Comparative pharmacokinetics and pharmacodynamics of lansoprazole oral capsules and suspension in healthy subjects

Exploring the impact of ethnicity on drug pharmacokinetics using PBPK models: A case study with lansoprazole in Japanese subjects

AIMS

The aim of this study is to demonstrate the use of PBPK modelling to explore the impact of ethnic differences on drug PK.

METHODS

A PBPK model developed for lansoprazole was used to predict the clinical PK of lansoprazole in Japanese subjects by incorporating the physiological parameters of a Japanese population into the model. Further verification of the developed Japanese population with clinical studies involving eight other CYP substrates-omeprazole, ticlopidine, alprazolam, midazolam, nifedipine, cinacalcet, paroxetine and dextromethorphan-was also carried out.

RESULTS

The PK of lansoprazole in both Caucasian and Japanese subjects was well predicted by the model as the observed data were within the 5th and 95th percentiles across all the clinical studies. In age- and sex-matched simulations in both the Caucasian and Japanese populations, the predicted PK (mean ± SD) of a single oral dose of 30-mg lansoprazole was higher in the Japanese population in all cases, with more than twofold higher AUC of 5.98 ± 6.43 mg/L.h (95% CI: 4.72, 7.24) vs. 2.46 ± 2.45 mg/L.h (95% CI: 1.98, 2.94) in one scenario. In addition, in two out of the nine clinical DDIs of lansoprazole and the additional CYP substrates simulated using the Japanese population, the predicted DDI in Japanese was more than 1.25-fold that in Caucasians, indicating an increased DDI liability.

CONCLUSIONS

By accounting for various physiological parameters that characterize a population in a PBPK model, the impact of the different identified interethnic differences on the drug's PK can be explored, which can inform the adoption of drugs from one region to another.

Quality evaluation of extemporaneous delayed-release liquid formulations of lansoprazole

PURPOSE

The quality attributes of extemporaneous delayed-release liquid formulations of lansoprazole for oral administration were evaluated.

METHODS

A novel liquid formulation (3 mg/mL) of Prevacid FasTab in an Ora-Blend vehicle was prepared and compared with the Prevacid FasTab 30 mg and Prevacid-sodium bicarbonate 1 M formulation (3 mg/mL). The latter formulation was combined with hydrochloric acid 0.1 N, and the remaining lansoprazole content was assayed by high-performance liquid chromatography (HPLC). A batch of delayed-release liquid formulation was prepared to evaluate content uniformity. For content assay, three samples were prepared for each evaluated condition and each sample was analyzed in triplicate by HPLC.

RESULTS

The lansoprazole in the sodium bicarbonate formulation was extensively degraded by quantities of hydrochloric acid 0.1 N in excess of 100 mL. Storage time and temperature had a significant effect on lansoprazole stability in the Ora-Blend formulation. The drug remained stable for seven days when the formulation was stored at 4.5-5.5 °C, but storage at 21-22 °C or the reduction of pH with citric acid accelerated lansoprazole degradation. The amount of lansoprazole released from the Ora-Blend formulation during the buffer stage of the dissolution test decreased with increases in formulation storage time, in formulation storage temperature, and in the amount of lansoprazole released and degraded during the acid stage of the test.

CONCLUSION

An extemporaneous formulation consisting of lansoprazole microgranules in Ora-Blend maintained acceptable quality attributes when stored for three days at 4.5-5.5 °C.

Use of clinical simulation centers in health professions schools for patient-centered research

INTRODUCTION

Professional practice assessment research performed in clinical simulation centers is a research method that also creates opportunity for multidisciplinary investigator collaboration.

METHODS

Nursing and pharmacy school clinical simulation laboratories at the University of Utah were used to conduct time-and-motion (TM) studies of medication dispensing and administration. Time data were then used to determine personnel and supply costs associated with different medication dosage forms and delivery methods. A case study from a completed research project describes the use of TM and activity-based costing analyses to assess medication preparation and administration time and cost differences related to three proton pump inhibitor dosage forms. Standardized doses were prepared by pharmacists or technicians and subsequently administered by nurses to a mannequin in the simulation center by seven different administration scenarios. Simulation scenarios were developed in a manner that held the independent variables constant, so that time and cost differences between dosage forms and administrations methods could be quantified.

RESULTS

A detailed example of one approach to use of simulation centers for TM studies and activity-based costing analyses is provided. The advantages of isolating processes of interest from the day-to-day complexity of patient care are shown. Results illustrate how simulations based on professional school simulation centers may be used to assess health care processes at the microlevel with potential for projection to the macrolevel.

CONCLUSIONS

Studies based on health professional schools simulation centers may offer a novel method of evaluating health care processes at the microlevel.

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.

Inhibition of atazanavir oral absorption by lansoprazole gastric acid suppression in healthy volunteers

STUDY OBJECTIVE

To determine whether the pharmacokinetics of atazanavir, a protease inhibitor used to treat human immunodeficiency virus (HIV) infection, are altered by its coadministration with lansoprazole, a proton pump inhibitor.

DESIGN

Single-dose, open-label, complete-crossover study.

SETTING

Clinical research center.

SUBJECTS

Ten healthy adult volunteers.

MEASUREMENTS AND MAIN RESULTS

In phase A, subjects received a single oral dose of atazanavir 400 mg alone. In phase B, the same subjects received oral lansoprazole 60 mg, and after 24 hours they were given a second dose of oral lansoprazole 60 mg with atazanavir 400 mg. Eleven blood samples were collected from each subject over a 24-hour period for determination of atazanavir plasma concentrations by a validated high-performance liquid chromatography assay. Pharmacokinetic analysis was performed by standard noncompartmental methods. Nine subjects completed the study, and no significant adverse events were reported. Absorption of atazanavir was significantly reduced when it was coadministered with lansoprazole, as evidenced by a 94% decline in mean area under the concentration-time curve during the 24 hours after administration (AUC(0-24)) (p<0.01). The mean +/- SD AUC(0-24) for phase A was 16.3 +/- 9.0 microM x hour versus 0.95 +/- 1.8 microM x hour for phase B (p<0.01). The mean +/- SD maximum concentration of atazanavir was 3.2 +/- 1.7 microM for phase A and 0.13 +/- 0.19 microM for phase B (p<0.01).

CONCLUSION

Acid suppression markedly reduced the bioavailability of atazanavir in this group of healthy volunteers. Based on these results, atazanavir should not be coadministered with lansoprazole or other proton pump inhibitors.

Comparative study and optimisation of the administration mode of three proton pump inhibitors by nasogastric tube

Patients in intensive care often develop stress-induced ulcers. As a preventive measure, proton pump inhibitors (PPIs) are administered by nasogastric tube. However, some PPIs can block the tube. The aim of this study was to compare the behaviour of three PPIs (omeprazole, lanzoprazole and esomeprazole) during the transit of the granules through the tube and to optimise their modes of administration. For each IPP, the experiment was designed to study the influence of four variables: the tube material (silicone or polyurethane), the solvent used to dilute the granules (water or apple juice), the mode of administration (in two or three doses) and the rinse volume (10 or 20 ml). We counted the granules before transit and at the tube outlet, and assayed the active drug ingredient by UV spectrometry. The assay showed complete transit of esomeprazole through the tube, but average losses of omeprazole and lanzoprazole of 39 and 33%, respectively, were observed. No significant improvement was obtained by the variables 'diluent' and 'mode of administration'. The variable 'rinse' had a significant influence. For lanzoprazole, a polyurethane tube allowed recovery of on average 86% of the active ingredient. Esomeprazole is thus the choice PPI for the treatment of patients by nasogastric tube. Using a polyurethane tube and a rinse volume of 20 ml, the administration of lanzoprazole by tube can be considered. Use of omeprazole is not recommended because none of the modes of administration tested ensured that a sufficient concentration of active ingredient reached the stomach.

Proton pump inhibitors for acid suppression in the intensive care unit: Formulary considerations

PURPOSE

The rationale for limiting the proton pump inhibitor (PPI) products included in an institutional formulary, factors to consider when making formulary decisions about PPI products, the results and limitations of cost-effectiveness analyses of PPI therapy in critically ill patients, the role of clinical practice guidelines in improving PPI use in the intensive care setting, and how these guidelines can be developed are discussed.

SUMMARY

Therapeutic interchange may make it possible to limit the number of PPI products included in the formulary and reduce costs without compromising the efficacy or safety of drug therapy. The results of studies comparing the pharmacokinetics, pharmacodynamics, and efficacy of different PPI dosage forms and routes of administration; practical considerations; safety; and costs are among the factors to consider when making formulary decisions. Some of the newer oral PPI products offer advantages over older ones in improved palatability and ease of preparation, storage, and administration. The cost-effectiveness of intravenous (i.v.) PPIs for preventing the recurrence of peptic ulcer bleeding has been demonstrated, but the cost-effectiveness of oral therapy for this indication and both oral and i.v. therapy for preventing stress-related mucosal bleeding has not been well established.

CONCLUSION

Intravenous PPIs are cost-effective for patients at risk for the recurrence of peptic ulcer bleeding. The introduction of new oral PPI products that can be administered as a suspension has expanded the therapeutic options for critically ill patients. The use of clinical practice guidelines can optimize the use of PPIs in the intensive care setting.

Comparison of the pharmacokinetics of lansoprazole 15- and 30-mg sachets for suspension versus intact capsules

OBJECTIVE

The pharmacokinetic profiles of single doses of lansoprazole 15- and 30-mg sachets for suspension were compared with those of corresponding doses of lansoprazole oral capsules.

METHODS

Healthy adult male and female subjects were randomized (1:1 ratio) into 2 Phase 1, open-label, single-dose, 2-sequence, 2-period complete crossover studies. In the first study, each subject received 1 lansoprazole 15-mg sachet mixed with water and 1 lansoprazole 15-mg oral capsule; in the second study, each subject received 1 lansoprazole 30-mg sachet mixed with water and 1 lansoprazole 30-mg oral capsule. Administration of the 2 formulations was separated by a washout period of > or =7 days. Blood samples were collected before and after each administration to assess the pharmacokinetic parameters of lansoprazole and bioequivalence between suspension and capsule.

RESULTS

Thirty-six subjects (19 males, 17 females) with a mean (SD) age of 32.0 (9.6) years and mean (SD) body weight of 68.6 (10.5) kg received lansoprazole 15 mg. Thirty-six subjects (22 males, 14 females) with a mean (SD) age of 38.0 (8.3) years and mean (SD) body weight of 75.1 (9.7) kg received lansoprazole 30 mg. The pharmacokinetic parameters of the 15- and 30-mg lansoprazole sachets for suspension were similar to those of the corresponding doses of the oral capsules. The mean (SD) values for C(max) and AUC from time 0 to infinity (AUC(0-infinity) for the lansoprazole 15-mg sachet (591.9 [242.3] ng/mL and 1614 [2065] ng.h/mL, respectively) did not differ significantly from those for the lansoprazole 15-mg capsules (578.6 [275.2] ng/mL and 1620 [2290] ng.h/mL, respectively). These parameters also did not differ significantly between the lansoprazole 30-mg sachet and 30-mg capsule: mean (SD) C(max), 1103 (428.3) and 1077 (465.6) ng/mL, respectively; mean (SD) AUC(0-infinity), 2655 (1338) and 2669 (1311) ng.h/mL, respectively. The 90% Cls for C(max) and AUC(0-infinity) ratios were contained within the 0.80 to 1.25 equivalence range, supporting bioequivalence.

CONCLUSIONS

These findings suggest that the 15- and 30-mg lansoprazole sachets for suspension are bioequivalent to the corresponding doses of oral capsules. The sachet for suspension may provide an alternative route of administration to patients who have difficulty swallowing solid oral formulations.

Evaluation of the pharmacokinetics and pharmacodynamics of intravenous lansoprazole

AIM

To compare the pharmacokinetics and pharmacodynamics of lansoprazole 30 mg administered intravenously in 0.9% NaCl or in polyethylene glycol, or orally.

METHODS

Twenty-nine subjects received lansoprazole orally on days 1-7 and intravenous lansoprazole in NaCl on days 8-14. Blood samples were collected on days 1, 7, 8 and 14. Fasting basal acid output and pentagastrin-stimulated maximal acid output were determined on days -1, 8, 9 and 15. Thirty-six different subjects received one of four regimen sequences: intravenous lansoprazole in NaCl, intravenous in polyethylene glycol, per orally, or intravenous placebo, each for 5 days. Twenty-four hour intragastric pH was recorded on days 1 and 5.

RESULTS

Intravenous and per oral lansoprazole for 7 days produced equivalent basal acid output and maximal acid output suppression. Pharmacokinetics and mean pH values with intravenous lansoprazole in NaCl or polyethylene glycol were equivalent. Both produced mean pH and percentages of time pH above 3, 4, 5 and 6 that were significantly greater than did per orally.

CONCLUSIONS

Intravenous lansoprazole inhibits acid secretion as effectively in NaCl as in polyethylene glycol, and its onset of action is faster than per oral lansoprazole.

Gastroesophageal reflux in children: pathogenesis, prevalence, diagnosis, and role of proton pump inhibitors in treatment

A substantial percentage of infants, children and adolescents experience gastroesophageal reflux disease (GERD) and its accompanying symptoms, as well as disease complications. The diagnosis of GERD in children is made based upon the child's history, and data derived primarily from pH monitoring tests and endoscopy. In those children with confirmed reflux disease, the options for management parallel those recommended in adult patients, with the first step consisting of lifestyle changes. Surgical procedures may also be performed; however, these are rarely recommended prior to an adequate course of pharmacologic therapy, and appropriate case selection is important. Among the current pharmacotherapeutic options available in the US, the prokinetic agents and the acid-inhibitory agents (histamine-2 receptor antagonists, proton pump inhibitors) are the most widely used. The clinical utility of the prokinetic agents has been limited by the recent withdrawal of cisapride from the US marketplace and the potential for irreversible central nervous system complications with metoclopramide. Numerous clinical studies performed in adults, and several studies involving children, have demonstrated that the proton pump inhibitors are more effective than the histamine-2 receptor antagonists in the relief of GERD symptoms and healing of erosive esophagitis. In children, omeprazole and lansoprazole may be administered as the intact oral capsule, or in those who are unable or unwilling to swallow, the granule contents of the capsule may be mixed with soft foods (e.g. apple sauce) or fruit drinks/liquid dietary supplements prior to oral administration with no detrimental effects on pharmacokinetics, bioavailability, or pharmacodynamics. Studies performed with omeprazole and lansoprazole in children have shown pharmacokinetic parameters that closely resemble those observed in adults. In over a decade of use in adults, the proton pump inhibitor class of agents has been found to have a good safety profile. Studies involving children have also shown these agents to be well tolerated. In numerous drug-drug interaction studies performed with these two proton pump inhibitors, relatively few clinically significant interactions have been observed.

Comparative pharmacokinetics and safety of lansoprazole oral capsules and orally disintegrating tablets in healthy subjects

BACKGROUND

Many individuals with acid-related gastrointestinal disorders have difficulty in swallowing oral agents.

AIM

To compare the bio-availability of a single dose of lansoprazole orally disintegrating tablet with that of an intact capsule.

METHODS

One hundred and twenty healthy subjects participated in two prospective, Phase I, open-label, two-period cross-over studies to receive lansoprazole, 15 mg or 30 mg. Within each study, subjects were randomized into two parallel cohorts consisting of 30 subjects per regimen, dispensed in opposing sequence over two periods separated by a 7-day washout period. Blood samples were collected on day 1 of both periods to determine the pharmacokinetic parameters.

RESULTS

Tmax occurred at 1.8 and 2.0 h with the 15-mg and 30-mg tablets, respectively. Dose proportional increases in Cmax, AUCt and AUC infinity were observed in the 15-mg and 30-mg groups. The terminal elimination half-lives (t1/2) were identical in both dose groups (1.18 h). Lansoprazole administered as the orally disintegrating tablet was bio-equivalent to the intact capsule formulation with respect to Cmax, AUCt and AUC infinity.

CONCLUSIONS

Lansoprazole orally disintegrating tablets, 15 mg and 30 mg, are bio-equivalent to the respective dose administered as the intact capsule. This novel dosage formulation represents an option for patients who have difficulty in swallowing oral agents.

Proton-pump inhibitors for stress ulcer prophylaxis in critically ill patients

OBJECTIVE

To evaluate the use of proton-pump inhibitors (PPIs) for stress ulcer prophylaxis in critically ill adults.

DATA SOURCES

Computerized biomedical literature search of MEDLINE (1966-June 2002) was conducted using the MeSH headings proton-pump inhibitor, ulcer, critical care, and acid. References of selected articles were reviewed. A manual search of critical care, surgery, trauma, gastrointestinal, and pharmacy journals was conducted to identify relevant abstracts.

DATA SYNTHESIS

Traditional medications used for stress ulcer prophylaxis include antacids, histamine(2) receptor antagonists (H(2)RAs), and sucralfate. Few studies have evaluated PPIs for stress ulcer prophylaxis. The majority of studies have demonstrated that enteral or intravenous administration of PPIs to critically ill patients elevates intragastric pH and consistently maintains pH > or =4.0. PPIs are safe and seem to be as efficacious as H(2)RAs or sucralfate for prevention of bleeding from stress-related mucosal damage (SRMD) and they may provide cost minimization. The small patient populations limit the results of comparative studies.

CONCLUSIONS

Available data indicate that PPIs are safe and efficacious for elevating intragastric pH in critically ill patients. PPIs should be used only as an alternative to H(2)RAs or sucralfate since the superiority of PPIs over these agents for preventing SRMD-associated gastrointestinal bleeding has not been established. Additional comparative studies with adequate patient numbers and pharmacoeconomic analyses are needed before PPIs are considered the agents of choice for stress ulcer prophylaxis.

A comparison of simplified lansoprazole suspension administered nasogastrically and pantoprazole administered intravenously: effects on 24-h intragastric pH

AIM

To compare the 24-h intragastric pH effects of simplified lansoprazole suspension, 30 mg, administered nasogastrically, with pantoprazole, 40 mg, administered intravenously.

METHODS

Thirty-six healthy adults were enrolled and given simplified lansoprazole suspension, 30 mg (nasogastrically), or pantoprazole, 40 mg (intravenously), once daily for five consecutive days in a cross-over fashion. Intragastric pH was monitored at baseline and on Days 1 and 5 of each treatment period. The pharmacokinetic parameters of lansoprazole and pantoprazole were also determined on Days 1 and 5.

RESULTS

No statistically significant changes in pharmacokinetic parameters occurred between Days 1 and 5 with either regimen, except for pantoprazole Cmax. On Days 1 and 5, significantly higher mean 24-h intragastric pH values were observed with 30 mg simplified lansoprazole suspension compared with 40 mg intravenous pantoprazole (Day 1, 3.13 vs. 2.67; Day 5, 3.95 vs. 3.61, respectively; P < 0.05). Additionally, 30 mg simplified lansoprazole suspension produced significantly (P < 0.05) higher percentages of time intragastric pH was above 3, 4, 5 or 6 as compared with 40 mg intravenous pantoprazole throughout Days 1 and 5.

CONCLUSIONS

A 30 mg dose of simplified lansoprazole suspension administered nasogastrically was consistently more effective at controlling intragastric pH than pantoprazole, 40 mg, administered intravenously.