Effect of texture on the intrinsic dissolution behaviour of acetylsalicylic acid and tolbutamide compacts

Abstract

Preferred orientation of crystallites, i.e. texture, is a common result when a sample with an irregular habit of particles is compacted to form a tablet. Since texturization alters the random distribution of the crystal planes on the surface of the compacted sample, the dissolution properties of highly texturized tablets could differ from the properties of a tablet with a less preferred orientation. Three batches from both acetylsalicylic acid and tolbutamide were recrystallized using different crystallization parameters to obtain powders with different texturization behaviour. Several X-ray diffraction procedures were used to characterize the texture and other crystallographic properties of the samples. The intrinsic dissolution profiles were measured using the channel flow technique. In addition, the attachment energy of the crystal planes lying on the surface of the compacts was calculated theoretically. The results indicate that the most texturized compacts had a clearly lower intrinsic dissolution rate than the compacts with a lower degree of preferred orientation. By combining the results of the texture measurements with the calculated attachment energy values, the surface energies of the samples could be estimated and the estimated energy values were in agreement with the results of the dissolution studies. Moreover, it was found that by using the results of the texture measurements, the habit of the sample particles can be successfully predicted.

Crystal Habits of Itraconazole Microcrystals: Unusual Isomorphic Intergrowths Induced via Tuning Recrystallization Conditions

“…The MD parameter (0 ≤ MD ≤ 1) is an indication of the degree of the preferred orientation of the sample on the sample holder, which in turn is related to the crystal shape. A value of 0 is an indication of absolute preferred orientation, which is usually observed with flat anisotropic crystals, while a value of 1 is an indication of randomly oriented powder (zero preferred orientation) and indicates isotropic crystal shapes 38 .…”

Influence of Crystal Habit on the Dissolution of Simvastatin Single Crystals

“…Crystal habit can significantly influence for instance the disintegration capability 14 of tablets, their crushing strength, 15 compactibility 16 and the dissolution behaviour. 14,16 It is known 13,17,18 that different crystal planes possess different surface energy properties and can therefore exhibit different dissolution kinetics which are demonstrated among others in the work of Tenho et.al. 17 who used this technique to study the dissolution behaviour of acetylsalicylic acid and tolbutamide and Prasad et al 13 on paracetamol single crystals.…”

“…14,16 It is known 13,17,18 that different crystal planes possess different surface energy properties and can therefore exhibit different dissolution kinetics which are demonstrated among others in the work of Tenho et.al. 17 who used this technique to study the dissolution behaviour of acetylsalicylic acid and tolbutamide and Prasad et al 13 on paracetamol single crystals. These published studies suggest that it is possible to modify the dissolution rate of the active pharmaceutical ingredients by altering only their crystal habits.…”

Avaliação do impacto de diferentes variáveis no ensaio de dissolução intrínseca de metronidazol

“…Pelos resultados apresentados, verificou-se que o processo de micronização tem influência nas propriedades reológicas do metronidazol, sendo assim, a redução das partículas desse fármaco para a produção de formas sólidas deve ser avaliada, uma vez que tal processo pode intensificar os problemas no momento da fabricação. (AULTON, 2002;TENHO et al, 2007;VIEGAS et al, 2001).…”