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It refers to the process in which the solubility of the drug in the solvent increases and forms a single-phase associative colloid solution after the surfactant forms micelles, and the added surfactant that plays a solubilizing effect is called a solubilizer.
1. Cationic
The main part of the structure of cationic solubilizer is a pentavalent nitrogen atom, represented by quaternary ammonium salts, which is characterized by large water solubility, good surface activity and strong disinfection and sterilization. However, cationic solubilizer has large toxic and side effects, and it is rarely used as a solubilizer, such as bromobenzylammonium (bromogeramine).
2. Anionic
Anionic solubilizers play a surface active role in anions. Because of their strong physiological effects, such as hemolysis, irritation, etc., they are generally used for external preparations. Such solubilizers include soaps, sulfates (such as sodium dodecyl sulfate), sulfonates (such as sodium dodecyl benzene sulfonate, sodium taurocholate), etc.
3. Amphoteric type
In the molecule of zwitterionic solubilizer, there are two kinds of atomic groups: cation and anion. The cation mainly has the atomic group of quaternary ammonium salt, and the anion mainly has the atomic group of carboxylic acid, sulfonic acid, phosphoric acid, sulfate. In alkaline aqueous solution, the solubilizer is anionic surfactant with good foaming property and strong decontamination power; It is a cationic surfactant in acidic aqueous solution, with strong bactericidal power and certain toxicity, and is rarely used as a solubilizer.
4. Non ionic
Non ionic solubilizers do not dissociate in water. Polyols and their polymers form hydrophilic groups in the molecules, and various higher fatty acids or higher fatty alcohols and alkyl or aryl groups form lipophilic groups. They combine with hydrophilic groups by ester bond or ether bond. There are many different types of solubilizers due to their chemical non dissociation. Such solubilizers are not easily affected by electrolytes and pH values of solutions, and they have less toxicity and hemolysis, At present, it is the most widely used and can be used for oral, external, injection and other dosage forms.
The selection of the solubilizer should be based on the properties of the solubilizer and the requirements of the preparation, and the type and amount of the solubilizer should be fully combined with the characteristics of the solubilizer, and the factors affecting the solubilizer effect and the impact on drug absorption should be considered during use. Choose a solubilizer with low toxicity, small side effects, large amount of solubilization, and easy availability.
1. Chain length of hydrocarbon chain
The hydrocarbon chain length, molecular weight and type of the solubilizer of the homologous solubilizer have an influence on the solubilization effect. The longer the hydrocarbon chain, the smaller the CMC. When forming micelles, the capacity of the central area of the hydrocarbon core is larger, and the solubilization effect is stronger, so the solubilization ability increases with the growth of the hydrocarbon chain. For homologous ionic solubilizers, the CMC decreases by 1/2 for each additional carbon atom in the hydrocarbon chain; for homologous non-ionic solubilizers, due to the relatively weak polarity of the hydrophilic group, the number of carbon atoms decreases. The effect of the increase is more obvious, about every 2 carbon atoms added to the hydrocarbon chain, the CMC can be reduced to 1/10 of the original.
2. Hydrophilic-lipophilic balance value
The higher the HLB value, the stronger the hydrophilicity; the lower the HLB value, the stronger the lipophilicity. Surfactants with different HLB values are suitable for different purposes.
3. Cloud point
For preparations containing surfactants with a peak phenomenon, when the temperature reaches the peak point, the surfactants are precipitated, and the solubilization and emulsifying properties are reduced, so that the solubilized substances are precipitated or the corresponding emulsions may be destroyed. After the temperature drops, it will return to its original state, but some are difficult to restore. Therefore, some preparations that require sterilization, such as injections and eye drops, require a certain degree of stability, and a solubilizer with a breaking point above 85 °C must be selected.
It refers to the process in which the solubility of the drug in the solvent increases and forms a single-phase associative colloid solution after the surfactant forms micelles, and the added surfactant that plays a solubilizing effect is called a solubilizer.
1. Cationic
The main part of the structure of cationic solubilizer is a pentavalent nitrogen atom, represented by quaternary ammonium salts, which is characterized by large water solubility, good surface activity and strong disinfection and sterilization. However, cationic solubilizer has large toxic and side effects, and it is rarely used as a solubilizer, such as bromobenzylammonium (bromogeramine).
2. Anionic
Anionic solubilizers play a surface active role in anions. Because of their strong physiological effects, such as hemolysis, irritation, etc., they are generally used for external preparations. Such solubilizers include soaps, sulfates (such as sodium dodecyl sulfate), sulfonates (such as sodium dodecyl benzene sulfonate, sodium taurocholate), etc.
3. Amphoteric type
In the molecule of zwitterionic solubilizer, there are two kinds of atomic groups: cation and anion. The cation mainly has the atomic group of quaternary ammonium salt, and the anion mainly has the atomic group of carboxylic acid, sulfonic acid, phosphoric acid, sulfate. In alkaline aqueous solution, the solubilizer is anionic surfactant with good foaming property and strong decontamination power; It is a cationic surfactant in acidic aqueous solution, with strong bactericidal power and certain toxicity, and is rarely used as a solubilizer.
4. Non ionic
Non ionic solubilizers do not dissociate in water. Polyols and their polymers form hydrophilic groups in the molecules, and various higher fatty acids or higher fatty alcohols and alkyl or aryl groups form lipophilic groups. They combine with hydrophilic groups by ester bond or ether bond. There are many different types of solubilizers due to their chemical non dissociation. Such solubilizers are not easily affected by electrolytes and pH values of solutions, and they have less toxicity and hemolysis, At present, it is the most widely used and can be used for oral, external, injection and other dosage forms.
The selection of the solubilizer should be based on the properties of the solubilizer and the requirements of the preparation, and the type and amount of the solubilizer should be fully combined with the characteristics of the solubilizer, and the factors affecting the solubilizer effect and the impact on drug absorption should be considered during use. Choose a solubilizer with low toxicity, small side effects, large amount of solubilization, and easy availability.
1. Chain length of hydrocarbon chain
The hydrocarbon chain length, molecular weight and type of the solubilizer of the homologous solubilizer have an influence on the solubilization effect. The longer the hydrocarbon chain, the smaller the CMC. When forming micelles, the capacity of the central area of the hydrocarbon core is larger, and the solubilization effect is stronger, so the solubilization ability increases with the growth of the hydrocarbon chain. For homologous ionic solubilizers, the CMC decreases by 1/2 for each additional carbon atom in the hydrocarbon chain; for homologous non-ionic solubilizers, due to the relatively weak polarity of the hydrophilic group, the number of carbon atoms decreases. The effect of the increase is more obvious, about every 2 carbon atoms added to the hydrocarbon chain, the CMC can be reduced to 1/10 of the original.
2. Hydrophilic-lipophilic balance value
The higher the HLB value, the stronger the hydrophilicity; the lower the HLB value, the stronger the lipophilicity. Surfactants with different HLB values are suitable for different purposes.
3. Cloud point
For preparations containing surfactants with a peak phenomenon, when the temperature reaches the peak point, the surfactants are precipitated, and the solubilization and emulsifying properties are reduced, so that the solubilized substances are precipitated or the corresponding emulsions may be destroyed. After the temperature drops, it will return to its original state, but some are difficult to restore. Therefore, some preparations that require sterilization, such as injections and eye drops, require a certain degree of stability, and a solubilizer with a breaking point above 85 °C must be selected.
