Antibiotic Medium 35 (USP) - BioReagent

Cat. No.: A1528614

GRADE & PURITY BioReagent

Storage

Room temperature

Shipped In

Normal

Overview

For microbiological assay of antibiotic potency

Specifications

Specifications & Purity

BioReagent

Storage

Room temperature

Shipped In

Normal

Grade

BioReagent

Product Line

Biological Products

Application Protocols

No item-specific, vendor-validated protocols are provided in the Product Data. The following is general, literature-based guidance for compendial microbiological antibiotic assays using USP media; always follow the relevant USP monograph and your laboratory SOPs.

General workflow (literature/general):

• Preparation: Weigh the required mass of the dehydrated medium and dissolve in purified water to the prescribed volume (exact g/L: Not specified for this item; consult CoA/Spec Sheet and USP monograph). Sterilize by autoclaving. For plates, cool to dispensing temperature and pour under aseptic conditions.
• Assay setup: Prepare USP reference standard solutions of the antibiotic and serial dilutions per monograph. Standardize the inoculum of the specified test organism to the required turbidity or CFU density.
• Execution: For agar diffusion assays, apply standards/samples to wells or discs on inoculated plates; for turbidimetric assays, inoculate broth containing standards/samples. Incubate under specified conditions.
• Readout: Measure inhibition zone diameters (agar) or turbidity/optical density (broth). Construct dose–response curves and interpolate sample potency as directed by the USP method.
• Suitability: Verify linearity, precision, and parallelism per compendial criteria. Include positive/negative controls.

Documentation: Record lot numbers (medium, agar, standards), preparation parameters (pH, sterilization), and instrument calibrations. Decontaminate all biological waste by autoclaving or validated disinfection before disposal.

Biological Roles

As a formulated culture medium, Antibiotic Medium 35 (USP) does not have biological activity in the conventional sense of a single metabolite or ligand. Instead, it functions as a nutrient matrix designed to support the growth of specified microorganisms under controlled conditions for antibiotic potency assays (literature/general).

General functional aspects of assay media (literature/general):

• Carbon and energy sources: Carbohydrates and peptides supply fermentable substrates and amino acids to sustain growth at reproducible rates.
• Nitrogen and growth factors: Peptones/yeast-derived components provide amino acids, vitamins, and trace elements.
• Ionic balance and buffering: Inorganic salts and buffers stabilize osmotic pressure and pH, maintaining organism responsiveness and consistent antibiotic diffusion or growth kinetics.
• Assay consistency: Defined ranges of pH and cation concentration are critical to maintain sensitivity of test organisms to antibiotics, minimizing variability in inhibition zones or turbidity response.

Because composition is standardized compendially, the medium facilitates reproducible biological responses across labs and over time, enabling comparison to USP reference standards. Specific organism–medium pairings, inoculum densities, and incubation parameters are specified in the relevant USP monograph and should be followed precisely for valid assay outcomes.

Buffer Applications

This product is not a discrete buffering agent but a complex culture medium with intrinsic buffering capacity appropriate to its intended microbiological assay use (literature/general).

• Not typically used to prepare standalone buffer systems for biochemical assays.
• If a defined buffer is required for sample preparation or organism handling outside the context of the USP microbiological assay, select an appropriate dedicated buffer (e.g., phosphate, Tris) and verify compatibility with the compendial method.

For antibiotic assays that require specific pH control, the target pH and tolerances are defined in the USP monograph for Antibiotic Medium 35. Follow those instructions and verify pH after sterilization and cooling, as thermal processing can shift pH (literature/general).

Green Alternatives

While culture media do not have direct chemical “green solvent” alternatives, sustainability considerations apply to preparation and use.

Opportunities (literature/general):

• Energy efficiency: Optimize autoclave loads and cycles to reduce energy and water consumption. Validate shorter cycles where microbiological efficacy is maintained.
• Waste reduction: Prepare only the volume needed to minimize expired plates/broth. Use refillable, reusable glassware instead of single-use plastics when permitted by your QA system.
• Water stewardship: Use on-demand water purification to limit wastage; capture non-contaminated cooling water where facilities permit.
• Packaging: Consolidate orders to reduce shipment frequency; recycle or properly dispose of packaging materials.

Comparison of preparation formats:

• Dehydrated medium (this product): Lower shipping weight/volume, longer shelf life, reduced cold-chain needs, customizable batch sizes.
• Ready-to-use plates/broth: Higher convenience but greater packaging and transport footprint; typically shorter shelf life and more cold-chain demand.

Trade-offs:

• Reusability and sterility assurance must be balanced against sustainability. In regulated laboratories, validated single-use components may be mandatory. Implement green practices within the bounds of method suitability and compliance.

Document your process controls (e.g., autoclave efficacy testing) to ensure environmental measures do not compromise microbiological performance.

Pharmaceutical Uses

Intended use is for laboratory research and quality control; not for clinical or therapeutic use. Research Use Note: For research use only (item-specific).

Role in pharmaceutical QC (literature/compendial general):

• Microbiological assay matrix: Used in compendial microbiological potency assays of antibiotics where the USP specifies Antibiotic Medium 35. Provides standardized growth response conditions for designated test organisms.
• Method verification: Employed in assay suitability testing, including growth promotion and demonstration of linear, accurate dose–response relationships against USP reference standards.
• Manufacturing support: Utilized in in-process control and release testing of antibiotic products where microbiological methods are required or used as orthogonal confirmation to chemical assays.

Compliance considerations:

• The label “(USP)” indicates alignment with the USP monograph for this medium. Users operating under GMP/GLP should confirm lot-specific compliance via CoA and perform receipt qualification (e.g., pH, growth/assay suitability) per site SOPs.
• Documentation: Retain CoA, SDS, and preparation logs (weighing records, autoclave cycles, plate lot numbers) to ensure data integrity and traceability.

This product should be used strictly within validated methods and does not substitute for regulatory guidance. Always consult the specific USP chapters and monographs that reference Antibiotic Medium 35 for full procedural requirements.

Physical Properties

Item-specific physicochemical constants (bp, mp, density) are not applicable to a complex dehydrated medium and are generally not defined.

Item-specific data:

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Solubility in water: Qualitatively soluble; prepared by dissolving the specified mass in purified water (literature/general for dehydrated media). Exact concentration: Not specified for this item; refer to CoA/Spec Sheet and USP monograph.
• pH of prepared medium: Not specified for this item; refer to CoA/Spec Sheet and USP monograph for the acceptance range at the preparation temperature.
• Refractive index, logP, pKa, UV cutoff: Not applicable/not defined for a complex medium; Not specified for this item; refer to CoA/Spec Sheet.

General/literature guidance (for microbiological media):

• Form: free-flowing powder or granules designed to dissolve on heating with stirring.
• Preparation: typically involves complete dissolution in high-purity water, adjustment to the prescribed volume, and sterilization by autoclaving (literature; follow USP and institutional SOPs).
• Final medium clarity and color may vary by lot and composition but should meet USP appearance criteria after sterilization (literature/general).

Quality & Grades

• Grade: BioReagent (item-specific). This designation indicates suitability for laboratory biological applications, including microbiology and cell-based workflows, with attention to bioburden and performance characteristics relevant to life science research.
• Compendial context: The product name specifies Antibiotic Medium 35 (USP), indicating formulation aligned to the USP monograph for this medium (literature/compendial). Users should confirm lot-specific conformity (e.g., pH of the prepared medium, growth/assay performance) via the Certificate of Analysis and, where applicable, in-house qualification.
• Stabilizers/antimicrobials: Not typically added to dehydrated media; Not specified for this item; refer to CoA/Spec Sheet.
• UV absorbance/trace contaminants: Not specified for this item; refer to CoA/Spec Sheet.

Practical quality notes for assay media (literature/general):

• Media intended for antibiotic microbiological assays require tight control of nutrient composition, cation content, and pH to ensure consistent diffusion/growth characteristics and dose–response curves. Vendors typically qualify each lot using USP-designated test organisms and reference standards.
• Water quality and sterilization conditions materially affect performance. Use purified water (e.g., ASTM Type 1/2) and validated autoclave cycles. Filter sterilization is generally not used with complex media unless specified.
• For regulated QC environments, retain lot CoAs and perform receipt testing (e.g., pH check, growth promotion/assay suitability) per pharmacopeial general chapters and site SOPs.

Reaction & Applications

This product is not used as a chemical reagent in synthetic reactions. Its application domain is microbiological assay and culture in accordance with pharmacopeial methods.

Core applications (literature/general for USP antibiotic assay media):

• Microbiological assay of antibiotics: Preparation of agar plates or broth for turbidimetric or agar diffusion assays as described in USP chapters and monographs. The controlled composition ensures reproducible growth of specified test organisms and consistent diffusion of antibiotic standards and samples.
• Quality control in pharmaceutical manufacturing: Routine potency testing and verification of antibiotic dosage forms by microbiological methods where required or used as confirmatory alongside instrumental assays.
• Method validation and verification: Suitability testing (e.g., linearity, precision of zone diameters or turbidity response) with USP reference standards and compendial strains.

Practical tips:

• Accurately weigh the dehydrated medium per the USP-prescribed mass/volume ratio (exact g/L: Not specified for this item; refer to CoA/Spec Sheet and USP monograph).
• Dissolve completely, adjust to final volume, and sterilize (typically autoclave) under validated conditions. Cool to dispensing temperature before pouring plates to minimize condensation (literature/general).
• Use freshly prepared medium or follow validated hold times and storage conditions. Excessive overheating can caramelize carbohydrates or alter pH, impacting assay results.
• Standardize inoculum density of test organisms and use calibrated antibiotic standards to construct dose–response curves or reference zones per USP.

For detailed organism selection, incubation conditions, and endpoint criteria, consult the specific USP monograph that stipulates Antibiotic Medium 35.

Reaction Conditions

Not applicable to chemical reactions. However, preparation and use conditions for the medium are critical for assay performance (literature/general guidance):

• Reconstitution: Dissolve the specified mass of dehydrated medium in purified water to the prescribed final volume (exact g/L: Not specified for this item; refer to CoA/Spec Sheet and the USP monograph for Antibiotic Medium 35).
• Sterilization: Autoclave using a validated cycle appropriate for complex media (e.g., gravity or pre-vacuum cycles per institutional SOP). Avoid prolonged overheating that can alter carbohydrate components and pH.
• Agar plates (if applicable): Cool sterilized medium to a dispensing temperature before pouring to minimize condensation; allow plates to solidify on a level surface and dry to the desired surface moisture before use (literature/general).
• Broth assays (if applicable): Equilibrate medium to incubation temperature before inoculation to reduce lag-phase variability.
• Incubation: Follow organism- and method-specific temperature and time parameters specified in the relevant USP assay chapter.
• Controls: Always include USP reference standards and control replicates to confirm assay suitability (linearity/precision) on the day of use.

Because assay sensitivity depends on pH, cation content, and diffusion characteristics, verify these attributes per your SOPs after preparation. Discard any medium that shows precipitation, contamination, or out-of-spec pH.

Safety & Handling

GHS classification and specific hazard statements are not provided in the Product Data; consult the SDS for authoritative information.

Item-specific safety data:

• Signal word: Not specified for this item; refer to SDS.
• H-statements / P-statements / Pictograms: Not specified for this item; refer to SDS.

General laboratory safety for dehydrated culture media (literature/general):

• PPE: Wear lab coat, nitrile gloves, and safety glasses when handling powder and prepared media. Avoid inhalation of dust; weigh in a fume hood if dust generation is possible.
• Hygiene: Avoid ingestion and contact with eyes/skin. Wash hands after handling. Do not pipette by mouth.
• Sterilization hazards: Use caution when autoclaving; do not overfill vessels. Allow pressure to return to ambient before opening. Beware of superheating and hot liquids; use heat-resistant gloves and eye/face protection.
• Incompatibilities: Store away from strong oxidizers and moisture. Keep container tightly closed to prevent caking and degradation.
• Microbiological risk: Prepared media are suitable for microbial growth. Handle using appropriate biosafety practices. Decontaminate spent media and cultures by autoclaving or validated chemical disinfection per institutional biosafety SOPs.
• Spill response: Avoid dust. Collect using a HEPA-filtered vacuum or damp methods; dispose according to local regulations. For liquid media, absorb with inert material and disinfect before disposal.

Always defer to the product SDS and your institutional safety policies for comprehensive guidance.

Solvent Selection

This product is a dehydrated microbiological medium and is intended to be dissolved in water; selection of organic solvents is not applicable.

• Primary solvent: Purified water (e.g., ASTM Type 1 or Type 2; USP Purified Water) is typically used for preparation (literature/general). Avoid tap water due to variable ions/chlorine that can impact assay performance.
• Miscibility: The reconstituted medium is aqueous. Addition of organic solvents is not recommended for antibiotic assay media unless a validated method specifically requires a co-solvent for standard/sample preparation, which should not be mixed into the bulk medium.
• Practical tips:
  • Pre-warm water (room temperature to ~40–50 C) to facilitate dissolution with gentle stirring (literature/general).
  • Avoid foaming; introduce powder slowly.
  • Use clean, detergent-free glassware; residual surfactants can interfere with microbial growth and diffusion.

If alternative solvent systems are required for dissolving antibiotic standards or samples, prepare these separately according to the relevant USP assay and do not alter the base medium composition unless the method so specifies.

Storage & Reconstitution

Item-specific storage and shipping:

• Storage conditions: Room temperature (item-specific). Protect from moisture and excessive heat. Keep container tightly closed.
• Shipped in: Normal conditions (item-specific).

Reconstitution/preparation (general, literature-based; follow USP monograph and CoA):

• Water: Use purified water (e.g., USP Purified Water or ASTM Type 1/2) to avoid ionic/chlorine interferences.
• Concentration: Prepare according to the USP-prescribed mass per liter for Antibiotic Medium 35 (exact value Not specified for this item; refer to CoA/Spec Sheet and USP monograph).
• Dissolution: Add powder gradually with stirring. Gentle warming can aid dissolution. Avoid excessive aeration/foaming.
• Sterilization: Autoclave using a validated cycle suitable for complex media. Do not overprocess to prevent pH drift and component degradation.
• Post-sterilization: Cool to the appropriate temperature before use or plate pouring. Check pH at the specified temperature; adjust only if permitted by the compendial method.

Holding and stability (literature/general):

• Dehydrated powder: Store dry; reseal promptly after opening. Use desiccant as needed.
• Prepared broth/agar: Use promptly for compendial assays. If storage is necessary, follow validated hold times/temperatures; inspect for contamination, precipitation, dehydration, or excessive condensation before use.

Research Use Note: For research use only. Always consult the product label, CoA/Spec Sheet, and the applicable USP monograph for Antibiotic Medium 35 for exact preparation and acceptance criteria.

Structure & Identity

Antibiotic Medium 35 (USP) is a complex, multi-component microbiological culture medium standardized by the United States Pharmacopeia for antibiotic assay work. As a formulated blend rather than a single compound, it does not have a single defined molecular structure.

• Product type: Dehydrated culture medium blend (microbiological assay medium)
• Composition nature: Complex mixture (typically peptones/infusions, salts, carbohydrates, buffers, etc., per USP monograph for Antibiotic Medium 35; exact composition is controlled by the monograph and manufacturer specification)
• Molecular formula: Not applicable to mixtures; Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not applicable to mixtures; Not specified for this item; refer to CoA/Spec Sheet.
• SMILES / InChI / InChIKey: Not applicable for complex mixtures; Not specified for this item; refer to CoA/Spec Sheet.
• Structural features (descriptive): A dehydrated granular or powdered blend intended to be dissolved in purified water to yield a defined growth medium with controlled nutrient content and pH (as specified in the USP monograph for Antibiotic Medium 35). No discrete 2D/3D molecular structure applies.

Notes:

• Identity is established by conformance to the USP Antibiotic Medium 35 monograph (literature/compendial reference). Verify lot-specific conformity and composition via the Certificate of Analysis.

Synthetic Utility

Not applicable. Antibiotic Medium 35 (USP) is a microbiological culture medium and is not used as a reagent or building block in chemical synthesis. It contains a complex mixture of biological nutrients and salts that have no defined role in organic or inorganic reaction chemistry.

For synthetic workflows, select solvents and reagents designed for chemical transformations. This medium should be reserved for its intended microbiological assay function.

Target Specificity

Not applicable. This product is a culture medium and does not target molecular epitopes, organisms, or pathways in the manner of antibodies, probes, or small-molecule inhibitors. Any organism specificity arises from the compendial method design (i.e., selection of test strains for antibiotic assays) rather than intrinsic molecular targeting by the medium itself.

Refer to the USP monograph that specifies Antibiotic Medium 35 for the designated test organism(s) and inoculum parameters (literature/compendial).

Frequently Asked Questions

How should this product be stored?

Store at room temperature.