Effects of Spray-Drying and Choice of Solid Carriers on Concentrations of Labrasol(®) and Transcutol(®) in Solid Self-Microemulsifying Drug Delivery Systems (SMEDDS)

Solid self-microemulsifying drug delivery systems (SMEDDS) have been used increasingly for improving the bioavailability of hydrophobic drugs. Labrasol(®) and Transcutol(®) are used widely as surfactant and solubilizer in the formulation of solid SMEDDS. We investigated the effects of spray-drying and the use of different solid carriers on concentrations of Labrasol(®) and Transcutol(®) in solid SMEDDS with scutellarin as the formulated drug. Liquid and gas chromatography tandem mass spectrometry (LC-MS and GC-MS) methods were developed for measuring low concentrations of Labrasol(®) and Transcutol(®). In the preparation of solid SMEDDS, lactose, hydroxypropylmethyl cellulose (HPMC) and microcrystalline cellulose (MCC) were used as solid carriers. Judging from the retention ratios of Labrasol(®) and Transcutol(®), the droplet size of solid SMEDDS increased after spray-drying of liquid SMEDDS, and concentrations of these excipients decreased after the solidifying procedure. In such reduction, Lactose and HPMC were found to preserve Labrasol(®) and Transcutol(®) better than MCC during spray-drying, and the resultant droplet sizes were smaller than that of MCC. Labrasol(®) and Transcutol(®) showed good thermal stability at 60 °C degree for 10 days. It can be concluded that spray-drying could increase the droplet size of solid SMEDDS and decreased the concentration of Labrasol(®) and Transcutol(®) therein, while water-soluble solid carriers could preserve Labrasol(®) and Transcutol(®) better than insoluble carriers in the solid SMEDDS.