Background: Excipients with improved functionality have continued to be developed by the particle engineering strategy of co-processing. The aim of this study was to evaluate the compaction and tableting properties of composite particles of microcrystalline cellulose (MCC) and crospovidone (CPV) engineered by co-processing. Results: Heckel analysis of the compaction behavior revealed a decrease in plasticity of co-processed excipient (CPE) when compared to MCC due to an increase in Heckel yield pressure from 144 to 172 MPa. The compressibility-tabletability-compactibility (CTC) profile revealed a decrease in individual parameters for CPE when compared to MCC. CPE was found to be more sensitive to the lubricant effect of sodium stearyl fumarate (SSF) when compared to MCC and less sensitive to magnesium stearate (MST) when compared to MCC. A higher dilution potential was obtained for MCC (60%) compared to 44% for CPE when metronidazole was used as model drug. Tableting properties revealed that metronidazole tablets generated with CPE by direct compression disintegrated within 15 min and gave a rapid drug release when compared to MCC as a direct compression (DC) excipient. Conclusion: The compaction and tableting properties of CPE were characterized and yielded tablets with better disintegration and drug release profile when compared to MCC. This study, therefore, confirms the suitability of co-processing as a proven strategy in engineering the performance of excipients.

The functionality of a co-processed excipient is usually derived from its composition and the proportion of each excipient that is incorporated to yield a composite excipient. The aim of this study was to assess the impact of binder as a formulation variable on the material and tableting properties of developed co-processed excipients containing gelatin (SGS) and microcrystalline cellulose (SMS) as binders respectively in the same proportion. Two co-processed excipients, SGS and SMS were generated by combining tapioca starch (90%), gelatin or microcrystalline cellulose (7.5%) and colloidal silicon dioxide (2.5%) using the co-fusion method. Particle size analysis and morphological assessment were carried out by light microscopy and scanning electron microscopy (SEM) respectively. DSC analysis was performed to evaluate the thermal behaviour of both materials and flow properties were assessed by measuring parameters like angle of repose, bulk and tapped densities, Carr's index and Hausner's ratio. Compaction behaviour of both materials was determined using Heckel and Walker equations and the compressibility-tabletability-compactibility (CTC) profile for each material was obtained. Particulate and bulk-level properties of SGS and SMS revealed spherical-shaped, free-flowing powders characterized by a glass transition event typical of amorphous polymers. Compaction analysis demonstrated greater degree of plastic deformation with SMS resulting in better tableting properties with respect to tensile strength and disintegration time. The outcome of the study shows that the choice of binder used in the formulation of a co-processed excipient plays a crucial role in defining the material and tableting properties of the co-processed excipient.

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that cogranulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of coprocessing influences the powder and tableting properties of the co-processed excipient.