This document summarizes USP dissolution testing apparatus and procedures. It describes 7 different apparatus for testing dissolution of solid oral dosage forms including baskets, paddles, cylinders and flow-through cells. Key steps are outlined for each apparatus, including preparation of the dosage form sample, equilibrating the dissolution medium, operating conditions, sampling time points and procedures. Temperatures and rotations speeds are specified. The goal is to perform dissolution testing under standardized and reproducible conditions to evaluate drug release characteristics.

1. USP DISSOLUTION STUDIES

2. DISSOLUTION A process in which a solid substance solubilizes in a given solvent. i.e. mass transfer from the solid surface to the liquid phase. USP DISSOLUTION APPARATUS • Apparatus 1 - Basket (37º) • Apparatus 2 - Paddle (37º) • Apparatus 3 - Reciprocating Cylinder (37º) • Apparatus 4 – Flow-Through Cell (37º)

3. • Apparatus 5 – Paddle over Disk (32º), Transdermal Delivery System, use paddle and vessel from Apparatus 2 with a stainless steel disk assembly to hold the transdermal on the bottom of vessel. • Apparatus 6, Cylinder (32º), Transdermal Delivery System, use Apparatus 1 except replace the basket shaft with a stainless steel cylinder element. • Apparatus 7, Reciprocating Holder, for transdermal delivery systems and also a variety of dosage forms

4. APPARATUS 1: The assembly consists of the following : A covered vessel, Transparent material, A motor, A metallic drive shaft, A cylindrical basket, The water bath permits the holding of temp inside vessel at 37±0.5 ̊C The vessel is a cylindrical with hemispherical bottom with dimension and capacity of.

6. Use 40mm mesh cloth.

9. The dosage unit is allowed to sink to the bottom of the vessel before rotation of the blade.

12. Equilibrate the dissolution medium to 37±o.5 ̊c

14. Within the time interval, withdraw a specimen from zone midway between the surface of the dissolution medium and the top of the rotating basket or blade , not less than 1cm from vessel wall.

18. Equilibrate the dissolution medium to 37 + 0.5°

19. Place 1 dosage-form unit in each of the six reciprocating cylinders.

20. Operate the apparatus

21. During the upward and downward stroke, the reciprocating cylinder moves through a total distance of 9.9 to 10.1 cm

22. Within the time interval specified withdraw a portion of the solution under test from a zone midway between the surface of the dissolution medium and the bottom of each vessel.

24. The pump forces the dissolution medium upwards through the flow-through cell.

25. The pump has a delivery range between 240 and 960 mL per hour, with standard flow rates of 4, 8, and 16 mL per minutes.

26. The cell is immersed in a water bath and the temperature is maintained at 37 + 0.5°

28. Place 1 dosage form unit on top of the beads.

29. Assemble the filter head and fix the parts together by means of a suitable clamping device.

30. Introduce by the pump the dissolution medium warmed to 37 + 0.5° through the bottom of the cell.

31. Collect the eluate by fractions at each of the times stated.

33. The temperature is maintained at 32 + 0.5°C

34. A distance of 25 + 2 mm between the paddle blade and the surface the disk assembly is maintained during the test.

36. Apply the transdermal system disk assembly.

37. The system may be attached to the disk by a suitable adhesive.

38. Place the disk assembly flat at the bottom of the vessel with the release surface facing up and parallel to of the paddle blade and surface of the dissolution medium.

39. Operate the apparatus

40. At each sampling time interval, withdraw a sample from a zone midway between the surface of the dissolution medium and the top of the blade, not less than 1 cm from the vessel wall.

42. The dosage unit is placed on the cylinder at the beginning of each test.

44. Equilibrate the dissolution medium to 32 + 0.5°C

45. Prepare the test system prior to test as follows.

46. Remove the protective liner from the system and place the adhesive side on a piece of cuprophan.

48. Press the cuprophan covering to remove trapped air bubbles.

49. Place the cylinder in the apparatus and immediately rotate at the rate specified

50. Within the time interval specified, withdraw a quantity of dissolution medium for analysis from a zone midway between the surface of the dissolution medium and the top of the rotating cylinder, not less than 1 cm from the vessel wall.

52. A motor and drive assembly to reciprocate the system vertically

53. A set of suitable sample holders.

55. Taking care to eliminate air bubbles between the substrate release surface

56. Attach the system to a suitable sized sample holder with a suitable O-ring.

58. Reciprocating a frequency of about 30 cycles per minutes with an amplitude of about 2 cm.

59. Remove solution containers from the bath, cool to room temperature.

61. Thank you