Adsorption and in vitro release of vitamin B1 by synthetic nanoclays with montmorillonite structure

• Mt samples of different compositions were prepared by hydrothermal synthesis.
• VB1 adsorption data followed the Langmuir model.
• VB1 release profile followed the Higuchi model.
• The optimal Mt compositions for further drug delivery systems development were chosen.

Modelling experiments on vitamin B1 (thiamine hydrochloride) intercalation into synthetic montmorillonite (Mt) structures of the systematically varied compositions Na2x(Al2(1–x),Mg2x)Si4O10(OH)2 ∙ nH2O (where 0 < x < 1) were performed. Mt samples were prepared by hydrothermal synthesis during 72 h at the temperature 350 °C and a pressure of 70 MPa. In vitro release of vitamin B1 (VB1) in simulated gastric (SGF) and intestinal (SIF) fluids was performed. It was established that the intercalation of VB1 depends primarily on the composition and cation-exchange capacity of Mt and, to a lesser extent, on the pH of the solution. The adsorption data were fitted with several common isotherms, but the best regression parameters were obtained for the Langmuir model. Adsorption type was determined as the cation-exchange reaction according to the Dubinin–Radushkevich model. The release profile of VB1 from the VB1–Mt composite followed the Higuchi model. The maximum amount of released VB1 reached 54 wt.% and 19 wt.% in SGF and SIF, respectively, for synthetic Mt. For natural Mt K10, these values reached 37 wt.% and 11 wt.%, respectively. For the first time, the optimal Mt compositions for further drug delivery systems development were chosen.