Optimization of Betulin Colloidal Aqueous Suspension Pretreatment for Determination of Particle Characteristics

Abstract

Dynamic light scattering (DLS) is a well-established technique to analyze particle size in a liquid medium and sample preparation is an essential step of the analysis to obtain reliable data. In this study, the pretreatment of an aqueous suspension containing betulin particles was studied to characterize the colloidal betulin particles in supramolecular hydrogels obtained by the liquid antisolvent precipitation from purified and unpurified betulin samples. Parameters of two-step homogenization process using rotor and ultrasonic homogenizer, particle concentration, and pH were systematically varied to obtain stable aqueous suspensions that meet the requirements of DLS technique for good particle size analysis. It was found that the purified betulin particles have a higher tendency to agglomerate and their suspension is stable in a narrower concentration and pH range than unpurified. Particle size analysis in suspensions prepared independently shows good reproducibility of sample preparation.

Innovative Approach to Enhance Bioavailability of Birch Bark Extracts: Novel Method of Oleogel Development Contrasted with Other Dispersed Systems

“…When compared to the BBE suspension in oil, oleogel administration resulted in a 6 times higher betulin concentration. This difference is attributed to the fact that the oleogel contains smaller BBE particles than the oil suspension, resulting in a larger surface area and, consequently, improved bioavailability [ 11 , 23 , 38 , 39 , 40 , 46 ].…”

“…When compared to the BBE suspension in oil, oleogel administration resulted in a 6 times higher betulin concentration. This difference is attributed to the fact that the oleogel contains smaller BBE particles than the oil suspension, resulting in a larger surface area and, consequently, improved bioavailability [11,23,[38][39][40]46]. The lowest peak concentration of betulin was observed in rat plasma following the administration of the BBE suspension in water, a concentration that was as much as 5-fold The lowest peak concentration of betulin was observed in rat plasma following the administration of the BBE suspension in water, a concentration that was as much as 5-fold lower than in the oil suspension group.…”

“…Because of their reversible nature, these hydrogels are highly attractive for the inclusion of bioactive substances [ 37 ]. In our earlier investigations, physical hydrogels with a paste-like consistency were produced using the antisolvent precipitation technique for BBE [ 38 , 39 ]. This process resulted in a reduction in BBE particle sizes, potentially enhancing bioavailability.…”

Evaluation of Oleogels Stabilized by Particles of Birch Outer Bark Extract through a Novel Approach

“…Several studies have shown that naturally occurring pentacyclic triterpenes, such as betulin, lupeol, and betulinic acid, can spontaneously self-assemble in liquids to form supramolecular structures [8][9][10]. For example, birch outer bark extractive micro/nanoparticles obtained by liquid antisolvent precipitation after filtration form a hydrogel-like structure with a high liquid content (up to 97 wt.%) [11][12][13]. A similar self-assembly for extractive particles has also been described in an oil medium.…”