Standard Operating Procedure for Emulsification-Solvent Evaporation Technique in Nanoparticle Formulations

1) Purpose

This SOP outlines the emulsification-solvent evaporation technique for preparing nanoparticles. This method is widely used for encapsulating hydrophobic drugs into polymeric nanoparticles.

2) Scope

This SOP applies to all personnel responsible for preparing nanoparticle formulations using the emulsification-solvent evaporation technique.

3) Responsibilities

• Operators: Responsible for following the emulsification-solvent evaporation method accurately.
• QA: Ensures that the nanoparticle formulation meets particle size and encapsulation efficiency specifications.

4) Procedure

4.1 Polymer Dissolution

4.1.1 Solvent Selection

• 4.1.1.1 Select an appropriate organic solvent (e.g., dichloromethane) to dissolve the polymer (e.g., PLGA).

4.1.2 Drug Loading

• 4.1.2.1 Dissolve or suspend the drug in the polymer solution under gentle stirring.

4.2 Emulsification

4.2.1 Formation of Emulsion

• 4.2.1.1 Add the polymer-drug solution into an aqueous phase containing a surfactant (e.g., PVA) under high-speed stirring to form an emulsion.
• 4.2.1.2 Use a homogenizer to reduce the size of the emulsion droplets to achieve nanoscale particles.

4.3 Solvent Evaporation

4.3.1 Removal of Solvent

• 4.3.1.1 Evaporate the organic solvent under reduced pressure or constant stirring, leading to nanoparticle formation as the polymer solidifies.
• 4.3.1.2 Continue stirring until all solvent has evaporated.

4.4 Washing and Collection of Nanoparticles

4.4.1 Centrifugation

• 4.4.1.1 Centrifuge the nanoparticle suspension to collect the particles and discard the supernatant.
• 4.4.1.2 Wash the particles with distilled