Mesoporous magnesium carbonate as a drug delivery vehicle for stabilising amorphous drugs and regulating their release rate

Abstract: In today’s drug discovery, the number of candidate drugs based on new molecular entities with poor aqueous solubility is increasing. Since poor aqueous solubility of an active pharmaceutical ingredients (APIs) is associated with low bioavailability and thus limite their therapeutic effect, this is often a great challenge in the development of new drugs when oral administration is the preferred route of administration. A number of different strategies have been developed to circumvent this problem where salt formulations of an API is the most widely employed method. However, new strategies are needed since there is no one solution that solves this issue for all substances. In recent time, the concept of stabilizing poorly soluble APIs in their amorphous form has gained a lot of attention since amorphous compounds exhibit a higher apparent solubility compared to their crystalline counterparts. Amorphous substances are prone to crystallize if left in a non-constricted environment and thus need to be stabilized if the amorphous state is to be conserved until administration. Inorganic mesoporous materials have been proposed as an interesting type of excipients that can conserve the amorphous state of APIs. In this work, the focus was to investigate the possibilities of using a mesoporous type of magnesium carbonate to stabilize the amorphous state of different APIs. Due to the nanometer sized pores in the material, complete conservation of amorphous APIs was obtained. This resulted in both an increase in in vitro release rate and a higher solubility of the substances which may translate to both a faster onset of action and an improved therapeutic effect of the APIs in a clinical situation. The long term stability of formulations was also investigated showing promising results.The results presented in this work show that mesoporous magnesium carbonate represents an interesting type of excipient for oral formulations of APIs with poor aqueous solubility.