Ml. Rebelo et Me. Pina, RELEASE KINETICS OF TRETINOIN FROM DERMATOLOGICAL FORMULATIONS, Drug development and industrial pharmacy, 23(7), 1997, pp. 727-730
Tretinoin, or retinoic acid, can be used in the treatment of a variety
of skin diseases, depending on its concentration. Formulations contai
ning tretinoin 1% have been used in the therapy of malignant cutaneous
diseases, namely, Kaposi's syndrome. In lower concentrations, it has
been used in antiacne formulations and in the treatment of anti-aging
effects on photodamaged skin. The aim of the present study was to dete
rmine the variation profile of in vitro release of tretinoin, in order
to establish the drug's partition coefficient between its carrier and
the stratum corneum. The samples studied were formulations of tretino
in 0,05% in carbopol 940 (a synthetic polymer), sodium carboxymethylce
llulose (a semisynthetic polymer), and carob gum (a natural polymer) g
els. The release profiles obtained from these formulations were compar
ed to release profiles of tretinoin creams. The formulations studied e
xhibited both good chemical and physical stabilities when submitted to
rheological determinations, pH measurements, and drug dosage, through
out a 6-month period. The obtained results show that identical polymer
viscosities result in identical release profiles; however, the releas
e kinetics of tretinoin varies strongly in the way in which the drug i
s incorporated in the formulation (whether it is a solution or a suspe
nsion).