TAPI’s PSD measurement techniques and best practices

TAPI’s PSD measurement techniques and best practices

TAPI’s PSD measurement techniques deliver customer benefits

By Adi Ben-Yaakov, TAPI R&D Physical Team Leader


PSD method development validation and analysis 

Active Pharmaceutical Ingredients have several important physical properties including polymorphism, water content, density and particle size. Particle Size Distribution, or PSD, has a direct influence on material properties such as: flowability, handling, dissolution rate, stability, and efficacy of delivery.

Video Products Guide How to

Watch our PSD best practices video now to see how TAPI can support your needs, and share it with your colleagues!

 >>> Contact us if you have any questions on PSD methods or the information provided in this video


PSD is one of the most important physical properties of powder APIs. To ensure robust formulation, it is essential that PSD measurement be accurate, repetitive and consistent. TAPI uses industry-leading best practices for PSD method development, such as microscopy and laser diffraction, to support more than 370 APIs and Help us to meet each customer’s unique needs and specifications.


Examples for suggested solutions in case the results are not the same as your API supplier:


Case: Using different PSD methods - TAPI PSD method is by wet dispersion of the API and customer's by dry dispersion.

  • Impact: In most cases the customer will get much lower results than our CoA, sometimes OOS.
  • Solutions: one of the sides adopting the other's method OR TAPI will develop and use a third method that will obtain similar results like the customer's.


Case: Using the same PSD method with slight differences in measurement protocol or equipment - Both TAPI and customer methods are by wet dispersion of API but one of the methods is more aggressive.

  • Impact: In many cases the customer will get different results than our CoA, sometimes OOS.
  • Solution: aligning the method / sample preparation aggressiveness/gentleness like in customer's method at TAPI QC in order to obtain similar results like the customer's.


TAPI recommends our customers make use of TAPI’s years of experience and adopt our improved PSD measurement methods to help to ensure accurate and compliant results. This short video shares the practices and processes we recommend, advises on the important customer benefits offered by TAPI, and shows some of the state-of-the-art tools and techniques we use to deliver precise PSD characterizations and comprehensive analysis for each API.

Please feel free to contact us with any questions, or if you need TAPI's support with PSD related information for your API related projects