Enhancing the water dispersibility of paclitaxel by complexation with hydrophobic peptides

•Hydrophobic peptides with high molecular weights (Pep-A) enhanced the water dispersibility of paclitaxel (Ptx).•The complex between Pep-A and Ptx was found to exist as a hydrocolloidal material with a particle size around 147–215 nm.•The major peptides in Pep-A were identified using MALDI LIFT-TOF/TOF MS and found to be relatively hydrophobic peptides originating from the C-terminal of β-casein.

The complex between paclitaxel (Ptx) and a peptide mixture (Pep) was prepared to enhance of the water-dispersibility of Ptx. Pep was prepared by enzymatic hydrolysis of casein, followed by fractionation using ammonium sulfate precipitation and ultrafiltration. The Ptx and Pep complex (Ptx–Pep) was prepared by mixing an ethanol solution of Ptx and an aqueous solution of Pep followed by lyophilization. The water dispersibility test of Ptx–Pep prepared using different fractions of Pep demonstrated that a fraction (Pep-A), containing relatively hydrophobic peptides with high molecular weights, was effective in enhancing the water dispersibility of Ptx. The sequences of the major peptides in Pep-A were identified by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry with “LIFT” technique. The water dispersibility of the complex between Ptx and Pep-A (Ptx–Pep-A) was independent of pH, even though it is positively or negatively charged under strongly acidic and neutral conditions. As the particle size of Ptx–Pep-A in aqueous media was 147–215 nm, Ptx–Pep-A was present as a hydrocolloidal material in aqueous media.

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