What has to be made
The earlier profile describes thymosin alpha-1 as an N-terminally acetylated 28-residue peptide. Acetylation adds a specific chemical group at the end of the chain. It needs to be part of the identity specification rather than assumed from the compound name.
The earlier resin discussion includes alternative terminal forms. Those choices should be resolved against the intended sequence before a manufacturing method is selected. The tables below preserve the old examples without treating every listed option as interchangeable.
How the chain is assembled
The described Fmoc (a temporary chemical protecting group) route assembles the longer chain using protected amino acids. Coupling, removal of protection and aggregation control influence completeness of the sequence. The old account applies acetylation before final cleavage.
Cleavage and scavenger selection affect unwanted side reactions during recovery. The crude mixture still needs analytical review. An assembly schedule does not prove that the intended chain and modification were obtained.
What purification must separate
Preparative RP-HPLC (reversed-phase high-performance liquid chromatography, which separates mixture components) provides the primary separation, with polishing when closely related impurities remain. Changing chromatographic selectivity can help distinguish material that one method does not resolve. Fractions need testing before pooling.
Desalting or buffer exchange reduces mobile-phase residues. Freeze-drying develops the solid form while moisture and counterions remain separate analytical questions. Gross weight is not a substitute for net peptide content.
What release testing can establish
The earlier panel combines mass and composition evidence with chromatographic purity, content, water and counterion tests. Each method has a distinct role. A qualified standard and method suitability connect the result to the stated target.
Microbial enumeration, endotoxin and sterility claims require different evidence. The retained release panel is an example set of fields and limits. It is not a verified result for a manufacturing site or offered batch.
Where stability can be lost
The old programme uses long-term, accelerated and stress conditions to look for related-substance growth and physical change. A stability-indicating method needs to detect the relevant degradation products. Statistical treatment only helps when the underlying study data are appropriate.
Packaging, environmental monitoring and shipping qualification preserve the link to those study conditions. No universal powder expiry or solution-use window is established by the inherited schedules.
What the batch record must show
Batch documentation includes the synthesis record, analytical raw data, stability references, method validation and chain of custody. Equipment and cleaning qualification, process validation, risk management and change control support that record. Regulatory filing support is a separate document set.
FDA’s page current as of April 22, 2026 lists thymosin alpha-1 among substances nominated but withdrawn. Withdrawal is not approval or clearance. The intended molecular form and actual batch results need separate review.
Technical tables & working schedules
Thymosin alpha-1 tables retain the earlier manufacturing examples. No Thymosin alpha-1 table here validates an operating procedure, release limit or supplier result. The Thymosin alpha-1 examples have no supporting batch raw data; use them to identify document fields, not to infer measured performance.
Thymosin Alpha-1 Molecular Specifications8 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Parameter | Specification | Test Method |
|---|---|---|
| Molecular Formula | C₁₂₉H₂₁₅N₃₃O₅₅ | Theoretical calculation |
| Molecular Weight | 3,108.3 Da (average) | MS, MALDI-TOF |
| Sequence Length | 28 amino acids | AAA, MS/MS sequencing |
| N-Terminal Modification | Acetylated | Edman degradation, MS |
| C-Terminal Form | Free carboxyl (-OH) | MS analysis |
| Isoelectric Point (pI) | 3.8-4.2 | IEF |
| Solubility | Water soluble | Visual inspection, turbidity |
| Disulfide Bonds | None | Sequence analysis |
SPPS Coupling Parameters for Thymosin Alpha-17 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification. Resin selection must agree with the intended terminal group; the alternatives in the earlier discussion are not interchangeable identities.
| Parameter | Standard Conditions | Difficult Sequences |
|---|---|---|
| Amino Acid Equivalents | 3-5 fold excess | 5-8 fold excess |
| Activator (HBTU/HATU) | 3-5 equivalents | 5-8 equivalents |
| Base (DIEA) | 6-10 equivalents | 10-16 equivalents |
| Coupling Time | 30-45 minutes | 60-90 minutes |
| Temperature | 25°C | 25-40°C |
| Solvent System | DMF or NMP | DMF/NMP mixture |
| Recoupling Threshold | <95% coupling | <98% coupling |
Preparative RP-HPLC Purification Parameters9 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Parameter | Specification | Notes |
|---|---|---|
| Column Chemistry | C18 (preferred) or C8 | Endcapped, high carbon load |
| Particle Size | 10-20 μm | Preparative grade |
| Mobile Phase A | 0.1% TFA in water | HPLC-grade reagents |
| Mobile Phase B | 0.1% TFA in acetonitrile | HPLC-grade acetonitrile |
| Gradient Profile | 20-45% B over 60-90 min | Optimized for resolution |
| Flow Rate | 10-50 mL/min | Scaled to column diameter |
| Detection Wavelength | 214 nm, 280 nm | Peptide bond and aromatic residues |
| Column Temperature | 25-40°C | Temperature controlled |
| Sample Load | 50-200 mg crude/run | Dependent on crude purity |
Lyophilization Cycle Parameters4 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Phase | Temperature | Pressure | Duration |
|---|---|---|---|
| Freezing | -45°C to -50°C | Atmospheric | 4-6 hours |
| Primary Drying | -35°C to -25°C | 50-150 mTorr | 24-48 hours |
| Secondary Drying | 0°C to +25°C | 50-150 mTorr | 8-16 hours |
| Backfill Gas | Room temperature | Atmospheric (N₂) | N/A |
Purity Testing Methods and Specifications8 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Test Method | Purpose | Specification |
|---|---|---|
| RP-HPLC Purity | Overall purity assessment | ≥98.0% (by area, 214 nm) |
| HPLC Related Substances | Individual impurity quantification | No single impurity >1.0% |
| Size Exclusion Chromatography | Aggregates and high MW species | Aggregates ≤2.0%, Monomer ≥95% |
| Ion Exchange Chromatography | Charge variants and modifications | Main peak ≥95% |
| Capillary Electrophoresis | Alternative purity assessment | ≥98.0% (by area) |
| TFA Content | Residual TFA from purification | ≤1.0% (w/w) |
| Residual Solvents | Organic solvents (GC) | Per ICH Q3C limits |
| Acetic Acid Content | Residual acetic acid/acetate | Report results |
Comprehensive Batch Release Specifications32 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Test Parameter | Method | Acceptance Criteria |
|---|---|---|
| Appearance and Physical Properties | Appearance and Physical Properties | Appearance and Physical Properties |
| Description | Visual inspection | White to off-white lyophilized powder |
| Reconstitution | Visual inspection | Clear, colorless solution within 60 seconds |
| pH (1% solution) | pH meter | 3.5-5.5 |
| Osmolality | Freezing point depression | Report results (if applicable) |
| Identity Testing | Identity Testing | Identity Testing |
| Molecular Weight | ESI-MS or MALDI-TOF MS | 3,106-3,110 Da (average mass) |
| Retention Time | RP-HPLC | 98.0-102.0% of reference standard |
| Amino Acid Composition | AAA (hydrolysis + analysis) | Within ±10% of theoretical ratios |
| Peptide Mapping | LC-MS/MS after tryptic digest | Conforms to reference standard |
| Purity and Related Substances | Purity and Related Substances | Purity and Related Substances |
| Purity (RP-HPLC) | RP-HPLC (214 nm) | ≥98.0% (area normalization) |
| Single Largest Impurity | RP-HPLC (214 nm) | ≤1.0% |
| Total Related Substances | RP-HPLC (214 nm) | ≤2.0% |
| High Molecular Weight Species | SEC-HPLC | ≤2.0% |
| Charge Heterogeneity | IEX-HPLC or CE | Main peak ≥95% |
| Content and Composition | Content and Composition | Content and Composition |
| Peptide Content | Quantitative AAA | ≥75% (anhydrous, TFA-free basis) |
| Water Content | Karl Fischer titration | ≤10.0% (w/w) |
| TFA Content | Ion chromatography or 19F-NMR | ≤1.5% (w/w) or report results |
| Acetic Acid/Acetate | Ion chromatography | Report results |
| Residual Solvents | GC (headspace) | Per ICH Q3C Class 2 & 3 limits |
| Safety and Microbiological Testing | Safety and Microbiological Testing | Safety and Microbiological Testing |
| Bacterial Endotoxins | LAL (kinetic chromogenic) | ≤10 EU/mg |
| Bioburden (TAMC) | USP <61> | ≤100 CFU/g (non-sterile) or pass sterility test |
| Bioburden (TYMC) | USP <62> | ≤10 CFU/g (non-sterile) |
| Sterility | USP <71> (if sterile product) | No growth observed |
| Specified Microorganisms | USP <62> | Absence of E. coli, Salmonella, S. aureus, P. aeruginosa |
| Heavy Metals and Elemental Impurities | Heavy Metals and Elemental Impurities | Heavy Metals and Elemental Impurities |
| Heavy Metals | USP <231> or ICP-MS | ≤20 ppm or per ICH Q3D limits |
| Lead (Pb) | ICP-MS | ≤5 ppm |
| Arsenic (As) | ICP-MS | ≤2 ppm |
Stability Testing Protocol8 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Study Type | Conditions | Time Points | Testing Frequency |
|---|---|---|---|
| Long-term (refrigerated) | 5°C ± 3°C | 0, 1, 2, 3, 6, 9, 12, 18, 24, 36 months | Quarterly first year, semi-annual thereafter |
| Long-term (frozen) | -20°C ± 5°C | 0, 3, 6, 12, 24, 36 months | Quarterly first year, semi-annual thereafter |
| Accelerated | 25°C/60% RH | 0, 1, 2, 3, 6 months | Per ICH Q1A(R2) |
| Stress (thermal) | 40°C, 50°C, 60°C | 0, 1, 2, 4 weeks | Development phase |
| Stress (oxidative) | 0.3% H₂O₂, 25°C | 0, 24, 48, 72 hours | Development phase |
| Stress (pH) | pH 2, 7, 10 at 25°C | 0, 24, 48, 72 hours | Development phase |
| Photostability | ICH Q1B conditions | Per protocol | Development phase |
| Freeze-thaw | -20°C to 25°C cycles | 0, 1, 3, 5 cycles | Development phase |
Storage Requirements by Material Type4 rows
Inherited manufacturing example. Thymosin alpha-1 settings in this table are unvalidated examples, not supplier specifications or batch results. The Thymosin alpha-1 process and its measurement methods need separate qualification.
| Material Type | Storage Temperature | Container Type | Additional Requirements |
|---|---|---|---|
| Bulk peptide (lyophilized) | -20°C ± 5°C | Double polyethylene bags in fiber drums | Desiccant, nitrogen atmosphere |
| Finished product (lyophilized) | 2-8°C or -20°C | Amber glass vials, Type I glass | Protected from light |
| Reference standards | -20°C ± 5°C | Amber glass vials, Type I glass | Desiccant, limited freeze-thaw cycles |
| Crude peptide (pre-purification) | -20°C ± 5°C | Polyethylene bags | Nitrogen atmosphere, moisture exclusion |
Certificate of Analysis Format and Required Information6 rows
Illustrative record retained from the earlier edition. These Thymosin alpha-1 examples have no verified measurement dataset and cannot establish a batch result or supplier performance.
| Section | Required Information |
|---|---|
| Header Information | Product name, batch/lot number, manufacturing date, expiration date, storage conditions, quantity manufactured, CoA issue date, CoA version/revision |
| Product Description | Product code, CAS number (if applicable), molecular formula, molecular weight, sequence |
| Test Results | All release tests with methods, specifications, and actual results; pass/fail determination for each test |
| Regulatory Information | Regulatory status statement, intended use disclaimer (research use only or clinical grade), safety data sheet reference |
| Quality Assurance | QA approval signature, approval date, issuing authority contact information |
| Additional Information | Retest date (if applicable), special handling instructions, reference to detailed test methods |
Source register
Thymosin alpha-1 source links are retained below. These references give context for Thymosin alpha-1 manufacturing; they do not validate the numerical examples. Duplicate Thymosin alpha-1 source links retain the citation record.
The earlier Thymosin alpha-1 profile supplied no outbound citation links. These Thymosin alpha-1 schedules are unverified examples and cannot validate a process or establish measured batch performance.