Polymorphism, Crystallinity and Hydrophilic-Lipophilic Balance (HLB) of Cetearyl Alcohol and Cetyl Alcohol as Raw Materials for Solid Lipid Nanoparticles (SLN)

Abstract

The use of Solid Lipid Nanoparticles (SLN) has become a very popular approach in the development of innovative pharmaceutical drug delivery systems. The first step is the assessment the lipids' suitability. This paper is focused on the physicochemical characterization of lipids, namely cetyl alcohol and cetearyl alcohol, for the production of SLN. The bulk lipids were analyzed by Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD) without any treatment, after tempering the raw materials (bulk lipid) for 1 hour at 80 °C, and after their spray-drying process. Hydrophilic-Lipophilic Balance (HLB) values were determined using a combination of surfactants (polysorbate 20 and trioleate sorbitan) for the production of the hot o/w emulsion. Results of DSC and WAXD showed that after the thermal stress applied to the bulk lipids, both the melting point and the intensity of the refractogram peaks have decreased. Cetyl alcohol and cetearyl alcohol crystallized in more unstable polymorphic forms, which anticipate the suitability of these lipids for the production of SLN. The best HLB values obtained for the produced emulsions were 15.5, 16.0, and 16.7, combining accepted surfactants. The results showed that both cetearyl alcohol and cetyl alcohol are adequate lipids for the development of stable SLN.

Development and Thermophysical Profile of Cetyl Alcohol-in-Water Nanoemulsions for Thermal Management

“…Such multiphase colloidal structures (also called "α-gel") contain bilayers made of hexagonally-packed crystals of surfactants and fatty alcohols, which give rise to a creamy texture of the sample [62], which is uninteresting for heat transfer applications. Those gels, whose main binding forces are electrostatic in nature [61], were not observed for cetyl alcohol-in-water emulsions prepared using nonionic polyoxylated surfactants [66], for example. In order to reduce the interactions between cetyl alcohol and SDS, in our present study, we limited SDS:dispersed phase ratio to 1:80 (in mass) and incorporated a nonionic Brij 30 into the emulsions.…”

EXPERIMENTAL DEVELOPMENT AND MOLECULAR DOCKING: NANOSTRUCTURED LIPID CARRIERS (NLCs) OF COENZYME Q10 USING STEARIC ACID AND DIFFERENT LIQUID LIPIDS AS LIPID MATRIX

“…The hydrophobic and van der Waals interactions did not lead to forming new functional groups. The EE of the co-Q10 NLC (F6, (7) and (F8) were>80%, as shown in table 7. These were due to the addition of liquid lipids into the SA lead to order crystal structure became disordered.…”

“…These components are the factors that determine the formation of a stable emulsion during the NLC manufacturing process. The required HLB (rHLB) of matrix lipid and amount of surfactants are the factors that determining emulsion stability [6,7,[17][18][19].…”

“…The CI was calculated by comparing the enthalpy of co-Q10 NLC with the enthalpy of SA (equation 1). Lipid crystallinity affects EE and DL [7,27]. The CI of co-Q10 NLC (F6), (F7), and (F8) are presented in table 6.…”

“…These components determine emulsion stability during the NLC production process. The required hydrophilic-lipophilic balance (rHLB) value of the lipid matrix should be matched to the HLB value of the surfactants to obtain stable emulsion [6,7]. In the present study, Tween 80 (HLB=15) and Span 80 (HLB=4.3) [8] were used as a combination of surfactants, SA as a solid lipid, OA, IPM, and IPP as liquid lipids.…”