Abstract
The poor aqueous solubility of new and existing drug compounds represents a significant challenge in pharmaceutical development, with numerous strategies currently being pursued to address this issue. Amorphous solids lack the repeating array of atoms in the structure and present greater free energy than their crystalline counterparts, which in turn enhances the solubility of the compound. The loading of drug compounds into porous materials has been described as a promising approach for the stabilisation of the amorphous state but is dependent on many factors, including pore size and surface chemistry of the substrate material. This review looks at the applications of mesoporous materials in the confinement of pharmaceutical compounds to increase their dissolution rate or modify their release and the influence of varying pore size to crystallise metastable polymorphs. We focus our attention on mesoporous silicon, due to the ability of its surface to be easily modified, enabling it to be stabilised and functionalised for the loading of various drug compounds. The use of neutron and synchrotron X-ray to examine compounds and the mesoporous materials in which they are confined is also discussed, moving away from the conventional analysis methods.
Highlights
By plotting the experimental MLC along with the theoretical MLC and PFC as a function of surface area and pore volume, the authors were able to identify their influence on drug-loading fraction, with four zones describing loading within the pores or on the surface of the mesoporous silica, which could prove beneficial to future investigations looking into compound-loading onto mesoporous materials
Transmission electron microscopy (TEM) images of the porous substrate showed that a aluminothermic reduction produces a less porous substrate than magnesiothermic reduction, with the porous silicon composed of layers [105]
Porous materials can influence the polymorphic form of the confined crystalline state or stabilise the disordered amorphous state confined within them, which shows promise as a way of improving the dissolution rate of poorly water-soluble drugs
Summary
Half of all the newly developed compounds entering the drug development pipeline suffer from unfavourable physicochemical properties which affect their bioavailability and, the efficacy of the treatment [1]. The solid phase can be subcategorised into two divisions according to their order of molecular packing/arrangement: the crystalline and amorphous states. Crystalline materials are ordered in a repeating pattern, creating a three-dimensional crystal structure held together by intermolecular forces, including hydrogen bonding and van der Waals forces. Crystalline materials are at their most stable state with atoms packed in a way that reduces their total potential energy [2]. Due to their high stability, a large amount of energy is needed to break the intermolecular forces in the crystal structure. When crystalline solids are melted, they produce a well-defined melting point, determining the energy needed to break down the crystal structure. Hreocwryesvtaelrl,isiet uispdoniffciocunlttactot wdiettheramnianqeutehoeussoleunbviilritoynomfeanmt o[1r0p]h. ous compounds due to their tendency to recrystallise upon contact with an aqueous environment [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
