Reduced bioavailability of oral amoxicillin tablets compared to suspensions in Roux‐en‐Y gastric bypass bariatric subjects

• Published in: British journal of clinical pharmacology Vol. 85; no. 9; pp. 2118 - 2125
• Main Authors: Montanha, Maiara Camotti, Santos Magon, Thiago Ferreira, Souza Alcantara, Conrado, Simões, Caroline Ferraz, Silva, Sandra Regina Bin, Kuroda, Cristina Megumi, Yamada, Sérgio Seiji, Oliveira, Lucas Eduardo Savóia, Nasser, Daoud, Junior, Nelson Nardo, Mazucheli, Josmar, Diniz, Andrea, Paixão, Paulo Jorge Pereira Alves, Kimura, Elza
• Format: Journal Article
• Language: English
• Published: England John Wiley and Sons Inc 01-09-2019
• Subjects: Administration, Oral; Adult; amoxicillin; Amoxicillin - administration & dosage; Amoxicillin - blood; Amoxicillin - pharmacokinetics; Anti-Bacterial Agents - administration & dosage; Anti-Bacterial Agents - blood; Anti-Bacterial Agents - pharmacokinetics; Area Under Curve; Biological Availability; Cross-Over Studies; Double-Blind Method; Female; gastric bypass; Gastric Bypass - adverse effects; Humans; Male; Middle Aged; Original; pharmacokinetic; relative bioavailability; Suspensions; Tablets; amoxicillin; relative bioavailability; pharmacokinetic; gastric bypass
• DOI: 10.1111/bcp.14023
• EISSN: 1365-2125
• ISSN: 0306-5251

Aims
To evaluate the relative bioavailability of oral amoxicillin (AMX) tablets in comparison to AMX suspension in Roux‐en‐Y gastric bypass bariatric subjects.
Methods
A randomized, double‐blind, cross‐over study was performed on the bioavailability of oral AMX tablets and suspension in Roux‐en‐Y gastric bypass subjects operated at least 3 months previously . Doses of 875 mg of the AMX tablet or 800 mg of the AMX suspension were given to all the subjects, allowing a washout of 7 days between the periods. Blood samples were collected at 0, 0.25, 0.5, 1, 1.5, 2, 4, 6 and 8 hours after drug administration and the AMX levels were quantified by liquid chromatography coupled with triple quadrupole tandem mass spectrometry. The pharmacokinetic parameters were calculated by noncompartmental analysis, normalized to an 875 mg dose and the bioavailability of the AMX from the tablets was compared to that from the suspension formulation.
Results
Twenty subjects aged 42.65 ± 7.21 years and with a body mass index of 29.88 ± 4.36 kg/m2 were enrolled in the study. The maximum AMX plasma concentration of the tablets and the suspension (normalized to 875 mg) were 7.42 ± 2.99 mg/L and 8.73 ± 3.26 mg/L (90% confidence interval of 70.71–99.11), and the total area under the curve from time zero to infinity were 23.10 ± 7.41 mg.h/L and 27.59 ± 8.32 mg.h/L (90% confidence interval of 71.25–97.32), respectively.
Conclusion
The tablets presented a lower bioavailability than the suspension formulation and the total absorbed amount of AMX in these subjects was lower in comparison to the standard AMX absorption rates in nonbariatric subjects, regardless of the formulation.