The cardiopulmonary effects and quality of anesthesia after induction with alfaxalone in 2-hydroxypropyl-ß-cyclodextrin in dogs and cats: a systematic review.

To systematically review the quality of evidence comparing the cardiopulmonary effects and quality of anesthesia after induction with alfaxalone vs. other anesthetic agents in dogs and cats. Studies published from 2001 until 20th May 2013 were identified with the terms 'alfaxan' OR 'alfaxalone' OR 'alphaxalone' in electronic databases: Discovery, PubMed, ScienceDirect, and Wiley Interscience. The study design and risk of bias of all included studies were assessed. Twenty-two studies from 408 (22 of 408, 5.39%) satisfied the inclusion criteria. Fourteen studies (14 of 22, 64%) focused on dogs and nine (9 of 22, 40%) on cats. One study had both dogs and cats as subjects. (Hunt et al., 2013) Twelve studies were rated an LOE1, and six of these as ROB1. One, seven, and two studies were rated as LOE2, LOE3, and LOE5, respectively. In dogs, strong evidence shows that induction quality with either alfaxalone-HPCD or propofol is smooth. Moderate evidence supports this finding in cats. In dogs, moderate evidence shows that there is no significant change in heart rate after induction with either alfaxalone-HPCD or propofol. In cats, moderate evidence shows no significant difference in postinduction respiratory rate and heart rate between alfaxalone-HPCD and propofol induction. Strong evidence shows dogs and cats have smooth recoveries after induction using either alfaxalone-HPCD or propofol, before reaching sternal recumbency.

The pharmacokinetics of pimobendan enantiomers after oral and intravenous administration of racemate pimobendan formulations in healthy dogs.

Pimobendan is a benzimidazole-pyridazinone derivative, marketed as a racemic mixture for the management of canine heart failure. Pharmacokinetics of the enantiomers of pimobendan and its oral bioavailability have not been described in dogs. The aim of this study was to describe pharmacokinetics of three formulations of pimobendan in healthy dogs: the licensed capsule product, and novel liquid and intravenous formulations. A three-period, nested randomized two-treatment crossover design was used. Pimobendan was administered p.o. at 0.25 and i.v. at 0.125 mg/kg. Blood and plasma samples were analysed by liquid chromatography-mass spectrometry. Noncompartmental modelling was used to describe the pharmacokinetics. Parameters were compared between formulations using a general linear model. Bioequivalence of the oral formulations was tested using CI90 for AUC(0-∞) and Cmax . Bioavailability of pimobendan after oral dosing was 70%. Liquid and capsule formulations were bioequivalent only for AUC. The positive enantiomer of pimobendan (PE) had a larger volume of distribution than the negative enantiomer (NE) (281 ± 48 vs. 215 ± 68 mL/kg; P = 0.003) and a shorter half-life (21.7 vs. 29.9 min; P = 0.004). The NE was distributed more quickly than the PE into blood cells. Enantiomers of pimobendan have differing absorption, distribution and elimination. The pharmacokinetics of pimobendan in healthy dogs was described.

Pharmacokinetics of enrofloxacin following oral and subcutaneous administration in the common ringtail possum (Pseudocheirus peregrinus).

[Correction added on 23 March 2015, after first online publication: Terminal half-life values of enrofloxacin is corrected in the fourth sentence of the abstract] Clinically healthy common ringtail possums (n = 5) received single doses of 10 mg/kg enrofloxacin orally and then 2 weeks later subcutaneously. Serial plasma samples were collected over 24 h for each treatment phase, and enrofloxacin concentrations were determined using a validated HPLC assay. Pharmacokinetic parameters were determined by noncompartmental analysis. Following oral administration, plasma concentrations were of therapeutic relevance (Cmax median 5.45 µg/mL, range 2.98-6.9 µg/mL), with terminal-phase half-life (t½ ) shorter than in other species (median 3.09 h, range 1.79-5.30 h). In contrast, subcutaneous administration of enrofloxacin did not achieve effective plasma concentrations, with plasma concentrations too erratic to fit the noncompartmental model except in one animal. On the basis of the AUC:MIC, enrofloxacin administered at 10 mg/kg orally, but not subcutaneously, is likely to be effective against a range of bacterial species that have been reported in common ringtail possums.

Bioequivalence of a new liquid formulation of benazepril compared with the reference tablet product.

OBJECTIVE: To compare the bioequivalence and 'switchability' of two formulations of benazepril (tablet and liquid) after oral administration. DESIGN: Randomised cross-over design, followed by parallel comparison. METHODS: Twelve mixed-breed dogs were administered either a tablet (Group A) or liquid formulation (Group B) of benazepril orally at 0.45 mg/kg daily for 4 days. With no washout period, the dogs then received the alternative treatment at the same dose for a further 4 days. Blood samples taken prior to treatment and serially after treatment were analysed for plasma concentrations of benazepril and benazeprilat and the activity and concentration of angiotensin-converting enzyme (ACE). The calculated percentage inhibition of ACE was defined as the primary outcome variable. RESULTS: No statistically significant differences were found between groups A and B for any variable evaluated. The mean (± SD) percentage of ACE inhibition was 85.5 ± 7.04% for the liquid formulation and 85.9 ± 6.66% for the tablet formulation. The mean of the ratios was 1.00 (80% confidence interval 0.96-1.04). No evaluated effect term (sequence, formulation or period) had any statistical effect on any outcome variable. CONCLUSION: This study supports a conclusion that, based on pharmacodynamic response, the liquid formulation of benazepril is bioequivalent to the reference tablet formulation. Further, the lack of a sequence effect supports the switchability of these two formulations.

Bioavailability of two L-thyroxine formulations after oral administration to healthy dogs.

OBJECTIVE: To describe the pharmacokinetics of two veterinary formulations of L-thyroxine available in Australia. METHODS: A two-phase randomised, crossover, open-label trial followed by a third-phase parallel-dosing trial was conducted in 11 healthy dogs with an investigative oral L-thyroxine liquid formulation and a reference tablet formulation. Blood sampling was done at defined intervals and serum total L-thyroxine concentrations were measured by radioimmunoassay. The post-dose concentrations were plotted as a function of time for each period and the relative bioavailability of the two formulations were compared using a general linear model with factors for dog, phase, sequence and formulation. RESULTS: Following oral administration of the reference tablet at the dose of 100 µg/kg, a maximum plasma concentration of approximately 96.2 nmol/L (baseline endogenous corrected) was reached within 3.77 h. For the investigative liquid preparation at a dose of 50 µg/kg, the maximum plasma concentration was 60.1 nmol/L (baseline endogenous corrected), which was reached within 3.59 h. CONCLUSION: The geometric mean of the relative bioavailability for the liquid/tablet product was 1.1, which suggests that the relative bioavailability of thyroxine following administration of tablet or liquid formulation is similar.