Reactive/Cytotoxic Compound Handling Protocols

Purpose: To safely prepare mother (stock) solutions for high-activity compounds while minimizing operator exposure and degradation risk.

Procedure:

1. Perform all preparation steps in a fume hood with proper ventilation.
2. Wear appropriate PPE-nitrile gloves, lab coat, and protective eyewear; double-glove if the compound has known dermal absorption.
3. Dissolve compounds in anhydrous DMSO or ethanol at concentrations typically ranging from 1-10 mM. Avoid aqueous buffers at this stage.
4. Use amber glass vials or polypropylene tubes to prevent adsorption and light degradation.
5. Label containers with full chemical name, concentration, date, and operator initials.
6. Store stock solutions at -20°C or -80°C in small aliquots to avoid repeated freeze-thaw cycles.

Purpose: To ensure reliable cellular exposure while avoiding off-target or cytotoxic effects.

Procedure:

1. Begin with serial dilutions from the stock using sterile medium or PBS with ≤0.1% DMSO.
2. Maintain final solvent concentration below 0.1% in culture media to minimize solvent-related effects.
3. Always perform preliminary dose–response assays (e.g., cell viability or metabolic activity) to define the minimum effective concentration.
4. Document exposure time carefully—short exposure (e.g., 30 min–2 h) may suffice for highly reactive compounds.
5. For consistency, prepare fresh working solutions immediately before use; most reactive compounds degrade rapidly at room temperature.

Purpose: To maintain reproducibility across experiments and mitigate variability introduced by compound source or handling.

Procedure:

1. Compare new batches to reference aliquots via HPLC or LC-MS analysis when possible.
2. Record lot number, supplier, purity (%), and preparation date in lab logs.
3. For compounds with instability concerns, visually inspect for changes in color, clarity, or odor before use.
4. When switching suppliers, revalidate concentration–response behavior using the same assay system.
5. Keep all raw data traceable to specific compound batches to ensure accountability and reliability in publication or review.

Purpose: To minimize environmental exposure and ensure laboratory safety compliance.

Procedure:

1. Collect liquid waste containing reactive or cytotoxic agents in dedicated solvent-resistant containers labeled "Hazardous Waste."
2. Decontaminate working surfaces using 70% ethanol followed by detergent after compound use.
3. Avoid autoclaving waste containing organic solvents.
4. Follow institutional biosafety guidelines for disposal through chemical waste management services.
5. In case of accidental contact, rinse immediately with water and seek assistance per MSDS guidance.