PharmaCalc

Extended-release (ER) dosage forms are tested against multiple time points with two-sided ranges, not against the single Q threshold used for immediate release. USP <711> evaluates ER products under Acceptance Table 2 in three levels, L1, L2, L3. The ranges for each time point come from the individual monograph (or the approved specification) and are expressed as percentages of labeled content; the final time point carries a minimum (“not less than”) requirement.

The logic differs from immediate release for a reason: an ER product can fail in two directions. Releasing too slowly risks lack of efficacy; releasing too fast — dose dumping — risks toxicity. A one-sided Q criterion cannot detect the second failure mode, which is exactly why interim points are ranges.

Scope note: delayed-release products are different again — <711> tests them in an acid stage and a buffer stage under Acceptance Tables 3 and 4. This calculator covers extended release.

Testing continues through the levels unless the results conform at L1 or L2. The tolerances (10%, 20%) are percentages of labeled content, in the same terms as the stated ranges.

Scenario: monograph specification for a hypothetical ER tablet — 1 h: 20–40% dissolved; 4 h: 45–65%; 8 h: not less than 80%.

1. Test six units at L1.
   Example Data

   Unit	1 h (%)	4 h (%)	8 h (%)
   1	25	50	84
   2	28	55	88
   3	31	58	86
   4	33	61	91
   5	29	53	83
   6	35	57	90

2. Apply the L1 criteria: every 1 h value sits in 20–40; every 4 h value in 45–65; every 8 h value ≥ 80.
   Interpretation

   Conforms at L1 — test complete.
3. Contrast — how an L2 continuation works: had unit 6 read 42% at 1 h, it lies outside the 20–40 range and L1 is not met; testing proceeds to L2 with six more units.
   L2 questions

   Does the 12-unit average at each time point sit inside each range (and ≥ 80 at 8 h)?
   Is any single unit more than 10% of labeled content outside a range — for the 1 h range, below 10% or above 50%?
   A unit at 42% is outside the range but within the +10% tolerance; a unit at 52% would fail L2 outright at that time point regardless of averages.

• Ranges are inputs: the stated ranges come from the monograph or approved specification; this calculator applies the Table 2 logic to the ranges you enter, it does not supply ranges.
• Multiple range sets: where a monograph specifies more than one range set, the acceptance criteria apply individually to each range.
• Time points: generally expressed in hours and monograph-specific; a typical specification uses at least three points covering the early, middle, and final portions of the release profile.
• IR is different: immediate-release products use Acceptance Table 1 (Q-based, one-sided) — a different calculator on this site. Do not apply Q-based logic to ER data or Table 2 logic to IR data.

• USP–NF General Chapter <711>, Dissolution — Interpretation, Extended-Release Dosage Forms, Acceptance Table 2 (official text). Note: some earlier editions numbered the ER table differently; the current official text is Acceptance Table 2.