Salt form screening is a pivotal strategy in solid-state chemistry used to modify the physicochemical properties of Active Pharmaceutical Ingredients (APIs) without altering their pharmacological activity. For ionizable drug candidates, selecting the optimal salt form can significantly enhance solubility, dissolution rate, bioavailability, and physical stability. BOC Sciences offers comprehensive salt screening services, utilizing expert solid-state characterization. We help clients identify the most developable crystalline forms for their drug candidates, resolving challenges related to hygroscopicity, polymorphism, and processability to accelerate early-stage drug development.
BOC Sciences delivers expert salt form screening to optimize your drug's solid-state properties, ensuring a smoother path to formulation.
BOC Sciences applies rational salt selection strategies to a wide range of ionizable compounds, customizing the counter-ion library based on the API's acid-base properties.
Submit your compound details, and our solid-state experts will design a tailored screening protocol to optimize your compound's performance.
We initiate the project by communicating with clients to understand specific development goals (e.g., solubility, stability) and receiving the compound samples to define the project scope.
We evaluate the compound's pKa, solubility, and structure to select a scientifically relevant library of counter-ions, ensuring a sufficient pKa difference (ΔpKa > 2) for stable salt formation.
Hits are analyzed by XRPD and PLM. Leading candidates undergo secondary profiling (DSC, TGA, DVS, Solubility) to assess stability and hygroscopicity.
We deliver a comprehensive report ranking the salt forms based on developability criteria, recommending the optimal form for scale-up and formulation.
Poor aqueous solubility is a major hurdle in drug development. Our salt screening services identify high-solubility salt forms that significantly improve dissolution rates, thereby enhancing oral absorption and bioavailability for BCS Class II compounds.
We address physical and chemical instability issues. By selecting the right counter-ion, we can increase the melting point to prevent melting during processing or select non-hygroscopic forms to maintain stability under humid storage conditions.
Some APIs exhibit poor flow, stickiness, or difficult filtration properties. We screen for salts with optimal crystal habit (e.g., prisms vs. needles) to improve powder flow properties, bulk density, and tableting performance.
Salt formation is an excellent method for purification. We design screenings to find salt forms that naturally reject process impurities during crystallization, providing a high-purity solid form as an alternative to complex chromatographic purification.
Partner with BOC Sciences to leverage our solid-state chemistry expertise. We provide rapid, data-driven salt screening to transform your problematic API into a developable, high-quality drug substance.
We go beyond basic identification. Our integrated analytical suite (XRPD, DSC, TGA, DVS, NMR) provides a complete picture of the solid-state properties of every candidate to support critical decision-making.
Our screening is driven by development needs. We prioritize salts that are not only stable and soluble but also manufacturable, scalable, and chemically compatible with common excipients.
Our solid-state chemists have extensive experience in crystallography and pre-formulation. We provide expert interpretation of complex data, guiding you to the best decision for your program.
We ensure a smooth transition from lab-scale screening to process development. By integrating solid-state science with process chemistry, we validate that your selected form remains robust during scale-up.
Client Needs: A client had a promising BCS Class II weak base with extremely low aqueous solubility (< 1 µg/mL), resulting in poor oral bioavailability in animal models. They needed a salt form to improve dissolution.
Challenges: The free base was highly crystalline and difficult to dissolve in common screening solvents. Initial attempts with simple mineral acids (HCl) resulted in hygroscopic salts that were difficult to handle.
Solution: Leveraging our rational counter-ion selection algorithm based on pKa differences, BOC Sciences executed a targeted high-throughput screening utilizing a diverse range of organic sulfonic acids. By systematically optimizing solvent polarity and supersaturation levels, we successfully isolated highly crystalline Mesylate and Tosylate salts, confirming their stoichiometry and purity through rigorous solid-state characterization (XRPD, NMR) to ensure superior developability.
Outcome: The Mesylate salt demonstrated a 60-fold increase in aqueous solubility and a significantly faster dissolution rate compared to the free base. The client selected this form for further development, achieving target exposure levels in subsequent PK studies.
Client Needs: A pharmaceutical company was developing an HCl salt of a drug candidate, but the material was deliquescent at RH > 50%, requiring expensive moisture-controlled manufacturing suites.
Challenges: The drug had limited counter-ion options due to pKa constraints. The client needed a stable, non-hygroscopic alternative without losing the solubility advantage of the HCl salt.
Solution: Our solid-state experts employed a crystal engineering approach, specifically screening dicarboxylic acids known to promote dense crystal packing networks. Through iterative crystallization experiments and real-time Dynamic Vapor Sorption (DVS) profiling, we identified a unique 1:1 Fumarate salt structure where the lattice energy landscape favored exceptional physical stability, effectively blocking moisture ingress even under elevated humidity conditions.
Outcome: The Fumarate salt was successfully scaled up. It maintained good solubility while solving the moisture stability issue, allowing the client to manufacture the drug product in standard facilities, reducing costs.
Client Needs: During the scale-up of a Citrate salt, a client observed batch-to-batch variability in melting point and dissolution, suspecting uncontrolled polymorphism.
Challenges: The system was prone to forming metastable polymorphs and solvates depending on the cooling rate and solvent composition. The client needed a robust process to produce the thermodynamically stable form consistently.
Solution: To definitively resolve the phase capability, BOC Sciences conducted exhaustive thermodynamic mapping using competitive slurry experiments and solvent-mediated phase transformation studies across multiple temperature ranges. We constructed a precise energy-temperature diagram to identify the true stable polymorph and developed a controlled seeding strategy that effectively suppresses metastable zones, ensuring process robustness.
Outcome: We developed a controlled crystallization process seeded with the stable polymorph. This ensured consistent production of the desired form, eliminating batch variability and securing the solid-state integrity of the API.
Salt form screening can significantly optimize a compound’s solubility, stability, and manufacturability, providing candidate forms with superior physicochemical properties. Systematic evaluation helps identify potential issues early and reduce development risk. BOC Sciences offers extensive experience to provide multi-dimensional salt screening strategies and scientifically feasible optimization solutions.
Salt form selection is influenced by a compound’s acid-base properties, crystallization behavior, solubility, and interactions with solvent systems. Different salts may vary in manufacturability, stability, and solubility. BOC Sciences considers these factors comprehensively, using high-throughput experimental design and data analysis to identify the optimal salt combinations, improving R&D efficiency.
Salt form screening can optimize solubility, crystal stability, physical-mechanical properties, and solvent compatibility, enhancing compound development feasibility. Scientific screening and evaluation allow clients to obtain more stable and processable forms. BOC Sciences provides systematic experimental design and performance assessment to ensure results are scalable and practically valuable.
Efficient salt form screening relies on a systematic strategy and high-throughput platforms. By optimizing combinations of salts such as hydrochloride, sulfate, and sulfonate under varied experimental conditions, potential candidates can be rapidly identified. BOC Sciences uses mature workflows and data analysis to increase screening speed and success rate, helping clients save development costs.
Salt form screening services cover candidate salt selection, solubility measurement, crystal analysis, stability assessment, and screening strategy optimization. BOC Sciences provides end-to-end support, from experimental design to result analysis, helping clients identify the optimal salt form while ensuring reliability and operability of the compound’s physicochemical properties.
We were stuck with a gummy, amorphous free base for months. BOC Sciences' salt screening team quickly identified a crystalline besylate salt that transformed our development program. Their solid-state expertise is top-notch.
— Dr. Miller, Director of Chemistry, Biotech Startup
The final report provided by BOC Sciences was comprehensive and clear. The XRPD and DVS data were critical for us to select the right form for our IND-enabling studies. Highly recommended for pre-formulation work.
— Dr. Davis, VP of Development, Global Pharmaceutical Company
We needed a rapid salt screen to improve the bioavailability of our lead compound. The team delivered excellent results within a tight timeline, and the communication throughout the project was seamless.
— Dr. Evans, Senior Scientist, Research Institute
Identifying the salt was just the start; BOC Sciences also helped us scale up the crystallization process to the gram scale, delivering high-purity material for our tox studies. A reliable partner.
— Dr. Wilson, CMC Manager, Biopharma Enterprise
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