Chocolate, an effective means of oral drug delivery in rats (2002)

Huang-Brown, K. M., Guhad, F. A.

Abstract

We trained the animals to smell the chocolate and develop a taste for it by holding the animal and placing the chocolate into its mouth using a blunt metal applicator (in our project we used a 14-gauge oral gavage needle). No esophageal contact, nor any placement more proximal than the oral cavity was necessary. We handled the rats gently to avoid association of chocolate with averse stimuli. To train the rats to expect the treatment, we opened and closed the cage before chocolate administration. .. After individual administration and return of the animal to the cage, the caregiver then offered drug-free chocolate as a reward at the front of the cage with the blunt end of the gavage needle to condition the animals to this manner of treatment. ...Results from this technique demonstrated appropriate levels of drug absorption. .. The animals do not require individual housing, enhancing their social environment and reducing space usage. .. Housing the animals used for this study in groups of three per cage allowed for easy identification of animals as they received their chocolate pellets. ...The chocolate vehicle is ideal for timed delivery or when a drug needs to be administered at a certain time of day. .. In this study, 3 of 57 rats (5%) failed to become accustomed to the chocolate even after the training period and had to be restrained for drug administration.