Pharmacokinetics of Gentamicin C after IV, IM, SC and Oral Administration , C , C 1 1a and C 2 in Broiler Chickens 2a

Abstract

The pharmacokinetics and bioavailability of four major gentamicin components (C 1 , C 1a , C 2 and C 2a ) in chicken plasma administered at 5 mg/kg body weight by different routes of administration (IV, IM, SC and oral) was determined using reversed-phase high performance liquid chromatography (RP-HPLC) and pre-column derivatization with Phenylisocyanate (PIC). All the components, except for C 1a were well absorbed (bioavailability of 60% or greater) following administration by the IM and SC routes. The bioavailability of C 1a was 58% and 35% following IM and SC administration, respectively. The apparent volume of distribution (V ss and Vd area ) for the C 1 component was significantly smaller than for any of the other components individually or combined. In addition, the C 1 component had a significantly shorter t½β and MRT following intravenous administration and a higher C max /Dose following intramuscular administration. This study showed significant differences in some pharmacokinetics parameters between four gentamicin components (C 1a , C 2a , C 1 and C 2 ) after administration of single mixture of gentamicin by different routes in chickens. The differences may have clinical and toxicological implications, and could explain the high variation in total gentamicin pharmacokinetics.

Comparative Pharmacokinetics of Gentamicin C1, C1a and C2 in Healthy and Infected Piglets

“…The PK of gentamicin has been studied in several species, including dogs [1], horses [2], chickens [10], fish [11], cats [13], pigs [14], sheep [15], calves [16], and buffalo calves [17]. Other than a single PK study reported several decades ago that used the intravenous (IV) route of administration [14], there are no gentamicin PK studies in piglets after the commonly used intramuscular (IM) or oral routes of administration.…”

“…Human and animal studies have indicated that different components of gentamicin possess different potentials for toxicity, with some studies attributing the observed ototoxicity and nephrotoxicity of gentamicin mainly to the C 2 component [7][8][9]. Various levels of the different components contained in different gentamicin formulations, as well as significant differences observed in some pharmacokinetic parameters between different gentamicin components, could have clinical or toxicological implications [9,10]. However, reported differences in the pharmacokinetics (PK) of gentamicin components are not consistent across species [2,[10][11][12], emphasizing the importance of conducting PK studies of gentamicin components in species of interest such as piglets.…”

“…The PK of gentamicin has been studied in several species, including dogs [1], horses [2], chickens [10], fish [11], cats [13], pigs [14], sheep [15], calves [16], and buffalo calves [17].…”