Final answer:
In pharmaceutical dispersions, surfactants effectively decrease the water contact angle for improved dispersion and can promote flocculation. They may also increase the viscosity of emulsions depending on specific factors. However, a higher HLB value in surfactants corresponds to increased hydrophilicity, not lipophilicity.
Step-by-step explanation:
Role of Surfactants in Pharmaceutical Dispersions
Surfactants play a crucial role in the pharmaceutical field, particularly when it comes to the formulation of dispersions for oral administration. The following statements can be addressed regarding their role:
Surfactants decrease the water contact angle of dispersed drug particles, leading to a better wetting and dispersion.
Surfactants can increase the viscosity of the continuous phase in pharmaceutical emulsions, depending on their concentration and the system.
Flocculation can be promoted by surfactants, which encourages the formation of loose agglomerates in the dispersion medium that can settle but are easily redispersed.
As for the hydrophilic-lipophilic balance (HLB), when the HLB value of surfactants increases, it indicates a greater hydrophilicity rather than an increase in lipophilicity.
Based on these roles, we can confirm that statements A) and C) are true. However, statement B) is only sometimes true, as the effect of surfactants on viscosity depends on many factors including the nature of the surfactant and the specific formulation of the emulsion. Statement D) is incorrect, as an increase in HLB value correlates with increased hydrophilicity.