STP1466: Fast Scan Differential Scanning Calorimetry Distinguishes Melting, Melting-Degradation/Sublimation and Thermal Stability of Drugs

    Riga, Alan T.

    Golinar, Michael

    Alexander, Kenneth S.

    Pages: 8    Published: Jan 2007


    Abstract

    In order to establish a structure and property (melting and oxidative or thermal degradation, or both) relationship for a United States Pharmacopeias (USP) set of standard drugs, they were evaluated by fast scan differential scanning calorimetry. A critical problem in characterizing the endothermic melting of a drug is to determine the melting range and if a chemical melts and immediately degrades. The stability of standard drugs is based on a comparison of their thermal properties at widely varying ramp or heating rates from 10 to 100°C/min. A stable crystalline drug has an obvious melting endotherm followed by a stable baseline. An unstable crystalline drug melts and immediately degrades as viewed by a shifting melt endotherm with heating rate. The USP thermally stable standards evaluated in this study include vanillin (melt temperature, (Tm, 80.4°C), acetanilide (Tm, 114°C), acetophenetidin (Tm, 135°C), sulfanilamide (Tm, 165°C), sulfapyridine (Tm, 191°C), and caffeine (Tm, 235°C and Tsublimation, (220°C). In addition to the USP samples a number of commercial and model drugs, like benzoic acid (Tm, 122°C and Tsublimation, (120°C), lidocaine-.HCl and procaine. HCl were also examined. Their melt profiles were ranked as stable or unstable post fusion by the fast scan DSC technique and are reported.


    Paper ID: STP45231S

    Committee/Subcommittee: E37.01

    DOI: 10.1520/STP45231S


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