Contact Angles of Pharmaceutical Powders

Nucleation and crystal growth in supersaturated solutions of a model drug

“…The interfacial tensions have been calculated using literature data on contact angles and surface tension together with Eqs. (12) and (13) [29][30][31]. The values of χ were calculated from Eq.…”

Prediction of Contact Angle for Pharmaceutical Solids from Their Molecular Structure

“…It is not surprising that in some cases Models 1–3 are unable to reproduce experimental contact angles, since none of the models take into consideration the packing effects due to crystal structure, particle size, particle surface characteristics or batch to batch variation of the materials, which affect their physical properties and surface energetics. For example, Lerk et al14 reported that the contact angle of a solid is affected by its crystallographic structure. The β‐form of chloramphenicol palmitate had a water contact angle of 108° and the α‐form had a water contact angle of 122°.…”

“…The models presented in this study are derived from a heterogeneous series of molecules/materials, and therefore, could be more general than the model that Sheridan et al presented. Nevertheless, our models are limited also only to substances whose contact angle is measured with the same method Lerk used and that are quite similar to those from which the model is derived 14. For example, it would not be appropriate to use Model 1 to predict a protein's contact angle.…”

“…The experimentally measured (by the h ‐ ε method) water contact angle values for the materials ( n = 34) were obtained from the data reported by Lerk et al13,14 and are listed in Table 1. The h ‐ ε method is a sessile drop method, where a drop of liquid is formed on a cake of the test material, which has been previously saturated with the liquid.…”

“…Reproducibility of the measured contact angle values was found to be generally better than 2°, and even in the worst case ( viz . isoniazid and sulfisoxazole) it was no worse than 4° 13,14. Since Lerk used the same contact angle measuring technique for the series, the experimental values used in this study can be assumed to have only possible systematic errors or errors due to the uncontrolled differences in the surface state order/disorder of the materials.…”