Atomistic Description of the Solubilisation of Testosterone Propionate in a Sodium Dodecyl Sulfate Micelle

Abstract

Large-scale molecular dynamics simulations were used to study the structural and dynamic properties of the solubilization process of testosterone propionate (TSTP) within sodium dodecyl sulfate (SDS) micelles. We observed that the TSTP spontaneously adsorb onto the SDS micelles and preferentially reside among the polar head groups of the SDS molecules. We found that the SDS micelle is slightly aspherical in size and has a surface area of ∼170 Å(2)/molecule, while the SDS+TSTP micelle is more aspherical and has a surface area of ∼156 Å(2)/molecule. The structural properties of the interior of the SDS micelle and the hydration of the SDS headgroup are largely undisturbed by the presence of the TSTP. However, there seems to be a correlation between the location of the TSTP molecules and the location of Na(+) counterions on the surface of the SDS micelle. Additionally, we also observe that the TSTP molecules diffuse on the surface of the SDS micelle and try to organize themselves such that they are approximately equidistant from one another.

A novel method for constructing continuous intrinsic surfaces of nanoparticles

“…This is crucial to our understanding of the encapsulation process of drugs within micelles, which in turn affects the ability of SDS micelles to act as vectors in oral drug delivery. In the future, we plan to build upon our previous work [17, 41] by performing well-tempered metadynamics simulations to obtain the free energy landscape as a function of depth of insertion of various different testosterone derivatives into surfactant micelles. The collective variables used in metadynamics calculations must be continuous functions to ensure energy conservation.…”

“…The aggregation numbers of SDS and TP were found to be 76 and 13, respectively, as calculated from recent neutron scattering experiments on SDS micelles in the presence of TP at equilibrium [17]. First, a spherical micelle structure was built using the Packmol software package [48] consisting of 76 SDS monomers in vacuo.…”

“…Nevertheless, an accurate description of the nanoparticle interface is seldom incorporated into analysis. In this study, we propose a novel method of constructing the continuous intrinsic surface of nanoparticles and apply this to a sodium dodecyl sulfate (SDS) micelle in the presence of testosterone propionate (TP), a system which we have studied in detail in previous work [17]. …”

“…These structures, which include micelles, monolayers, bilayers, lamellar, and other cubic phases, have wide applications in areas such as pharmaceuticals, mineral separation processes, environmental remediation, the food industry, personal care products, and petroleum recovery [18–25]. Since the first MD study of an SDS micelle published in 1990 [26], the structural and interfacial properties of these systems have been investigated in greater detail [27–34] and recently, interest in studying the encapsulation of solutes within SDS micelles has flourished with an abundance of work being produced in this area [17, 35–40]. In all of these studies, the micelle structure is quantified, at least partially, using radial density plots.…”

Characterization of 3D Voronoi tessellation nearest neighbor lipid shells provides atomistic lipid disruption profile of protein containing lipid membranes

“…Note that Voro++ has been used in several biophysical and biochemical molecular modeling studies, particularly in micelle systems. [38–41] This work focuses on 3D lipid shell isolation and analysis.…”