*2.3. Solubility of Drug in Lipids and Surfactants*

Preliminary screenings were carried out to evaluate the solubility of clarithromycin in various solid lipids and surfactants according to a method described in the literature [25]. Briefly, a weighed quantity (10 mg) of lipid or surfactant was taken in glass vials and melted above its melting point on a water bath (EIE Instruments, Ahmedabad, India). To the melted solution of lipids or surfactant, 10 mg clarithromycin was added and subsequently vortexed. Then, additional increments of lipid or surfactant were added until the drug was completely solubilized or form a homogenous mixture. The lipid in which clarithromycin showed maximum solubility, and the surfactant where it exhibited minimum solubility were selected for the development of an SLN formulation.
