Design, synthesis and characterization of a PEGylated stanozolol for potential therapeutic applications

• Published in: International journal of pharmaceutics 2020-01, Vol.573, p.118826-118826, Article 118826
• Main Authors: Vergallo, Cristian, Torrieri, Giulia, Provenzani, Riccardo, Miettinen, Sini, Moslova, Karina, Varjosalo, Markku, Cristiano, Maria Chiara, Fresta, Massimo, Celia, Christian, Santos, Hélder A., Cilurzo, Felisa, Di Marzio, Luisa
• Format: Article
• Language: English
• Subjects: Biopolymers; Conjugated drug delivery systems; PEGylation; Polyethylene glycol (PEG) derivatives; Stanozolol
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2019.118826

Stanozolol (STZ) conjugated with α-methoxy-ω-amino polyethylene glycol with nominal molecular weight (MW) of 10,000 Da, (MeO-PEG-NH)10kDa-STZ, was synthesized to maintain the native therapeutic activity of drugs and have a water soluble and stable compound, showing the same therapeutic property of STZ. The resulting PEGylated STZ presents a promising and reliable drug to treat testosterone deficiencies. [Display omitted] Stanozolol (STZ) is a drug used to treat serious disorders like aplastic anemia and hereditary angioedema. It is also indicated as an adjunct therapy for the treatment of vascular disorders and growth failures. Encouraging results obtained using animal models demonstrated that STZ increases bone formation and mineralization, thus improving both density and biomechanical properties. Like natural androgens, such as TST and 5α-dihydrotestosterone (5α-DHT), STZ binds androgen receptor (AR) to activate AR-mediated signaling. Despite its therapeutic effects, this synthetic anabolic–androgenic steroid (AAS), or 5α-DHT derivative, due to its high lipophilicity, is poor soluble in water. Thus, to increase the water solubility and stability of STZ, as well as its bioavailability and efficacy, an innovative PEGylated STZ (STZ conjugated with (MeO-PEG-NH2)10kDa, (MeO-PEG-NH)10kDa-STZ) was synthesized. As confirmed by chromatography (RP-HPLC) and spectrometry (ATR-FTIR, 1H NMR, elemental CHNS(O) analysis, MALDI-TOF/TOF) analyses, a very pure, stable and soluble compound was obtained. Acetylcholinesterase (AChE) competitive ELISA demonstrated that the resulting PEGylated STZ competes against biological TST, especially at lower concentrations. Cytotoxicity of increasing concentrations (1, 10, 25 or 50 µM) of STZ and/or (MeO-PEG-NH)10kDa-STZ was also evaluated for up 80 h by performing the MTT assay on human osteosarcoma Saos-2 cells, which express AR and are responsive to STZ. PEGylation mitigated cytotoxicity of STZ, by increasing the cell viability values, especially at higher drug concentrations. Furthermore, these results suggest that (MeO-PEG-NH)10kDa-STZ is a promising and reliable drug to be used in clinical conditions in which TST is required.