oral drug administration 88 animal experiment 54 rat 40 article 38 nonhuman 38 human 36 Rats 34 Animal 30 Female 30 Support, Non-U.S. Gov't 30 female 30 Male 26 controlled study 24 male 24 Liver 22 priority journal 22 adult 20 animal model 18 clinical article 18 liver 18 drug efficacy 16 porphyrin 16 Porphyrins 14 Rats, Inbred Strains 14 animal cell 14 mouse 14 Animals 12 drug blood level 12 intoxication 12 Adult 10