Formulation and process · Formulation and process
“Our API won't dissolve properly, and we have been trying solvents for weeks.”
Solve a solubility problem before you run out of material
When a substance will not go into solution, every trial costs material and time. CovaSyn computes solubility, pH profile and solvent mixtures up front and narrows down which few experiments are worth running. You receive a traceable evaluation that your lab reviews and decides on.
Starting point
When you need this
- The substance crashes out unexpectedly during work-up or transfer.
- Formulation needs a pH range in which the API stays in solution.
- A solvent has to be replaced, for ICH Q3C reasons or for sustainability.
- The salt form is still open, and a screen would tie up the lab for several weeks.
Result
What you get
pH-solubility profile
Solubility across the pH range from structure and pKa, showing where your molecule stays in solution and where it precipitates.
Solvents and mixtures
A ranked list of suitable solvents and binary mixtures, with miscibility and a note on the ICH Q3C class.
Narrowed-down salt forms
Which counterions are even plausible at your pKa, so the screen starts with a few candidates instead of many.
Report with the calculation path
Inputs, model and result are in the report, so your expert can trace and sign off every number.
Three ways
Yourself, together, or done for you
Run it yourself
Draw the molecule in the sketcher or use the tools through the CovaSyn MCP directly in Claude, ChatGPT or Cursor.
Go to MCPLearn it together
In a workshop your team learns how to answer questions like this with AI, cleanly and traceably.
See workshopsDone for you
We run the evaluation with our tools and deliver the finished report. Your expert reviews and signs off.
See Done-for-You
CovaSyn
The tools behind it
Deterministic calculations instead of guessed answers: the same tools we use for Done-for-You work are available to you directly.
Covasolve
Solubility prediction, pH-solubility curves, solvent recommendation, mixtures, miscibility, and cooling and antisolvent crystallization.
Covachem
pKa values and a physicochemical profile, from which ionisation and salt formation follow.
Covabasic
Structure validation, LogP and core data, so every further calculation starts from a clean structure.
Audience
Who it is for
For formulation, CMC and process development teams at contract labs, CDMOs, generics manufacturers and specialty chemicals companies, wherever a solubility problem is holding up a project.
What the computation does not replace
- Predictions do not replace measurement. They reduce the number of experiments; confirmation in the lab remains.
- Polymorphism and dissolution kinetics are only partly captured by a calculation from structure; that needs data from your lab.
Insights
Read on
pH-Solubility Profiles and Salt Selection
How to build a pH solubility profile for salt selection, with real CovaSolv numbers on ibuprofen, and where Henderson-Hasselbalch stops being true.
Read articleSolubility Prediction Model Accuracy: How to Read It
Solubility prediction model accuracy explained: scaffold vs random splits, RMSE 0.689 on 4,193 held-out rows, and why apparent is not intrinsic solubility.
Read articleSolvent Selection Under ICH Q3C: A Data Question
Solvent selection under ICH Q3C explained: what Class 1, 2 and 3 mean, the ppm limits, and how predicted solubility narrows the candidate list before lab.
Read articleGreen Solvent Substitution Without Losing Solubility
Green solvent replacement in pharma: rank ICH Q3C Class 3 alternatives to DCM and chloroform by predicted solubility before you book lab time.
Read article
Questions
Common questions
What can I do if my API won't dissolve?
First check whether the molecule is ionisable: then pH often shifts solubility by orders of magnitude, and a salt form can help. If it is neutral, solvent, mixtures and temperature decide. CovaSyn computes these options from structure, so you only test the promising ones in the lab.
How accurate is a solubility prediction?
Accurate enough to rank candidates and avoid failed experiments, not accurate enough to replace a measurement. Our insights article on model accuracy shows where the limits are.
Can you replace a solvent under ICH Q3C?
Yes. We suggest alternatives with similar solvation behaviour, take miscibility and the ICH Q3C class into account and show which combinations dissolve your molecule best.
Who can evaluate our solubility problem for us?
CovaSyn does this as Done-for-You: you describe the problem in the intro call, we agree on data and scope, and you typically receive the report within 5 working days once we have your data. Handled confidentially from the start.
Can I run this myself?
Yes. In the sketcher you draw the molecule and see core data instantly; the solubility tools are available through the CovaSyn MCP directly in your AI assistant.
Formulation and process
Related problems we solve
Crystallization process design: cooling or antisolvent
Our crystallization yield is too low, and we don't know whether to cool or use an antisolvent.
See solutionDesign of experiments (DoE): from design to analysis
We have too many factors and too little material, and nobody on the team is sure which design fits.
See solutionProcess optimization and process capability (Cpk, Ppk)
Our Cpk is too tight, and we don't know which parameter drives the variation.
See solution
Next step
Tell us about your solubility problem.
30 minutes on Microsoft Teams with the CovaSyn team. If it is not a fit, we will say so.