[Study on the repeated oral administration method in infant rats]

Area of Science:

• Pharmacology
• Toxicology
• Animal Models

Background:

• Accurate drug administration in infant rats is essential for preclinical research.
• Existing methods may not be suitable for the delicate physiology of neonatal rodents.

Purpose of the Study:

• To develop and validate a novel technique for repeated oral administration in infant rats.
• To determine the maximum safe dosage volumes for single and repeated oral administration in this model.

Main Methods:

• Infant rats were isolated from dams for one hour prior to administration.
• A specialized gastric tube was used for slow, controlled oral delivery of Chinese ink.
• Dosage volumes of 0.01, 0.04, and 0.08 ml/g body weight were tested.
• General condition and gastrointestinal tract distribution of the ink were monitored.
• Pathological examinations were conducted.

Main Results:

• The optimal administration technique involved isolating pups, gentle restraint, and slow injection via a 2 cm gastric tube.
• Maximum safe volumes were determined as 0.04 ml/g body weight for single administration and 0.01 ml/g body weight for repeated administration.
• Daily administration of vehicle solutions (distilled water, 1% CMC, 1% tragacanth gum) at 0.1 ml/g body weight for 44 days showed no adverse effects in rats from postnatal day 4.

Conclusions:

• A reliable and safe method for repeated oral drug administration in infant rats has been established.
• This technique facilitates accurate assessment of drug toxicity and pharmacological activity in neonatal rodent models.
• The determined maximum volumes provide critical parameters for future preclinical safety and efficacy studies.