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| Formulation class | Class 1 | Class II | Class IIIA (fine emulsion) | Class IIIB (microemulsion) | Class IV |
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| Materials used in formulation | Oils without surfactants | Oils and O/W soluble surfactants | Lipid/oils, surfactants-cosurfactant ratio, cosolvents (both aqueous soluble and insoluble components) | Lipid/oils, surfactants-cosurfactant ratio, cosolvents (both aqueous soluble and insoluble components) | Water-soluble surfactants and cosolvents (no oils) |
| Characteristics | Nondispersible | Emulsification (SEDDS) with aqueous-insoluble substances | SEDDS/SNEDDS/SMEDDS molded using aqueous solvable substances | SEDDS/SMEDDS formed using aqueous soluble substances and the amount of oil is less | Disperses classically to produce a micelles solution |
| Digestion characteristic | Requires digestion | Ingested easily | Ingestion not essential | Ingestion not compulsory | Partial ingestion |
| Advantages | Simple GRAS capsule compatibility | Unlikely, on dispersion loose solvent capacity | On dispersion, clear or almost clear dispersion | On dispersion, clear or almost clear dispersion | (i) Formulation has good solvent capability |
| Disadvantages | Poor solvent capability | Relatively coarse O/W dispersion, ingestion probably but not decisive | On dispersion, possibility is loose of solvent capability or ingestion | On dispersion, possibility is loose of solvent capability or ingestion | On dispersion, possibility is loose of solvent capability |
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