Rheological properties of pharmaceutical substrates produced with Celugel.

Abstract

Background: Hydrogels, containing a large amount of water and exhibiting high biocompatibility, can improve the rheological properties of formulations and adhere well to the application site. In Poland, only 1 hydrogel substrate is currently approved for pharmaceutical compounding: Celugel, based on hydroxyethyl cellulose (HEC).

Objectives: The aim of this study was to investigate how the variation in the raw material composition of Celugel-based hydrogels affects their osmotic pressure values and selected rheological properties.

Material and methods: Ten gel formulations were prepared using a commercial Celugel as the base, with varying percentages of added water, alongside a consistent 5 wt% addition of sucrose. The research methods employed include osmotic pressure, dynamic viscosity, pH measurement, and surface tension using the du Noüy ring tensiometer.

Results: The composition of the formulation has a significant impact on the osmotic pressure. Nearly all of the hydrogels exhibited hyperosmotic characteristics relative to living tissues, with measured osmotic pressure values ranging from 160 mOsm/kg H2O to 1,480 mOsm/kg H2O. As anticipated, the viscosity of the formulations increased proportionally with the growing concentration of Celugel ranging from 2.19 mPa·s to 562.87 mPa·s.

Conclusion: The composition of Celugel significantly influences its rheological properties and osmotic pressure values, with the concentration of the gelling agent being the most impactful factor. The results suggest that Celugel is suitable for use in formulations intended for nasal administration.