ABSTRACT
CONTEXT: Polyamidoamine (PAMAM) dendrimers have attracted lots of interest as drug carriers. And little study about whether pluronic-attached PAMAM dendrimers could be potential drug delivery systems has been carried on. OBJECTIVE: Pluronic F127 (PF127) attached PAMAM dendrimers were designed as novel drug carriers. METHODS: Two conjugation ratios of PF127-attached PAMAM dendrimers were synthesized. (1)H nuclear magnetic resonance ((1)H-NMR), Fourier transform infrared spectrum (FTIR), element analysis and ninhydrin assay were used to characterize the conjugates. Size, zeta potential and critical micelle concentrations (CMC) were also detected. And DOX was incorporated into the hydrophobic interior of the conjugates. Studies on their drug loading and drug release were carried on. Furthermore, hemolysis and cytotoxicity assay were used to evaluate the toxicity of the conjugates. RESULTS AND DISCUSSION: PF127 was successfully conjugated to the fifth generation PAMAM dendrimer at two molar ratios of 19% and 57% (PF127 to surface amine per PAMAM dendrimer molecular). The conjugates showed an increased size and a reduced zeta potential. And higher CMC values were obtained than pure PF127. Compared with unconjugated PAMAM dendrimer, PF127 conjugation significantly reduced the hemolytic toxicity and cytotoxicity of PAMAM dendrimer in vitro. The encapsulation results showed that the ability to encapsulate DOX by the conjugate of 19% conjugation ratio was better than that of 57% conjugation ratio. And the maximum is â¼12.87 DOX molecules per conjugate molecule. Moreover, the complexes showed a sustained release behavior compared to pure DOX. CONCLUSION: Findings from the in vitro study show that the PF127-attached PAMAM dendrimers may be potential carriers for drug delivery.
Subject(s)
Dendrimers/chemistry , Doxorubicin/administration & dosage , Drug Delivery Systems , Poloxamer/chemistry , Animals , Antibiotics, Antineoplastic/administration & dosage , Antibiotics, Antineoplastic/chemistry , Antibiotics, Antineoplastic/toxicity , Chemistry, Pharmaceutical/methods , Delayed-Action Preparations , Doxorubicin/chemistry , Doxorubicin/toxicity , Drug Carriers/chemistry , Drug Liberation , Hemolysis/drug effects , Humans , MCF-7 Cells , Magnetic Resonance Spectroscopy , Particle Size , RabbitsABSTRACT
Pluronic modified polyamidoamine (PAMAM) conjugate (PF127-PAMAM) was prepared and the inhibiting effect of MDR against MCF-7/ADR was investigated with doxorubicin (DOX) as model drug. 1H NMR and FTIR spectra showed that the conjugate was synthesized successfully. Element analysis accurately measured that 27.63% amino of per PAMAM was modified by pluronic (PAMAM : PF127, 1 : 35.37 mole ratio). PF127-PAMAM showed an increased size and a reduced zeta potential compared to PAMAM. PF127-PAMAM had lower hemolytic toxicity and cytotoxicity due to the reduced zeta potential and the protection of PF127. Each PF127-PAMAM molecular could load 19.58 DOX molecules, and the complex exhibited sustained and pH-sensitive release behavior. PF127-PAMAM/DOX exhibited weaker cytotoxicity than free DOX in MCF-7 cells; while the complex showed much stronger reverse effect of drug resistance in MCF-7/ADR cells, and resistance reversion index (RRI) was as high as 33.15.
