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Thermal study of four irradiated imidazoline derivatives in solid state

“…The DSC spectrum of XM shows an increase in its melting point, while that of AN a decrease in its melting point. A considerable increase in the melting point of irradiated XM is a phenomenon we have observed for the first time in our investigation of radiolysis of therapeutic substances [16][17][18][19][20][21]. It is supposed that this increase is related to a considerable radiolysis of this compound (three radiolysis products detected by TLC) and a high concentration of the radicals formed (the highest from among the compounds studied in this work).…”

“…Differential scanning calorimetry (DSC) has been recently often used in analysis of medicaments [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. For many years it has been an important tool in the study of drug polymorphism [2][3][4][5][6].…”

“…Many authors recommend this method for investigation of phase equilibria in multicomponent systems and for detection of inconsistencies between two biologically active substances [8] or between the therapeutic substance and emollients used in drug formulation technology [9][10][11][12]. The DSC method has been also appreciated by the authors working on evaluation of stability of therapeutic substances [13][14][15][16][17][18][19]. It has been successfully applied in estimation of the thermal [13], photochemical [14] and radiochemical stability of drugs [15][16][17][18][19][20][21].…”

“…The DSC method has been also appreciated by the authors working on evaluation of stability of therapeutic substances [13][14][15][16][17][18][19]. It has been successfully applied in estimation of the thermal [13], photochemical [14] and radiochemical stability of drugs [15][16][17][18][19][20][21]. Determination of the radiochemical stability of therapeutic substances (and emollients) has become of increasing importance in view of growing application of radiation sterilisation, an effective method of sterilisation and decontamination of drugs [22].…”

Análise térmica aplicada a fármacos e formulações farmacêuticas na indústria farmacêutica

“…O comitê da ICH também definiu, por meio da Guidance (1987), que se o fenômeno de polimorfismo for conhecido, uma instrução geral deve constar na monografia farmacopeica da seguinte forma: "a substância exibe o fenômeno de polimorfismo". [41][42][43][44][45][46][47][48][49][50] Moneghini et al relataram através de análises de DSC e DRX que o fármaco atenolol, um anti-hipertensivo, se apresentou na forma cristalina com os agentes dispersores povidona e polivinilpirrolidona/ vinil acetato, e na forma amorfa com os dispersores crospovidona e eudragit E. Os resultados coincidem com aqueles de maiores taxas de dissolução do fármaco na fase amorfa. 47 Leitão identificou quatro formas polimórficas da terfenadina, utilizando condições de recristalização diferentes para a obtenção das formas cristalinas, sendo usados solventes e temperaturas variadas e empregando DSC e DRX para caracterização dos polimorfos.…”