Conjugation of amiodarone to a novel cardiomyocyte cell penetrating peptide for potential targeted delivery to the heart

Figures

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  FIGURE 1. Structure of amiodarone hydrochloride.

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  SCHEME 1. Solid phase synthesis of thiolated cardiac targeting peptide (CTP-thiol). (A) (i) Solid. Phase peptide synthesis (Polystyrene solid support of Rink amide MBHA resin is represented by the golden ball, (ii) 20% Piperidine, DMF; (B) 3-(Tritylthio)propionic acid, TBTU, HOBt, DIPEA, DMF; (C) TFA:TIPS:H2O:EDT (94:1:2.5:2.5); (D) Preparative HPLC purification followed by MALDI characterization.

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  SCHEME 2. Activation of cardiac targeting peptide. (A) 2,2′-Dithiobis (5-nitropyridine) (DTNP) in 80% TFA (aq.) for 15 min; (B) Preparative HPLC purification followed by MALDI analysis.

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  SCHEME 3. Synthesis of the Amiodarone-thiol intermediate. (A) Amiodarone HCl, Sodium iodide (NaI), 1,2,2,6,6-Pentamethylpiperidine, acetonitrile overnight at 37°C; (B) Preparative HPLC purification followed by MALDI analysis.

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  SCHEME 4. Synthesis of Amiodarone-CTP conjugate. (A) Npys-S-CTP, 20% 1 M ammonium acetate in DMF, 2 h at room temperature; (B) Preparative HPLC purification followed by MALDI analysis.

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  FIGURE 2. CTP-SS-Amiodarone in perfusion buffer at 37°C at time 0 h.

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  FIGURE 3. CTP-SS-Amiodarone in perfusion buffer at 37°C for 7 days.

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  FIGURE 4. Conduction velocities in guinea pig hearts treated with vehicle only (control; n = 10), amiodarone (n = 4), CTP-amiodarone (n = 4), or CTP alone (n = 4). All two-tailed p-values are for pair-wise comparisons to control animals.

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  SCHEME 5. Schematic representation of the final Amiodarone-SS-CTP conjugate.