Dissolution Testing in Pharmaceutical Analysis (Part 3)

The dissolution test is a key test parameter for assessing the performance of solid and semi-solid dosage forms in both drug development and quality control.

In part 1 of this article, we gave you a summary of the test's purpose and the apparatuses according to the European Pharmacopoeia. In part 2, we provided an overview of the requirements laid down in dissolution guidances and associated documents. Part 3 now deals with automation in dissolution testing.

Automation of Dissolution Tests

Dissolution testing is very work and time-intensive. The test consists of several steps:

• media preparation
• filling of the medium
• insertion of the tablets
• sampling
• analysis of the samples
• removal of the sinkers
• cleaning of the apparatus

Depending on the dosage form, the entire test can take a long time. For this reason, automation of the test can be helpful. Dissolution systems with varying degrees of automation are available from different manufacturers.

With regard to the degree of automation, a distinction can be made between semi-automatic and fully automatic dissolution systems. In fully automated dissolution systems, all steps are automated. In semi-automatic systems, sample collection is typically automated, as this is a particularly work-intensive step.

The following variants can be used:

• manually operated systems and HPLC / UV Offline measurement
• automated sampling device (ASD) and HPLC / UV Offline measurement
• semiautomated systems equipped with online analytics

• fully automated systems with online analytics

Advantages and Disadvantages of Automating Dissolution Tests

Automation in dissolution testing offers a number of advantages. These include:

• reduction of the workload for the laboratory staff
• minimization of possible sources of error
• better reproducibility
• less variability of test results
• increase in sample throughput
• automatic pH change of the medium is possible
• constant cleaning process

However, the advantages mentioned are also counterbalanced by some disadvantages that need to be taken into account when making a decision:

• high purchase costs
• comparatively high effort and associated costs for qualification
• increased effort for method validation Method validation
• higher maintenance effort