its recommendation in skin care products. Moreover,
there is no information on what concentration levels in
cosmetics that can safely be applied to human skin
without skin irritation, efficacy studies are also lacking.
Despite this lack of scientific data, a large number of
cosmetic products are available worldwide containing
Hibiscus calyx extract(18).
Since Roselle extracts contain several polar
and acidic compounds, their chemical properties have
hampered their use in skin products due to skin irritation
and low skin permeation(19,20). To improve these
disadvantages, liposome technology was applied to
formulate Roselle extracts such that they can be used
in cosmetic products. Liposomes are widely used as
carriers for a variety of chemical compounds and have
application for topical drug delivery(21). Liposomes not
only enhance skin permeation, but also moisturize the
skin. The composition and properties of liposomes play
an important role in their interaction and possible
penetration into the epidermis. Lipids, one class of
components in liposome formulations, hydrate the skin,
even in the absence of active ingredients. This is
enough to improve skin elasticity and barrier
function, which are among the main causes of skin
aging(22). In this study, various formulations of
liposomes containing Roselle calyx extracts were
prepared with different lipid compositions. The
objectives of this study were to investigate the physical
and chemical properties of the liposomes containing
Roselle calyx extracts and evaluate their stability,
antioxidant efficiency as well as dermal toxicity. The
skin permeability and skin irritability of liposome
formulations were compared with those of unformulated
extract solutions, using in vitro and in vivo techniques.