Routes of Drug Administration:

The route of administration is the path by which a drug or any other substances comes in contact with or is introduced into animal’s body.

# Factors Affecting Route of Drug Administration:

1. Physico-chemical properties of drug: Drugs with high lipid solubility are more readily absorbed from all routes including G.I tract. Polar and ionized drug are ineffective by oral route and are administered by parenteral routes.
2. Formulation of drug: Some drugs are insoluble in water and available as suspension or emulsion (procaine penicillin). Such drugs are not suitable for intravenous route.
3. Nature of drug: Peptides and acid labile drugs are rapidly destroyed in the G.I tract. Such drugs are primarily administered by parenteral routes.
4. Onset of action required: Several routes produce slow onset of action. Such routes are not suitable for emergency conditions.
5. Site of desired action: Topical route is more suitable for localized conditions whereas parenteral routes are more useful for systemic and generalized effects.
6. Biotransformation: Some drugs have very short half-lives dose to their very rapid biotransformation. Such drugs are administered only by intravenous route.
7. Condition of the patient: Oral route is not suitable for unconscious, uncooperative or vomiting patient. On the other hand, parenteral routes are less effective against gastrointestinal parasites.

Important routes of drug administration in animals are categorized into four groups:

1. Oral/ Enteral route
2. Parenteral route
3. Inhalation/Pulmonary administration
4. Topical administration/Local administration