Degradation Kinetics of Fluorouracil-Acetic-Acid-Dextran Conjugate in Aqueous Solution

Abstract

The degradation kinetics of fluorouracil-acetic-acid-dextran conjugate (FUAC-dextran) was investigated in various buffer solutions with different pH value and physiological saline solution at 60 degrees C and 37 degrees C, respectively. The hydrolytic reaction displayed pseudo-first-order degradation kinetics. Hydrolytic rate constant obtained was the function of pH value and independent of species of buffering agents. The smallest rate constant was observed at pH round 3.00. The activation energy of the hydrolytic reaction was estimated from Arrhenius equation as 88.73 +/- 6.00 kJ.mol-1. The special base catalytic degradation of the conjugate was observed from acidic to slight alkaline condition and the special base catalytic rate constants were calculated. The conjugate was more stable in physiological saline than that in buffer solution at pH 7.00 or 9.00 at 37 degrees C. The results revealed that the conjugate was stable in acidic condition and will degrade in alkaline condition.

Multimonth controlled small molecule release from biodegradable thin films

“…In analogous polymer-drug systems, the half-life (t 1/2 ) at pH 7.4 and 37°C of small molecules conjugated to dextran can vary greatly with the drug type and polymer backbone. For example, 5-fluorouracil (t 1/2 = 0.73 d) (32), benzoate (t 1/2 = 7.5 d) (33), naproxen (t 1/2 = 7.6 d) (34), and ketoprofen/ibuprofen/naproxen (t 1/2 = 7. as starch-naproxen (t 1/2 = 33 d) (34) and hyaluronic acid-cortisone (t 1/2 = 3.6 d) (36), demonstrate a potentially broad range. We found that our polymer-drug compound has a substantially longer half-life compared with most reported conjugates (Table 1), making it an ideal candidate for long-term sustained release formulations.…”

pH-Responsive Nanofibers for Precise and Sequential Delivery of Multiple Payloads

“…Because dextran ester cannot be dissolved in pure water, small amounts of potassium carbonate were added to dissolve it. Because alkaline solutions may induce a hydrolysis of dextran ester, 47 NMR spectra were taken immediately after the synthesis. The anomeric proton in C1 position of dextran was identified at 4.97 ppm, whereas protons at the C2−C6 positions were detected at 3.46−4.05 ppm (Figure S1b).…”

“…Because dextran ester cannot be dissolved in pure water, small amounts of potassium carbonate were added to dissolve it. Because alkaline solutions may induce a hydrolysis of dextran ester, NMR spectra were taken immediately after the synthesis.…”