Polysaccharides in Pharmaceutical Development
What are Polysaccharides?
Polysaccharides are complex carbohydrates composed of multiple monosaccharide units linked by glycosidic bonds. The specific monosaccharide units present in a polysaccharide define its identity and properties. The monosaccharide composition, sequence, and branching patterns contribute to the unique nature of each polysaccharide. Common monosaccharide units include glucose, galactose, mannose, and others, forming intricate macromolecular structures with varying degrees of complexity.
Examples of polysaccharides are:
- Starch: Found in plants, starch is a storage form of energy that can be broken down into glucose when needed.
- Glycogen: Present in animals, glycogen serves as a storage form of glucose in the liver and muscles.
- Cellulose: A structural polysaccharide in plant cell walls, providing rigidity and strength.
- Hyaluronic Acid: An essential component of connective tissues and synovial fluid in joints.
- Xanthan gum: a polysaccharide derived from the fermentation of sugars by the bacterium Xanthomonas campestris.
- Chitosan is derived from chitin, found in the exoskeleton of arthropods and insects, as well as in fungal cell walls.
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 polysaccharide 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 polysaccharides to pick the most appropriate polysaccharide manufacturer, select the most suitable polysaccharide grade for their finished dosage form, or define customized polysaccharide specifications to control product performance, quality and safety.
Chemical Composition of Polysaccharides
Polysaccharides are long chains of monosaccharide units linked together by glycosidic bonds.
The arrangement of monosaccharide units within a polysaccharide is dictated by glycosidic bonds, which form between the anomeric carbon of one monosaccharide and a hydroxyl group of another. The linkage patterns contribute to the overall structure and properties of the polysaccharide.
The variability in glycosidic linkages, whether alpha or beta, linear or branched, profoundly influences the physicochemical characteristics of polysaccharides. For instance, the beta-1,4 linkages in cellulose impart rigidity, making it a crucial component of plant cell walls.
The immense structural diversity among polysaccharides arises from the combination of monosaccharide composition, glycosidic linkages, molecular weight, and stereochemistry. This diversity allows for a spectrum of functionalities, enabling tailored applications in pharmaceutical formulations.
Polysaccharides in Pharma
Polysaccharides play a pivotal role in pharmaceutical formulations. The integration of polysaccharides into pharmaceutical formulations has witnessed a significant surge in recent years, driven by the multifaceted properties and diverse functionalities these complex carbohydrates offer.
In pharmaceutical applications, the choice of monosaccharide units in a polysaccharide can be tailored to achieve specific properties.
For example, glucose-based polymers, such as dextran and pullulan, are renowned for their biocompatibility and versatility in drug delivery systems. Polysaccharides act as carriers, encapsulating drugs and facilitating controlled release for enhanced therapeutic efficacy. They protect drugs from degradation in the harsh gastrointestinal environment.
Properties of Polysaccharides
- Biocompatibility and Biodegradability:
Polysaccharides exhibit high biocompatibility, reducing the risk of adverse reactions.
Biodegradability ensures minimal environmental impact and clearance from the body over time. - Hydrophilicity:
Most polysaccharides are hydrophilic, influencing their solubility and interaction with water-soluble drugs. - Molecular Weight:
The molecular weight of polysaccharides varies, impacting their viscosity, gelation properties, and drug-loading capacity. The molecular weight, determined by the number and arrangement of monosaccharide units, is a critical parameter influencing their pharmaceutical applications. Polysaccharides can exhibit a wide range of molecular weights, from low-molecular-weight heparins to high-molecular-weight hyaluronic acid.
In drug delivery, molecular weight is closely linked to the encapsulation and release capabilities of the polysaccharide. Higher molecular weight polysaccharides may form more stable drug carriers, affecting drug delivery kinetics. - Gel-Forming Ability:
Certain polysaccharides possess gel-forming capabilities, enabling the development of controlled-release formulations. - Stability:
Polysaccharides contribute to the stability of pharmaceutical formulations by preventing drug degradation and improving shelf life.
