The manufacture of ointments, liquids, and creams is an important part of pharmaceutical compounding in hospitals and industry. These formulations are commonly used for topical, oral, or external administration and must be prepared carefully to ensure safety, uniformity, and therapeutic effectiveness. Understanding formulation principles, preparation techniques, and quality control measures is essential for pharmacists involved in compounding and small-scale manufacturing.
Manufacture of Ointments
Ointments are semi-solid preparations intended for external application to the skin or mucous membranes. They may be medicated or non-medicated and use bases such as hydrocarbons, absorption bases, water-removable bases, or water-soluble bases.
Types of Ointment Bases
- Hydrocarbon bases: Petrolatum, paraffin; provide emollient effect.
- Absorption bases: Allow incorporation of water (e.g., lanolin).
- Water-removable bases: Oil-in-water emulsions, easily washable.
- Water-soluble bases: Do not contain lipids (e.g., PEG ointment).
Methods of Ointment Preparation
1. Trituration Method
Mechanical mixing using a mortar and pestle. Used for levigating solids in small-scale compounding.
2. Fusion Method
Used for ointments requiring melting of ingredients.
- Oily components are melted first.
- Aqueous phase is heated separately.
- Both phases are mixed while warm, then cooled with stirring.
Equipment Used
- Ointment slab or tile
- Mixer or planetary mixer
- Water bath
- Stainless-steel kettles
- Colloid mill (for uniformity)
Quality Control of Ointments
- Uniformity of content
- Viscosity test
- Microbial limit test
- Drug release testing
- Stability evaluation
Packaging
- Aluminum tubes
- Plastic collapsible tubes
- Wide-mouth jars
- Labeling with storage conditions
Manufacture of Liquid Dosage Forms
Liquid formulations include solutions, syrups, suspensions, elixirs, and emulsions. They are widely used for oral, topical, and external applications.
General Steps in Liquid Preparation
- Selection of vehicle (water, alcohol, glycerin, oils).
- Dissolution of active ingredients.
- Filtration to remove particulate matter.
- Preservation using antimicrobial agents.
- Flavor and color addition when required.
- Bottling under clean conditions.
Common Liquid Dosage Forms
1. Solutions
Clear, homogeneous mixtures of solute and solvent. E.g., paracetamol oral solution.
2. Suspensions
Insoluble drug particles dispersed in a liquid medium. Require suspending agents.
3. Emulsions
Mixtures of oil and water stabilized by emulsifying agents.
4. Syrups
Concentrated sugar solutions used as vehicles for oral pediatric preparations.
Quality Control Tests for Liquids
- pH testing
- Viscosity measurement
- Microbial limits testing
- Assay of active ingredients
- Physical stability (appearance, phase separation)
Packaging
- Amber-colored bottles
- Dropper bottles for eye and ear drops
- Well-sealed caps for stability
- Proper labeling for dosage and storage
Manufacture of Creams
Creams are semi-solid emulsions meant for external application. They may be oil-in-water (O/W) or water-in-oil (W/O) emulsions.
Ingredients
- Oil phase: fatty acids, waxes, cetyl alcohol
- Aqueous phase: purified water, humectants
- Emulsifying agents
- Preservatives
- Active pharmaceutical ingredients
Manufacturing Process
1. Preparation of Oil Phase
Melting of waxes, oils, and emulsifiers at controlled temperature.
2. Preparation of Aqueous Phase
Heating water and dissolving heat-stable ingredients.
3. Emulsion Formation
- The aqueous phase is slowly added to the oil phase (or vice versa) with stirring.
- Cooled with continuous mixing to form a smooth cream.
Equipment Used
- Mixing vessels
- Homogenizers
- Water bath
- Temperature-controlled kettles
Quality Control Tests for Creams
- Viscosity
- Microbial limits
- Consistency and spreadability
- pH and stability
- Drug content uniformity
Packaging
- Tubes
- Plastic containers
- Air-tight jars
Role of Pharmacists in Manufacturing
- Ensure accurate compounding and measurement.
- Maintain aseptic and hygienic conditions.
- Monitor quality control processes.
- Ensure compliance with pharmacopeial standards.
- Label and package products appropriately.
- Provide patient counseling on storage and use.
Detailed Notes:
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