By Allen Studzinski, NOW Quality Assurance Department, May 12, 2004Some people prefer their nutritional supplements in tablets, yet others prefer theirs in capsules. In this article, we will take a look at the technical differences between these two forms.
At NOW, we continually monitor tablet disintegration. This is important because a tablet that breaks down too slowly will fail to provide the specific nutrient to critical intestinal sites, decreasing absorption and potentially causing gastrointestinal upset. As such, we have strict specifications for tablet disintegration, testing every lot to assure that it meets industry specifications.
We also check tablet friability (chipping) and hardness (breaking strength) where necessary. Our mineral tablets, for example, unlike those from many other manufacturers, disintegrate in less than 45 minutes, as specified by the United States Pharmacopoeia (USP).
We test tablets for disintegration using specialized and standardized equipment. We typically use water or simulated stomach or intestinal fluids, where required. Vinegar (acetic acid) or any other arbitrary chemical is not an appropriate test medium.
NOW's Quality Control Department recently tested a tablet that disintegrated almost instantly when dropped into a glass of water. We are looking at newer technologies for improved tablet disintegration, because a tablet that disintegrates this fast in only water is not good. Reactivity with moisture in the air could cause tablet agglomeration or disintegration in the bottle and could potentially cause problems with swallowing.
Capsules are usually made from animal source gelatin or, if vegetarian, from starch hydrolysate or hydroxypropyl methylcellulose, a plant fiber derivative. At NOW, we strive to use the smallest capsule possible, minimizing the use of excipients.
Here is a brief summary of the relative characteristics of encapsulated and tableted supplements:
ADVANTAGES OF CAPSULES
Unique mixes and ingredients are possible
Sealed hard gelatin caps can be good oxygen barriers
Protection for sensitive ingredients
Shell normally breaks down/opens in 4 minutes
Reduced gastrointestinal irritation
Odorless, tasteless, easy to swallow
Oil and fat-soluble nutrient delivery
ADVANTAGES OF TABLETS
Well accepted, elegant
Custom size, shape, and appearance
Notching possible for dose splitting
Low cost coatings for enteric delivery
Dissolution control for quick, delayed, or extended release
DISADANTAGES OF CAPSULES
Bulky materials can result in large capsule size
Can be susceptible to moisture
Ingredients can interact with capsule shell
More difficult to fill accurately
Capsule or lubricant allergies/sensitivities are possible
Softgel contents restricted to a tight pH range
DISADVANTAGES OF TABLETS
Excessive compaction, poor dissolution
Granulation technique can add heat/moisture to viable components
Customer concerns/self-testing of tablet dissolution
Problems with irritant compounds exacerbated by poor tableting
Because capsules and tablets each have their merits, our customers can rest assured that the quality and research and development departments at NOW Foods are on top of the latest technologies that provide you with the highest quality in both delivery systems.