Polymers in Pharmaceutical Development
What are Polymer Excipients?
Polymers are large molecules composed of repeating structural units called monomers. These monomers are covalently bonded together to form a long chain or network. The process by which monomers are chemically bonded to create a polymer is known as polymerization.
Polymers can be found in various forms, including natural and synthetic polymers. Polymer excipients are substances that are added to pharmaceutical formulations to serve various purposes, such as improving the stability, bioavailability, and overall performance of the drug product. These excipients are typically polymeric in nature, meaning they consist of long chains of repeating units. Polymer excipients can be derived from natural sources or synthesized chemically.
Examples of excipient polymers:
- Polyvinylpyrrolidone (PVP): PVP is a water-soluble polymer used as a binder, disintegrant, and stabilizer in tablets and capsules. It can also be used in topical formulations.
- Polyethylene Glycol (PEG): PEG is a polyether compound that is often used as a solubilizing agent, lubricant, and humectant in various dosage forms, including creams, ointments, and oral solutions.
- Acrylic Polymers (Eudragit series): Various types of acrylic polymers, such as Eudragit L, Eudragit RS, and Eudragit S, are used for enteric coating and controlled-release applications in oral dosage forms.
- Polyethylene Oxide (PEO): PEO is a water-soluble polymer used as a binder and matrix former in oral controlled-release formulations.
- Polyvinyl Alcohol (PVA): PVA is often employed as a film-coating agent for tablets and capsules. It provides a protective layer and enhances the appearance of the dosage form.
- Polysaccharides: complex carbohydrates like cellulose, starch and their derivatives are used as binder, disintegrant, filler, and diluent.
Figure 1 Cellobiose, the polymeric structure of cellulose
Excipient Characterization Services
Excipia offers fast and flexible hands-on services to quantify and reveal and compare hidden polymer excipient properties like :
the presence of potential reactive impurities or functional groups, degradation products and related substances, just like molecular weight distributions and many other featured characteristics.
In addition, we can help users of polymer excipient to pick the most appropriate polymer excipient manufacturer, select the most suitable polymer excipient grade for their finished dosage form, or define customized polymer excipient specifications to control product performance, quality and safety.
Chemical Composition of Polymer excipients
Polymer excipients used in pharmaceuticals can be natural or synthetic. The natural polymers are typically polysaccharides, complex carbohydrates composed of multiple monosaccharide. The composition of synthetic excipient polymers can vary.
Commonly employed polymers include:
Synthetic Polymers:
- Polyvinylpyrrolidone (PVP).
- Polyethylene glycol (PEG).
- Polyacrylic acid derivatives (e.g., carbomers).
- Polymethacrylates.
Natural Polymers:
- Cellulose derivatives (e.g., hydroxypropyl cellulose, ethyl cellulose).
- Starch and its derivatives.
- Xanthan gum.
- Gelatin.
Polymers in Pharma
Polymer excipients play a crucial role in the pharmaceutical industry, serving as essential components in drug formulations. These polymers are versatile substances that contribute to the stability, solubility, and overall performance of pharmaceutical products.
Pharmaceutical Applications:
Polymer excipients find widespread use in pharmaceutical formulations across different dosage forms, such as tablets, capsules, creams, and gels. Their primary functions include:
- Binder and Disintegrant:
Facilitate tablet formation by binding powders together. Promote tablet disintegration for efficient drug release. - Sustained Release:
Control drug release over an extended period, improving patient compliance. - Viscosity Modifiers:
Enhance the viscosity of liquid formulations, ensuring uniform drug distribution. - Film Coating:
Provide a protective layer on tablets, improving taste, appearance, and stability. - Solubility Enhancement:
Improve the solubility and bioavailability of poorly water-soluble drugs. - Stabilizers:
Protect drugs from degradation due to environmental factors like light, moisture, and oxygen.
Properties of Polymer Excipients
Polymer excipients exhibit a range of properties crucial for their pharmaceutical applications:
- Mechanical Properties:
Good compressibility for tablet formation.
Film-forming ability for coating applications. - Chemical Stability:
Inert nature to prevent chemical interactions with active pharmaceutical ingredients. - Hygroscopicity:
Ability to absorb and retain moisture to ensure stability. - Thermal Stability:
Resistance to temperature changes during manufacturing processes. - Solubility:
Tailored solubility characteristics for controlled drug release.
