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The particle-powder-processability interplay – powder characterization in pharmaceutical development
The particle-powder-processability interplay – powder characterization in pharmaceutical development
Q1. Have any computational methods proved useful when evaluating the 1st wave drug substance batch? For example, morphology prediction calculations for calculating particle shape.
we are currently in the evaluation of complementing computational methods for predictions of morphology and in my opinion, there are already some promising approaches. Up to now, we rely on experimental data (also as PSD measurements are quite quick and do not require a huge amount of sample) and use supportive AI applications e.g. in evaluation of SEM images.
Q2. Could you comment a bit on how well the results for neat API fit for or translate into the final formulation?
This is a very important aspect and in my opinion and as depicted with the P3 cycle also a big step to take for direct correlations between API and processability. How dominating the API properties will be, is on the one hand of course depending on the drug load. On the other hand, it depends on the nature of interactions between API and excipients. So we have seen powder blends with 20% drug load, performing almost like neat API in certain aspects. But it can also be the other way around that drug loads up to 60% are still dominated by the excipient/formulation.
Q3. Did you already define limits for processability e.g. in terms of flowability? And if yes, based on which method?
Yes we did e.g. for the direct compression process. The method with highest predictability in our studies was the ring shear tester.
Thermodynamics versus Kinetics: who wins the crystallization race?
Thermodynamics versus Kinetics: who wins the crystallization race?
Q1. Slide 26: Have you tested other morphology prediction calculations like Attachment energy or modified attachment energy to see how it effects the subsequent rugosity calculations?
No, we have not tested other methods. We plan to do this in the future. Whilst, this will be indeed a good improvement, I would not expect to make a significant difference in the overall particle rugosity.
Q2. Slide 36: Here you show that introducing impurities can change the kinetics. Polymer additives can change crystal morphologies for some systems, do you think this is related to a change in the kinetics?
The work by Weizmann institute team has shown how different impurities, including polymers, can interact differently with different crystal faces resulting in morphological changes. So, yes, polymers may also have the potential to impact kinetics of crystal faces differently.
Q3. You have been successful in the pharmaceutical industry, the CCDC and as an academic. How would your career advice differ depending on if one wants to go to industry or pursue an academic track?
Thanks for this question, which I could discuss for hours and hours! I have personally loved working in all these three environments. For me, the most important thing is the people I work with. I have been privileged to work with great people in all these three environments. I would advice that you need to keep passionate and learn to work enthusiastically with a team to succeed in any environment. Above anything, many of my choices have been dictated by family circumstances at the time. I value family and people above everything else, and if that is right and you are passionate, brilliant science will follow.
Q4. Slide 27: Have you compared the rugosity trend between known and unobserved but themodynamically stable polymorphs from CSP landscapes? For example, molecule XXIII or Galunisertib both have stable forms that are predicted but never observed.
Rugosity work is ongoing in my group and we are now looking into further systems and applications to CSP landscapes. Please keep an eye on the literature for some more exciting work.
Q5. a water activity value can favor a certain anhydrous polymorph?
No, the water activity will determine whether the hydrate is favoured over the anhydrous forms or the other way around. It will not impact the relative stabilities of anhydrous forms.
Q6. How one can generate paracetamol less stable form in bulk knowing that impurities playing role
You need the impurities to produce form II so that form I is blocked from nucleating and growing.
Q7. Slide 16: Any dvs study or water slurry performed on anhydrous form to check the conversion?
Yes, we did slurries to determine the critical water activity, please see the paper.
Q8. would you comment on Oswald's role implying more stable polymorph nucleates slower than metastable form?
The Oswald rule of stages is just a case of many scenarios whereby the metastable form is “easier” to nucleate than the stable form. However, not all systems behave like this and there is a very large body of examples in the literature where this is not the case. For example, form II paracetamol does not follow the Oswald rule.
Physical Properties Control in the Process of Crystallization of Ulotaront Hydrochloride
Physical Properties Control in the Process of Crystallization of Ulotaront Hydrochloride
Q1. Slides 26 -28, the PSD control is eternal topic in crystallization. For the reactive crystallization, it becomes more complicate as the reaction kinetics, mixing and mass transfer, and crystallization kinetics all play important roles for the PSD control. Could you explain what is the current control strategy on the PSD control in manufacturing and what is the consideration behind?
The PSD control for Ulotaront Hydrochloride is quite challenging as multiple parameters are involved, especially in scale-up manufacturing. In terms of the current PSD control strategy, firstly, the mixing assessment has to be done to define the mixing regime in the reactor. This will facilitate the dosing tubing design (subsurface dosing) and configuration, and it also enables the impeller selection and helps to define agitation rate. Secondly, the parameters affect the PSD has to be defined according to the kinetics study results. The parameters include the dosing profile, temperature, and agitation rate (de to its effect on secondary nucleation). The idea is to have all the critical process parameters defined based on the current process understanding in order to have robust and reliable control over the PSD.
Solid Formulations in Agriculture
Solid Formulations in Agriculture