Influence of Panthenol, Chlorphenesin and Lignocaine on the Physical Characteristics of Solidified Sodium Stearate-Based Sticks(SSSS)

Abstract

Cosmetic sticks provide many consumer advantages over the more readily used aerosol sprays, creams and lotions. In view of the many advantages offered by solidified sodium stearate-based sticks (SSSS), a program was set up to evaluate them as potential bases for the inclusion of topically active medicaments. The present publication elucidates the influence of Panthenol, Chlorphenesin and Lignocaine on the main physical characteristics of some SSSS bases, including their disintegration time, hardness, penetrability, softening point, yield by abrasion and rate of drying by evaporation. The investigated SSSS bases contained glycerol, propylene glycol (PG), polyethylene glycol 400 (PEG 400) or PEG 600 as humectant.

-The disintegration time of the studied bases was generally lowered by the three medicaments; however, glycerol or PG-formulated stick bases had their disintegration time slightly prolonged or unaffected by the addition of Chlorphenesin or Lignocaine;

-Panthenol generally lowered the hardness of SSSS bases but the least variation in this parameter was noticed with PG bases; hardness was generally increased with Chlorphenesin or Lignocaine, but to a lesser extent with the latter;

-generally speaking, Panthenol markedly increased the penetrability of the investigated stick bases; Chlorphenesin and Lignocaine did the same thing but to a lesser extent;

-the softening point of SSSS bases was generally lowered in presence of Panthenol or Lignocaine; Chlorphenesin did not generally affect the softening point of the stick bases; anyhow, the softening point of the investigated medicated sticks moved within the limits of safety, as far as the resistance to handling and storage in areas with occasional hot summers is concerned;

-Panthenol appreciably increased the yield by abrasion of all investigated bases; Lignocaine and Chlorphenesin did not appreciably influence this parameter except in the case of PEG 400 bases where the yield was markedly increased in presence of Lignocaine;

-the rate of drying of all the investigated stick bases was greatly lowered on addition of Panthenol; Chlorphenesin and Lignocaine affected this parameter to a much lesser extent.