Status of surfactants as penetration enhancers in transdermal drug delivery

Abstract

Surfactants are found in many existing therapeutic, cosmetic, and agro-chemical preparations. In recent years, surfactants have been employed to enhance the permeation rates of several drugs via transdermal route. The application of transdermal route to a wider range of drugs is limited due to significant barrier to penetration across the skin which is associated with the outermost stratum corneum layer. Surfactants have effects on the permeability characteristics of several biological membranes including skin. They have the potential to solubilize lipids within the stratum corneum. The penetration of the surfactant molecule into the lipid lamellae of the stratum corneum is strongly dependent on the partitioning behavior and solubility of surfactant. Surfactants ranging from hydrophobic agents such as oleic acid to hydrophilic sodium lauryl sulfate have been tested as permeation enhancer to improve drug delivery. This article reviews the status of surfactants as permeation enhancer in transdermal drug delivery of various drugs.

Formulation and Artificial Sebum Effects on the Percutaneous Absorption of Zinc Pyrithione through Excised Human Skin

“…This process was postulated previously with regard to the atypical dose-effect curve observed for the lateral diffusivities of Zn[ 14 C]PT dosed from water and the 1% body wash [44]. It is possible that the anionic surfactants present in the 1% body wash (e.g., sodium lauryl sulfate) could occupy these binding sites and minimize this interaction [48]. If the ZnPT+ complex ion is the species capable of binding with intracellular SC proteins, the formation of a ZnPT-sodium lauryl sulfate ligand exchange product could negate this effect by substantially increasing the lipophilicity of the compound [49] thereby lowering partitioning into the corneocytes.…”

Both children and adult patients with difficult‐to‐treat atopic dermatitis have high prevalences of concomitant allergic contact dermatitis and are frequently polysensitized

“…As permeability to hydrophilic solutes may increase through imperfection in lipid layers39 and in AD stratum corneum lipid organization is affected,40 this may increase permeability of hydrophilic zwitterionic surfactants such as CAPB and DMAPA. Additionally, other surfactants, such as present in wool alcohols, may also increase penetration of other compounds 41. Also, the influence of emollients on the skin microbiome42, 43 could change the tolerance against several allergens44 making frequent emollient applicators more prone to ACD.…”

Monitoring the Distribution of Surfactants in the Stratum Corneum by Combined ATR-FTIR and Tape-Stripping Experiments

“…A primarily widely accepted view is that, at surfactant concentrations exceeding the CMC, only surfactant monomers can penetrate into the skin, either because surfactant micelles are not surface active or because they are too large to penetrate into the SC [3,15]. The theory suggests that the skin friendliness of nonionic surfactants is linked to a decreased CMC compared to their anionic counterparts because fewer monomers are available to penetrate the skin [7,19]. However, this theory is challenged by a generally dose-dependent increase of skin irritation beyond the CMC [3,20].…”

“…Besides the possibility of tracking exogenous components from the spatial distribution of their characteristic vibrational bands, this approach allows a simultaneous analysis of molecular effects on SC lipid and protein conformation in different layers of the SC [4,5,6]. Information regarding these parameters is of great interest due to the reported molecular effects of surfactants such as the binding and denaturation of skin surface proteins and the solubilization or disorganization of intercellular lipids [1,2,7]. …”

“…Anionic surfactants are known to damage the skin barrier, while nonionic surfactants have been long recognized as those with the least potential of irritancy [7]. Moreover, increased attention to the environment has produced a growing interest in the field of natural surfactants such as APG and sugar esters.…”