New model for intravenous drug administration and blood sampling in the awake rat, designed to increase quality and throughput for in vivo pharmacokinetic analysis

Pharmacokinetics of Hydroxytyrosol and Its Sulfate and Glucuronide Metabolites after the Oral Administration of Table Olives to Sprague-Dawley Rats

The pharmacokinetics (PK) of hydroxytyrosol and its metabolites were characterized following oral administration to Sprague-Dawley rats of 3.85 and 7.70 g of destoned Arbequina table olives/kg. Plasma samples were analyzed using a fully validated method consisting of liquid extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Noncompartmental PK analysis of hydroxytyrosol demonstrated linear PK between doses of 2.95 and 5.85 mg hydroxytyrosol/kg. Half-life was approximately 2.5 h, while mean residence time was around 4 h. Clearance occurred by conversion to two sulfate and two glucuronide conjugates. The area under the plasma concentration-time curve (AUC) ratios of metabolites versus parent hydroxytyrosol was approximately 7-9-fold for the sulfate and below 0.25 for the glucuronide, indicating sulfation as the predominant metabolic pathway. Despite extensive metabolism, hydroxytyrosol remained in plasma for up to 8 h with AUCs of 4293 and 8919 min·nmol/L for the doses of 3.85 and 7.70 g/kg, respectively. Therefore, table olives provide a more sustained plasma profile than other foods containing hydroxytyrosol, which may enhance its health-protecting activities.

Real-Time Mapping of Ultratrace Singlet Oxygen in Rat during Acute and Chronic Inflammations via a Chemiluminescent Nanosensor

Sensing nonradiation-induced singlet oxygen (¹ O₂ ) in whole-animal is deemed as one of the most challenging tasks in noninvasive techniques due to the µs level lifetime of ¹ O₂ and quenching by numerous reductants in tissues. Here a distinct chemiluminescent (CL) nanosensor (NTPE-PH) that boasts ultrahigh concentrated CL units in one nanoparticle is reported. Taking advantage of the intramolecular energy transfer mechanism that promises high energy transfer efficiency and the aggregation-induced emission behavior that guarantees high CL amplification, the NTPE-PH sensor is sensitive to a nm level ¹ O₂ . Experiments demonstrate that the NTPE-PH yields a highly selective CL response toward ¹ O₂ among common reactive oxygen species. With proved low cytotoxicity and good animal compatibility, real-time mapping of ultratrace ¹ O₂ in whole-animal during acute and chronic inflammations is first achieved. It is anticipated that the NTPE-PH sensor can be a useful tool for monitoring ¹ O₂ variation during immune response and pathological processes corresponding to different stimuli, even with drug treatment included.

Population pharmacokinetics of maslinic acid, a triterpene from olives, after intravenous and oral administration in rats

SCOPE

Maslinic acid is a bioactive minor component of Olea europaea L. with health-enhancing activities and no harmful effects. A pharmacokinetic (PK) study was conducted to determine its bioavailability for future studies of maslinic acid in humans.

METHODS AND RESULTS

Intravenous (1 mg/kg) and oral (50 mg/kg) administrations to Sprague-Dawley rats were performed. Blood was obtained several times over 24 h and PKs were analyzed with NONMEM 7.2, applying a population approach. Body weight was included a priori in the model with fixed allometric exponents, based on allometric principles. Plasma concentrations versus time were best characterized by a two-open compartment model with first-order absorption and linear elimination. Maslinic acid had a relative rapid oral absorption with a peak concentration after administration at 0.51 h and a bioavailability of 5.13%. Once in bloodstream, it distributed extensively into tissues, since the central and peripheral distribution volumes were 8.41 L/70 kg and 63.6 L/70 kg, respectively. The clearance (8 L/h/70 kg) was related to unaltered renal excretion. The prediction-corrected visual predictive check confirmed its stability and predictive ability.

CONCLUSION

An allometric population PK model was performed for maslinic acid, which adequately described and predicted plasma concentrations.

Residual fraction of the area under the curve as a qualitative criterion in pharmacokinetic studies

The aim of the present study was to determine whether the residual area under the curve (AUC(res%); expressed as % of total value of AUC) could be used as a parameter for the qualitative evaluation of pharmacokinetic studies.We propose new criteria for the qualitative evaluation of pharmacokinetic analysis. Two sets of hypothetical data that illustrate the relationship between concentration and time were used for the analysis of drug pharmacokinetics. Non-compartmental analysis was applied for the calculations. The results obtained from the hypothetical data were compared with those obtained from an in vivo study in which 3-week-old broiler chickens were administered 10 mg/kg b.w. enrofloxacin intravenously (iv) or per os (po). In the first set of data (A-D), AUC(res%) values were as follows: A= 16.29% and B = 20.79% for iv administration and C = 29.61% and D = 27.90% for po administration. In the next set of data (E-G), AUC(res%) values after oral administration were 25.30% (E), 23.18% (F), and 20.79% (G). The AUC(res%) values after iv administration of enrofloxacin were similar to po administration; the range of iv and po administration values were 14.35% to 17.50% and 11.14% to 28.33% of the total AUC, respectively. The analysis of the hypothetical data indicates that AUC(res%) is not an optimal method for the evaluation of pharmacokinetic studies.