Incorporating chitosan (CS) and TPP into silk fibroin (SF) in fabricating spray-dried microparticles prolongs the release of a hydrophilic drug

In this investigation, drug delivery characteristics of incorporating CS and anhydrous tri-polyphosphate (TPP) into SF in fabricating microparticles by a spray-dried technique were examined. Among various formulas, SF/CS microparticles at 10/4.0 (weight ratio) had the highest positive zeta potential (23.0 ± 3.60 mV (n = 3)) while SF ones showed a negative zeta potential (−14.7 ± 1.5 mV (n = 3)). The equilibrium swelling ratio of SF/CS (10/4.0) microparticles was 9.80 ± 0.77 times of themselves in a dry state, which was higher than those of SF and SF/CS (10/4.0)-TPP (0.05%) ones (e.g., 5.50 ± 0.58 and 7.43 ± 1.43 times, respectively). The release period for a model hydrophilic drug, tetracycline·Hcl (Tc), from SF was two days which prolonged to four and ten days for SF/CS (10/4.0) and SF/CS (10/4.0)-TPP (0.05%) microparticles, respectively. Through this investigation, new microparticulate SF/CS (10/4.0)-TPP (0.05%) is highly promising for drug delivery applications.