Glyceryl monooleate-water cubic phase gel as a stability enhancer of conventional and peptide drugs

Glyceryl monooleate (GMO or Monoolein) is a polar lipid which swells in water forming gels with different liquid crystalline phases, one of which is the cubic phase. The overall objective of this study was to evaluate the ability of the GMO-water cubic phase gel as a chemical and physical stability enhancer of drugs, study the mechanism of stabilization and evaluate it as a biodegradable sustained-release matrix for drugs. The objective was achieved with the help of the following four specific aims: (1) to determine the ability of the GMO cubic phase gel to protect cefazolin and cefuroxime, used as model drugs, from chemical instability reactions such as hydrolysis, (2) to determine the ability of the GMO cubic phase gel to protect insulin, a model peptide, from physical instability reactions such as aggregation and precipitation and determine the integrity of the native conformation of insulin in the gel, (3) to evaluate the sustained-release characteristics of the cubic phase gel and the stability of insulin in the gel in terms of its biological activity in a suitable animal model and (4) to characterize the physicochemical nature of the gel, determine the water mobility in the gel, evaluate the effect of viscosity on the physical stability of insulin and thus determine the mechanism of stabilization. Cefazolin was shown to be significantly more stable in the cubic phase gel than in solution at 22...