Evaluation of surface and bulk characteristics of cellulose I powders in relation to compaction behavior and tablet properties.

The particle properties and solid-state characteristics of two celluloses, Avicel PH101 and cellulose obtained from the alga Cladophora sp., were evaluated and related to the compaction behavior and the properties of the tablets made from them. The surface area of the celluloses was measured at different levels of penetration capacity, ranging from external surface area of particles to molecular texture with Blaine permeametry, Kr-gasadsorption, and solid-state NMR.

Characteristics of hydroxypropyl methylcellulose influencing compactibility and prediction of particle and tablet properties by infrared spectroscopy.

Particle characteristics, chemical substitution, compaction behavior, and tablet properties of hydroxypropyl methylcellulose powders from two different suppliers were related using multivariate data analysis. By Principal Component Analysis it was shown that the the degree of substitution of the HPMC powders did not correlate to the particle and compaction properties as strongly as anticipated. Particle shape and powder surface area seem to be more important for the compaction behaviour of the powders than the degree of substitution.

Characterisation of particle properties and compaction behaviour of hydroxypropyl methylcellulose with different degrees of methoxy/hydroxypropyl substitution.

The particle characteristics and compaction behaviour of hydroxypropyl methylcellulose (HPMC) powders from two different suppliers were studied regarding effects of methoxy/hydroxypropyl substitution. Samples included Methocel K4M (low substitution ratio), E4M (medium) and F4M (high) and the corresponding substitution ratios from Metolose: 90 SH 4000, 60 SH 4000, and 65 SH 4000. Characterisation of the particle properties and compaction behaviour of the pure polymers suggested that reported differences in drug release behaviour of Methocel E4M compared with the other two powders may be related to the lower powder surface area, differing particle morphology and lower fragmentation propensity during compaction.

Structural studies of the O-specific side-chains of the Escherichia coli O2 lipopolysaccharide.

The structure of the O-specific side-chains of the Escherichia coli O2 lipopolysaccharide has been investigated, different 1H- and 13C-n.m.r.