SPAN 60 and TWEEN 60 surfactant-based niosomal vesicles: from preparation to molecular dynamics simulations

The role of vesicular systems in the field of drug delivery has led to increased research in the optimization of these novel delivery methods. Niosomes are bilayer structures that are capable of encapsulating lipophilic and hydrophilic compounds. In this study, niosomal systems formed from either Span 60 or Tween 60 non-ionic surfactants were investigated through experimental work and molecular dynamics simulations. Niosomes were prepared using thin-film hydration (TFH) and organic phase injection (OPI) methods and characterized in terms of particle size, polydispersity index, zeta potential, morphology, and encapsulation efficiency. A low-molecular-weight active pharmaceutical ingredient, tetracaine, and its water-soluble form, tetracaine HCl, were employed to understand the effect of pH on the encapsulation efficiency (EE) of the process. The molecular dynamics simulation of the niosomal system provided information on the distribution of Span 60 or Tween 60 surfactant molecules within the bilayer and the behavior of the tetracaine molecule.