Delivery with Chitosan-coated Liposomes and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: February 26, 2009, from the March 2009 issue of Cosmetics & Toiletries.

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When a trivalent alcohol like glycerin is added, the quaternary systems show plastic responses even after violent shear. The phase transition behavior implies that the glycerin molecules are hardly incorporated into the lamella layers of lipophilic groups but remain in the water layers to increase their strength. This was confirmed through differential scanning calorimetry and small angle x-ray scattering.

Interesting Raw Materials
Delivery of tamarind with chitosan: Phetdee et al. have published on the development of chitosan-coated liposomes for sustained delivery of tamarind fruit pulp extract to the skin.¹⁷ In this study, chitosan-coated liposomes were developed. To entrap lyophilized tamarind extract containing alpha hydroxy acids (AHAs) with tartaric acid, reverse phase evaporation was used to obtain well-formed liposomes loaded with the extract. The highest entrapment efficiency of 68.3 ± 3.0% into the liposomes was obtained with liposomes consisting of phosphatidylcholine and cholesterol in a molar ratio of 2:1 after the extrusion process. The average particle size of the prepared liposomes was 158 ± 26 nm showing a negative zeta potential of -6 mV. For the preparation of the chitosan-coated liposomes, two selected independent parameters were varied—chitosan concentrations of 0.1, 0.5 and 1.0% w/v and volumes of the chitosan solutions of 1.2 mL and 3 mL—to study the effects of such parameters on the entrapment efficiency of the extract-loaded liposomes.

Variation in the volumes of the chitosan solution did not affect the entrapment efficiency of the liposomes. However, the entrapment efficiency of the AHAs in the chitosan-coated liposomes significantly increased with increasing chitosan concentration. The size of the chitosan-coated liposomes was in the range of 200–300 nm with a positive zeta potential in the range of 6–29 mV. An in vitro release study using a dialysis technique was performed to evaluate the release profile of the tartaric acid from the chitosan-coated liposomes. The results showed the effect of the chitosan-coated liposomes on the lower release rate and on the amount of tartaric acid in comparison with that of the uncoated liposomes. The study in an in vitro skin cell model indicated the developed system could enhance the potential of tamarind AHAs on the stimulation of human keratinocyte proliferation twice as much as the solution of the tamarind extract.

Oil gelling agent for cosmetics: Yoshida describes the characteristics of a new oil gelling agent for cosmetics and its application.¹⁸ An oligomeric polyamide gelation agent, distearylamine-terminated dilinoleic acid-ethylenediamine copolymer^f was examined using diisostearyl malate as the solvent. The characteristics of the gelling agent were: safety, confirmed by a closed patch test for 48 hr and a test stimulating the mucous membrane for 24 hr; miscibility, with oil agents in a use range of 40–50%; transparency, evaluated at a range of 400–800 nm; and hardness^g. Oil agents with an ester group and/or a hydroxyl group were superior in the transparency and hardness, as compared with oil agents without these groups. Proposed formulas for a transparent lipstick and a hair styling treatment product are shown in Formulas 9 and 10.

The quality of the formulated products was assessed for styling power and found to be as effective as commercial products without the need for natural wax. High humidity was found to affect product performance much less in products incorporating the oil gelling agents than in commercial products without them.