Surfactants oral dosage forms

Self-emulsifying drug delivery systems are oral dosage forms consisting of drug, oils, surfactants, and sometimes cosolvents (Constantinides, 1995 Pouton, 1997 Pouton, 2000). On addition to water... 

In another example of a polyethylene glycol/surfactant, solid dispersion is presented by Dannenfelser et al. (2004) with a poor water-insoluble drug exhibiting only a g1i7iL aqueous solubility. At 40 mg/mL, the PEG 3350/polysorbate 80 solid dispersion exhibited similar exposure as that of a cosolvent-surfactant solution and a ten-time increase over a dry blend formulation, thus enabling a solid oral dosage form for clinical trials. 

Oral dosage forms may contain various other additives to increase the solubility and hence oral bioavailability of the drag, such as co-solvents, buffers and surfactants. Newer technologies may also incorporate additives such as enzyme inhibitors, to prevent premature degradation of enzymatically labile drags. For example, the inclusion of trypsin inhibitors, such as soyabean trypsin inhibitor and aprotinin, have been shown to be effective in enhancing the effect of insulin in rats. Penetration enhancers may also be included to facilitate the uptake of poorly absorbed moieies. These are discussed below in Section 6.7.4. 

One major concern regarding the safety profile of ME systems intended for oral administration is the comparatively high amphiphile content. Both o/w and w/o ME systems are amphiphile-rich systems compared to conventional emulsions and would contain in the most conservative case up to 15-20% w/w surfactant-cosurfactant. This is further complicated by the limited models available to evaluate chronic toxicology in comparison to conventional oral dosage forms such as tablets [91]. 

In the context of oral dosage forms containing surfactants, these agents may play a role in reducing the rate... 

There are several competing mechanisms for surfactant-induced effects when solid oral dosage forms are administered. When solutions are administered. 

Table 3 Typical Surfactants Used in Oral Liquid Dosage Forms...

Hypersensitivity reactions can occur due to the presence of contaminants or excipients in pharmaceutical dosage forms (e.g., outbreaks of eosinophilia-myalgia syndrome associated with oral tryptophan contaminants in various drugs). Another example is the anaphylactoid reactions to the surfactant Cremaophor EL, which is used in paclitaxel (Taxol). 

Emulsions have been widely used as vehicles for oral, topical, and parenteral delivery of medications. Although the product attributes of an emulsion dosage form are dependent on the route of administration, a common concern is the physical stability of the system, in particular the coalescence of its dispersed phase and the consequent alteration in its particle-size distribution and phase separation. The stabilization mechanism(s) for an emulsion is mainly dependent on the chemical composition of the surfactant used. Electrostatic stabilization as described by DLVO theory plays an important role in emulsions (0/W) containing ionic surfactants. For 0/W emulsions with low electrolyte content in the aqueous phase, a zeta potential of 30 mV is found to be sufficient to establish an energy maximum (energy barrier) to ensure emulsion stability. For emulsions containing... 

Sprays are liquid dosage forms aerosolized into the oral cavity for transmucosal drug delivery. Due to the formation of small droplets upon aerosolization of the liquid, sprays can achieve shorter lag times and a faster onset of action than other liquid formulations. Oral-lyn is a micellar system utilizing a blend of surfactants as permeation enhancers and formulation stabilizers. The product is one application of the RapidMist system patented by Generex Biotechnology Corporation that has also been used to develop products for vaccine delivery, pain management, and weight loss. 

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