Two-Stage Desorption-Controlled Release of Fluorescent Dye and Vitamin from Solution-Blown and Electrospun Nanofiber Mats Containing Porogens

Abstract

In the present work, a systematic study of the release kinetics of two embedded model drugs (one completely water soluble and one partially water soluble) from hydrophilic and hydrophobic nanofiber mats was conducted. Fluorescent dye Rhodamine B was used as a model hydrophilic drug in controlled release experiments after it was encapsulated in solution-blown soy-protein-containing hydrophilic nanofibers as well as in electrospun hydrophobic poly(ethylene terephthalate) (PET)-containing nanofibers. Vitamin B2 (riboflavin), a partially water-soluble model drug, was also encapsulated in hydrophobic PET-containing nanofiber mats, and its release kinetics was studied. The nanofiber mats were submerged in water, and the amount of drug released was tracked by fluorescence intensity. It was found that the release process saturates well below 100% release of the embedded compound. This is attributed to the fact that desorption is the limiting process in the release from biopolymer-containing nanofibers similar to the previously reported release from petroleum-derived polymer nanofibers. Release from monolithic as well as core-shell nanofibers was studied in the present work. Moreover, to facilitate the release and ultimately to approach 100% release, we also incorporated porogens, for example, poly(ethylene glycol), PEG. It was also found that the release rate can be controlled by the porogen choice in nanofibers. The effect of nanocracks created by leaching porogens on drug release was studied experimentally and evaluated theoretically, and the physical parameters characterizing the release process were established. The objective of the present work is a detailed experimental and theoretical investigation of controlled drug release from nanofibers facilitated by the presence of porogens. The novelty of this work is in forming nanofibers containing biodegradable and biocompatible soy proteins to facilitate controlled drug release as well as in measuring detailed quantitative characteristics of the desorption processes responsible for release of the model substance (fluorescent dye) and the vitamin (riboflavin) in the presence of porogens.

Interactions between Surfactants in Solution and Electrospun Protein Fibers: Effects on Release Behavior and Fiber Properties

“…In vitro release of a compound encapsulated in insoluble fibers has previously been correlated to the porosity of the fibers 19,20,42 . From those studies it was found that the release was facilitated by a twostep mechanism; desorption of the compound from the nanoporous surface of the fibers, as the rate 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 13 limiting step, followed by diffusion from the fiber matrix into the buffer.…”

“…As a result, only compounds situated at the surface of the fibers were released, as long as the fibers were intact. Modulating the porosity, and thus the surface area, for instance by addition of porogens, such as poly(ethylene glycol), or varying the polymer nature, concentration, or molecular weight, modified the maximum released amount, and also the compound release profile 19,42,43 . In Figure 1 (Figure 2).…”

“…During optimization of the fiber properties, special attention should be paid for instance to the hydrophilicity of the fibers, fiber stability, and drug release profiles (in case of encapsulated compounds) 12 . Drug release and stability properties are often studied in vitro in water 19,20 , phosphate buffer 21 , phosphate-buffered saline (PBS) 8,[22][23][24][25][26][27][28][29][30][31][32][33] , or other similar buffers not containing specific physiologically occurring compounds 34,35 . Depending on the application of the electrospun fibers, they will be exposed to different physiological environments, which contain compounds such as bile salts, proteins, and salts.…”

Synthesis, antimicrobial, and release behaviors of tetracycline hydrochloride loaded poly (VInyl alcohol)/chitosan/ZrO2 nanofibers

“…27 The mechanism governing drug release kinetics from degradable matrices is complex owing to alterations in polymer phase properties during degradation, causing changes in drug diffusivity and permeability with time. 40 Two representative mechanisms were reported on the release characteristics from nanofibers: one is desorption limited release, [41][42][43] the other is Fickian diffusion (M t /M 1 < 0.6). 38,44,45 In the present work, Fickian diffusion model for M t /M 1 < 0.6 was adopted as follows:…”

Theranostic Fibers for Simultaneous Imaging and Drug Delivery

“…8,11,12 Electrospun fibers have been found to be good candidates for a wide variety of biomedical applications such as cardiovascular stents, 13 wound healing, 14 and the controlled release of active ingredients. [15][16][17] Electrospun drug-loaded fibers have been broadly explored for targeted release, for improving the dissolution rate of poorly water-soluble drugs, and for encapsulating multiple functional components. [18][19][20] The simplest process involves a single needle, and produces monolithic fibers.…”