Investigation of Dispersion Kinetics of Particulate Lubricants and their Effect on the Mechanical Strength of MCC Tablets

Fig. 5 Schematic representation of particle size based theoretical surface coverage by assuming that each lubricant particle occupies the hexagonal shaped surface according to its median particle size.

Abstract

Introduction

Tablets are commonly produced by internally adding particulate lubricants, which are known to possibly lower the mechanical strength of tablets. This reduction is caused by the coverage of matrix forming components by lubricant particles, resulting in decreased interparticulate interactions. The known incompatibilities with some active compounds of the predominantly used lubricant, magnesium stearate, call for the in-depth characterization of alternative lubricants.

Purpose

Investigation of the dispersion behavior of five commonly applied pharmaceutical lubricants by mathematically modeling the dispersion kinetics for short and extended mixing times.

Methods

The dispersion behavior of five different pharmaceutical lubricants were examined by systematically varying lubricant concentration and mixing time of binary formulations and evaluating the kinetic of tensile strength reduction by theoretically estimating the surface coverage based on particle sizes.

Results

For short mixing times, a unifying relationship between compactibility reduction and theoretical surface coverage was identified. Subsequently, for extended mixing times, distinct differences in the shear strength and dispersion kinetics of the investigated lubricants were found.

Conclusions

The lubricant particle size controls the tensile strength reduction if short mixing times are applied. For extended mixing times, the investigated lubricants can be divided into two groups in terms of dispersion kinetics. Possible underlying reasons are discussed in detail in order to enhance the general understanding of lubricant dispersions in tablet formulations.

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Materials

Microcrystalline cellulose (MCC; Vivapur 200®, JRS Pharma GmbH, Germany) was used as diluent. Magnesium stearate (MgSt; Ligamed MF-2-V, Peter Greven GmbH, Germany), sodium stearyl fumarate (SSF, PRUV®, JRS Pharma GmbH, Germany), stearic acid (SA; Ligamed SA-1-V, Peter Greven GmbH), hydrogenated vegetable oil (HVO; LUBRITAB®, JRS Pharma GmbH, Germany), and glyceryl dibehenate (GDB; COMPRITOL® 888 ATO, Gattefossé, France) were used as lubricants. Lubricants were deagglomerated by means of a 355 μm sieve before being mixed.

Puckhaber, D., Kwade, A. & Finke, J.H. Investigation of Dispersion Kinetics of Particulate Lubricants and their Effect on the Mechanical Strength of MCC Tablets. Pharm Res (2023). https://doi.org/10.1007/s11095-023-03602-0