💊 Tablet dissolution test (dissolution)
Determination of dissolution rate of active substance from tablets and capsules in simulated gastrointestinal environment. Key bioequivalence test for generic drugs.
Overview
Dissolution test is one of the most important pharmaceutical tests, allowing assessment of active substance release from solid dosage forms (tablets, capsules) in vitro. Results correlate with drug bioavailability in vivo — drug must dissolve before being absorbed.
The test is performed in basket apparatus (apparatus 1, Ph.Eur./USP) or paddle apparatus (apparatus 2) in 500–1000 mL dissolution medium (buffer pH 1.2 / 4.5 / 6.8 or 0.1 M HCl). Samples are taken at specified time points and active substance concentration is determined (HPLC or UV). Acceptance criterion: Q = 80% in 30–45 min (immediate release) or profile according to specification.
Method principle
Tablet/capsule is placed in basket (apparatus 1, 100 rpm) or on vessel bottom with paddle (apparatus 2, 50–75 rpm) in 500–1000 mL dissolution medium thermostated at 37.0 ± 0.5°C. Medium samples are taken at specified time points (e.g., 5, 10, 15, 30, 45, 60 min), filtered, and analyzed spectrophotometrically (UV) or chromatographically (HPLC). Result: dissolution profile — plot of % released active substance vs. time.
Applications
- Quality control of solid drugs (tablets, capsules)
- Generic drug registration (in vitro bioequivalence)
- Stability studies — dissolution profile over time
- Formulation development — selection of excipients, coatings, polymers
- Batch release control — batch release
- Comparison of original and generic drugs (f2 similarity factor)
Key parameters
| Parameter | Value |
|---|---|
| Apparatus | Apparatus 1 (basket), Apparatus 2 (paddle) |
| Medium volume | 500, 900, or 1000 mL |
| Temperature | 37.0 ± 0.5°C |
| Rotation speed | 100 rpm (basket), 50–75 rpm (paddle) |
| Q criterion | ≥80% in 30–45 min (typically) |
| Number of units | 6 (S1), 12 (S2), 24 (S3) per USP |
Standard
- Standard number
- European Pharmacopoeia 2.9.3
- Title (PL)
- Badanie szybkości rozpuszczania tabletek i kapsułek
- Title (EN)
- Dissolution test for solid dosage forms
Step-by-step procedure
1. Medium preparation
Prepare 6×900 mL medium (e.g., 0.1 M HCl). Degas under vacuum or ultrasound 15 min. Heat to 37°C.
2. Vessel filling
Fill 6 vessels with 900 mL medium each. Check temperature (37.0 ± 0.5°C). Set rotation speed (50 or 100 rpm).
3. Test start
Place 1 tablet in each vessel/basket. Start stirring. Start timer.
4. Sample collection
Collect 5–10 mL medium at: 5, 10, 15, 30, 45, 60 min. Filter through 0.45 µm. Replace volume with fresh medium.
5. UV/HPLC analysis
Measure absorbance (UV) or concentration (HPLC) of active substance in collected samples.
6. Calculations and evaluation
Calculate % release at each point. Check Q criterion. Evaluate compliance with specification (S1/S2/S3).
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Dissolution apparatus (6 or 8 positions) | Agilent 708-DS, Sotax AT 7smart, Erweka DT 826 | 60 000–180 000 PLN |
| UV-VIS spectrophotometer | Agilent Cary 60, Shimadzu UV-1900i, Thermo Evolution 201 | 25 000–60 000 PLN |
| HPLC (if required) | Agilent 1260, Shimadzu Nexera | 200 000–400 000 PLN |
| Syringe filters | PVDF 0.45 µm, Full Flow, 25 mm | 1–3 PLN/pc |
| Automatic pipettes | Eppendorf Research Plus 1–5 mL | 800–2 000 PLN |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Hydrochloric acid 0.1 mol/L | 7647-01-0 | Medium pH 1.2 (stomach simulation without enzymes) |
| Acetate buffer pH 4.5 | — | Sodium acetate + acetic acid, per Ph.Eur. |
| Phosphate buffer pH 6.8 | — | KH₂PO₄ + NaOH, per Ph.Eur. (intestine simulation) |
| SLS (sodium lauryl sulfate) | 151-21-3 | Surfactant 0.5–2%, for poorly soluble substances |
| Active substance standard | — | Certified CRM (Ph.Eur. Reference Standard) |
Health and safety (OHS)
- HCl — corrosive, acid-resistant gloves and safety glasses
- SLS — irritant, avoid eye contact
- Medium 37°C — moderate burn risk
- Active substances — pharmacologically active, use gloves