Abstract
We have studied the thermal behaviour of lorazepam ( a) and oxazepam ( b), defined the crystal form and the thermal stability. After recrystallization in several solvents under known temperature and pressure conditions the thermoanalytical study of samples has shown polymorphs for ( a) and ( b) and pseudopolymorphs for ( a), ( a) Polymorphs are I ( t f = 183°C), II ( T f =173°C), III ( T f =170°C). IV ( T f, =163°C), V ( T f =158°C), VI ( T f, =153°C), and seven pseudopolymorphs, three of which are clathrate type of 1:1 molar composition with propanol, chloroform and isopentanol. We have found eight polymorphs for ( b): I ( T f = 207°C), II ( T f=201°C), III ( T f=193°C), IV ( T f=189°C). A, B, C and D show a solid ⇌ solid transition. Commercial samples of (a) are form I, those of ( b) are form II. A spectral and dissolution kinetic study completes the thermoanalytical results in relation to biological availability.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
