Oral rabeprazole vs. intravenous pantoprazole: a comparison of the effect on intragastric pH in healthy subjects

Bioavailability, safety, and pharmacodynamics of delayed-release dexlansoprazole administered as two 30 mg orally disintegrating tablets or one 60 mg capsule

BACKGROUND

Dual delayed-release dexlansoprazole is approved for use in adults as a 30 mg orally disintegrating tablet (ODT) or as 30 mg and 60 mg capsules. The pharmacokinetics, pharmacodynamics, and safety profile of two dexlansoprazole 30 mg ODTs were compared with one dexlansoprazole 60 mg capsule in this randomized, phase I, open-label, single-center, multiple-dose, two-period crossover study.

METHODS

Participants were randomized in one of two treatment sequences, each comprised two 5-day treatment periods during which two dexlansoprazole 30 mg ODTs or one 60 mg capsule was administered once daily. Pharmacokinetic parameters and the mean intragastric pH profile for the 24-hour period after dosing on days 1 and 5 were described. Adverse events were monitored during study duration and followed up with a phone call 5-10 days after the last dose of study drug.

RESULTS

On day 1, peak observed plasma concentration (Cmax) values were similar between two 30 mg ODTs (1047 ng/ml) and one 60 mg capsule (1164 ng/ml). Systemic exposure, measured by the area under the plasma concentration-time curve (AUC), was approximately 25% lower after ODT administration. On day 5, mean pH after daily doses of two 30 mg ODT or one 60 mg capsule was 4.33 and 4.36, respectively; both regimens maintained intragastric pH above 4.0 for 60% of the 24-hour period. Headache was the most commonly reported adverse event (observed in 19.2% of participants); no adverse events leading to study withdrawal occurred.

CONCLUSIONS

While systemic exposure (AUC) was 25% lower with ODT, peak concentrations (Cmax) after administration of two dexlansoprazole 30 mg ODTs and one 60 mg capsule were similar. The 24-hour intragastric pH control after administration of two dexlansoprazole 30 mg ODTs was equivalent to one dexlansoprazole 60 mg capsule. Both ODT and capsule were well tolerated.

Pharmacokinetics and pharmacodynamics of an orally disintegrating tablet formulation of dexlansoprazole

BACKGROUND

The pharmacokinetics and pharmacodynamics of a novel orally disintegrating tablet (ODT) formulation of delayed-release dexlansoprazole 30 mg was evaluated versus the dexlansoprazole 30 mg capsule in this phase I, open-label, multiple-dose, randomized, two-period crossover study.

METHODS

Healthy adults received daily doses of 30 mg dexlansoprazole ODT or 30 mg dexlansoprazole delayed-release capsule for 5 days during two treatment periods, separated by a 7-day washout interval. Blood samples for dexlansoprazole plasma concentrations and intragastric pH measurements were collected through 24 hours postdose on days 1 and 5 of each period.

RESULTS

Bioequivalence between the 30 mg ODT and 30 mg capsule dosage forms was demonstrated by the primary endpoints of dexlansoprazole peak concentration (C_max) and systemic exposure (AUC) values contained within the prespecified 90% confidence interval (CI) range of 0.80-1.25. Additional primary endpoints of intragastric mean pH values and percentage of time with pH > 4 over the 24-hour postdose interval were equivalent for dexlansoprazole ODT and dexlansoprazole capsule. Treatment-emergent adverse events were reported in 23% and 28% of participants receiving the ODT and capsule formulations, respectively. Headache was the most common adverse event in both treatment regimens (5.8% with ODT and 6.0% with capsule).

CONCLUSIONS

Administration of dexlansoprazole 30 mg ODT or 30 mg capsule provided equivalent plasma exposure when either was administered as a single dose or as once daily doses for 5 days. Pharmacodynamic equivalence between the two formulations was demonstrated by similar intragastric pH parameters on both day 1 and day 5. No effect of day on dexlansoprazole pharmacokinetics was observed. Dexlansoprazole ODT and dexlansoprazole capsule were both well tolerated.

Relative potency of proton-pump inhibitors-comparison of effects on intragastric pH

AIM

Comparative potency of proton-pump inhibitors (PPIs) is an important clinical issue. Most available trials have compared the different PPIs at one or a few selected specific dosages, making it difficult to derive quantitative equivalence dosages. Here we derived PPI dose equivalents based on a comprehensive assessment of dose-dependent effects on intragastric pH.

METHODS

All available clinical studies reporting the effects of PPIs on mean 24-h intragastric pH were sought from electronic databases including Medline. Studies included were restricted to those targeting the Caucasian population, and healthy volunteers or gastroesophageal reflux disease (GERD) patients. The dose-effect relationships for mean 24-h intragastric pH and for percentage of time with pH > 4 in 24 h were analyzed for each PPI using pharmacodynamic modeling with NONMEM and a model integrating all available data.

RESULTS

Fifty-seven studies fulfilled the inclusion criteria. Based on the mean 24-h gastric pH, the relative potencies of the five PPIs compared to omeprazole were 0.23, 0.90, 1.00, 1.60, and 1.82 for pantoprazole, lansoprazole, omeprazole, esomeprazole, and rabeprazole, respectively. Compared with healthy volunteers, patients with GERD needed a 1.9-fold higher dose and Helicobacter pylori-positive individuals needed only about 20% of the dose to achieve a given increase in mean 24-h intragastric pH.

CONCLUSION

The present meta-analysis provides quantitative estimates on clinical potency of individual PPIs that may be helpful when switching between PPIs and for assessing the cost-effectiveness of specific PPIs. However, our estimates must be viewed with caution because only a limited dose range has been tested and not exactly the same study conditions were applied for the different substances.

Proton pump inhibitors: an update of their clinical use and pharmacokinetics

BACKGROUND

Proton pump inhibitors (PPIs) represent drugs of first choice for treating peptic ulcer, Helicobacter pylori infection, gastrooesophageal reflux disease, nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal lesions (complications), and Zollinger-Ellison syndrome.

RESULTS

The available agents (omeprazole/esomeprazole, lansoprazole, pantoprazole, and rabeprazole) differ somewhat in their pharmacokinetic properties (e.g., time-/dose-dependent bioavailability, metabolic pattern, interaction potential, genetic variability). For all PPIs, there is a clear relationship between drug exposure (area under the plasma concentration/time curve) and the pharmacodynamic response (inhibition of acid secretion). Furthermore, clinical outcome (e.g., healing and eradication rates) depends on maintaining intragastric pH values above certain threshold levels. Thus, any changes in drug disposition will subsequently be translated directly into clinical efficiency so that extensive metabolizers of CYP2C19 will demonstrate a higher rate of therapeutic nonresponse.

CONCLUSIONS

This update of pharmacokinetic, pharmacodynamic, and clinical data will provide the necessary guide by which to select between the various PPIs that differ-based on pharmacodynamic assessments-in their relative potencies (e.g., higher doses are needed for pantoprazole and lansoprazole compared with rabeprazole). Despite their well-documented clinical efficacy and safety, there is still a certain number of patients who are refractory to treatment with PPIs (nonresponder), which will leave sufficient space for future drug development and clinical research.