6. UNIT OPERATIONS

In the pharmaceutical industry, unit operations form the foundation of drug manufacturing processes. Each step in converting raw materials into a finished dosage form — such as tablets, capsules, or injections — involves a specific unit operation.
Understanding these operations is essential for producing safe, effective, and high-quality pharmaceutical products.

Definition of Unit Operations

A Unit Operation is a basic physical step involved in the conversion of raw materials into final products.
It deals with physical changes (not chemical) such as size reduction, mixing, filtration, drying, and extraction.

In simple terms, unit operations are the building blocks of all pharmaceutical manufacturing processes.

ORIGINAL NOTES:

Objectives of Unit Operations

• To simplify and standardize manufacturing processes.
• To ensure uniformity and reproducibility of pharmaceutical products.
• To enhance product quality, stability, and bioavailability.
• To optimize production time and reduce cost.
• To ensure compliance with Good Manufacturing Practices (GMP).

Principles of Unit Operations

Each unit operation follows one or more of the following basic principles:

1. Mechanical Processes – Size reduction, size separation, mixing.
2. Fluid Handling Processes – Filtration, sedimentation, centrifugation.
3. Mass Transfer Processes – Drying, extraction, adsorption, distillation.
4. Heat Transfer Processes – Evaporation, sterilization, and drying.
5. Diffusion Processes – Used in extraction and purification.

These principles are applied systematically to achieve the desired physical modification of materials.

Examples of Unit Operations in Pharmaceutics

1. Size Reduction (Comminution):
   Reducing the size of solid particles using equipment like hammer mill and ball mill.
2. Size Separation (Sieving):
   Classifying powders according to Indian Pharmacopoeia (IP) using sieves or a cyclone separator.
3. Mixing:
   Achieving uniform blending using equipment like double cone blender, turbine mixer, or triple roller mill.
4. Filtration:
   Removing insoluble particles from liquids using membrane filters or sintered glass filters.
5. Drying:
   Removing moisture from materials using fluidized bed dryers or freeze drying (lyophilization).
6. Extraction:
   Separating active constituents from plant or animal sources using solvent extraction, maceration, or percolation.

Applications of Unit Operations

• Used in the manufacture of solid, liquid, and semisolid dosage forms.
• Ensure product consistency and process control.
• Improve flow properties and compressibility of powders.
• Enhance purity and stability of final formulations.
• Help in scaling up production from laboratory to industry.

Importance in Pharmaceutical Industry

• Ensures quality assurance: Each unit operation contributes to the final product’s safety and efficacy.
• Facilitates process optimization: Helps in controlling variables like temperature, pressure, and particle size.
• Regulatory compliance: Required under GMP and Pharmacopoeial standards.
• Improves efficiency: Reduces waste and enhances batch uniformity.