If you have been reading about solvent and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-03-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
Documentation supports reproducibility and traceability. Records often include lot number, solvent composition, final concentration, preparation date, and storage location. Such details help distinguish procedural variation from actual sample instability. Questions remain about how best to predict long-term stability from short-term accelerated studies, because peptide degradation pathways differ widely. For many peptides, the relationship between in vitro solution stability and biological behavior is incompletely understood and is an active area of research.
After reconstitution, a peptide solution is typically stored under conditions that limit degradation. Cool temperatures slow hydrolysis and oxidation, while freezing can preserve samples for longer periods. Repeated freeze-thaw cycles may promote aggregation or precipitation, so aliquoting before freezing is a common laboratory practice. The optimal storage temperature depends on the peptide sequence, buffer composition, and expected duration. Solutions containing oxidizable residues may benefit from inert gas overlays or antioxidants, though compatibility with the specific peptide must be considered.
Aseptic technique matters because aqueous peptide solutions can support microbial growth. Sterile solvents, clean workspaces, and sterile filtration can reduce contamination. The choice of filter material and pore size must avoid peptide loss through adsorption, especially for hydrophobic or low-concentration samples. Visual inspection for particles, turbidity, or color change provides a simple initial check, but it cannot confirm identity or purity. Analytical methods such as reversed-phase high-performance liquid chromatography and mass spectrometry are used to verify composition and detect degradation products.
Water is common, but not universal; hydrophobic peptides may require organic co-solvents like acetonitrile or dimethyl sulfoxide. Acidic peptides may dissolve better in dilute acetic acid or ammonium hydroxide, while basic peptides may favor slightly acidic conditions. Buffer choice matters because pH can affect charge, solubility, and aggregation. Some peptides require sonication or gentle mixing, whereas vigorous vortexing can cause foaming and surface denaturation. The target concentration is typically calculated from the labeled peptide mass and the volume of solvent added.
Dissolution involves hydration of polar and charged groups, disruption of intermolecular interactions in the lyophilized powder, and transition to a thermodynamically favored solution state. Not all powder dissolves readily; aggregation, incomplete lyophilization, or high molecular weight can slow reconstitution. The resulting solution may contain particulates or oligomers that affect downstream measurements. Researchers often verify complete dissolution by visual inspection and spectrophotometric or chromatographic methods. The relationship between reconstitution conditions and long-term stability remains an active area of study.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature (lyophilized) | -20 °C or lower | Desiccant and sealed container limit moisture |
| Typical storage temperature (reconstituted) | 2-8 °C short term; frozen for longer | Freeze-thaw cycles may damage peptide |
| Appearance of solution | Clear to slightly opalescent | Turbidity or particles suggest aggregation or contamination |
| Identity method | Mass spectrometry | Confirms molecular mass and detects modifications |
| Purity method | Reversed-phase HPLC | Separates peptide from related impurities |
After reconstitution, peptide solutions are generally less stable than lyophilized powders, and hydrolysis, oxidation, deamidation, and aggregation can occur in solution. Stability depends on peptide sequence, concentration, pH, buffer composition, temperature, light exposure, and dissolved oxygen. Many research protocols store reconstituted solutions at 4 °C for short periods or at -20 °C or -80 °C for longer periods. Repeated freeze-thaw cycles can promote aggregation and loss of activity. The optimal storage condition is peptide-specific and often determined empirically rather than predicted from sequence alone.
Quality control after reconstitution often includes visual inspection for particulates, pH measurement, and concentration determination by ultraviolet absorbance at 280 nm when aromatic residues are present. Reverse-phase high-performance liquid chromatography can assess purity and reveal degradation peaks. Mass spectrometry confirms molecular identity and detects modifications such as oxidation or truncation. Size-exclusion chromatography can quantify aggregates and oligomers. These methods are established for many peptides but may require optimization for hydrophobic or chemically modified sequences.
Solvent choice depends on the peptide's sequence, charge, and solubility profile. Sterile water is common for freely soluble peptides, while aqueous buffers or dilute acid or base may be needed for others. Some sequences contain hydrophobic regions that resist water alone and require a small amount of organic co-solvent. The solvent's pH can affect charge state, aggregation, and stability. Because peptides vary widely, no single universal reconstitution liquid exists, and suppliers often provide a recommended solvent based on testing of a specific lot or sequence.
After a solvent is added, the vial is typically swirled or gently inverted rather than shaken vigorously. Shaking can introduce air and shear forces that promote foaming or aggregation, especially for longer peptides. Dissolution may take several minutes, and the solution should become clear unless the peptide is intentionally in suspension. Concentration is calculated from the mass of peptide stated on the vial label divided by the total liquid volume. If the dried peptide contains salts or counterions, the actual peptide content may be lower than the nominal mass.
Reconstitution is the process of adding a liquid to a lyophilized peptide so that the dried material dissolves into solution. Lyophilization removes water from a frozen peptide preparation under reduced pressure, leaving a porous solid or powder. The dried form often has greater long-term stability than a liquid because hydrolysis and oxidation are slowed. In laboratory work, reconstitution is usually the first step before dilution, analysis, or further experiments. The result is a stock solution whose concentration depends on the volume of solvent added and the amount of peptide in the vial.
Die Bachem Holding AG ist ein schweizerisches Chemieunternehmen, das Weltmarktführer bei der Herstellung von Peptiden ist. Der Hauptsitz des 1971 gegründeten Unternehmens ist Bubendorf im Kanton Basel-Landschaft in der Schweiz. Neben dem Standort Bubendorf hat Bachem einen weiteren grossen Produktionsstandort in der Schweiz in Vionnaz im Kanton Wallis. Weitere Produktionsstandorte befinden sich in den USA in den kalifornischen Städten Vista und Torrance und in Grossbritannien in St Helens nahe Liverpool. Der Vertriebs- und Distributionsstandort befindet sich des Weiteren in Tokio (Japan). Per Ende 2024 beschäftigte die Bachem Holding AG weltweit 2207 Mitarbeiter, erwirtschaftete einen Umsatz von 605,3 Millionen CHF und erzielte einen Reingewinn von 120,2 Millionen CHF. Kommerzielle Wirkstoffe machen 57 % des Umsatzes aus, Prozessentwicklung 34 %, Forschung und Spezialitäten 9 %.
== Geschichte == 1971 gründete Peter Grogg das Unternehmen Bachem mit zwei Angestellten. Unternehmenssitz war zunächst Liestal bei Basel, bis das Unternehmen 1977 mit acht Angestellten in das nahe gelegene Bubendorf umzog, wo auch heute noch der Hauptsitz liegt. Die 1999 übernommene Peninsula Laboratories aus San Carlos (Kalifornien) firmiert heute als BMA Biomedicals. 2007 wurde der Geschäftsbereich Clinalfa von Merck gekauft. Für die Zeit von der Firmengründung 1971 bis zum Börsengang im Jahr 1998 sind keine Zahlen zur Geschäftsentwicklung veröffentlicht. Im Jahr des Börsengangs 1998 lag der Umsatz der Bachem Gruppe bei 96 Millionen CHF. Bis 2001 stieg der Umsatz – auch akquisitionsbedingt – auf 141 Millionen CHF. Der in Nordamerika erwirtschaftete Umsatzanteil lag im Jahr 2007 bei rund 40 %. Bachem konnte im Jahr 2018 einen Umsatz von 282,5 Millionen CHF mit einem Reingewinn von 46,6 Millionen CHF erzielen. Das operative Ergebnis (EBIT) lag im Jahr 2018 bei 54,8 Millionen CHF. Per Jahresende 2018 beschäftigte die Bachem Gruppe insgesamt 1140 Personen in 1097 Vollzeitstellen, 2024 waren es 2207 Vollzeitstellen. Bachem stellt Oligonukleotide zur Behandlung von genetischen Erkrankungen für Eli Lilly her.
=== Bachem Holding AG === Die Bachem Gruppe hat seit dem Jahre 2003 eine Holding Struktur. Die Aktien sind an Schweizer Börse SIX Swiss Exchange mit dem Kürzel BANB kotiert. Die Mehrheit der Aktien befindet sich im Besitz des Firmengründers Peter Grogg.
Bubendorf, Schweiz: Hauptsitz der Bachem AG. Gegründet 1971. Herstellung von Peptiden als pharmazeutische Wirkstoffe und als Chemikalien für die Forschung. Vionnaz, Schweiz: 1973 als Sochinaz gegründet und 2001 durch Bachem übernommen. Herstellung komplexer organischer Moleküle als pharmazeutische Wirkstoffe. St. Helens, Grossbritannien: Bachem UK Ltd. Gegründet 1992 und mit Peninsula Laboratories übernommen. Herstellung von Peptiden als Forschungschemikalien und europäisches Kompetenzzentrum für immunologische Produkte. Torrance, Kalifornien, USA: Bachem Americas, Inc. Gegründet 1971 und 1996 durch Bachem übernommen. Herstellung von Peptiden als pharmazeutische Wirkstoffe und als Forschungschemikalien. Gegründet 2007: Vertriebsgesellschaft für alle Produkte der Bachem Gruppen in Nord-, Mittel- und Südamerika. Vista, Kalifornien, USA: Gegründet 1987 und 2015 durch Übernahme der American Peptide Company akquiriert. Entwicklung und Herstellung von pharmazeutischen Wirkstoffen. Tokio, Japan: Gegründet im Juni 2018 als Vertriebsstandort und Lokalpräsenz für die Bachem Holding AG in Japan und Asien.
Sources: de.wikipedia.org
Short-term storage is often at refrigerated temperatures, while longer storage may use freezing. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation. Container material and headspace can also affect stability.
Mass spectrometry is commonly used to confirm molecular mass and detect modifications. Reversed-phase high-performance liquid chromatography can assess purity and separate related impurities. These methods are complementary rather than interchangeable.
Turbidity can indicate aggregation, precipitation, or microbial contamination. It may also result from incomplete dissolution or undissolved excipients. The cause is not identifiable from appearance alone.
Lyophilized peptide is a dry powder made by freeze-drying, while reconstituted peptide is dissolved in a solvent. The dry form generally offers longer storage at appropriate temperatures. Reconstitution introduces water and increases the risk of degradation.