Kinetics of degradation of cefetamet pivaloyloxymethyl ester and its hydrochloride in solid phase
Anna Jelińska1, Marianna Zajac, Leszek Dobrowolski
1Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Medical Sciences 6 Grunwaldzka Str., 60-780 Poznań, Poland. ajelinsk@amp.edu.pl
Abstract:
The influence of temperature and relative humidity on the stability of cefetamet pivoxil (CFP) and its hydrochloride (CFP.HCl) in solid phase was investigated. The process of degradation was studied using HPLC with UV detection. The degradation of CFP and CFP.HCl occurring at air humidity RH>50% is an autocatalytic first-order reaction with respect to substrate concentration, while at 0% relative humidity of the ambient air it is a first-order reaction relative to substrate concentration for CFP.HCl, and a reversible first-order reaction for CFP. The rate constants (k) were determined in dry air at 373 K, 378 K, 383 K, 388 K and 393 K; at air humidity RH = 76.4% at 333 K, .343 K, 353 K, 363 K and 373 K; and at 363 K at air humidity RH>50%. The kinetic and thermodynamic parameters of the degradation were calculated.
Related Concept Videos
Phase I Reactions: Hydrolytic Reactions
An important hydrolytic reaction is ester hydrolysis. Ester bonds, often found in prodrugs, are broken down, increasing the solubility of drugs like aspirin and lidocaine for more straightforward elimination. Amide hydrolysis is another critical reaction, targeting amide bonds prevalent...
Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
Amides to Carboxylic Acids: Hydrolysis
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Drug Metabolism: Phase I Reactions
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
Microbial Bioremediation of Pesticides

