Tablet Friability Testing Guide: Procedures, USP <1216> & Lab Efficiency

This guide covers USP <1216> Tablet Friability in detail: the apparatus, the sample-size rule, the friability formula with a worked example, the 1.0% limit and the retest rules. For a practical overview of how friability testers work and why tablets fail, see our tablet friability tester guide.

Friability test formula: friability (%) = (W1 − W2) / W1 × 100, where W1 is the dedusted tablet weight before tumbling and W2 the weight after 100 rotations at 25 rpm. Under USP <1216>, a mean weight loss of not more than 1.0% is acceptable for most products.

Free tool: check your weight-loss result against the 1.0% limit with our tablet friability calculator.

What USP <1216> Covers

USP <1216> is harmonised with Ph. Eur. 2.9.7; the Chinese Pharmacopoeia method is ChP 0923. It applies to most compressed, uncoated tablets and measures the weight a sample loses when it is tumbled in a standard drum.

USP <1216> Procedure, Step by Step

Apparatus: a drum of transparent synthetic polymer with an internal diameter of 283–291 mm and a depth of 36–40 mm, rotating at 25 ± 1 rpm. A curved projection inside the drum carries the tablets up and lets them fall about 156 mm on each turn.

1. Sample size: for tablets with a unit weight of 650 mg or less, take whole tablets as close as possible to 6.5 g; for heavier tablets, take 10 whole tablets.
2. Initial weight (W1): carefully dedust the tablets and weigh the sample accurately.
3. Tumbling: place the tablets in the drum and rotate it 100 times (25 rpm for 4 minutes).
4. Final weight (W2): remove the tablets, dedust them again and weigh.
5. Calculation: work out the percentage weight loss.

Acceptance Limit and Retest Rules

• A maximum mean weight loss of not more than 1.0% is considered acceptable for most products.
• The test is normally run once. If the result is doubtful or the weight loss is above the target, the test is repeated twice more and the mean of the three tests is used.
• If any tablet is obviously cracked, cleaved or broken after tumbling, the sample fails.
• If tablets tumble irregularly because of their size or shape, the drum is tilted so its base sits at about 10° to the horizontal and the tablets no longer bind together.
• Effervescent and chewable tablets may have different specifications; hygroscopic tablets should be tested in a humidity-controlled environment.

To check that your instrument meets the drum and speed requirements, see our friability tester verification guide.

Instruments for USP <1216> Testing

The CJY-300E has two drums with an inside diameter of 286 mm and a depth of 39 mm, a speed range of 20–100 rpm and a count or timer mode; the sample is weighed on your own analytical balance.

The Modern Approach: 4-in-1 Efficiency (SY-6DN)

Traditionally, QC labs needed separate machines for hardness, friability, disintegration and dissolution, which takes up bench space and spreads data across different logs. The SY-6DN Intelligent 4-in-1 Tablet Tester combines the four tests in one instrument:

• Friability: one drum (inside diameter about 287 mm, depth 38 mm, drop height 156 mm), default 25 rpm and 100 rotations.
• Hardness: 10–350 N plus diameter 2–25 mm (the same module as the YPD-350N).
• Disintegration: one basket station with 6 tubes, 30–32 strokes/min.
• Dissolution: 6 vessels, USP Apparatus 1 (basket) and 2 (paddle), 10–300 rpm.

Why Engineering Teams Choose the SY-6DN

• Save space: one instrument instead of four.
• Data integrity: three-level user management, audit trail and USB export on one platform.
• Cost efficiency: one instrument to buy, qualify and maintain instead of four — contact our sales team for pricing.

Conclusion

USP <1216> is a short test with strict rules: the right sample size, 100 rotations at 25 rpm, a mean weight loss of not more than 1.0% and no broken tablets. Get those right and the result is defensible in any audit.

See SY-6DN specifications →

Frequently Asked Questions

Q: What is the formula for tablet friability?

A: Friability (%) = (W1 − W2) / W1 × 100, where W1 is the dedusted sample weight before tumbling and W2 the dedusted weight after 100 rotations. For example, 6.512 g before and 6.471 g after gives 0.63%.

Q: What is the USP friability limit?

A: Under USP <1216>, a maximum mean weight loss of not more than 1.0% is acceptable for most products. If the result is doubtful or above target, two more tests are run and the mean of the three is used. Any obviously cracked, cleaved or broken tablet means the sample fails.

Q: How many tablets are needed for a USP friability test?

A: For tablets with a unit weight of 650 mg or less, take whole tablets as close as possible to 6.5 g. For tablets heavier than 650 mg, take 10 whole tablets.

Q: What apparatus settings does USP <1216> require?

A: A drum with an internal diameter of 283–291 mm and a depth of 36–40 mm, rotating at 25 ± 1 rpm for 100 rotations, with tablets falling about 156 mm on each turn. The CJY-300E drums (286 mm × 39 mm) and the SY-6DN friability drum (about 287 mm × 38 mm) fall within these dimensions.