Studies on direct compression of tablets. XXII. Investigation of strength increase upon ageing and bonding mechanisms for some plastically deforming materials

Abstract Strength increase as a function of time has been measured for tablets of five plastically deforming materials. The addition of small amounts of magnesium stearate was also tested for all materials in this context. The effect of ageing was evaluated by measuring the radial tensile strength immediately after compression and again after 2 days storage. The contribution of bonding with intermolecular forces as compared to bonding with solid bridges capable of penetrating the lubricant film was evaluated. Stress relaxation resulting in increased areas of interparticulate attraction was suggested to be a common denominator for strength increase in the unlubricated compacts. Solid bridges contributed to the strength increase upon ageing only for sodium chloride. Bonding with intermolecular forces seems in general to be the dominating bonding mechanism for the investigated materials.

[1]  L L Augsburger,et al.  Plastic flow during compression of directly compressible fillers and its effect on tablet strength. , 1977, Journal of pharmaceutical sciences.

[2]  J. N. Mcmullen,et al.  The effect of interparticulate friction and moisture on the crushing strength of sodium chloride compacts , 1985 .

[3]  G. Bolhuis,et al.  BONDING CHARACTERISTICS BY SCANNING ELECTRON-MICROSCOPY OF POWDERS MIXED WITH MAGNESIUM STEARATE , 1978 .

[4]  P. Rue,et al.  Time‐dependent deformation of some direct compression excipients * , 1978, The Journal of pharmacy and pharmacology.

[5]  J. Newton,et al.  Determination of tablet strength by the diametral-compression test. , 1970, Journal of pharmaceutical sciences.

[6]  C. Nyström,et al.  Studies on direct compression of tablets XVII. Porosity—pressure curves for the characterization of volume reduction mechanisms in powder compression , 1986 .

[7]  N. Lordi,et al.  Mechanism of Hardness of Aged Compacts , 1984 .

[8]  G. Alderborn,et al.  Moisture adsorption and tabletting. II. The effect on tensile strength and air permeability of the relative humidity during storage of tablets of 3 crystalline materials , 1989 .

[9]  F. P. Bowden,et al.  The Friction and Lubrication of Solids , 1964 .

[10]  N. N. Greenwood,et al.  Chemistry of the elements , 1984 .

[11]  C. Nyström,et al.  Studies on direct compression of tablets XXI. Investigation of bonding mechanisms of some directly compressed materials by strength characterization in media with different dielectric constants (relative permittivity) , 1990 .

[12]  G. Alderborn,et al.  Studies on direct compression of tablets X. Measurement of tablet surface area by permeametry , 1985 .

[13]  G. Alderborn,et al.  Moisture adsorption and tabletting. I. Effect on volume reduction properties and tablet strength for some crystalline materials , 1989 .

[14]  C. Nyström,et al.  Studies on direct compression of tablets XVI. The use of surface area measurements for the evaluation of bonding surface area in compressed powders , 1986 .

[15]  E. Shotton,et al.  Some observations on the ageing of sodium chloride compacts * , 1970, The Journal of pharmacy and pharmacology.