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An attractive approach to increase the aqueous apparent solubility of poorly soluble drugs is to formulate them in their amorphous state. In the present study, celecoxib, a poorly soluble drug, was successfully loaded into mesoporous magnesium carbonate (MMC) in its amorphous state via a solvent evaporation method. Crystallization of celecoxib was suppressed, and no reaction with the carrier was detected. The MMC formulation was evaluated in vitro and in vivo in terms of oral bioavailability. Celebra®, a commercially available formulation, was used as a reference. The two celecoxib formulations were orally administrated in male rats (average of n = 6 animals per group), and blood samples for plasma were taken from all animals at different time points after administration. There was no statistical difference (p > 0.05) in AUCinf between the two formulations. The results showed that MMC may be a promising drug delivery excipient for increasing the bioavailability of compounds with solubility-limited absorption. [ABSTRACT FROM AUTHOR]

Abstract Mesoporous magnesium carbonate (MMC) was synthesized and tested for its ability to separate CO 2 from N 2. The pure gas CO 2 uptake of MMC was around 1.5 mmol/g at 101 kPa, 0 °C. The N 2 uptake under the same conditions was less than 0.1 mmol/g. Al(NO 3) 3 , Al 2 O 3 , K 2 CO 3 and KNO 3 were introduced into the porous structure of MMC as additives. All of the additives tested increased the CO 2 uptake of MMC and increased its selectivity towards CO 2. The incorporation of 5 wt.% K 2 CO 3 increased the CO 2 uptake of MMC up to over 3.2 mmol/g. The ideally adsorbed solution theory was used to calculate the CO 2 selectivity of MMC and MMC with additives for a hypothetical gas mixture that contained 15% CO 2 : 85% N 2. The CO 2 selectivity at 101 kPa (0 °C) was around 60. MMC with 5 wt.% K 2 CO 3 had a CO 2 selectivity of over 150 under the same conditions. Vacuum swing cyclic CO 2 adsorption/desorption showed that the CO 2 uptake on MMC with 5 wt.% K 2 CO 3 decreased after each cycle. Heat regeneration (up to 250 °C, for 10 minutes) could recover most of the lost CO 2 capacity after each cycle. Heat regeneration indicatively improved the cyclic performance of this adsorbent. MMC with 5 wt.% K 2 CO 3 was the best performing adsorbent in this study and can potentially be further developed into a good CO 2 adsorbent for temperature swing adsorption (TSA) processes. [ABSTRACT FROM AUTHOR]

Lipid-based formulations can circumvent the low aqueous solubility of problematic drug compounds and increase their oral absorption. As these formulations are often physically unstable and costly to manufacture, solidification has been suggested as a way to minimize these issues. This study evaluated the physicochemical stability and in vitro performance of lipid-loaded mesoporous magnesium carbonate (MMC) particles with an average pore size of 20 nm. A medium chain lipid was loaded onto the MMC carrier via physical adsorption. A modified in vitro lipolysis setup was then used to study lipid release and digestion with 1H nuclear magnetic resonance spectroscopy. The lipid loading efficiency with different solidification techniques was also evaluated. The MMC, unlike more commonly used porous silicate carriers, dissolved during the lipolysis assay, providing a rapid release of encapsulated lipids into solution. The digestion of the dispersed lipid-loaded MMC therefore resembled that of a coarse dispersion of the lipid. The stability data demonstrated minor degradation of the lipid within the pores of the MMC particles, but storage for three months did not reveal extensive degradation. To conclude, lipids can be adsorbed onto MMC, creating a solid powder from which the lipid is readily released into the solution during in vitro digestion. The chemical stability of the formulation does however merit further attention. [ABSTRACT FROM AUTHOR]

A mesoporous magnesium carbonate (MMC) material that was first described in 2013 is currently being investigated for several industrial and life-science-based applications. In this paper, the effect of functionalising the surface of MMC with amine groups on the water interaction properties of the material is investigated in detail. Amine functionalisation enhanced the stability and water sorption-release properties of the material. This is explained by the low affinity between amine-functionalised MMC and water molecules, as attested by the high free/total water ratio shown by dielectric spectroscopy. This low affinity had an impact on the total amount of adsorbed water at low relative humidities (RHs) but not at high RHs. The functionalisation of MMC with amine groups also stabilised the material in moist environments, hindering spontaneous crystallisation. These results provide a more fundamental understanding of the water interaction properties of MMC and are also expected to facilitate optimisation of the stability of materials like this for novel drug formulations and other life-science applications, as well as for their use in humidity control. [ABSTRACT FROM AUTHOR]

(3-Aminopropyl)triethoxysilane (APTES) was used to modify the surface of mesoporous magnesium carbonate (MMC). The as-synthesized MMC had an average pore diameter of ∼5 nm, but amine grafting occurred preferentially on the walls of the largest MMC pores. Analysis of ibuprofen (IBU) loading and release showed that IBU remained stable in the amorphous phase in all the MMC and modified MMC samples. The kinetics of IBU release from the modified MMC were assessed and used to evaluate the effects of the different functional groups. The release rate showed that the release of IBU could be controlled by adjusting the amine surface coverage of MMC and also by changing the surface groups. It was concluded that the interaction between the grafted functional groups in the modified MMC and the OH in the carboxyl groups of IBU was the most important factor for prolonging the release of the drug. These results are expected to lead to investigation of other as yet unexplored applications for MMC, including using it as a plastic additive and for gas separation. [ABSTRACT FROM AUTHOR]