A spectrophotometric technique was used to determine the acidity constants of 4-dedimethylamino sancycline (Col-3), a new antitumor drug. The apparent pK(a) values of Col-3 in 0.5% methanol aqueous media at approximately 25 °C with a constant ionic strength of 0.2 were calculated manually and graphically to be 5.64 ± 0.17 (pK(a1)) and 8.35 ± 0.07 (pK(a2)). In addition, the computer program SQUAD was used to confirm Col-3 pK(a) values. The pK(a) values obtained by SQUAD were pK(a1) 5.63 ± 0.14 and pK(a2) 8.39 ± 0.04. These results are in agreement with the tetracycline- like structure of Col-3.
ASJC Scopus subject areas
- Pharmaceutical Science