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

Mcim Amin,Sm Albawani,Mw Amjad

doi:10.4314/tjpr.v11i4.9

Abstract

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.

Highlights

In 2008, among various dosage forms in medicine, tablets still account for 80% of the drug delivery systems administered to human [1]
Most of the studies on direct compression technique are concerned with the compaction behavior and binding properties of excipients
Only this study has found the values of Hausner ratio and Carr’s index for dextrate and ethyl cellulose

Summary

Introduction

In 2008, among various dosage forms in medicine, tablets still account for 80% of the drug delivery systems administered to human [1]. Tablets are produced by applying a certain compression pressure on a bed of powder. A tablet contains a combination of two or more powders to obtain a compact with the desired properties. In addition to active pharmaceutical ingredient, various excipients are important for production of elegant tablets with desired mechanical strength, disintegration and dissolution time. These include antiadherents, binders, enterics, disintegrants, fillers, flavours, colours, lubricants, glidants, sorbents, preservatives and sweeteners. Most of the studies on direct compression technique are concerned with the compaction behavior and binding properties of excipients. Each excipient has its own compaction behaviour and may change the compaction properties of the powder mixture and influence the strength of tablets or other tableting properties

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Conclusion