An excipient is a pharmacologically inactive substance formulated alongside the active pharmaceutical ingredient (API) in a medication or drug product. Excipients play various essential roles in pharmaceutical formulations, contributing to the stability, bioavailability, manufacturability, and overall performance of the drug product.
Why use an excipient
Here are some key functions and examples of excipients:
Binder
Excipients such as cellulose derivatives, starches, and polyvinylpyrrolidone (PVP) are used as binders to hold the ingredients of a tablet or capsule together, ensuring proper tablet hardness and integrity.
Disintegrant
Disintegrants, like croscarmellose sodium, crospovidone, and sodium starch glycolate, aid in the rapid breakdown of tablets or capsules into smaller particles upon contact with fluids in the gastrointestinal tract, facilitating drug dissolution and absorption.
Filler or Diluent
Fillers or diluents, such as lactose, microcrystalline cellulose, and mannitol, are used to increase the bulk volume of a tablet or capsule, allowing for the proper dosage of the active ingredient to be achieved and aiding in the manufacturing process.
Glidant or Lubricant
Glidants, like colloidal silicon dioxide, and lubricants, such as magnesium stearate and stearic acid, reduce friction between the tablet or capsule and the processing equipment during manufacturing, ensuring smooth tablet compression and preventing sticking.
Coating Agent
Coating agents, including film-forming polymers like hydroxypropyl methylcellulose (HPMC) and shellac, are used to provide a protective outer layer to tablets or capsules, improving swallowability, masking taste, enhancing stability, and facilitating controlled or delayed release of the drug.
Solubilizer or Surfactant
Solubilizers or surfactants, such as polysorbate 80 and sodium lauryl sulfate, are added to formulations to improve the solubility or dispersion of poorly soluble drugs, thereby enhancing bioavailability and efficacy.
Preservative
Preservatives like benzalkonium chloride and methylparaben are used in liquid formulations to prevent microbial growth, ensuring product stability and extending shelf life.
Flavoring and Sweetening Agents
Flavoring agents (e.g., fruit flavors) and sweetening agents (e.g., sucrose, sorbitol) are added to oral liquid medications to improve taste and palatability, enhancing patient compliance, especially in pediatric and geriatric populations.
Coloring Agents
Coloring agents, including dyes and pigments approved for pharmaceutical use, are added to tablets, capsules, or oral liquids for aesthetic purposes, aiding in product identification and differentiation.
Antioxidants and Stabilisers
Antioxidants like ascorbic acid and stabilizers such as citric acid or EDTA (ethylenediaminetetraacetic acid) are included in formulations to prevent degradation of the active ingredient due to oxidation or other chemical reactions, ensuring product potency and shelf life.
Excipient – A critical component in pharmaceuticals
Overall, excipients are critical components of pharmaceutical formulations, contributing to the safety, efficacy, and overall quality of drug products. Their selection and use are carefully evaluated during the formulation development process to meet specific requirements and regulatory standards.
