Co-Amorphous Formation of Simvastatin-Ezetimibe: Enhanced Physical Stability, Bioavailability and Cholesterol-Lowering Effects in LDLr-/-Mice

Preparation and Characterization of a Rifampicin Coamorphous Material with Tromethamine Coformer: An Experimental-Theoretical Study

Rifampicin (RIF) is an antibiotic used to treat tuberculosis and leprosy. Even though RIF is a market-available drug, it has a low aqueous solubility, hindering its bioavailability. Among the strategies for bioavailability improvement of poorly soluble drugs, coamorphous systems have been revealed as an alternative in the increase of the aqueous solubility of drug systems and at the same time also increasing the amorphous state stability and dissolution rate when compared with the neat drug. In this work, a new coamorphous form from RIF and tromethamine (TRIS) was synthesized by slow evaporation. Structural, electronic, and thermodynamic properties and solvation effects, as well as drug-coformer intermolecular interactions, were studied through density functional theory (DFT) calculations. Powder X-ray diffraction (PXRD) data allowed us to verify the formation of a new coamorphous. In addition, the DFT study indicates a possible intermolecular interaction by hydrogen bonds between the available amino and carbonyl groups of RIF and the hydroxyl and amino groups of TRIS. The theoretical spectra obtained are in good agreement with the experimental data, suggesting the main interactions occurring in the formation of the coamorphous system. PXRD was used to study the physical stability of the coamorphous system under accelerated ICH conditions (40 °C and 75% RH), indicating that the material remained in an amorphous state up to 180 days. The thermogravimetry result of this material showed a good thermal stability up to 153 °C, and differential scanning calorimetry showed that the glass temperature (Tg) was at 70.0 °C. Solubility studies demonstrated an increase in the solubility of RIF by 5.5-fold when compared with its crystalline counterpart. Therefore, this new material presents critical parameters that can be considered in the development of new coamorphous formulations.

Drug-drug co-amorphous systems: An emerging formulation strategy for poorly water-soluble drugs

Overcoming the poor water solubility of small-molecule drugs is a major challenge in the development of clinical pharmaceuticals. Amorphization of crystalline drugs is a highly effective strategy to improve their aqueous solubility. However, amorphous drugs are thermodynamically unstable and likely to crystallize during manufacturing and storage. Recently, drug-drug co-amorphous systems have emerged as a novel strategy to not only enable enhanced dissolution and physical stability of the individual drugs within the system but also to provide a strategy for combination therapy of the same or different clinical indications. This review serves to highlight advances in the methods used to manufacture and characterize drug-drug co-amorphous systems, summarize drug-drug co-amorphous applications reported in recent decades, and provide an outlook on future possibilities and perspectives.

Co-amorphous Drug Delivery Systems: a Review of Physical Stability, In Vitro and In Vivo Performance

Over the past few decades, co-amorphous solids have been used as a promising approach for delivering poorly water-soluble drugs. Co-amorphous solids, comprising pharmacologically relevant drug substances or excipients, improve physical stability, solubility, dissolution, and bioavailability compared with single amorphous ingredients. In this review, we have summarized recent advances in physical stability and in vitro and in vivo performances of co-amorphous solids. We have highlighted the role of molar ratio, molecular interaction, and mobility that affects the physical stability of co-amorphous solids. This review delves deep as to how co-amorphous solids affect the physicochemical properties in vitro and in vivo. We also described the challenges to the formulation of co-amorphous solids. A better understanding of the mechanisms of the physical stability, in vitro and in vivo performance of co-amorphous solids, and proper selection of the co-former is likely to expedite the development of robust co-amorphous-based pharmaceutical formulations and can address the challenges associated with the delivery of poorly soluble drugs.

Amorphous and Co-Amorphous Olanzapine Stability in Formulations Intended for Wet Granulation and Pelletization

The preparation of amorphous and co-amorphous systems (CAMs) effectively addresses the solubility and bioavailability issues of poorly water-soluble chemical entities. However, stress conditions imposed during common pharmaceutical processing (e.g., tableting) may cause the recrystallization of the systems, warranting close stability monitoring throughout production. This work aimed at assessing the water and heat stability of amorphous olanzapine (OLZ) and OLZ-CAMs when subject to wet granulation and pelletization. Starting materials and products were characterized using calorimetry, diffractometry and spectroscopy, and their performance behavior was evaluated by dissolution testing. The results indicated that amorphous OLZ was reconverted back to a crystalline state after exposure to water and heat; conversely, OLZ-CAMs stabilized with saccharin (SAC), a sulfonic acid, did not show any significant loss of the amorphous content, confirming the higher stability of OLZ in the CAM. Besides resistance under the processing conditions of the dosage forms considered, OLZ-CAMs presented a higher solubility and dissolution rate than the respective crystalline counterpart. Furthermore, in situ co-amorphization of OLZ and SAC during granule production with high fractions of water unveils the possibility of reducing production steps and associated costs.

Low-molecular-weight fucoidan bidirectionally regulates lipid uptake and cholesterol efflux through the p38 MAPK phosphorylation

Atherosclerosis (AS) is the pathological basis of many cardiovascular and cerebrovascular diseases, in which macrophage-derived foam cells are the critical step and a typical pathological feature of early atherosclerosis. We previously confirmed that low-molecular-weight fucoidan (LMWF) had a good anti-AS effect, but the mechanism is still unclear. Here with aim to investigate the inhibitory effect of LMWF on foam cells and its molecular mechanism. Oil red O staining showed that LMWF effectively alleviated lipid accumulation and the formation of foam cells. Flow cytometry detection showed that LMWF promoted foam cells apoptosis. In addition, immunofluorescence showed that LMWF inhibited macrophage scavenger receptor A1 (SR-A1)-mediated lipid uptake and promoted ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol outflow. Western blot showed that LMWF downregulated SR-A1 protein expression and upregulated ABCA1 protein expression by inhibiting p38 mitogen activated protein kinase (p38MAPK) phosphorylation. Moreover, the mRNA transcriptions of Stat1, Elk-1, and Myc were downregulated when treated with LMWF. It concluded that, LMWF achieved bidirectional regulation of SR-A1 and ABCA1, then prevented the formation of foam cells, finally ameliorated the development of AS.