6-O-Ascorbic acid alkanoates (ASCn, where n is the no. of carbon atoms in the alkyl chain) behave as surfactants and form stable supramol. assemblies in water, depending on chem. structure, concn. and temp. In concd. water dispersions, ASCn form liq. cryst. structures (' coagels'), below the crit. micellar temp. (CMT), with a typical Krafft phenomenon. Such semisolid systems incorporate and stabilize drugs like anthralin, which is insol. and unstable in aq. media. The rheol. behavior of coagels obtained from aq. ASC8, ASC10, ASC11, ASC12, ASC14 and ASC16 was evaluated and related to the coagel structure. For ASC8, ASC12, ASC14 and ASC16 complex rheol. was obsd. and spur values were detd. This behavior is indicative of a high three-dimensional structure. The spur value represents a sharp point of structural breakdown at low shear rate. At this point the semisolids acquire pseudoplastic flow with a very low viscosity. Instead, ASC10 and ASC11 coagels showed pseudoplastic flow and-in the case of ASC11-thixotropy was obsd. The ASCn coagel rheol. behavior and their capability to load pharmacol. active compds. point to a potentially valuable capacity for such systems as drug carriers.
Coagels from alkanoyl-6-O-ascorbic acid derivatives as drug carriers: structure and rheology / Palma, S.; JIMENEZ KAIRUZ, A.; Fratoni, L.; LO NOSTRO, Pierandrea; Manzo, R.; Allemandi, D.. - In: IL FARMACO. - ISSN 0014-827X. - STAMPA. - 58:(2003), pp. 1271-1276. [10.1016/j.farmac.2003.07.010]
Coagels from alkanoyl-6-O-ascorbic acid derivatives as drug carriers: structure and rheology
LO NOSTRO, PIERANDREA;
2003
Abstract
6-O-Ascorbic acid alkanoates (ASCn, where n is the no. of carbon atoms in the alkyl chain) behave as surfactants and form stable supramol. assemblies in water, depending on chem. structure, concn. and temp. In concd. water dispersions, ASCn form liq. cryst. structures (' coagels'), below the crit. micellar temp. (CMT), with a typical Krafft phenomenon. Such semisolid systems incorporate and stabilize drugs like anthralin, which is insol. and unstable in aq. media. The rheol. behavior of coagels obtained from aq. ASC8, ASC10, ASC11, ASC12, ASC14 and ASC16 was evaluated and related to the coagel structure. For ASC8, ASC12, ASC14 and ASC16 complex rheol. was obsd. and spur values were detd. This behavior is indicative of a high three-dimensional structure. The spur value represents a sharp point of structural breakdown at low shear rate. At this point the semisolids acquire pseudoplastic flow with a very low viscosity. Instead, ASC10 and ASC11 coagels showed pseudoplastic flow and-in the case of ASC11-thixotropy was obsd. The ASCn coagel rheol. behavior and their capability to load pharmacol. active compds. point to a potentially valuable capacity for such systems as drug carriers.File | Dimensione | Formato | |
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