Cationic Moieties in Polystyrene Gels Swollen with d-Limonene Improved Transdermal Delivery System

Abstract

d-limonene, a terpene and natural compound, has been found to be an excellent penetration enhancer for transdermal drug delivery (TDD). It hence has been incorporated within various transdermal formulations. Herein, we report the application of polystyrene gel swollen with d-limonene and its derivatives for TDD. Poly(styrene-co-divinylbenzene) (PS gel), poly(styrene-co-divinylbenzene-co-4-vinylpyridine) (PS-4VP) gel and poly(styrene-co-divinylbenzene-co-(vinylbenzyl) trimethylammonium chloride) (PS-VBAC gel) were employed as chemical gels to improve the stability of the TDD substrates. The drug permeation properties from the PS gels swollen in limonene were examined, regarding the effect of its network density as well as their rheological properties. The lowest density of the network showed the highest steady flux of the permeation at 43.7 ± 0.3 μg/cm2. FT-IR spectra were confirmed for PS-4VP and PS-VBAC, bearing cationic moieties and they could control the release of ibuprofen by the electrostatic interaction at the interface of organogel and skin. The steady state flux of skin permeation got low values from 55.2 ± 0.8 to 11.6 ± 2.0 μg/cm2, when the cationic moieties were increased. Moreover, the chemical network of PS gel swollen in limonene showed high mechanical stability illustrated by elastic modulus (G’) of about 98 kPa for 10% cross-linked PS gel. The developed PS gels swollen in limonene show highly promising results, suggesting their possible application in TDD.

Urea-Based Low-Molecular-Weight Pseudopeptidic Organogelators for the Encapsulation and Slow Release of (R)-Limonene

“…It has many applications and is often used as a versatile alternative to toxic solvents generally obtained from fossil fuel sources . A variety of products for food and cosmetic industries and for household purposes originally represented the largest market for limonene. , Numerous biological and pharmacological activities have been reported for this compound, − being among the first natural pesticide ingredients used for environmentally friendly pest control and providing an excellent penetration enhancement for transdermal drug delivery (TDD) when various transdermal formulations are applied as gels. , Therefore, the encapsulation of this flavor oil is of great interest for different applications. − …”

“…17,18 Numerous biological and pharmacological activities have been reported for this compound, 19−22 being among the first natural pesticide ingredients used for environmentally friendly pest control 23 and providing an excellent penetration enhancement for transdermal drug delivery (TDD) when various transdermal formulations are applied as gels. 24,25 Therefore, the encapsulation of this flavor oil is of great interest for different applications. 26−29 Gel formulations are of clear interest in this regard.…”