Protein bound drugs are pharmacokinetically inactive where unbound drugs are pharmacologically active.Highly protein bound drugs have reduced Pharmacological effect (invitro) with Albumin. Free drug concentration in the plasma is responsible for the observed pharmacological effect or therapeutic response. Oseltamivir phosphate is an antiviral drug used in the treatment and prophylaxis of both influenza virus A and influenza virus B. It is currently the drug of choice for the prevention of influenza virus infection . Invitro Protein binding study of oseltamivir phosphate was carried out for 200 mins and The percentage of bound drug was found to be 80% and percentage of free drug was found to be 20%.In co-administration of Oseltamivir phosphate with Ampicillin, The percentage of bound drug was found to be 68.6% and percentage of free drug was found to be 31.40% Increase in percentage of free drug was found to be 57%, shows beneficial drug interaction.
