Explotab® Sodium Starch Glycolate
Mechanism of Action +
### Polymer Chemistry and Modification Sodium starch glycolate (Explotab®) is synthesized through a two-step chemical modification of native starch (typically potato starch, though rice, wheat, or corn can be used). Native starch exhibits relatively poor water absorption and tends to form a viscous, sticky gel when hydrated, which can actually impede tablet disintegration by blocking further water penetration—a phenomenon known as 'viscous plugging.' To overcome this, the starch undergoes carboxymethylation and crosslinking.
First, carboxymethylation introduces hydrophilic carboxymethyl ether groups to the starch polymer backbone. This drastically increases the polymer's affinity for water (hydrophilicity), allowing it to draw moisture in rapidly via capillary action. Second, the polymer is crosslinked. Crosslinking creates a three-dimensional structural network that prevents the highly hydrophilic polymer chains from fully dissolving into a gel. Instead of dissolving, the water hydrates the polymer chains, causing them to uncoil and expand, but the crosslinks hold the overall structure together.
### The Physics of Superdisintegration The primary mechanism of action for Explotab® is volumetric expansion, or 'swelling.' When a tablet containing Explotab® enters the aqueous environment of the stomach, the sodium starch glycolate particles act like microscopic sponges. They wick water into the tablet matrix and swell up to 300 times their original volume. Because tablets are tightly compressed during manufacturing, there is very little free space within the matrix. The massive swelling of the Explotab® particles generates immense multidirectional stress against the cohesive forces of the tablet binders. This stress rapidly overcomes the tensile strength of the tablet, causing it to shatter into fine granules.
### Impact on Pharmacokinetics As an inactive excipient, Explotab® does not have its own pharmacokinetic profile (it is not absorbed into the bloodstream and does not exert systemic physiological effects). However, it plays a critical role in the pharmacokinetics of the active pharmaceutical ingredients (APIs) or dietary supplements it is formulated with. By ensuring rapid and complete disintegration, Explotab® maximizes the surface area of the active ingredients exposed to gastrointestinal fluids. This accelerates the dissolution rate, which is often the rate-limiting step for the absorption of poorly water-soluble compounds (BCS Class II and IV drugs). Consequently, formulations utilizing Explotab® typically exhibit a shorter time to maximum concentration (Tmax) and a more reliable, consistent maximum concentration (Cmax) compared to formulations lacking a superdisintegrant.
Is sodium starch glycolate safe to use? +
What is sodium starch glycolate type A Explotab? +
What are the benefits of sodium starch glycolate? +
What products contain sodium starch glycolate? +
How does sodium starch glycolate affect drug absorption? +
Is Explotab a dietary supplement? +
Does sodium starch glycolate contain gluten? +
Can I be allergic to Explotab? +
Why is it called a 'superdisintegrant'? +
How much Explotab is typically used in a tablet? +
Does Explotab have any side effects? +
What is the difference between Explotab and standard starch? +
How does crosslinking improve sodium starch glycolate? +
What happens if a tablet doesn't have a disintegrant? +
Is Explotab vegan? +
Does Explotab add calories or carbs to a supplement? +
How does Explotab interact with stomach acid? +
What is the difference between Explotab and Vivastar? +
Everything About Explotab® Sodium Starch Glycolate Article
## Introduction to Explotab® Sodium Starch Glycolate
When you take a dietary supplement or a pharmaceutical tablet, you expect the active ingredients to be absorbed into your body quickly and efficiently. However, a compressed tablet is essentially a dense rock of powders bound tightly together. If that tablet does not break apart in your digestive tract, the active ingredients will pass right through you, rendering the product useless. This is where Explotab® comes in.
Explotab®, the trademarked brand name for Sodium Starch Glycolate manufactured by JRS Pharma, is a 'superdisintegrant.' It is an inactive pharmaceutical excipient designed to do one specific job: blow the tablet apart from the inside out the moment it touches water. By ensuring rapid and complete disintegration, Explotab® guarantees that the active ingredients you paid for are actually released and absorbed by your body.
## The Science of Superdisintegrants
Historically, tablet manufacturers used native starches (like standard corn or potato starch) to help tablets break apart. Native starch works by wicking water into the tablet, causing a mild swelling effect. However, native starch has significant limitations. It requires high concentrations (often 10-20% of the tablet weight) to be effective, and when it gets wet, it tends to form a sticky, viscous gel. This gel can actually block further water from entering the tablet, a problem known as 'viscous plugging,' which delays the release of the active ingredients.
To solve this, formulation scientists developed superdisintegrants. Sodium starch glycolate is created by chemically modifying native starch—specifically potato starch, in the case of Explotab®—through two processes: carboxymethylation and crosslinking.
### Carboxymethylation This process attaches hydrophilic (water-loving) carboxymethyl ether groups to the starch molecules. This drastically increases the starch's ability to attract and absorb water rapidly.
### Crosslinking If the starch were only carboxymethylated, it would dissolve completely into a thick gel upon contact with water. Crosslinking creates chemical bridges between the polymer chains. These bridges prevent the starch from dissolving. Instead, as water rushes in, the polymer chains uncoil and expand, but the crosslinks hold them together. The result is massive volumetric expansion without gel formation.
## How Explotab Works: Mechanism of Action
The mechanism of action for Explotab® is purely mechanical and physical. It is an odorless, tasteless, white to off-white powder that is mixed with the active ingredients before the tablet is compressed.
When you swallow a tablet containing Explotab®, it enters the aqueous environment of your stomach. The sodium starch glycolate particles immediately begin wicking gastric fluid into the tablet matrix via capillary action. Because of the chemical modifications described above, the Explotab® particles swell up to 300 times their original volume.
Because the tablet was tightly compressed during manufacturing, there is no room for these particles to expand. The massive swelling generates immense internal pressure, overcoming the cohesive forces of the tablet binders. The tablet rapidly shatters into fine granules. This massive increase in surface area allows the digestive fluids to dissolve the active ingredients quickly, ensuring rapid absorption into the bloodstream.
## Clinical Evidence and Manufacturing Efficiency
The efficacy of sodium starch glycolate is well-documented in pharmaceutical literature. A performance equivalence study published in the *International Journal of Applied Science* evaluated the use of sodium starch glycolate (SSG) compared to modified maize starch (MMS) and native maize starch (MS) in paracetamol tablet formulations.
The researchers found that SSG is a 'high-tech disintegrant with remarkable rapid water penetration and extensive swelling capability.' In the study, a formulation using just 3% SSG provided excellent disintegration and dissolution properties. To achieve comparable results without SSG, the researchers had to double the concentration of modified maize starch to 6%. The study concluded that SSG's ability to swell 300 times its volume, unaffected by the high compression pressures of manufacturing, makes it an excipient of choice for reliable drug delivery.
## Grades of Explotab® and VIVASTAR®
JRS Pharma produces sodium starch glycolate under two primary brand names: Explotab® (ethanol-based manufacturing) and VIVASTAR® (methanol-based manufacturing). Because different active ingredients have different chemical sensitivities, JRS Pharma offers several specialty grades:
* **EXPLOTAB® (Standard):** Type A compendial grade, ideal for poorly water-soluble actives and matrices with higher pH values. * **EXPLOTAB® CLV:** Features increased crosslinking, specifically designed to hold up under the rigors of wet granulation manufacturing processes. * **EXPLOTAB® PCF:** A highly purified grade with a maximum of 0.7% sodium chloride, recommended for active pharmaceutical ingredients that are sensitive to ion content. * **EXPLOTAB® Low pH:** Complies with Type B compendial standards, featuring a pH of 3.0-5.0, ideal for acidic formulations. * **VIVASTAR® PSF:** A special grade with very low methanol content, suited for alcohol- and moisture-sensitive actives.
## Safety and Tolerability
Sodium starch glycolate is universally recognized as a safe, pharmacologically inactive excipient. It is used globally in thousands of over-the-counter and prescription medications, including common drugs like Cefaclor, Prednisone, and Propylthiouracil, as well as high-end dietary supplements.
Because it is not absorbed by the body, it has no systemic side effects. It simply passes through the gastrointestinal tract. The only minor consideration is for individuals with severe, anaphylactic allergies to potatoes, as Explotab® is derived from potato starch. However, the extensive chemical processing, purification, and washing steps involved in manufacturing Explotab® remove virtually all native proteins, making allergic reactions exceedingly rare.
## Conclusion
While you will never take Explotab® for its own physiological benefits, its presence on a supplement or medication label is a strong indicator of a high-quality product. By utilizing a premium superdisintegrant like Explotab® Sodium Starch Glycolate, manufacturers ensure that their tablets break down rapidly and completely, maximizing the bioavailability and effectiveness of the active ingredients you are paying for.