On this interview, trade specialists Nimesh Khadka and Keith Freel discover how Raman-based PAT enhances scorching soften extrusion by enabling real-time API monitoring, bettering course of management, and supporting High quality by Design in pharma.
Please may you give an summary of what scorching soften extrusion is and why it has turn out to be so essential in drug improvement?
Keith Freel: Scorching soften extrusion (HME) is a sophisticated, however now established, method for formulating medicine. It entails feeding an API with a polymer right into a heated extruder, the place the fabric is melted, blended, and formed.
Over 20 FDA-approved merchandise use HME as a result of it improves the solubility of poorly water-soluble medicine, stabilizes delicate molecules, and permits managed or sustained launch. It’s additionally steady, which is effective for scalability and high quality consistency. Past that, it helps modern dosage types resembling filaments for 3D printing or skinny movies for oral supply, making it extremely versatile.
Picture Credit score: Thermo Fisher Scientific – Transportable and Handheld Course of Raman Spectroscopy
Why is real-time monitoring of APIs throughout scorching soften extrusion essential for pharmaceutical manufacturing?
Nimesh Khadka: Scorching soften extrusion is broadly used to enhance drug solubility, bioavailability, and stability, however the course of is very dynamic. The state of the API—whether or not crystalline or amorphous—and its interplay with the polymer matrix straight have an effect on drug efficacy and high quality.
Conventional offline evaluation is gradual and might miss vital variations. Actual-time monitoring with Course of Analytical Know-how (PAT), resembling Raman spectroscopy, permits us to quantify APIs constantly, assess their bodily state, and detect interactions as they occur. This not solely improves course of understanding but in addition enhances consistency, reduces batch-to-batch variation, and helps regulatory expectations for high quality by design.
How does Course of Analytical Know-how (PAT), and Raman particularly, match into the High quality by Design framework?
Keith Freel: PAT is integral to High quality by Design (QbD). QbD begins with defining a high quality goal product profile, figuring out vital high quality attributes (CQAs), and linking them to course of parameters.
PAT instruments like Raman spectroscopy allow us to watch CQAs—resembling API focus, crystallinity, and dissolution—straight in actual time. That helps guarantee we stay throughout the outlined design area and provides us speedy suggestions to take care of management methods. Raman, particularly, supplies molecular-level info, which strengthens course of understanding and helps regulatory compliance by embedding high quality into the method slightly than testing for it afterwards.
Picture Credit score: Thermo Fisher Scientific – Transportable and Handheld Course of Raman Spectroscopy
What was your experimental setup, and why did you select acetaminophen because the mannequin compound?
Keith Freel: We mixed the Thermo Scientific Pharma-11 Twin Screw Extruder with the MarqMetrix Course of Raman Analyzer, putting the Raman probe within the heated die. Acetaminophen was chosen as a result of it’s a well-characterized API and a very good mannequin for finding out solubility and polymorphism. We used Soluplus because the polymer and ready blends of 0 %, 10 %, 25 %, and 50 % API. As the fabric moved by means of the extruder, Raman spectra had been collected each 20 seconds. This setup allowed us to check whether or not Raman may reliably monitor focus and bodily state throughout a dwell HME course of.
Picture Credit score: Thermo Fisher Scientific – Transportable and Handheld Course of Raman Spectroscopy
How efficient was Raman in quantifying API focus throughout extrusion?
Keith Freel: The Raman spectra confirmed clear adjustments similar to the acetaminophen focus. Utilizing partial least squares (PLS) regression with offline HPLC information for calibration, we constructed a predictive mannequin that was extremely correct. The basis imply squared error of calibration was round 0.5 %, and validation runs gave about 1.4 % error. This proved that Raman can present dependable, real-time quantification. Extra importantly, it captured transient variations, for instance, stabilization delays after focus adjustments, that may not have been seen with solely offline sampling.
May Raman additionally detect polymorphic transitions or recrystallization of the API?
Keith Freel: Sure, Raman is delicate to molecular kind. We in contrast our spectra with printed information for crystalline and amorphous acetaminophen and located that every one extrudates remained amorphous all through processing. No recrystallization was noticed. This functionality is vital as a result of polymorphic transitions can alter drug efficiency. Raman may also be utilized downstream, for instance, to watch cooling or stability research, making it a precious instrument past simply real-time course of monitoring.
At what level did the MarqMetrix All-in-One Course of Raman Analyzer show most dear in your examine?
Nimesh Khadka: The analyzer’s flexibility and robustness made it particularly precious throughout in-line monitoring. Its compact measurement allowed straightforward integration into the extruder setup, and its secure calibration lowered the necessity for upkeep.
By working in in-line mode, it offered steady, real-time information. We had been in a position to monitor acetaminophen focus, affirm its amorphous kind, and even detect refined API–polymer interactions. These insights had been vital for optimizing the method and guaranteeing product high quality. The power to make use of the identical instrument in at-line or on-line configurations additionally provides to its versatility in each improvement and manufacturing environments.
What benefits does Raman supply in comparison with different PAT instruments resembling NIR or UV-Vis?
Nimesh Khadka: Every method has strengths. UV-Vis is delicate however much less particular. NIR and Raman are each vibrational strategies, however NIR is absorption-based whereas Raman is scattering-based, with completely different choice guidelines. They’re complementary: some vibrations are stronger in NIR, others in Raman.
For instance, Raman is superb for non-polar bonds and is much less delicate to water, which is a giant benefit in aqueous programs. NIR, then again, could also be more practical if fluorescence interferes with Raman. What makes Raman particularly highly effective is its capacity to offer structural info, enabling us to check not simply concentrations but in addition polymorphism and API–polymer interactions.
How scalable is that this Raman-based PAT strategy, and the way do regulators view it?
Keith Freel: It’s scalable, although probe positioning should be rigorously thought of when shifting to bigger manufacturing programs. From a regulatory perspective, PAT is strongly inspired. The FDA and ICH have each promoted PAT by means of high quality by design initiatives. So long as Raman strategies are correctly validated and developed in response to pointers, they’re accepted as dependable instruments for guaranteeing constant product high quality in each scientific and industrial manufacturing.
Lastly, what alternatives are there for professionals to realize hands-on expertise with Raman in HME?
Keith Freel: On the College of Maryland Faculty of Pharmacy, we run the Tablets and Capsules quick course, which incorporates lectures and sensible labs. One of many periods integrates Raman spectroscopy with scorching soften extrusion utilizing the Pharma-11 extruder. Members learn to gather real-time information, construct fashions, and apply PAT rules in follow. It’s a singular alternative to bridge concept with hands-on coaching, which is vital for anybody working in superior pharmaceutical manufacturing.
About Nimesh Khadka 
Dr. Nimesh Khadka is a Senior Product Utility Specialist at Thermo Fisher Scientific and holds a PhD in Biochemistry from Utah State College. With in depth experience in analytical biochemistry, spectroscopy and chemometrics, he’s presently main efforts to champion Raman spectroscopy as a course of analytical expertise (PAT). As an lively member of the American Chemical Society, Nimesh stays on the forefront of rising applied sciences and is dedicated to driving innovation to fulfill buyer wants.
About Keith Freel 
Dr. Keith Freel holds a Ph.D.in Bodily Chemistry from Emory College and has in depth analytical chemistry experience. As Analysis Undertaking Director on the College of Maryland Faculty of Pharmacy, he oversees superior analytical initiatives supporting pharmaceutical and biomedical analysis. Beforehand, he spent over 5 years at Thermo Fisher Scientific as a Workers Scientist, the place he led R&D efforts throughout a variety of strategies together with FTIR, Raman, NIR, XRF, ICP-MS, and multivariate statistical evaluation.
About Thermo Fisher Scientific Inc.
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