# Quality Control of Tablets > Quality control tests for tablets in Pharmacy: IP weight variation limits, Roche friability, disintegration, dissolution apparatus and content uniformity. - Canonical URL: https://prepelephant.com/topics/allied/pharmacy/quality-control-tablets-tests - Exam / course: Allied Health · Subject: Pharmacy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Quality Control of Tablets", PrepElephant, https://prepelephant.com/topics/allied/pharmacy/quality-control-tablets-tests ## Direct answer Tablet quality control divides into in-process checks during compression and finished-product tests against pharmacopoeial limits. In-process, every half hour or so, operators verify weight, hardness, thickness and friability so a drifting press is caught mid-batch. On the finished batch the official battery runs: uniformity of weight with IP tolerances that tighten as tablets shrink (broadly 5 per cent above 250 mg to 10 per cent below 80 mg); hardness of roughly 4 to 8 kg; friability by Roche friabilator — 100 revolutions in 4 minutes, loss not more than 1 per cent; disintegration in water at 37 °C within 15 minutes for uncoated and 30 minutes for film-coated tablets; and dissolution in basket or paddle apparatus with 900 mL medium, where a Q point such as not less than 70 per cent at the stated time decides bioavailability-relevant acceptance. For potent low-dose tablets, weight variation is replaced by content uniformity, the per-unit assay weight can never guarantee. ## What you must remember - **In-process rhythm:** weight, hardness, thickness and friability at defined intervals, with adjustments and segregated output logged — the data trail inspectors read. - **Weight variation (IP style):** about 5 per cent above 250 mg, 7.5 per cent for 80-250 mg, 10 per cent below 80 mg; only isolated tablets may exceed the band. - **Friability:** Roche friabilator, 100 revolutions in 4 minutes, acceptance below 1 per cent weight loss. - **Disintegration:** uncoated 15 minutes, film-coated 30 minutes; enteric resists 0.1 N hydrochloric acid 2 hours, then breaks up in pH 6.8 buffer within about 60 minutes — breakup, not drug in solution. - **Dissolution:** basket (commonly 100 rpm) or paddle (50 or 75 rpm) in 900 mL at 37 ± 0.5 °C against the monograph's Q point, frequently NLT 70 per cent at a stated time for immediate release. - **Content uniformity replaces weight variation** when the active is about 25 mg or less, or 25 per cent or less of tablet weight — the quotable rule of thumb. - **Hardness:** about 4 to 8 kg by Monsanto or Pfizer tester; the examinable inversion — excessive hardness delays disintegration and dissolution. - **Other finished tests:** identification, assay, water content where specified, and visual defect inspection. ## A batch drifting, caught the QC way Halfway through a paracetamol run, the half-hourly check finds weights creeping high — a lower punch retracting slowly means dies are overfilling. The chart catches the drift ten minutes of production deep; the interval is segregated and the press reset. Finished, the batch faces the official tests: twenty tablets weighed individually, none beyond the 5 per cent band — pass; ten tablets dedusted, tumbled 100 revolutions, 0.6 per cent loss — pass; six tablets disintegrated within 8 minutes at 37 °C — pass; six units in the paddle at 50 rpm in 900 mL phosphate buffer pH 6.8 all above the 70 per cent Q point at 30 minutes — the drug is not only released from the press but released in the gut. Only the HPLC assay against a working standard seals label claim. The sequence is the teaching: physical tests look for manufacture errors, dissolution looks for the patient, and assay looks for the molecule. ## The confusions that decide marks Disintegration versus dissolution remains the separator: a tablet can disintegrate into fragments whose drug never dissolves, so "passed disintegration therefore bioavailable" is the sentence examiners fish for. The second is hardness versus friability — opposite directions of one mechanical story — plus the deliberate inversion that the hardest tablet may be pharmacologically the worst, since over-compression slows disintegration and dissolution for poorly soluble drugs. Third, know when weight variation is invalid: a 500 microgram drug in a 300 mg tablet cannot be dosed by weighing, hence content uniformity with its own acceptance tables. Finally, remember friability's arithmetic is a weight-loss percentage, not a force, and that weight-variation tolerances scale inversely with tablet mass — a fact routinely recited backwards. ## Frequently asked questions ### What does the Roche friabilator measure and what is its limit? It tumbles dedusted tablets 100 revolutions in 4 minutes and measures percentage weight loss from chipping and abrasion; not more than 1 per cent is the conventional acceptance. ### When is content uniformity performed instead of weight variation? When the active is low — commonly 25 mg or less, or 25 per cent or less of tablet weight — because tablet weight then cannot predict the dose each unit delivers. ### Why is dissolution more meaningful than disintegration? Disintegration confirms only breakup into fragments, while dissolution measures drug actually entering solution at body temperature and hydrodynamics — the step that precedes absorption. ### State the IP-style weight variation limits. About 5 per cent for tablets above 250 mg, 7.5 per cent for 80-250 mg and 10 per cent below 80 mg, with only isolated tablets beyond the band. ### Which parameters are checked in-process during compression? Weight, hardness, thickness and friability at regular intervals, so a drifting press is corrected mid-batch and affected output segregated.