A Comparative Study of the Compaction Properties of Binary and Bilayer Tablets of Direct Compression Excipients

Purpose: To comparatively evaluate the tableting properties of binary mixtures and bilayer tablets containing plastic deformation and brittle fracture excipients.Methods: Binary mixture and bilayer tablets of microcrystalline cellulose (MCC), ethyl cellulose, anhydrous lactose and dextrate were prepared by direct compression and the effect of compaction pressure on the materials was investigated by scanning electron microscopy (SEM). True, bulk and tap densities of excipients were determined. Furthermore, Heckel equation and Carr’s index were used to analyze the compression behaviour of the tablets.Results: The flowability of dextrate, based on Heckel and Carr’s Index data, was superior to that of other powder excipients tested. No significant difference was observed between the tensile strength of binary and bilayer tablets of the same composition. However, the tensile strength of binary and bilayer tablets of different compositions varied significantly (p < 0.001), e.g., the tensile strength of microcrystalline cellulose (MCC)/ethyl cellulose (EC) tablets (50/50) was 1.77 MPa while that of MCC/dextrate at 50/50 composition was 1.47 MPa.Conclusion: Binary mixture and bilayer tablets show similar behaviour when formulated using excipients of similar deformation properties. However, their behavior changes when excipients with different deformation properties are blended together.Keywords: Binary mixture, Bilayer tablet, Brittle fracture, Plastic deformation, Tensile strength

Dry Bacterial Cellulose and Carboxymethyl Cellulose formulations with interfacial-active performance: processing conditions and redispersion

Dry or powdered formulations of food additives facilitate transportation, storage, preservation and handling. In this work, dry formulations of bacterial cellulose and carboxymethyl cellulose (BC:CMC), easily redispersible and preserving the functionality of the never-dried dispersions are reported. Different processing parameters and their effect on the materials properties were evaluated, namely: (i) wet-grinding of BC (Hand-blender, Microcut Head Impeller, High-pressure Homogenizer), (ii) drying of BC:CMC mixtures (fast drying at130 °C and slow drying at 80 °C) and subsequent (iii) comminution to different particle sizes. The dispersibility of the obtained BC:CMC powders was evaluated, and their functionality after redispersion was assessed by measuring the dynamic viscosity, the effect in oil/water interfacial tension (liquidliquid system) and the stabilization of cocoa in milk (solidliquid system). The size of BC fibre bundles was of paramount relevance to its stabilizing ability in multiphasic systems. A more extensive wet-grinding of the BC fibres was accompanied by a loss in the BC:CMC functionality, related to the increasingly smaller size of the BC bundles. Indeed, as the Dv (50) of the wet BC bundles was reduced from 1228 to 55 µm, the BC:CMC viscosity profile dropped and the effect on interfacial tension decreased. This effect was observed both on the never-dried and dry BC:CMC formulations. On the other hand, the drying method did not play a major effect in the materials properties. In a benchmarking study, the BC:CMC formulations, at a low concentration (0.15%), had better stabilizing ability of the cocoa particles than several commercial cellulose products.Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-020-03211-9) contains supplementary material, which is available to authorized users.This study was supported by FCT under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020-Programa Operacional Regional do Norte. Daniela Martins also gratefully acknowledges FCT for the PhD scholarship, reference SFRH/BD/115917/2016.info:eu-repo/semantics/publishedVersio

Co-Processed Excipients for Dispersible Tablets–Part 1: Manufacturability

Co-processed excipients may enhance functionality and reduce drawbacks of traditional excipients for the manufacture of tablets on a commercial scale. The following study aimed to characterise a range of co-processed excipients that may prove suitable for dispersible tablet formulations prepared by direct compression. Co-processed excipients were lubricated and compressed into 10.5-mm convex tablets using a Phoenix compaction simulator. Compression profiles were generated by varying the compression force applied to the formulation and the prepared tablets were characterised for hardness, friability, disintegration and fineness of dispersion. Our data indicates that CombiLac, F-Melt type C and SmartEx QD100 were the top 3 most suitable out of 16 co-processed excipients under the conditions evaluated. They exhibited good flow properties (Carr’s index ˂ 20), excellent tabletability (tensile strength > 3.0 MPa at 0.85 solid fraction), very low friability (< 1% after 15 min), rapid disintegration times (27–49 s) and produced dispersions of ideal fineness (< 250 μm). Other co-processed excipients (including F-Melt type M, Ludiflash, MicroceLac, Pharmaburst 500 and Avicel HFE-102) may be appropriate for dispersible tablets produced by direct compression providing the identified disintegration and dispersion risks were mitigated prior to commercialisation. This indicates that robust dispersible tablets which disintegrate rapidly could be manufactured from a range of co-processed excipients