Inclusion Compound of Efavirenz and gamma-Cyclodextrin: Solid State Studies and Effect on Solubility

authors	Braga, SS; El-Saleh, F; Lysenko, K; Paz, FAA
nationality	International
journal	MOLECULES
author keywords	cyclodextrin inclusion; solution-phase; solid state; antiretroviral
abstract	Efavirenz is an antiretroviral drug of widespread use in the management of infections with human immunodeficiency virus type 1 (HIV-1). Efavirenz is also used in paediatrics, but due to its very poor aqueous solubility the liquid formulations available resort to oil-based excipients. In this report we describe the interaction of gamma-cyclodextrin with efavirenz in solution and in the solid state. In aqueous solution, the preferential host-guest stoichiometry was determined by the continuous variation method using H-1 NMR, which indicated a 3:2 host-to-guest proportion. Following, the solid inclusion compound was prepared at different stoichiometries by co-dissolution and freeze-drying. Solid-state characterisation of the products using FT-IR, C-13{H-1} CP-MAS NMR, thermogravimetry, and X-ray powder diffraction has confirmed that the 3:2 stoichiometry is the adequate starting condition to isolate a solid inclusion compound in the pure form. The effect of gamma-cyclodextrin on the solubility of efavirenz is studied by the isotherm method.
publisher	MDPI
isbn	1420-3049
year published	2021
volume	26
issue	3
digital object identifier (doi)	10.3390/molecules26030519
web of science category	12
subject category	Biochemistry & Molecular Biology; Chemistry, Multidisciplinary
unique article identifier	WOS:000615438900001