Republished from the official company website. Author and content source: Crystal Pharmatech.
A section-by-section guide to the preformulation report: the data that de-risks a program, and how much depth each section needs at each stage.
Originally published by Crystal Pharmatech. Republished with company attribution. Original technical perspectives, references and source links are retained.
A section-by-section guide to the preformulation report: the data that de-risks a program, and how much depth each section needs at each stage.
The preformulation package contains data collected during the physicochemical characterization of the API (active pharmaceutical ingredient) and serves as an early risk assessment document with respect to the API suitability as a drug substance candidate for development before the formulation development begins. For a small molecule, a complete package delivers: solid-form characterization (polymorph landscape), ionization and lipophilicity data (pKa, logP/logD), a pH-solubility profile, aqueous and biorelevant solubility, intrinsic dissolution rate, BCS classification, hygroscopicity measured by dynamic vapor sorption analysis, solid-form stability under stress (amorphization potential), forced degradation, and binary excipient compatibility. Together these define whether the molecule can be developed, what formulation strategy fits, and which risks must be managed. ICH Q6A frames the solid-form and specification expectations that this data supports.1
It is tempting to treat preformulation as a set of boxes to tick before the real formulation work starts. That framing is where programs get into trouble, because each measurement in a preformulation package corresponds to a specific downstream development risk. A missing or shallow section does not remove that risk. It simply defers it to a later stage, where it is far more expensive to address.
The examples are concrete. A pH-solubility profile that stops at aqueous buffer misses the biorelevant behavior that governs oral exposure. A hygroscopicity screen without a post-uptake form check misses a hydrate that will appear during wet granulation. An excipient compatibility study run only at ambient conditions misses the interaction that surfaces on accelerated stability months later. In each case, the data is inexpensive to generate early and costly to recover late. That is why the value of the preformulation package lies not in the data it contains, but in the decisions it enables and the failures it prevents.
A complete package spans three groups of properties: physicochemical, solid-form, and stability. The table below summarizes what each measurement establishes and why it matters downstream. Depth is stage-dependent, deepening from candidate selection through IND.
| Property | What It Measures / Why It Matters | Depth by Stage |
| pKa | Ionization vs. pH; drives solubility, permeability, and salt-formation feasibility | Calculated + one confirmation early; experimental across pH by IND |
| logP / logD | Lipophilicity of neutral (logP) and pH-dependent (logD) species; informs permeability and enabling-strategy need | Measured across GI-relevant pH range |
| pH-solubility + intrinsic dissolution | Solubility-limited absorption risk and GI pH effects; isolates solid-form dissolution; feeds BCS class | Aqueous + biorelevant (FaSSIF/FeSSIF); deepens toward IND |
| Solid-form (polymorph / hydrate / amorphous) | XRPD, DSC, TGA establish the working form and its stability; unrecognized forms are latent risks | Preliminary assessment early; fuller screen before form lock |
| Hygroscopicity | Moisture uptake vs. RH by DVS; paired XRPD reveals moisture-driven form change | DVS + post-run XRPD check |
| Forced degradation | Acid, base, oxidative, thermal, photolytic stress; identifies degradation pathways; supports stability-indicating method | First-pass preclinical; refined through development |
| Excipient compatibility | Binary API-excipient studies under stress; flags incompatibilities before prototypes | Stressed thermal / humidity / photo; guided by dosage form and route |
Solid-form and specification expectations are framed by ICH Q6A;1 hygroscopicity classification follows the European Pharmacopoeia;2 forced degradation follows ICH Q1A(R2) stress-testing conditions.3
A note on solubility. Aqueous solubility alone is not enough. A pH-solubility profile across the physiological range, paired with solubility in biorelevant media (fasted and fed state simulated intestinal fluid), reveals whether absorption will be solubility-limited and how GI pH transitions affect it. Intrinsic dissolution, measured from a compact of pure drug substance, isolates the solid form’s dissolution behavior from formulation effects and feeds directly into BCS classification.
A note on hygroscopicity. A DVS run paired with an XRPD check afterward reveals whether moisture triggers a form change, which is as important as the uptake value itself. The European Pharmacopoeia classifies materials by mass increase at 80% relative humidity and 25 °C: slightly hygroscopic (≥0.2% and <2%), hygroscopic (≥2% and <15%), very hygroscopic (≥15%), and deliquescent.2
A complete preformulation report is typically organized into ten sections. The structure below reflects what formulators and reviewers expect to find, and in roughly what order:
| # | Report Section | Typical Contents |
| 1 | Executive Summary | Developability assessment and go/no-go narrative; key risks flagged |
| 2 | Material Description and Appearance | Identity, batch, appearance, particle morphology (PLM) |
| 3 | Solid-Form Characterization | XRPD, DSC, TGA; polymorph, hydrate, and amorphous content assessment |
| 4 | Ionization and Lipophilicity | pKa, logP/logD across pH |
| 5 | Solubility and Dissolution | Aqueous and biorelevant solubility, pH-solubility profile, intrinsic dissolution rate, BCS classification |
| 6 | Hygroscopicity | Dynamic vapor sorption (DVS); classification and form change on moisture uptake |
| 7 | Solid-Form Stability | Physical and chemical stability under temperature, humidity, light, mechanical stress. |
| 8 | Forced Degradation | Acid, base, oxidative, thermal, photolytic stress; degradation pathways |
| 9 | Excipient Compatibility | Binary API-excipient studies under stress; incompatibilities flagged |
| 10 | Developability Conclusions | Integrated risk summary and recommended formulation direction |
A preformulation report can contain every required section and still be a weak deliverable. What distinguishes a strong package is not the presence of data but its completeness, relevance, and interpretation. Four things separate the two:
Material is the constraint that shapes an early preformulation package. At candidate selection, a program may have only a few grams of API, and the package must be scoped to that reality. A meaningful early package can be built from a modest quantity by prioritizing the measurements that most strongly influence the go/no-go decision: solid-form assessment, pKa and logD, a pH-solubility profile, with biorelevant media, hygroscopicity, and a first-pass forced degradation and excipient compatibility screen.
The depth of each section increases as the program advances and more material becomes available. What matters early is not exhaustive characterization but covering the axes that could disqualify the molecule or redirect the formulation strategy, so that no expensive surprise is deferred to a later, higher-stakes stage.
Crystal Pharmatech delivers integrated preformulation packages that connect directly to solid-state characterization, salt and cocrystal screening, and formulation development, so the data generated in preformulation flows without handoffs into the decisions it informs. Our preformulation work covers the full deliverables set described here: solid-form characterization, pKa and logP/logD, aqueous and biorelevant solubility with pH-solubility profiling and intrinsic dissolution, hygroscopicity by DVS, forced degradation, and binary excipient compatibility under stress.
For programs at candidate selection, our Developability Assessment condenses this into a single decision-focused study. With as little as 500 mg of API and approximately four weeks, it combines material-sparing physicochemical characterization with GastroPlus® PBPK modeling to benchmark lead candidates head-to-head, identify the most developable compound, and predict First-in-Human performance. It also informs the two decisions that shape everything downstream: whether a free form or a salt is preferred, and whether a conventional crystalline formulation or an amorphous solid dispersion approach will be required.
Because our preformulation, solid-state, and formulation teams operate as one workflow through the Mol2Med™ approach, the developability conclusions in a preformulation report translate directly into a formulation strategy, rather than sitting in a document that the next team has to re-interpret.
Preformulation is the physicochemical characterization of a drug substance before formulation begins. For a small molecule it involves solid-form characterization (XRPD, DSC, TGA), pKa and logP/logD, a pH-solubility profile with aqueous and biorelevant solubility and intrinsic dissolution, BCS classification, hygroscopicity by DVS, forced degradation, and binary excipient compatibility.1
.A preformulation report is typically organized into around ten sections, from an executive summary through solid-form characterization, physicochemical properties, stability, and excipient compatibility, to an integrated developability conclusion. Depth is stage-dependent: at candidate selection, each section covers the axes that could disqualify the molecule; by IND, the characterization is fuller and supported by experimental rather than calculated values.
The core deliverables are solid-form risk assessment, pKa, logP/logD, pH-solubility profile, biorelevant solubility, intrinsic dissolution rate, BCS classification, hygroscopicity classification by DVS,2 forced degradation pathways,3 and binary excipient compatibility results, closing with a developability conclusion and recommended formulation direction.
Authored by the Crystal Pharmatech Solid-State Research and Marketing Teams