INTERACTIONS AND AVAILABILITY OF NITROFURANTOIN IN THE PRESENCE OF SOME NONSTEROIDAL ANTIINFLAMMATORY DRUGS

The interactions of the non-steroidal anti-inflammatory drugs viz ibup rofen, flurbiprofen, ketoprofen and diclofenac sodium with nitrofurant oin are revealed and characterized in this study. The solubility of ni trofurantoin increased in the presence of the four non-steroidal anti- inflammatory drugs in the following rank order : flurbiprofen > ketopr ofen > ibuprofen > diclofenac sodium. The solubility of nitrofurantoin increased linearly with an increase in the concentrations of non-ster oidal anti-inflammatory drugs and a rise in temperature. The thermodyn amic parameters were calculated from the solubility data. The data obt ained indicate a possible complex formation between nitrofurantoin and each of flurbiprofen and ketoprofen. The non-steroidal anti-inflammat ory dr-rigs used had no profound effect on the dissolution characteris tics of nitrofurantoin. The apparent partition coefficient of nitrofur antoin between octanol and aqueous pH 1.2 significantly increased in t he presence of the tested non-steroidal anti-inflammatory drugs. Job's method of continuous variation was used to calculate the stoichiometr ic ratio of the complex. It was found that a 1/1 complex formed betwee n nitrofurantoin and each of ibuprofen, flurbiprofen and ketoprofen. T he presence of non-steroidal anti-inflammatory drugs per se showed mar ked changes in the UV and IR absorption of nitrofurantoin. These chang es may indicate a sort of molecular interaction between nitrofurantoin and the four non-steroidal anti-inflammatory drugs. Nitrofurantoin pr oduced a favourable antibacterial activity in the presence of flurbipr ofen, ketoprofen, ibuprofen or diclofenac sodium.