Starch as excipient
What is Starch?
Starch is a carbohydrate commonly found in plants, serving as a primary energy storage compound. It is a vital component of the human diet, contributing significantly to the world’s food supply. Beyond its nutritional role, starch plays a crucial role in various industries, including pharmaceuticals, due to its unique properties and versatile applications.
In the pharmaceutical industry, starch finds widespread use as an excipient, a substance added to medications to improve their physical and chemical properties. Starch serves various purposes, including as a binder, disintegrant, filler, and diluent in tablet formulations. Additionally, it acts as a stabilizer and thickening agent in liquid pharmaceuticals and as a coating material for drug delivery systems.
Composition and properties of Starch
Starch is composed of two main polymers: amylose and amylopectin. Amylose is a linear chain of glucose molecules linked by alpha-1,4-glycosidic bonds, while amylopectin is a branched polymer with alpha-1,6-glycosidic linkages at the branching points. The ratio of amylose to amylopectin varies among different starch sources, influencing their properties and applications.
Starch exhibits unique properties that make it valuable in pharmaceutical applications. It is biodegradable, non-toxic, and renewable, making it an eco-friendly choice. Starch granules have a unique structure, contributing to their ability to form gels, which is exploited in the pharmaceutical industry for controlled drug release and as a thickening agent.
Starch manufacturing
Starch is primarily extracted from plant sources such as corn, wheat, potatoes, and cassava. The extraction process involves milling the raw material, followed by a series of washing and separation steps to isolate the starch granules. Afterward, the starch undergoes purification and drying processes to produce a refined product suitable for various applications.
Starch synthesis in plants occurs through photosynthesis, where carbon dioxide and water are converted into glucose by the action of sunlight. The glucose is then polymerized into starch through enzymatic processes within the plant cells. Researchers have also explored microbial synthesis routes to produce starch through fermentation using genetically modified microorganisms.
Figure 1 Structural formula of Starch, amylose and amylopectin [Visakh P.M]
Stability and Degradation of Starch
The stability of starch depends on factors such as moisture content, temperature, and storage conditions. Starch is susceptible to hydrolysis, leading to a reduction in molecular weight and altered functional properties. Proper storage in dry and cool conditions is crucial to maintaining its stability.
Starch degradation can occur through enzymatic hydrolysis, thermal degradation, or chemical reactions. Enzymes such as amylases break down starch into simpler sugars, while excessive heat can lead to the breakdown of glycosidic linkages. Understanding and controlling degradation processes are essential for maintaining the quality and functionality of starch-based pharmaceutical formulations.
Advantage and disadvantages of Starch
Advantages of using starch in pharmaceuticals include its natural origin, biocompatibility, and versatility. It is readily available, cost-effective, and has a wide range of applications. However, challenges include its susceptibility to microbial contamination, potential allergenicity, and limitations in solubility, which may impact its use in certain formulations.
Starch plays a crucial role in the pharmaceutical industry, offering a natural and versatile excipient for various formulations. Its unique properties, coupled with ongoing research in synthesis and modification, continue to expand its applications and improve its performance in drug delivery systems. As pharmaceutical technology advances, starch remains a valuable component in the development of safe and effective medications.
Starch Characterization Services
Excipia is an independent contract service platform that focuses on the physicochemical characterization of pharmaceutical excipients and food ingredients like Starch; as a pure substance, as a raw material or when processed into end products.
More than 25 years in the development of pharmaceutical formulations have taught us that the limited information available on an excipient Certificate of Analysis (CoA) often falls short of explaining observed product or excipient characteristics and that more in-depth knowledge of the actual chemical excipient composition is essential to meet and understand specific formulation challenges.
Over the past 15 years, Excipia analytical scientists have spent tens of thousands of hours establishing unique, specific analytical and physicochemical methods with ingenious sample preparation techniques to characterize polysaccharides ans other pharmaceutical excipients.
In these years we have gained a lot of knowledge about many excipients, their properties and exact composition, the difference between batches, qualities, grades, and manufacturers, how to quantify them in medicines and how they can best be used in a formulation.
Excipia offers fast and flexible hands-on cellulose characterization services to reveal and compare hidden polysaccharides properties like:
- the presence of potential reactive impurities or functional groups,
- reducing power of polysaccharides,
- degradation products and related substances,
- relative molecular weight distributions,
- and many other polysaccharide characteristics.
In addition, Excipia can help users of polysaccharides to pick the most appropriate cellulose manufacturer, select the most suitable cellulose grade for their finished dosage form, or define customized cellulose specifications to control product performance, quality and safety.
Welcome to Excipia, a service platform of Avivia, dedicated to the composition, quality and quantity of excipients in medicinal products.
Discover our unique services such as quantitative excipient analysis, identification, selection or specific formulation development support. Don’t forget to check out our case studies.
Feel free to contact us using the “Contact” button or by sending a message to Excipia@avivia.nl.
Menno Wiltink
Founder of Excipia.