Disposition of ibuprofen in nephrectomized dogs

Treatment of ibuprofen intoxication with charcoal haemoperfusion in two dogs

Case history: Two dogs presented separately to the Small Animal Hospital, University of Florida (Gainsville, FL, USA) for ingestion of ibuprofen. The first dog ingested 561.8 mg/kg ibuprofen in addition to paracetamol and caffeine and vomited prior to admission. This patient also received fluid therapy for 8 hours prior to charcoal haemoperfusion. The second dog ingested 500 mg/kg of ibuprofen and the owners induced vomiting with hydrogen peroxide prior to presentation. Due to the severity of clinical signs, both patients were treated with charcoal haemoperfusion.Clinical findings: The concentrations of ibuprofen in the blood of the dogs prior to treatment were 478 and 301 mg/L. During the treatment ibuprofen concentrations were reduced by 95.8% and 45.5%, respectively, with no treatment side effects and minimal clinical signs after treatment.Diagnosis: Toxicity due to ingestion of ibuprofen toxicity that was successfully treated with charcoal haemoperfusion.Clinical relevance: In the cases described here minimal benefit was seen after 3 hours of treatment using one haemoperfusion cartridge. This is in contrast to a previously published report in which dogs were treated for 6 hours with two charcoal haemoperfusion cartridges. This suggests that one cartridge may be sufficient. The amount of ibuprofen ingested was not a reliable predictor of the concentration in blood at the initiation of treatment. Charcoal haemoperfusion is an effective means of reducing plasma concentrations of ibuprofen, however, its use may be limited by its cost and availability.

Ibuprofen-loaded ethylcellulose microspheres: release studies and analysis of the matrix structure through the Higuchi model

The following work deals with ibuprofen-loaded ethylcellulose microspheres. The drug exists either in a state of molecular dispersion or in crystalline form, depending on the encapsulation ratio. The in vitro release profiles have been studied and the Higuchi model applied to the experimental results. With an appropriate treatment of the results, it has been shown that the surface crystals responsible for the observed burst effect are really encapsulated by the polymer. The calculation of the tortuosity factor clearly shows that the release kinetics are controlled by the hydrophobicity of ethylcellulose and the geometry of the porous volume resulting from the dissolution of ibuprofen crystals. It thus appears that crystals are probably differently distributed in the matrix depending on the microsphere size.