ABSTRACT
Dolutegravir (DTG) is an integrase inhibitor, whose gastrointestinal absorption is impaired by the formation of chelates with multivalent metal cation preparations. However, little is known regarding the interactions of DTG with preparations containing other multivalent metal cations or with polycation polymer preparations. This study examined how the pharmacokinetics of DTG are affected by co-administration with Al(OH)3, LaCO3, and the polycation polymers bixalomer (Bxl) and sevelamer (Svl). Prior to oral administration of DTG (5 mg/kg), rats were orally administered Al(OH)3 (150 or 300 mg/kg), LaCO3 (50 or 75 mg/kg), Bxl (250 or 500 mg/kg), or Svl (300 or 600 mg/kg). Serum concentrations of DTG were then measured over the next 24 h. Compared to the administration of DTG alone, its co-administration with Al(OH)3, LaCO3, Bxl, and Svl led to reduced serum concentration of DTG, and consequently, a significantly reduced area under the curve. These comparisons also revealed a considerable reduction in the maximum concentration, suggesting that the interactions of these agents with DTG in the intestinal tract inhibit absorption of DTG. The above results demonstrate that Al(OH)3, LaCO3, Bxl, and Svl affect the pharmacokinetics of DTG and indicate the need for caution when combining any of the above preparations with DTG.
Subject(s)
Chelating Agents/pharmacokinetics , Heterocyclic Compounds, 3-Ring/pharmacokinetics , Oxazines/pharmacokinetics , Piperazines/pharmacokinetics , Polyelectrolytes/chemistry , Pyridones/pharmacokinetics , Animals , Cations/chemistry , Chelating Agents/analysis , Chelating Agents/chemistry , Drug Interactions , Heterocyclic Compounds, 3-Ring/blood , Heterocyclic Compounds, 3-Ring/chemistry , Male , Oxazines/blood , Oxazines/chemistry , Piperazines/blood , Piperazines/chemistry , Pyridones/blood , Pyridones/chemistry , Rats , Rats, Wistar , Tissue DistributionABSTRACT
OBJECTIVES: Raltegravir (RAL) that can form chelates with multivalent metal cations shows lateral interactions with multivalent metal cation and polycationic polymer. We investigated the interactions of RAL with multivalent metal cation preparations, Al(OH)3 and LaCO3 , and polycationic polymer preparations, bixalomer (Bxl) and sevelamer (Svl). METHODS: Immediately before the oral administration of 40 mg/kg RAL, the rats were administered orally with the vehicle, Al(OH)3 , LaCO3 , Bxl, or Svl, and the time course of RAL serum concentration was followed. The in vitro binding affinity of RAL with multivalent metal cation and polycationic polymer was also evaluated using isothermal titration calorimetry (ITC). RESULTS: When Al(OH)3 , LaCO3 , Bxl, or Svl was concomitantly administered with RAL, the maximum concentration and area under the curve were significantly lower than those when RAL was administered alone. ITC showed the interaction of RAL with Al(OH)3 as an enthalpy-driven reaction and its interactions with LaCO3 and Bxl as entropy-enthalpy mixed reactions. CONCLUSIONS: The interaction of RAL with Al(OH)3 , LaCO3, Bxl, or Svl can inhibit RAL absorption into the gastrointestinal tract, and thus, the multivalent metal cation and polycationic polymer are the modifying factors that can affect RAL pharmacokinetics.
