Acid degradation, case study

At times the solubility of a drug in water is insufficient at room temperature to allow a meaningful kinetic study, in which case it can, at times, be carried out at elevated temperature [58]. If done at several different temperatures, it may be possible to estimate the stability at room temperature by extrapolation. Frequently, a broad screen of stability is performed on the initial small sample used for initial performulation this is frequently referred to as forced decomposition studies [59], in which the drug is exposed to acid degradation, base degradation, aqueous degradation, drug powder... 

C. Galindo, P. Jacques and A. Kalt, Photochemical and photocatalytical degradation of an indigoid dye a case study of acid blue 74 (AB74). J. Photochem. PhotobioLA Chem., 141 (2001) 47-56. 

The first case study we will consider is the assay of aspirin together with its major degradation product salicylic acid [19], This application study was selected as the HPLC assay of aspirin is well covered in the literature and we could select factors to test from the variety of HPLC conditions used in these published methods. This test was performed using a reflected saturated factorial design requiring a total of 15 experiments. 

Case Study of 1,2-Dimethoxybenzene. For 1,2-DMB degradation all of the intermediate aliphatic compounds, with the exception of methanol, contained one or two ester or acid functionalities (89). Methyl ester functionalities obviously stem from the methoxy groups in 1,2-DMB C C bonds were present in most of these intermediates. Some of the aliphatic intermediate products included a CHOH and/or a CO group. The most interesting feature was the existence of aliphatic intermediate products... 

Metabolism Study The degradation of a protein to peptides and an amino acid moiety is commonly expected as a representative metabolic pattern. Therefore conventional biotransformation studies are not needed for biopharmaceuticals consisting of natural amino acids. However, metabolism studies of biopharmaceuticals containing nonnatural amino acid may provide useful information. In such cases radiolabeled proteins should be prepared to trace the pharmacokinetic behavior of the nonnatural amino acid fragments. 

Galindo C, Jacques P, Kalt A (2001) Photochemical and Photocatalytic Degradation of an Indigoid Dye A Case Study of Acid Blue 74 (AB74),/. Photochem. Photobiol. A Chem. 141 47-56. 

Case Study A.7 Scaled-Up Acid Degradation and Isolation Using Preparative HPLC Characterization by LC/MS, NMR, and IR Spectroscopy... 

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