DISSOLUTION SAMPLING STATION SS 8000INTRODUCTION

The Dissolution Sampling Station Model SS 8000 has been specifically designed for sampling from a Dissolution Tester.

Essentially, it is an automated sampling system capable of withdrawing volumetrically precise samples from a predetermined point within 8 dissolution vessels simultaneously. This can be achieved at user defined intervals or specified times. The aliquots are deposited directly into either sealed septum vials or test tubes for subsequent analysis.

The unit is extremely versatile in lending itself to a variety of detection techniques i.e., HPLC, UV-VIS, etc.  It is particularly useful for delayed release preparations and can operate unattended for long periods, for example, overnight.

Providing a sufficiently large aliquot is collected, it is also possible to evaluate two or more ingredients by simply re-running samples at different wavelengths or other destructive down stream chemistries later.

SYSTEM COMPONENTS

The system comprises three main elements:

1. The ‘Sample Station’ having a capacity of either 80 test tubes (10 ml), 1.2 ml or 4 ml sealed septum vials for HPLC (10 rows of 8)
2. The Peristaltic Pump which provides the motive force to transport the samples from the Dissolution Tester to the Sampling Station
3. The Control Module which serves to control the Sampling Station during operation
    

PRINCIPLE OF OPERATION

The principle of operation is very simple.

In this method, media from each of the dissolution vessels is circulated via an 8-line peristaltic pump through 8 switching valves prior to being returned to the dissolution vessel.

At user defined time intervals, the valves operate diverting a preset volume of sample into the sample collection lines whereupon the samples are dispensed into either the test tubes or in the case of the model for HPLC vials injected directly into the sealed septum vials by means of the electrically operated Vial Piercing Dispense Head.

The pump is then reversed to clear the sampling lines prior to the next sampling interval whereupon the operation is repeated.

The whole operation is controlled and monitored by the Control Module. The exact status of the test at any given time can be determined from the 4-line 20 character back-lit display provided for this purpose.

The HPLC vials containing the samples can be removed at any time and placed directly into an HPLC Autosampler.

In the case of the test tube (10 ml) version, the samples must be handled manually, for example by presenting them to the ‘sipper’ accessory of a suitable spectrophotometer.

This version is particularly useful where analytical techniques other than UV/VIS or HPLC are employed or where the samples require a degree of manipulation, for example to be diluted or mixed with a reagent prior to analysis.

MEDIA REPLACEMENT STATION

All of the relevant Pharmacopoeia state that the specified volume of media must be maintained to within /- 1%.

The Media Replacement Station provides for an equal amount of fresh media (equal to the sample removed) to be added to each of the 8 test vessels following the withdrawal of each set of samples in order to maintain the volume of media the dissolution vessels throughout the test. Pharmacopoeial requirements specify that any aliquots withdrawn for analysis should be replaced or corrected for in the calculations.

KEY FEATURES 

• Off-Line’ System specifically designed for dissolution studies 
•  Extremely compact (50 mm wide x 38 mm deep) excluding pump 
•  Easy menu-lead operating procedure via membrane keypad 
•  Fills direct into open or sealed HPLC vials as well as test tubes 
•  Accommodates up to 10 rows of 8 samples 
•  User selectable sampling intervals up to a maximum of 99 hours 
•  Reverse purge facility eliminates carryover 
•  Media replacement option 

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