Many new active pharmaceutical ingredients cannot be easily administered due to their hydrophobicity. Recently, an innovative drug delivery system called gelosomes has been developed to combat this problem. This system is made of gelled nanoparticles of castor oil containing 12-hydroxystearic acid (gelator) and polyvinyl alcohol (stabilizing agent). These nanoparticles are formed by the emulsification of melted organogel with an aqueous polyvinyl alcohol solution and subsequent cooling below the gelation temperature. In this study, a hydrophobic drug molecule was dissolved in these particles, and the <i>in vitro</i> drug delivery rates were studied. The hydrophobic molecule, indomethacin (logP = 4.2), has a carboxylic acid functionality and a water solubility of 0.9 mg/mL at pH 7.4. It was shown that this drug molecule could effectively be solubilized at 3% by weight within an organogel made of castor oil and 15% by weight 12-hydroxystearic acid, without affecting gelation. Furthermore, the nanoparticle emulsion displayed stability for more than four weeks. Dialysis of the indomethacin gelosomes exhibited an almost identical release profile to the drug alone. On the contrary, a model molecule with a basic functionality and even greater hydrophobicity, nile red (logP = 5.0) (water solubility &lt; 1 µg/mL), showed no release from the gelosomes, even after 30 hours of dialysis. Ultimately, the difference in solubility due to the molecules’ chemical structures affected their dialysis profiles, and should be considered as quite important when selecting drugs for gelosome delivery.

Evaluation of organogel nanoparticles as a means of drug delivery

249th National Meeting (2015)

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