Microbiological Equivalence of Serum Bacteriostatic and Bactericidal Activities of the Sera from Healthy Volunteers Receiving Original Meropenem (MeronemR) and Generic Meropenem (MeroR)
Visanu Thamlikitkul MD*, Surapee Tiengrim MSc*, Chalobol Chalermsri MD**, Pornsiri Chinsawangwatanakul MSc**, Siriluk Suddhichupaiboon MSc***
Affiliation : * Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand *** Siriraj Hospital, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
Background : Several generic meropenem formulations have been approved by Thai Food and Drug Adminis-
tration, Ministry of Public Health since 2008. Meropenem is a parenteral drug. Therefore, a study demonstrat-
ing a biological equivalence of generic meropenem is not required for drug registration in Thailand. The
objective of the study was to determine microbiological equivalence of serum bacteriostatic and bactericidal
activities of the sera from healthy volunteers receiving original meropenem (MeronemR) and generic meropenem
(MeroR).
Material and Method: This was a randomized crossover study in 16 adult healthy volunteers. Each subject
received one gram of MeronemR and MeroR in 50 ml of normal saline via intravenous infusion for 30 minutes.
The blood samples were drawn at baseline prior to receiving the study drug, at 30 minutes after initiating
infusion, and at 8 hours after initiating infusion. The serum bacteriostatic activity against E. coli ATCC
25922, K. pneumoniae, P. aeruginosa ATCC 27853 and A. baumannii was performed by disk diffusion The
serum bactericidal activity against E. coli ATCC 25922 was performed by Serum Bactericidal Titre.
Results : The average inhibition zone diameter of the serum samples from the subjects while receiving MeroR
against each tested organisms was < 1 mm smaller than that while receiving MeronemR and such difference
was not significantly different. All serum samples taken at 30 minutes after initiating MeronemR and MeroR
had bactericidal titres against E. coli ATCC 25922 > 1:256. Only 3 serum samples taken from the subjects
while receiving MeroR at 8 hours had less bactericidal titre for 1-fold dilution when compared with that of
MeronemR.
Conclusion : The sera from healthy volunteers receiving MeronemR and MeroR had microbiological equiva-
lence in terms of serum bacteriostatic and bactericidal activities.
Keywords : Microbiological Equivalence, Generic Drug, Meropenem
