|dc.description.abstract||Pigmentation disorders occur in multiple conditions (Hakozaki et al., 2006:105). Although many
modalities of treatments are available, none are completely satisfactory (Briganti et al.,
2003:101). Two cytokines normally present in the skin, transforming growth factor–beta1
(TGF–81) and tumour necrosis factor–alpha (TNF–9), have been shown to inhibit melanin
synthesis (Martinez–Esparza, 2001:972).
The stratum corneum has been commonly accepted as the main barrier to percutaneous
absorption. Many techniques have been applied to overcome this barrier properties and to
enhance penetration with varying success (Pellet et al., 1997:92).
The objective of this study was to investigate the topical delivery of the above mentioned
peptide drugs with aid of the Pheroid drug delivery system. Pheroid technology is a
delivery system that promotes the absorption and increases the efficacy of dermatological,
biological and oral medicines in various pharmacological groups (Grobler et al., 2008:4).
Pheroid entraps drugs with high efficiency and delivers them with remarkable speed to target
sites (Grobler, 2004:4). In order to avoid degradation of these peptides, bestatin hydrochloride
(an aminopeptidase inhibitor), was used (Lkhagvaa et al., 2008:386).
Topical drug delivery was achieved by means of vertical Franz cell diffusion studies performed
over a 6 and 12 h period. ELISA (enzyme linked immunosorbent assay) detection was used to
detect cytokine concentrations. Entrapped cytokine solutions were monitored by confocal laser
scanning microscopy (CLSM). Upon removal of donor and receptor compartments, skin discs
were subjected to tape stripping in order to establish the amount of active present within the
stratum corneum and epidermis as well as the remaining dermis (Pellet et al., 1997:92).
When comparing the two studies with each other, it is evident that the diffused concentration
values obtained with PBS (phosphate buffer solution, pH 7.4) was lower than that obtained with
the Pheroid drug delivery system. Both cytokine concentrations were successfully delivered
topically as a minimum of concentrations for both actives were detected. This positive result
was confirmed as well by the amount of active detected in stratum corneum–epidermis and