Pharmaceutical excipients are central to drug delivery inside the body. Usually, an excipient does not have medicinal properties; its standard objective is to smooth out the drug product’s manufacturing and ultimately expedite its physiological absorption. Pharma excipients also help improve the lubricity, disintegration process, taste, and play some kind of antimicrobial role. Choosing a suitable excipient to promote your pharmaceutical formulation is an essential step in the drug manufacturing process.
Origin and Definition of Excipients
The term ‘excipient’ comes from the Latin word ‘excipere,’ meaning to receive. So, the excipient receives an active substance. The excipients are generally defined exclusively as something other than the active substance contained in a dosage form.
According to the World Health Organisation, an active pharmaceutical ingredient means “a substance employed in a finished pharmaceutical product, designed to perform a pharmacological activity or to otherwise have an immediate effect in the diagnosis, mitigation, remedy or prevention of a disease, or to have an immediate effect in reviving, repairing or modifying physiological functions in a human body.”
Importance of Pharmaceutical Excipients
Excipients have a central role in the drug development processes, in the production of stable dosage forms and their consequent administration. A wrong selection of an excipient may even lead to severe intoxications.
With the progress in the productions of novel drug delivery systems, more sophisticated excipients are required to add specific properties to the final product. As the importance of pharmaceutical excipients only grows.
The term ‘multifunctional excipients’ applies to pharma excipients that can be co-processed or fulfill multiple roles in a dosage form or drug delivery system. For, e.g., a direct-compressible filler that also operates as a binder or a disintegrant.
The term ‘high functionality excipients’ means a single excipient that extends other properties to innovative drug delivery systems, improving the product’s overall execution with great economic benefits. An example of high functionality in pharmaceutical excipients is that they provide better flow or act as a disintegrant. All the while simultaneously allowing a higher drug loading in the dosage with its effective compressibility.
Selecting the Appropriate Excipient
Choosing excipients for a drug formulation is an essential step in drug production. A thoughtfully-chosen excipient can reduce manufacturing expenses by being multifunctional or can improve the patient experience with taste-masking properties. An excipient needs to suit the intended dosage type of the drug, display superior organoleptic properties, follow the pharmacopeial restrictions, be easy to source, and work efficiently.
The suitable excipient will hold the model pharmacokinetic properties for your planned pharmaceutical purpose. It will also function well with your existing tools or adapt quickly to your manufacturing program.
Determining factors can include the compound’s planned use, the amount of compound required (grams to tonnage), or environmental conditions that may impact an excipient. Other concerns involve potential toxicity, the source of the chemicals, and certain additional factors.
Categories of Excipients
Based on their functionality, excipients utilized in oral solid dosage applications have been categorized into groups such as disintegrants, diluents, binders, lubricants, glidants, plasticizers, stabilizers (like chelators, antioxidants, and pH-modifiers), release-controlling polymers, film-coating polymers, surfactant, sweeteners, flavors, and colorants.
Of the intragranular excipients utilized in the wet granulation procedure, the most popular functional excipients include:
- Fillers, generally a blend of microcrystalline cellulose (MCC) and lactose monohydrate;
- Binder, generally polyvinyl pyrrolidone (PVP) or hydroxypropyl cellulose (HPC) or;
- Disintegrant, generally sodium starch glycolate, croscarmellose sodium, or crospovidone.