Physiological neutral pH drives a gradual lamellar-to-reverse cubic-to-reverse hexagonal phase transition in phytantriol-based nanoparticles.

Dispersed systems of bicontinuous cubic phases, called cubosomes, show a drug release rate faster than those obtained using other liquid-crystalline phases. To minimize side effects associated with the accelerated release of incorporated drugs, compounds may be added in the dispersions to produce systems of slow initial release and then fast release only in the desired action region. This paper addresses the addition of 10.0% (w/w) of decyl betainate chloride (DBC), a cleavable surfactant, into phytantriol/Pluronic-based dispersions to generate lamellar-to-cubic-to-hexagonal phase transitions. Small-angle X-ray scattering (SAXS) was used to analyze the mesophases obtained with the addition of DBC and pH variation. Transmission electron microscopy (TEM) images confirmed the presence of niosomes after the addition of DBC. The niosomes formed in these systems are pH-responsive with lamellar-to-hexosomes transitions at pH ≥ 7.4. The system investigated herein is gastro-resistant presenting potential therapeutic role for controlled release of drugs in neutral or alkaline environments of the organism.