Fractal Analysis of β-Cyclodextrin–Indomethacin Particles Compacted by Ultrasound

Abstract

An association between indomethacin and beta-cyclodextrin (beta-CD) was obtained by compacting a 1:2 molar physical mixture by ultrasound. The product prepared by this technique was compared with the initial physical mixture and with materials having the same composition but prepared by a simple compaction and kneading process. The samples examined by scanning electron microscopy revealed morphological differences related to the methods of preparation. In particular the material obtained by ultrasound had a smooth surface and on milling produced particles of uniform size; moreover EDAX analysis (energy dispersion analysis by X-rays) also revealed a homogeneous distribution of the two components in each particle examined. Surface fractal dimension of the surface of these particles is very low, suggesting the presence of a regular and smooth surface whereas the sample obtained by kneading had a higher value. The reactive dimension related to dissolution was much higher than the corresponding surface dimension in all cases and had comparable values for all samples regardless of the techniques used. This behavior was attributed to the hydrophilicity of beta-CD, which levels the differences during dissolution and which could be originated by surface imperfections. Experimental results suggested that the material obtained by ultrasound had a dissolution rate comparable to that measured with the kneaded material. The use of ultrasound, however, can both reduce the production time and improve the homogeneity of the association between indomethacin and beta-CD.

Serum Albumin-Alginate Microparticles Prepared by Transacylation: Relationship between Physicochemical, Structural and Functional Properties

“…In response to tree-like patterns observed on many of these cross sections (example on Figure 10), a fractal analysis was carried out on each microphotograph to quantify the differences between microparticle internal structures 37,38 . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 22 Figure 10.…”

Overview of Amorphous Solid Dispersion Technologies

“…Ultrasonic-assisted compaction is a modified tabletting process that can provide heat, pressure, and shear due to ultrasonic energy to the powder mixture during compaction. The application of ultrasound to solubility enhancement is based on the fusion method and in some ways mimics the extrusion process (Fini et al 1997;Sancin et al 1999). The ultrasonic frequency vibration is applied at the same time as compaction force.…”

Emerging Technologies to Increase the Bioavailability of Poorly Water-Soluble Drugs

“…This processing technique was fi rst described by Fini et al ( 1997 ) in a preliminary study. The researchers evaluated the utility of ultrasonic-assisted compaction in the preparation of compositions containing indomethacin and b -cyclodextrin.…”