Cocrystals - the Champions League of Solid-State Pharma Formulation
Together with our partner Solidchem we organized a webinar about cocrystals on 15 April 2021.
We were surprised by the number of registrations: 147 from 21 countries.
One of the major challenges in pharmaceutical formulation is the low solubility of APIs. A very elegant, but non-trivial way to improve or even control the solubility and therefore bioavailability of an active compound is the formation of a cocrystal. Combined with non-volatile coformer molecules, the API forms a new crystalline single phase and thereby creates a new material that is different from simple polymorphs or physical mixtures of the API and conventional formulation ingredients. Thus cocrystals may also offer interesting opportunities to circumvent patent issues.
Nevertheless, up to now finding a suitable cocrystal usually requires expert knowledge and a vast variety of experiments.
This webinar will convey the experience of SOLID-CHEM in this field. It will provide information about advantages, but also the complexity and difficulties of cocrystal screening.
Furthermore, we will present a new method to improve the conventional screening approach by a goal-oriented way of using ternary phase diagrams prior to and in combination with the actual screening procedure.
The speaker Carsten Schauerte is the cofounder and managing director of SOLID-CHEM GmbH and has over 20 years of experience in the field. He has gained expertise with solid-state problems and cross-linked analytics. His highly motivated and research-oriented team was recently awarded the German Innovation Medal.
Graphenes, single and multiwall carbon nanotubes (CNTs) and many different applications from batteries to conducting composites were topic of this NanoCarbon annual conference initiated by the German Network NanoCarbon and the Nanoinitiative Bayern GmbH. Started in 2015, this conference has become more and more international and with 34 presentations, interactive “coffee rooms” and lively discussions after presentations, the new online format has been proven successful over the two day, 02.-03.03.2021.
My presentation “surface properties of graphenes, carbon blacks and carbon fibers by IGC” received a great deal of interest. No wonder, interaction behavior and surface functionalization was often mentioned, but analysis has been mostly restricted to SEM or TEM images or application results. We are now in contact with several institutes and are looking forward to contribute towards the many different applications.
On the 10th February we held another webinar about IGC with more than 60 registrations from Europe but also from India, China, Egypt and Canada which was a great surprise for us.
In this webinar we presented and explained step-by-step the sample preparation, choosing, how to fill column properly and how to run first experiments with alkanes and polar probes.
We also gave practical tips how to find the appropriate condition of sample weight, flow rate and temperature. Other points included to minimize the pressure drop with nano-scale material, how to use fibrous material or even how to use a shorter column for polar probes and a longer one for non-polar probes – and combine the data.
You find a graphical summary below or you may even watch the recording of the webinar on our Youtube channel, see linke below.
If you have any questions concerning IGC or any other method for surface characterization, feel free to contactus.
This article is about our partner SOLID-CHEM GmbH, its beginnings and why it has received the Innovation Medal, or in German “Stiftersiegel,” for Innovation by Research awarded by the German Donor’s Association (Stifterverband) for its intensive and dedicated activities in research.
The Beginning in 2010 SOLID-CHEM has its origin as a spin-off from University Duisburg-Essen, founded in 2010 at the Bochum University Campus by the two enthusiastic scientists Professor Dr. R. Boese and Dr. C. Schauerte.
“About three decades ago,” Boese recalls, “crystal engineering came up as part of solid-state chemistry and gained importance in organic and pharmaceutical Industry.” This was obvious with an increasing number of patent applications and litigations on polymorphism of APIs (Active Pharmaceutical Ingredients) and the request for experts in the field. Our research interests originated in crystallization techniques in crystallography but gradually shifted to co-crystals, salts, amorphous phases, and the characterization in the wide field of analytic techniques, - spectroscopic, diffraction, thermochemical, particle size determinations, etc.
Competences and early Challenges About ten years ago, they had an extensive network to Industry. With the desire for more independence and space, we recognized that all this would fit for a new business, so we looked for suited laboratories and basic lab equipment. Focused on material properties like solubility, bioavailability, melting temperature, shelf-life stability, hygroscopicity, filtering properties, compressibility, tableting ability, and so on, we were in the perfect position for recruiting our team from the previous research group at University. It appeared that we had to face many new challenges, such as organizing the internal structure and always having economic needs in vision. Carsten Schauerte was fortunate to spot suited laboratories right in time at a new-built technology center next to the Bochum Ruhr-University campus. “This was an ideal environment for us, with contacts, support for equipment and scientific environment, with the vicinity for discussions and collaboration, with numerous Universities and Institutes at a radius of less than 100 km, and the possibilities to host BSC and MSc students. But, it looks much easier than it was - and still is. We had to adapt to industry rules, strict deadlines, quick decisions and priorities, unexpected expenses, safety and employment law, plus the understanding and language of other disciplines, pharmacy, formulation specialists, technical, physical and theoretical chemists, and last but not least with patent lawyers."
Continuous Focus on Innovation “Besides all, we continuously invest in research, and we host BSC and MSc students to establish a dynamic exchange with Universities,” Carsten says with pride. “But innovation does not only deal with scientific issues. Real success only comes from collaboration across different disciplines. This is possible only if all the common languages are spoken- of organic, bio, theoretical, and technical chemists, plus pharmacists, and, last but not least, of patent lawyers. Today, solid-state forms of crystalline polymorphs, co-crystals, salts, or amorphous states are our daily business. We can identify, select, or even produce different solid-state forms of APIs even when they influence or mutually counteract each other”.
 The German Donor’s association (Stifterverband) is a powerful organization of 3’000 multinational companies, smaller enterprises and private persons with an annual funding volume of 150 mio EUR dedicated to science and education.
Are you fully aware that many essential physicochemical properties of an Active Pharmaceutical Ingredient (API) depend on its solid-state structure? Solubility, bioavailability at desired levels, shelf-life stability, hygroscopicity, compressibility, tableting ability, electrostatic charging, plus many others, can be crucial properties. And the decision is not trivial, which kind of solid-state form should be produced or selected for an API and which data are required by patent lawyers. Sophisticated analytical tools and the right expertise are essential for successful evaluations.
Inolytix AG represents now SOLID-CHEM GmbH in Switzerland By working together on analytical projects, it became clear that SOLID-CHEM GmbH, Bochum, Germany possesses special equipment of instruments and the right expertise – especially for the pharmaceutical industry but also for others. Customers reacted very positively, for example, “…now my favorite CRO for ssNMR….”. Therefore, we are pleased to announce that Inolytix AG is now an exclusive partner in Switzerland for services offered by SOLID-CHEM GmbH.
Offering a comprehensive service of solid-state analysis Exploring suitable solid-state forms (amorphous, polymorphs, salts, co-crystals, or solvates) requires a diverse methodological portfolio plus the expertise and the compounds for (co ) crystallization. Moreover, you need to precisely define all the appropriate analytical tools when matching your API with the final formulation. Many methods exist for determining solid-state forms because the intermolecular interactions responsible for the solid-state have a very subtle character. Diffraction- and thermochemical methods, particle determination, ssNMR, humidity determination, etc. - all this requires collaborating specialists overviewing such cross-networking analyses. Finally, they have to understand the different languages when speaking to organic, bio, theoretical, and technical chemists, to pharmacists, formulation specialists, and, last but not least, with patent lawyers.
It will be our pleasure and ambitious task to provide you with the best analytical services for solid solutions for the solid-state of pharmaceutical products ranging from
• pure APIs to complement tablet formulations • screening procedures of solid forms, • data for patents or stability tests
Any questions about your solid product form? Contact us, and let’s discuss it!
Please find below two supporting documents:
A one-page overview by SOLID-CHEM about Screening Procedures of different solid forms, e.g. polymorphs and characterization methods
A detailed presentation of the different characterization methods and applications with examples created by SOLID-CHEM and Inolytix
Inolytix, Aargau (Switzerland) - Inolytix is a startup launched in 2014 with the focus on accelerating product development and true understanding for the chemical and pharmaceutical industry. Through new and innovative analytical methods delivered by reliable and experienced partners such as SOLID-CHEM, Inolytix offers a customer-friendly service for R&D departments: providing the customer with a clear expert view and access to effective, but less known analytical methods, Inolytix manages the whole process from quotation to the industry- oriented report on the results. Contact: Dr. Ralf Dümpelmann (for Switzerland), Founder and Managing Director firstname.lastname@example.org, phone: +41 79 312 9327, www.inolytix.com
SOLID-CHEM GmbH (Germany, Bochum) - Founded by Prof. Boese and Dr. Schauerte as a spin-off from the University of Essen, SOLID-CHEM GmbH has become an expert center of solid solutions for the solid-state of pharmaceutical products. The philosophy is, to support customers with expert opinions based on experimental, scientific, carefully retrieved data and on precisely documented experiments. Results and reports from investigations can be potentially used for litigations, and therefore, scientific integrity is our absolute priority. Contact: Dr. Carsten Schauerte, Managing Director and Co-founder, email@example.com, phone: +49 234 936 90610, www.solid-chem.de
Surface analysis of solids as particles, fibers and plats can be very tricky. Dynamic gas adsorption with 15+ different gas probes, also known as Inverse Gas Chromatography (IGC), delivers very detailed information about surface energies, nanoroughness, polarity, acid/base properties (Lewis) and surface heterogeneity.
Adscientis has 20 years of experience of analyzing samples by IGC with now over 800 different projects for the industry. Recently, Adscientis made a great step forward in IGC with a new automated system (neuronicIC) of high flexibility, accuracy and transparency of all process conditions overcoming thereby many shortcomings of existing instruments. Inolytix, founded in 2014, is an enthusiastic promoter of innovative analytical techniques and IGC in particular from the beginning. Analytical challenges of the chemical and pharmaceutical industry are successfully solved especially of solid and surface properties. With respect to IGC, the focus is on the german-speaking market, i.e. Germany, Switzerland and Austria. The annual organization of the International IGC-Symposium is one of the examples of community support and expert network.
Inolytix and Adscientis start a globalcooperation Now, with the new IGC instrument, both experienced companies decided to join forces for a global collaboration. This involves common communications about the use of IGC, the new instrument properties, application notes, webinars and an extension of the IGC Symposium worldwide. “It is exciting to work so closely together and to use our mutual understanding of surface characterization on a global scale”, says Ralf Duempelmann, Managing Director and Founder of Inolytix. Eric Brendle, CEO of Adscientis adds “After six years of some cooperation with Inolytix, it is now just the right time for a closer cooperation. We share the same spirit and enthusiasm to move IGC towards the next level”.
Interested in surface and solids characterization? Having issues with qualities, batch-to-batch properties or understanding product modifications? Don’t hesitate to contact either one of the companies! Our expertise and their our willingness to characterize difficult surfaces will bring you forward – either using IGC or complementary analytical techniques.
Adscientis, Wittelsheim (France) - Adscientis, founded in year 2000, is today recognized as the most reliable IGC specialist. With over 800 customer projects, the company acquired a unique set of skills and know-how on IGC techniques for the surface characterization of powders ranging from carbon black to pharma products, fibers and flat surfaces. The art of using dynamic adsorption and 15+ gas probes is refined continuously to deliver reproducible and quantitative values of surface energy, nanoroughness, polarities, acid/base properties, surface heterogeneity, specific surface areas and even HSP values. The results address crucial challenges as quality issues, product development and application behaviors. The development of an automated and highly flexible IGC instrument is based on customer needs and a result of the long-term practical experience. Contact: Dr. Eric Brendle, CEO, e.brendle(at)adscientis.com, phone: +33 389 4800042, www.adscientis.com
Inolytix, Aargau (Switzerland) - Inolytix is a startup launched in 2014 with the focus on accelerating product development and true understanding for the chemical industry. Through new and innovative analytical methods delivered by reliable and experienced partners such as Adscientis, Inolytix offers a customer-friendly service for R&D departments: providing the customer with a clear expert view and access to effective, but less known analytical methods, Inolytix manages the whole process from quotation to the industry- oriented report on the results. Contact: Dr. Ralf Dümpelmann, Founder and Managing Director, firstname.lastname@example.org, phone: +41 79 312 9327, www.inolytix.com
I have worked for 20 years in the R&D of global chemical companies and I always appreciated their own, in-house analytical services. They are fast, have known methods, all costs are budgeted and best: costs appear only somewhere in the depths of SAP. Great!
Today, I’m running Inolytix Ltd and we bring innovative, less known analytical tools as external services into chemical companies. Why? It’s my believe and experience that many opportunities in understanding your F&E or quality issues are missed, simply because the known analytical methods are too often not the best. Or to quote Donald Rumsfeld “…there are also unknown unknowns, things we do not know we don't know.”
In this article, I’d like to discuss the advantages of in-house analytical services, the advantages of external analytical services and how to balance both in the best possible way. To be a bit provocative, I’m stating some common believes as myths and explain the truth behind. Are your experiences different or do you share similar stories? Would be great to know !
Myth #1: in-house analysis is the cheapest option Yes and no. For standard analysis like HPLC, being used on a daily basis, hardly anything can beat your own analytical laboratory. It is not only comparable in costs to the cheapest external laboratory (even though some outsourcing labs argue on price), but also fast and results can be easily discussed with the experts in-house. But for analytical methods not being used every day (like e.g. Raman-FTIR, XPS or IGC), things look very different: These analytical services (if available in-house) seem cheap too but in fact, they are not.
Truth #1: a lot of in-house costs are hidden Three factors seem to hide some of the true costs: First, service, maintenance and repair of analytical equipment is a considerable cost factor especially if not used on a regular basis. And these are cash-out costs. Second, method development for rarely used instruments are often difficult and time consuming. However, the analytical department needs to promote special methods, otherwise they will never be used – so costs are distributed. Least obvious, but very important is the third point: the value of expertise. Experts need exercise, many different samples and challenges. This is easy with daily analysis, but difficult with less used ones. Either the expertise is not very high or regular practice is costly – either way, this is not satisfying.
Myth #2: new analytical instruments amortize easily NO – at least in many cases. We all know this justification: the new instrument costs e.g. EUR 150’000. With 150 samples over 2 years, costing EUR 1’000/sample externally pay-back time would be 2 years only: a convincing argument! But really?? Before coming to Truth #2, I would like to mention a fact which makes it indeed easy to invest into new equipment – regardless of any follow-up costs. The investment budget for a new instrument is simply a different “box” than the operational budget. It is common sense to allocate some money for new instruments. However, this investment budget is often being fully used, irrespective of whether or not the new instrument is indeed useful and cost efficient.
Truth #2: operation, maintenance and expertise are expensive A true pay-back time calculation needs to incorporate all operating costs such as working time plus maintenance, method developments, amortization and the development of the required expertise to actually use the given instrument. The more underutilized the instrument is the worse becomes the calculation due to an increasing part of fixed costs. Let’s assume the in-house operating costs of the case mentioned above can be brought down to EUR 500 /sample. In this case, pay-back time doubles to 4 years! Some details are provided in an example including an FTIR instrument of USD 20’000 investment and external costs of USD 10’000. In conclusion, realistic pay-back times of analytical instruments are often much higher than anticipated. External services appear costly at first sight but in fact, they are often highly cost-efficient if compared on a 1:1 basis.
Myth #3: in-house experts are the best Surely, in-house experts are often very good, especially with methods they always use. But what about the other methods? Last year, I have visited a company sophisticated on rheology using rotary viscosimeters. But they did not know about micro-rheology offering new possibilities in their case. It needs a good balance between the NIH-syndrome (not-invented-here) and curiosity plus openness for new methods.
Truth #3: really good experts know when to ask for advice The solution for your analytical challenge may be in-house, but it might be also outside. Your experts are really good if they are curious, reach out to other experts and help to find the best analytical solution for you– and not just the one available. The first steps of external expertise are often free anyway. A short email or a phone call and you have more options to evaluate already. Surprisingly, I’m receiving these requests more often from development chemists than from analytical people.
In conclusion, there are many rational arguments to be more open towards external analytical services – to save money and to increase the understanding of the product properties.
Recordings of the presentations can be watched now.
When we had decide because of Covid19, if the annual IGC Symposium should take place in 2020, we did not expect this successful outcome. Instead of doing it onsite in person, we took the opportunity to offer it online. And suddenly the number or registrations increased rapidly. At the end we had more than 150 registrations from all over the world.
Another benefit of going online are the recordings that you can now watch afterwards, even if you did not attend the symposium. We published all those that we are allowed to publish on youtube. If you are interested in learning more about the applications and special details of inverse gas chromatography, you find the recordings below.
If you are interested in the slides you can download them here:
Our first online webinar "Introduction to Inverse Gas Chromatography (IGC) and Best Practice" on 8th June 2020 was a great success. More than 45 participants participated and actively engaged in the Q&A session. The initial objective of the webinar was to give newcomers in IGC a first understanding in this technology as a preparation for to 9th Int. IGC Symposium, 16th June 2020, see IGC Symposium website.
However, it seems, it was the beginning of an open, almost global dialogue about how to characterize powder and other surfaces by dynamic gas adsorption.
Summary of Introduction into Inverse Gas Chromatography
The webinar offered a brief, but concise overview in surface characterization of powders, fibres and even films by dynamic gas adsorption using 15 and more “gas probes” to “sense” the surface, also called Inverse Gas Chromatography (IGC).
Depending on the character of the gas probes, different parameters are obtained – quantitatively, sensitive and reproducible. The series of n-alkanes, e.g. hexane, heptane, octane, … provides the disperse surface energy 𝛾sd. The use of branched and cyclic alkanes provides information of a kind of nanoroughness either by exclusion of the bulkier probes compared to linear n-alkanes or by a kind of solubility by cyclic alkanes, characteristic for amorphous phases or organic coatings.
Several polar probes, ranging from chloroform to diethylether provide not only an overall specific polarity, but also an indication about the electron acceptor and donor properties, i.e. the Lewis acid and base character of the unknown surfaces.
The heterogeneity of the surface can be determined by saturating the surface at a defined p/p0 of a chosen probe molecule and interpretation of the desorption profile. The method provides not only the Adsorption Energy Distribution Function, but also the specific surface area, S(BET). Many advices on best practices, like the preparation of the samples or the concentration range of gas probes, are provided too.
During the webinar we mentioned different resources. Below you find the links for the participants or those, who are interested in the technology as such:
The Q&A session after the presentation highlighted many open questions and uncertainties around IGC as a technique. You find the questions and some of the answers below. We plan to answer them in a separate blog post. Follow us and stay tuned.
Do you know, that highly quantitative values for diffusion coefficients, adsorption isotherms of methanol on zeolites and energy distribution functions, as well as detailed characterization of recycled and artificially aged catalysts can all be performed by perfectly controlled adsorption and desorption processes? We have entirely redefined an instrument also known under the name “Inverse Gas Chromatography”, short IGC. Today, our setup is the most versatile instrument to study all kind of physisorption processes – not only for catalysts, but for many other powders, fibers and plates too.
We were so much looking forward to showing our poster (download below) about catalyst applications at the “53. Jahrestreffen Deutscher Katalytiker” scheduled for 11-13 March in Weimar – usually attracting around 600 experts! But: Due to the Corona crisis, this conference was cancelled. Now we are taking the online opportunity to explain the key features of our unique setup and explain the use by three very different applications.
Key feature of our IGC instrument is very flexible injection of any kind of volatile “probe” substance into the gas stream – either at very low concentrations, ideally “infinite dilution”, or at high concentrations at defined p/p0, e.g. 0.3, to allow a saturation of the surface. In IGC terms, these two regions are called IGC-ID and IGC-FC (finite concentration). An autosampler and a most accurate dosing system allows up to 48 different probe substances. We usually use 15 different apolar and polar molecular probes to characterize surfaces in its different dimensions.
A standard IGC characterization (IGC-ID) is done by using different n-alkanes at infinite dilutions to determine the disperse (apolar) surface energy 𝛾sd. Usually, we are adding seven different polar molecules ranging from chloroform to diethylether thereby covering electron acceptor (acidic) and donor (basic) probes. In the example, the customer wanted to characterize the changes of catalysts from fresh to used and the processes of recycling and artificially aging. The analysis revealed very clearly, that the recycling process is not only far from restoring the original surface properties but also increasing apolar properties far beyond those of fresh or used catalysts.
The ability to saturate the entire surface at a given p/p0 (IGC-FC) with any kind of probe molecule and to interpret the desorption isotherm in detail was used in a study of zeolites and methanol adsorption. The IGC-FC setup determines the adsorption isotherm, the specific surface area (BET), any irreversible adsorption and the Adsorption Energy Distribution Function (AEDF). The zeolites are very close in performance, but the adsorption of methanol and subsequent desorption revealed significant differences in the amount of irreversible bound methanol and in the distribution of the high energy sites. This way, it enabled a better selection and further optimization of the zeolites for application.
Also, saturation at a given p/p0 and desorption allows the determination of diffusion coefficients (D) in porous systems. In a setup called Zero Length Column (ZLC), a very small amount of sample is exposed to a given p/p0 and the sudden desorption front interpreted using a ln(c/c0) plot to obtain D by fitting the desorption curve. In the given example, the diffusion coefficients of toluene, cyclooctane and n-octane were determined for two different alumina beads. These examples show the power of the experimental setup by injecting any kind of volatile probes at different concentrations and accurately determine the physisorption behavior. The IGC framework provides a solid background to determine disperse surface energies but many more values can be obtained, like diffusion coefficients or adsorption energy distribution functions.