was 555 for omeprazole/alginate and 558 for omeprazole alone (ratio 99.55%, 90% confidence interval 82.75-119.75%; AUC(0-t) was 2050 for omeprazole/alginate and 2094 for omeprazole alone (ratio 97.90%, 90% confidence interval 87.83-109.12%); AUC(0-a) was 2247 for omeprazole/alginate and 2231 for omeprazole alone (ratio 100.74%, 90% confidence interval 90.05-112.70%). Mean values for T(max), K(el) and T(1/2) were also similar for the two treatment regimens.


CONCLUSIONS
As the 90 per cent confidence intervals for the geometric mean ratios for C(max), AUC(0-t), and AUC(0-alpha) are all contained within the bioequivalence interval of 80-125 per cent, it can be concluded that the administration of this liquid alginate suspension does not affect the pharmacokinetic profile of omeprazole.
Dettmar
P W
PW
Reckitt Benckiser Healthcare (UK) Ltd., Dansom Lane, Hull HU8 7DS, UK. peter.dettmar@technostics.com
Hampson
F C
FC
Jain
A
A
Choubey
S
S
Little
S L
SL
Baxter
T
T
D000293:Adolescent; D000328:Adult; D000464:Alginates / Q000008:administration & dosage*; D000863:Antacids / Q000008:administration & dosage*; D001682:Biological Availability; D018592:Cross-Over Studies; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005764:Gastroesophageal Reflux / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D008297:Male; D009853:Omeprazole / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D054328:Proton Pump Inhibitors
D000464:Alginates; D000863:Antacids; D054328:Proton Pump Inhibitors; D009853:Omeprazole