Stepwise Glucoheptoamidation of Poly(Amidoamine) Dendrimer G3 to Tune Physicochemical Properties of the Potential Drug Carrier: In Vitro Tests for Cytisine Conjugates

• Main Authors: Anna Czerniecka-Kubicka (Author), Piotr Tutka (Author), Marek Pyda (Author), Małgorzata Walczak (Author), Łukasz Uram (Author), Maria Misiorek (Author), Ewelina Chmiel (Author), Stanisław Wołowiec (Author)
• Format: Book
• Published: MDPI AG, 2020-05-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/pharmaceutics12050473; 1999-4923
• Keywords: PAMAM G3 dendrimer; glucoheptoamidation; dynamic light scattering; differential scanning calorimetry; cytisine conjugate; cytotoxicity; Pharmacy and materia medica; RS1-441
• Source: Pharmaceutics, Vol 12, Iss 5, p 473 (2020)

Third-generation poly(amidoamine) dendrimer (PAMAM) was modified by stepwise primary amine group amidation with <span style="font-variant: small-caps;">d</span>-glucoheptono-1,4-lactone. The physicochemical properties of the conjugates-size, ζ potential in lysosomal pH 5 and in neutral aqueous solutions, as well as intramolecular dynamics by differential scanning calorimetry-were determined. Internalization and toxicity of the conjugates against normal human fibroblasts BJ were monitored in vitro in order to select an appropriate carrier for a drug delivery system. It was found that initial glucoheptoamidation (up to 1/3 of amine groups of neat dendrimers available) resulted in increase of conjugate size and ζ potential. Native or low substituted dendrimer conjugates accumulated efficiently in fibroblast cells at nontoxic 1 µM concentration. Further substitution of dendrimer caused consistent decrease of size and ζ potential, cell accumulation, and toxicity. All dendrimers are amorphous at 36.6 °C as determined by differential scanning calorimetry (DSC). The optimized dendrimer, half-filled with glucoheptoamide substituents, was applied as carrier bearing two covalently attached cytisine molecules: a rigid and hydrophobic alkaloid. The conjugate with 2 cytisine and 16 glucoheptoamide substituents showed fast accumulation and no toxicity up to 200 µM concentration. The half-glucoheptoamidated PAMAM dendrimer was selected as a promising anticancer drug carrier for further applications.