Rout of administration as a factor effecting bioavailability. General talk... 1.The term bioavailability is defined as the rate and extent (amount) of absorption of unchanged drug from its dosage form1. 2.This is an attribute of the dosage form. 3.The affect of the drug depends on how the dosage form containing the drug releases the drug and at what rate it releases it. Then it also depends on the rate at which it is taken from its site of release to its site of action. When the same size of dose is administered... When the size of the dose to be administered is same, then bio-availability of a drug from its dosage forms depends upon three major factors. They are... 1.Rout of administration. 2.Patient related factors. 3.Pharmaceutical factors related to physico-chemical properties of the drug and characterstics of the dosage form. Now, Let us discuss one factor; ROUTE OF ADMINISTRATION. The bio-availability order is I.V>Nasal>I.M>Oral>Rectal>Topical with few exceptions. Reasons to backup this order... Will be blogged in my next blog. Reference: 1.Biopharmaceutics and pharmacokinetics. D.M. Brahmankar, Sunil B.Jaiswal. Page 323. 2.Biopharmaceutics and pharmacokinetics. D.M. Brahmankar, Sunil B.Jaiswal. Page 69. 3.Phamacology-1. Pharmaplus publications. This blog doesn't contain any plagiarized material