Ternary Amorphous Solid Dispersions Containing a High-Viscosity Polymer and Mesoporous Silica Enhance Dissolution Performance†.

The aim of this study was to evaluate the benefits of a ternary amorphous solid dispersion (ASD) that was designed as an immediate-release tablet with a high drug load (e.g., 40% w/w) to produce heightened maintenance of drug supersaturation during dissolution testing, which will be henceforth referred to as the "maintenance ability". Ternary ASD granules were produced by hot melt extrusion (HME) and were comprised of itraconazole (ITZ) 50%, hypromellose (HPMC) 20%, and mesoporous silica (XDP) 30%, where amorphous ITZ incorporated into HPMC was efficiently absorbed in XDP pores. The ternary ASD granules containing a high-viscosity HPMC (AF4M) produced a significantly heightened maintenance ability of drug supersaturation in neutral pH dissolution media in which crystalline ITZ solubility is below 1 µg/mL. The final tablet formulation contained 80% w/w of the ASD granules (40% w/w ITZ), had an acceptable size, and exhibited both sufficient tablet hardness and disintegration. The dissolution behavior of the ternary ASD tablet exhibited a supersaturation maintenance ability similar to that of the ASD granules. Under neutral conditions, the ternary ASD tablet showed immediate and higher ITZ release compared with the binary ASD tablets, and this phenomenon could be explained by the difference in ITZ/AF4M particle size in the tablet. In high-resolution scanning electron microscopy (SEM), it was observed that ITZ and AF4M in the ternary formulation could easily form nano-sized particles (<1 µm) during the absorption process into/onto XDP pores prepared by HME, which contributed to the immediate ITZ release from the ternary ASD tablet under neutral pH conditions. Therefore, the ternary ASD containing high-viscosity HPMC and mesoporous silica prepared by HME made it possible to design a high ASD content, small-size tablet with an ideal dissolution profile in biorelevant media, and we expect that this technology can be applied for continuous HME ASD manufacturing.

Solid-state NMR analysis of crystalline and amorphous Indomethacin: An experimental protocol for full resonance assignments.

Solid-state NMR (ssNMR) analysis of pharmaceutical materials relies on accurate resonance assignments. The relatively low sensitivity and resolution from the natural abundance and solid-state nature of the active pharmaceutical ingredient (API) and particularly the disordered structure of amorphous forms result in the ambiguous identification of NMR peaks. In this study, a robust protocol for unambiguously assigning 13C and 1H chemical shifts of crystalline and amorphous APIs has been established and successfully tested on γ-polymorph indomethacin. Specifically, one-dimensional (1D) 13C-edited experiments, two-dimensional (2D) 13C-detected homo- and heteronuclear correlations, and 2D 1H-detected techniques under ultrafast magic angle spinning (MAS) provide enhanced resolution to identify overlapped 13C resonances and assign confidently the 1H chemical shifts. This experimental strategy allows us to assign particularly those carbons and protons either unassigned or ambiguous identified due to the technical challenges in previous literature. Besides, the chemical shift comparison between the crystalline and amorphous forms can potentially report the molecular packing variations.

Enhanced Dissolution of a Porous Carrier-Containing Ternary Amorphous Solid Dispersion System Prepared by a Hot Melt Method.

The focus of our study was to employ a solvent-free, thermal process to evaluate the use of a porous carrier in a drug-polymer-porous carrier ternary formulation containing a high drug load (e.g., ≥50% w/w). The purpose of the study was to improve the dissolution properties of the biopharmaceutical classification system class II drug, indomethacin, in the ternary formulation. The effect that the selected polymer has on properties of the formulation was studied, and the formulation characteristics of hypromellose (AF15), copovidone (VA64), and polyvinyl alcohol-polyethylene glycol graft copolymer was evaluated to understand differences in dissolution rates and drug adsorption onto the porous carrier. The ternary formulations were manufactured using a thermal technique that relied on heating and mixing, without the necessity of mechanical shear. All thermally processed granules that employed the porous carrier exhibited immediate release compared with crystalline indomethacin and physical mixtures. In addition, the ternary formulations maintained supersaturation compared with the binary formulations without polymer. The results of this study indicated that the thermally processed ternary formulations containing a porous carrier demonstrated a much improved dissolution profile in nonsink conditions.

Predicting physical stability of ternary amorphous solid dispersions using specific mechanical energy in a hot melt extrusion process.

This study focuses on the relationship between drug dissolution properties, physical stability against recrystallization, and specific mechanical energy (SME) from a hot melt extrusion (HME) process of ternary amorphous solid dispersions (ASDs) containing indomethacin (IND), HPMC and mesoporous silica (XDP) prepared using different HME screw condition (the number of kneading zones/rotation speed). The screw condition greatly influenced the amorphous characteristics of the processed material and SME values. The higher SME samples demonstrated a larger parachute effect in dissolution test and reduced the rate of recrystallization upon exposure to elevated temperature/humidity conditions, which can be explained from the enhanced miscibility and interactions of IND/HPMC/XDP. The molecular investigation by solid-state NMR (ssNMR) suggested that higher SME input produced better IND/HPMC miscibility and interaction. Interestingly, XDP showed distinct contacts with IND and HPMC in the high-SME samples. The IND-HPMC interaction is not sufficient to maintain a highly mixed ASD at a high drug load without the assistance of XDP. Therefore, SME is a critical parameter for predicting enhanced dissolution and physical stability of IND in ASDs. Moreover, multi-nuclear and multi-dimensional ssNMR provide mechanistic understanding of molecular properties and bring new perspectives for preparation, analysis, and applications of XDP as a pharmaceutical carrier.