The impact of the degree of intimate mixing on the compaction properties of materials produced by crystallo-co-spray drying.

Direct compression remains one of the most favourable methods available to produce tablet compacts due to its simplicity, efficiency and cost effectiveness however, the technique still remains unsuitable for the majority of formulations due to materials exhibiting poor physical properties such as inadequate compressibility and deformation mechanisms. Whereas crystallo-co-spray drying of various blends has shown to improve the tabletting properties of poorly processable materials, the role of the solvent feed composition in altering the soluble fraction ratio of the excipient to the drug in a crystallo-co-spray dried agglomerate is not well understood. The aim of this work was to investigate the role of the soluble fraction of a drug (paracetamol) and an excipient (α-lactose monohydrate) on the tabletting properties of their crystallo-co-spray dried agglomerates produced via co-spray drying using various inlet feed solvent compositions in order to vary the soluble fraction of the excipient in the feed. It was found that an increase in excipient soluble fraction in the inlet feed resulted in a greater degree of intimate mixing in the final spray dried powder blend, which in turn led to an improvement in tabletting properties of the poorly processable drug.

Mechanochemical activation with cyclodextrins followed by compaction as an effective approach to improving dissolution of rutin.

Rutin is one of the most important flavonoids with poor bioavailability. This work aimed at addressing the issue of poor biopharmaceutical performance of rutin by applying a combination of complexation with secondary processing into tablets. Mechanical activation was the most suitable method of rutin complex formation with (2-hydroxypropyl)-ß-cyclodextrin (HP-ß-CD), while the ß-cyclodextrin (ß-CD) complex successfully formed by kneading with an ethanol/water mixture. Complexation was confirmed by thermal analysis, powder X-ray diffraction and vibrational spectroscopy. Dynamic vapour sorption showed that stability of powders at high humidity conditions was satisfactory, however, the ß-CD complex retained around 8% of moisture. The complexes were compacted with or without tricalcium phosphate (TRI-CAFOS) filler at a range of compression pressures (19-113 MPa). The best tabletability was determined for rutin/HP-ß-CD, compressibility for the TRI-CAFOS blends with complexes and compactibility for the rutin/HP-ß-CD + TRI-CAFOS mix. Dissolution studies showed quicker and more complete dissolution (pH 1.2) of rutin/HP-ß-CD tablets, however the compacts comprising the filler were superior than pure complexes. The tablets manufactured in this study appear to be promising delivery systems of rutin and it is recommended to combine rutin/HP-ß-CD with TRI-CAFOS and compact at 38-76 MPa.

Crystallo-co-spray drying as a new approach to manufacturing of drug/excipient agglomerates: Impact of processing on the properties of paracetamol and lactose mixtures.

The novel process of crystallo-co-spray drying of paracetamol and α-lactose monohydrate was investigated by varying the spray dryer inlet temperature and inlet feed solvent composition. A crystalline agglomerate was obtained with no change to the physical structure of either component throughout both investigations and with possible interactions between the hydroxyl groups of the α-lactose monohydrate and the amide and hydroxyl groups of the paracetamol detected. The percentage soluble fraction of the components in the inlet feed had the largest influence on the morphology of the final dried agglomerate. Low excipient soluble fraction resulted in an increase in paracetamol surface coating and high excipient soluble fraction produced agglomerates of highly mixed components. The use of crystallo-co-spray drying can serve as a method of producing an agglomerated blend of crystalline co-spray dried components leading to possible opportunities for process intensification with the reduction of process steps such as blending, agglomeration, drying and milling into one single stage.