Poly-vinylalcohol (PVA), conjugated with oleoyl (PVA-OL) or linoleoyl (PVA-LINOL) chain forms polymer micelles able to solubilize retinoic acid (ATRA). The functional properties of the solubilized systems were evaluated by dynamic light scattering (DLS) and correlated to the physico-chemical characteristics of ATRA and polymer solution. The mean diameter of the aggregates and the counts per second are indicative of the total micelle volume (TMV), used to predict the complexing ability of the amphiphilic micelles towards the hydrophobic drug. TMV was found higher for PVA-LINOL than for PVA-OL and increased at increasing polymer concentration. Increase of temperature increased TMV of both polymers. The effect of filtration on the nature of the final systems was also discussed. Changes, after filtration, was attributed to fragmentation occurring, when aggregates of size, larger than the filter pores, are forced to pass through these pores: aging of the systems in some cases again drives up the formation of larger aggregates. Thermodynamic entities for retinoic acid solubilization into polymer micelles were calculated, assuming that the process is a partition between the bulk solution and the hydrophobic core of micelles.
RETINOIC ACID (ATRA) SOLUBILIZATION IN PVA POLYMER MICELLES
G. ZUCCARI;
2005-01-01
Abstract
Poly-vinylalcohol (PVA), conjugated with oleoyl (PVA-OL) or linoleoyl (PVA-LINOL) chain forms polymer micelles able to solubilize retinoic acid (ATRA). The functional properties of the solubilized systems were evaluated by dynamic light scattering (DLS) and correlated to the physico-chemical characteristics of ATRA and polymer solution. The mean diameter of the aggregates and the counts per second are indicative of the total micelle volume (TMV), used to predict the complexing ability of the amphiphilic micelles towards the hydrophobic drug. TMV was found higher for PVA-LINOL than for PVA-OL and increased at increasing polymer concentration. Increase of temperature increased TMV of both polymers. The effect of filtration on the nature of the final systems was also discussed. Changes, after filtration, was attributed to fragmentation occurring, when aggregates of size, larger than the filter pores, are forced to pass through these pores: aging of the systems in some cases again drives up the formation of larger aggregates. Thermodynamic entities for retinoic acid solubilization into polymer micelles were calculated, assuming that the process is a partition between the bulk solution and the hydrophobic core of micelles.
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