Use of thermodynamics in understanding drug release from xanthan gum matrices: The influence of clay-drug complexes

Totea, Ana-Maria; Dorin, Irina; Laity, Peter R.; Conway, Barbara R.; Waters, Laura J.; Asare-Addo, Kofi

doi:10.1016/j.carpta.2020.100012

Cited by 4 publications

(1 citation statement)

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“…al. characterised and demonstrated the efficiency of drugclay complexes to control the release of propranolol and diltiazem. [1], [2], [4], [6], [17] Studying complexation between a wide variety of drugs and clay is of high importance in expanding the knowledge about controlled drug delivery and its exploitation.…”

Section: Structurementioning

confidence: 99%

Magnesium Aluminium Silicate-Metformin Hydrochloride Complexes - The Use of Isothermal Calorimetry for Probing Clay and Drug Nanocomplexations

Totea

Dorin²,

Laity

et al. 2021

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: This study reports the use of Isothermal Calorimetry (ITC) in understanding the complexation process occurring between Magnesium Aluminium Silicate (MAS) and metformin hydrochloride (MET), as a potential controlled release drug delivery system. The calorimetric results confirmed the binding between MET and MAS at various pHs (5, 7 and 9) and temperatures (25 ºC and 37 ºC). The overall change in enthalpy was found to be exothermic with a comparatively small entropic contribution to the total change in Gibbs free energy, implying that the binding was an enthalpically driven process. These findings suggest that the binding process was dominated by hydrogen bonding and electrostatic interactions. pH and temperature variation did not have a great impact on the binding, as observed from the similarity in enthalpy (ΔH), entropy (ΔS) or Gibbs free energy (ΔG), with the reaction being only slightly more exothermic at pH 5 and at 37 ºC. MAS and MET complex dispersions and particles were also formulated and analysed successfully using DSC, XRPD, ATR-FTIR, SEM/EDX, digital microscopy. 2D-SAXS. 2D-SAXS was able to differentiate between MAS particulates and MAS-MET complexes when analysed in their liquid form suggesting the importance of appropriate methodology and instrumentation used in characterisation.

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