Janus Films Fabricated Using Modified Electrospinning for Converting the Dosage Form of Watermelon Frost

Abstract The modernization of traditional Chinese medicine requires robust support and backing from advanced modern technology and functional materials. Herein, a novel type of Janus films with trans-scale structural characteristics was synthesized in a straightforward manner through the integration of modified coaxial electrospinning and modified triaxial electrospinning. The Janus films contain a bottom layer composed of electrospun monolithic hydroxypropyl methylcellulose (HPMC)-sucralose composite nanofibers from the modified coaxial process and a top layer comprising electrospun core (watermelon-HPMC)-sheath (HPMC-sucralose) nanofibers from the modified triaxial process. SEM and TEM characterizations clearly verified the linear morphologies and inner microstructures of both the monolithic and core–sheath nanofibers. XRD and FTIR indicated the mainly amorphous physical states of the components and their fine compatibility within the nanofibrous films. As soluble hydrogels, the Janus films were shown to rapidly gel upon contact with water. Using an artificial tongue and artificial saliva, the Janus films were demonstrated to enable sustained release of the loaded watermelon frost through adhesion to the base of the tongue in a diffusion–erosion combination mechanism with a duration significantly longer than that of the commercial spray. Furthermore, the topical delivery of Janus films was able to provide precise positioning of drug delivery, extend the drug delivery time period for a small administration frequency, and offer a pleasant drug delivery free of bitterness, verifying a successful formulation conversion from spray formulation to nanofilm formulation. The present protocols open up a new avenue not only for synthesizing brand-new hybrid configurations but also for formulation conversions from the traditional types to nanoproducts for sustainable social benefit.