Ch2nhch3

Scheme 45. Representative cathecol drug substances that are susceptible to oxidation.

Scheme 45. Representative cathecol drug substances that are susceptible to oxidation.

Aminosalycilic Acid Oxidation And Hrp
Scheme 46. Oxidation of 5-aminosalicylic acid.

captopril,186 and NSC-629243 (a derivative of thiocarbamic acid)187 are oxidized to disulfides (Scheme 48). Phenothiazines such as promethazine are oxidized via complex pathways and yield various products (Scheme 49).188189 As shown in Fig. 4, polyunsaturated molecules such as vitamin A,190 as well as other polyenes such as ergocalciferol, 191192 cholecalcif-erol,192 fumagillin,193 and filipin194 195 are susceptible to oxidation. In additional, phenylbu-tazone,196-199 sulpyrine,200,201 morphine,202 tetrazepam,203 hydrocortisone,204 and prednisolone205 are oxidized to various products, as shown in Scheme 50. Spiradoline is susceptible to oxidative degradation, resulting in the formation of an imidazolidine ring in addition to hydrolysis of the amide bond (Scheme 51).206 Sulfur atoms are becoming more common in new drug candidates and present a particular challenge owing to their propensity to oxidize to the corresponding sulfoxides and ultimately sulfones (Scheme 52).

oh oh oh oh

(^h—<phnhch(ch3)2 cho oh c2h5

(^h—<phnhch(ch3)2 cho oh c2h5

Scheme 47. Oxidation of procaterol.

Oxidant Drug
Scheme 48. Representative thiol drug substances that are susceptible to oxidation.
Scheme 49. Oxidation products of promethazine.
Figure 4. Representative polyene drug substances that are susceptible to oxidation.
Arbeitsblatt Kuh
Scheme 50. Other drug substances that are susceptible to oxidation.
Scheme 51. Hydrolysis and oxidation of spiradoline.

sulfoxide sulfone sulfoxide sulfone

Scheme 52. Oxidation of dialkyl sulfides to sulfoxides and sulfones.

Continue reading here: Photodegradation

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