Oral Delivery of Proteins and Peptides: Concepts and Applications - Challenges in Delivery of Therapeutic Genomics and Proteomics - page 504

composition, which will influence solubility and micellization and also by ion-pair
formation between the enhancer and the peptides or proteins Table 10.6 .
Chelating agents, such as EDTA, form complexes with calcium and magnesium
present around tight junction and destruct the integrity of tight junctions, thus easing
permeation of peptides across the membrane [172] .
Sodium lauryl sulfate (SLS) is an ionic surfactant, which disorganizes the entire
membrane architecture, affecting both protein and lipid structures. Expansion of
intercellular spaces and insertion of SLS molecules into the lipid structure has also
been observed [173] . SLS proved to be efficient in promoting an extensive enhance-
ment of the absorption of human calcitonin (hCT) [174] and insulin [175] .

Table 10.6 Types of Absorption Enhancers with Examples

Type of Penetration Enhancer Examples

Water -

Surfactants Sodium lauryl sulfate

Polyoxyethylene ethers
Tween

Fatty acids and derivatives Oleic acid

Caprylic acid
Acylcarnitines
Capric acid
Linoleic acid
Mono- and diglycerides

Sulfoxides Dimethyl sulfoxide

Diethyl sulfoxide

Pyrrolidones N-methyl-2-pyrrolidone

2-pyrrolidone

Alcohols, fatty alcohols, and glycols Ethanol

Propylene Glycol

Metal ion chelators EDTA

Citric acid
Salicylates

Bile salts Sodium glycocholate

Sodium taurocholate
Sodium deoxycholate
Sodium taurodihydrofusidate
Sodium glycodihydrofusidate

Essential oils, terpenes, and terpenoids Cineole, eucalyptol

Menthol, carvone
Limonene, nerolidol

Others Urea

Azone
Phospholipids
Ceramide analogs
Solvents at high concentration