MilliporeSigma
  • In situ gelling hexagonal phases for sustained release of an anti-addiction drug.

In situ gelling hexagonal phases for sustained release of an anti-addiction drug.

Colloids and surfaces. B, Biointerfaces (2011-06-28)
Jessica Phelps, M Vitória L B Bentley, Luciana B Lopes
ABSTRACT

In this study, fluid precursor formulations for subcutaneous injection and in situ formation of hexagonal phase gels upon water absorption were developed as a strategy to sustain the release of naltrexone, a drug used for treatment of drug addiction. Precursor formulations were obtained by combining BRIJ 97 with propylene glycol (PG, 5-70%, w/w). To study the phase behavior of these formulations, water was added at 10-90% (w/w), and the resulting systems were characterized by polarized light microscopy. Two precursor formulations containing BRIJ:PG at 95:5 (w/w, referred to as BRIJ-95) and at 80:20 (w/w, referred to as BRIJ-80) were chosen. Naltrexone was dissolved at 1% or suspended at 5% (w/w). Precursor formulations were transformed into hexagonal phases when water content exceeded 20%. Water uptake followed second-order kinetics, and after 2-4h all precursor formulations were transformed into hexagonal phases. Drug release was prolonged by the precursor formulations (compared to a drug solution in PBS), and followed pseudo-first order kinetics regardless of naltrexone concentration. The release from BRIJ-80 was significantly higher than that from BRIJ-95 after 48 h. The relative safety of the precursor formulations was assessed in cultured fibroblasts. Even though BRIJ-95 was more cytotoxic than BRIJ-80, both precursor formulations were significantly less cytotoxic than sodium lauryl sulfate (considered moderate-to-severe irritant) at the same concentration (up to 50 μg/mL). These results suggest the potential of BRIJ-based precursor formulations for sustained naltrexone release.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
BRIJ® O20, average Mn ~1,150
Sigma-Aldrich
ECO BRIJ® O20, average Mn ~1,150
Sigma-Aldrich
ECO BRIJ® O10
Sigma-Aldrich
Brij® O10
Sigma-Aldrich
Brij® 93, average Mn ~357