Potansiyel doksorubisin taşıyıcı sistemi olarak PEG-endozom parçalayıcı peptit konjugatının değerlendirilmesi

Abstract

Solid phase peptide and PEG conjugation with high efficiency  Preparation of pH sensitive drug delivery systems  Formation of selfassembled nanostructures Figure A. DOX release curves of the mPEG-oxime-DOX and mPEG-peptide-oxime-DOX obtained at pH 7.4 and pH 5.0 Purpose: In this study, it was aimed to assess the physicochemical and doxorubicin (DOX) release properties of a PEGylated TAT-derived peptide carrier system as a preliminary investigation. Theory and Methods: TAT-derived peptide with a sequence of G2RQR3QR3G2S was synthesized using Fmoc strategy in solid state. mPEG-COOH (Mn = 1900 Da) was conjugated to N-terminus of the peptide on the resin. DOX was conjugated to the mPEG-peptide conjugate via acid labile oxime bond. DOX-release, self-assembly, and stability properties of the resultant drug delivery system (DDS) denoted as mPEG-peptide-oxime-DOX were evaluated at pH 5.0 and pH 7.4 and compared with those of the control DDS lack of peptide sequence, mPEG-oxime-DOX. Drug release profiles of the DDSs were obtained using dialysis method. Size distribution and stability of the DDSs were determined via dynamic light scattering. Results: MALDI-TOF-MS analysis results indicated that both the peptide and the conjugate were synthesized successfully. For mPEG-oxime-DOX, pH dependent DOX release was obtained confirming pH responsive property of oxime bond. mPEG-peptide-oxime-DOX seemed to exhibit quite low DOX release (~10-15 %) for both pH, which suggested possible interactions between DOX and the peptide preventing DOX to pass through dialysis membrane. Initial median size (D50) value of the mPEG-oxime-DOX was measured as ~24 nm independent of pH. For mPEG-peptide-oxime-DOX, D50 values were obtained as ~3 nm and ~6 nm at pH 5.0 and pH 7.4, respectively and indicated its pH controlled aggregation behavior. Sizes of both DDSs, tended to increase upon incubation at physiological conditions for 1 day. Conclusion: Comparison of the stability behavior of the similar mPEG-DOX and mPEG-peptide-DOX conjugates developed in our group indicated that longer PEG chains should be used to enhance the stability of these kinds of DDSs.