Termodinamičko ispitivanje prijelaza acetanilida i fenacetina iz vode u organska otapala ; Thermodynamic study of the transfer of acetanilide and phenacetin from water to different organic solvents

U radu su određeni molarni (KCo/w) i razdjelni (Kxo/w) particijski koeficijenti acetanilida i fenacetina u sustavima oktanol/pufer, i-propil-miristat/pufer, kloroform/pufer i cikloheksan/pufer na 25,0, 30,0, 35,0 i 40 C. U svim slučajevima osim za cikloheksan, vrijednosti KCo/w i Kxo/w bile su veće od jedan. To ukazuje da su ova dva lijeka pretežno lipofilna. Gibbsova i van’t Hoffova termodinamička analiza su otkrile da je prijelaz tih lijekova iz vode u organska otapala spontan i da su uglavnom pokrenuti entalpijski za i-propil-miristat i kloroform te entropijski za oktanol i cikloheksan. ; The molar (KCo/w) and rational (KXo/w) partition coefficients in the octanol/buffer, i-propyl myristate/buffer, chloroform/buffer, and cyclohexane/buffer systems were determined for acetanilide and phenacetin at 25.0, 30.0, 35.0, and 40.0 °C. In all cases except for cyclohexane, the KCo/w and KXo/w values were greater than unity. This demonstrates that these two drugs have predominantly lipophilic behavior. Gibbs and van't Hoff thermodynamic analyses have revealed that the transfer of these drugs from water to organic solvents is spontaneous and that it is mainly driven enthalpically for i-propyl myristate and chloroform, and entropy-driven for octanol and cyclohexane.