Formulation components and manufacturing process

Formulation components and manufacturing process

Typical formulation components of oral solution dosage forms include

·           API.

·           Vehicle, which is usually aqueous but could also be vegetable oil.

·           Buffer for maintaining desired solution pH.

·           Sweetener, flavor, and color for improving palatability.

·           Taste masking agent, if required.

·           Antimicrobial preservative(s).

·           Antioxidant(s) or other stabilizer(s) (such as chelating agent), if and when needed.

·           Cosolvent(s) and/or surfactant(s), if and when needed.

Typical manufacturing process for solution dosage forms involves simple mixing of all ingredients to make a solution. However, several process vari-ables need to be carefully controlled to ensure a reproducible and high-quality manufacturing process, such as sequence of addition of ingredients, process equipment and parameters to control foaming and mixing dynam-ics, and temperature control.

Vehicle considerations include the selection of appropriate type and concentrations of pH-controlling buffer, flavor(s), sweetener(s), color(s), preservative(s), viscosity control agents in terms of their functionality, compatibility with each other and the API, and stability in solution. Vehicles used in oral solutions primarily include water, ethanol, glycerin, syrups, and various blends of these ingredients. Aqueous-miscible cosol-vents used in smaller concentrations include propylene glycol and polyeth-ylene glycol.

Most of the vehicles used for oral solutions can be used in topical solu-tions. In addition, topical solutions may also contain some amount of ace-tone, isopropanol, propylene glycol, polyethylene glycols, many oils, and numerous polymers.