Oxolinic acid

Oxolinic acid	Last updated: 07/09/2025
(Also known as: dioxacin; crop antibiotic)

GENERAL INFORMATION

Description

A synthetic fluoroquinolone antibacterial veterinary drug active against gram-negative bacteria

Examples of veterinary uses

Used to treat urinary tract and other infections

Examples of species treated

Fish; Cattle; Pigs; Poultry; Shrimps; Turtles

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

None

Chemical formula

C₁₃H₁₁NO₅

Canonical SMILES

CCN1C=C(C(=O)C2=CC3=C(C=C21)OCO3)C(=O)O

Isomeric SMILES

International Chemical Identifier key (InChIKey)

KYGZCKSPAKDVKC-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C13H11NO5/c1-2-14-5-8(13(16)17)12(15)7-3-10-11(4-9(7)14)19-6-18-10/h3-5H,2,6H2,1H3,(H,16,17)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
oxolinic acid	-

General status

Veterinary substance type

Antibiotic, Antibacterial, Antimicrobial, Antifungal, Medicinal drug

Substance groups

Quinolone compound

Minimum active substance purity

>98%

Known relevant impurities

8-hydroxy-1,3-dioxolo(4,5-g)quinoline-7-carboxylic acid, ethyl 5-ethyl-8-oxo-5,8-dihydro-1,3-ioxolo(4,5-gquinoline-7-carboxylate, 5-methyl-8-oxo-5,8-dihydro-1,3-dioxolo(4,5-g)quinoline-7-carboxylic acid

Substance origin

Synthetic

Mode of action

Works via two routes, by inhibiting the enzyme DNA gyrase and also acts as a dopamine reuptake inhibitor.

Molecular targets

[DNA gyrase subunit A, Antagonist]

CAS RN

14698-29-4

EC number

238-750-8

CIPAC number

None allocated

US EPA chemical code

PubChem CID

CLP index number

No data found

Therapeutic Class

Antiinfectants for systemic use: Antibacterials for systemic use

ATCvet Code

QJ01MB05

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: All food producing species)

Molecular mass

261.23

PIN (Preferred Identification Name)

IUPAC name

5-ethyl- 8-oxo- 5,8-dihydro [1,3] dioxolo [4,5-g] quinoline- 7-carboxylic acid

CAS name

5-ethyl-5,8-dihydro-8-oxo-1,3-dioxolo[4,5-g]quinoline-7-carboxylic acid

Forever chemical

Other status information

Annex 1 EC Reg. 2377/90

Relevant Environmental Water Quality Standards

Physical state

White to pale yellow crystalline solid

Commercial

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Availability status

Introduction & key dates

1989, first introduced Japan

Example products (past and present) using this active

Formulation and application details

Commercial production

Oxolinic acid is synthesised through a multi-step chemical process that begins with the nitration of 1,2-methylenedioxybenzene to produce 3,4-methylenedioxy-1-nitrobenzene. This intermediate is then hydrogenated to form 3,4-methylenedioxyaniline, which reacts with ethoxymethylenmalonic ester to yield a substitution product. Upon heating, this compound cyclises into an ethyl ester of 4-hydroxy-6,7-methylenedioxyquinoline-3-carboxylic acid. The ester undergoes hydrolysis in a basic medium, typically using dimethylformamide, and the resulting product is treated with ethyl iodide to introduce the ethyl group, culminating in the formation of oxolinic acid.

Impact on climate of production and use

Data for the amount of life cycle GHGs produced by oxolinic acid are not available in the public domain. However, whilst estimates vary, more general data suggests that between 14 and 30 kilograms of CO₂e is emitted per kilogram of substance produced.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

3.2

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

10000

Hexane

10000

Xylene

10000

Methanol

Melting point (°C)

315

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

4.68 X 10⁰¹

Calculated

Log P

1.67

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.55

Dissociation constant pKa) at 25 °C

6.3

Vapour pressure at 20 °C (mPa)

0.147

Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Surface tension (mN m⁻¹)

Refractive Index

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

550

Very persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Data for superficial sediments DT₅₀ 150-1000 days, various sediment depths

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

88% degraded after 9 days

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

Slightly mobile

K_oc (mL g⁻¹)

2260

Notes and range

Literature range for K_oc is 14 to 4510

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.77

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Oxolinoyl-beta-D-glucuronic acid
Note: Biologically active

Rat (Uriinary); Rabbit (Urine); Dog (Urinary)

5-ethyl-5,8-dihydro-8-oxo-1,3-dioxolo-[4,5,g]quinoline-7-carboxylic acid

Human

1-ethyl-1,4-dihydro-7-hydroxy-6-methoxy-6-oxoquinoline-3-carboxylic acid

Rat; Rabbit; Dog

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 525

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 1000

Eisenia foetida

Low

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 20

Moderate

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 10

Cyprinus carpio

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

35.0

Oncorhynchus mykiss 29 day

Low

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

4.6

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.38

Daphnia magna

Moderate

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹) (EC₅₀)

Raphidocelis subcapitata

Low

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 525

Rat

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

1.7

Rat

Other Mammal toxicity endpoints

Intravenous LD₅₀ = 177 mg kg⁻¹

Mouse

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

Metabolised and excreted as metabolites in urine and faeces

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

General human health issues

Harmfull if swallowed
May cause visual disturbances, fever, anorexia, urticaria, and photosensitivity reactions
May cause gastrointestinal tract problems
CNS toxicant
May damage vital organs

Handling issues

Property

Value and interpretation

General

Corrosive
Not explosive
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H302, H371
Environment: H411

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

oxolinic acid

French

acide oxolinique

German

Danish

Italian

Spanish

acido oxolinico

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	07/09/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242