Tizanidine is a fast-acting drug used for the management of muscle spasm, which may result from the effects of multiple sclerosis, stroke, an acquired brain injury, or a spinal cord injury. It may also be caused by musculoskeletal injury. Regardless of the cause, muscle spasticity can be an extremely painful and debilitating condition. Initially approved by the FDA in 1996, tizanidine is an Alpha-2 adrenergic receptor agonist reducing spasticity by the presynaptic inhibition of excitatory neurotransmitters that cause firing of neurons promoting muscle spasm.
Toxicology Report
Science-backed ERA derivation by certified toxicologists with ex-agency experts -
Tizanidine
Drug Overview
What is Tizanidine?
Masuu Global provides end-to-end Environmental Risk Assessment (ERA) support for pharmaceutical and healthcare products, covering Phase I environmental exposure assessment, Phase II environmental fate and effects assessment, data-gap analysis, testing strategy, laboratory coordination and final regulatory-ready reporting.
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What's included:
ERA Phase I Evaluation, ERA Phase II Evaluation, Consortium Testing Support (OECD Ecotoxicology Study)
ERA Phase I Evaluation, ERA Phase II Evaluation, Consortium Testing Support (OECD Ecotoxicology Study)
Regulatory Framework
Assessment Methodology
Masuu Global follows a science-based, tiered and risk-based ERA methodology, aligned with applicable international regulatory requirements. For human medicinal products, our approach is primarily guided by the EMA Guideline EMEA/CHMP/SWP/4447/00 Rev. 1, effective 1 September 2024, together with relevant OECD Test Guidelines and regional regulatory requirements.
EMA — Environmental Risk Assessment
Assessment of potential environmental exposure associated with the use, manufacture and disposal of medicinal products, with a structured approach to determine whether further environmental assessment is required.
Phase I — Environmental Exposure Assessment
Initial screening to determine potential environmental exposure, covering PEC calculation, physicochemical properties, usage and dosage data, environmental entry pathways, and persistence and fate considerations.
Phase II — Environmental Fate & Effects Assessment
Where Phase I indicates further assessment is required, Phase II provides detailed evaluation of environmental fate, persistence and ecological effects — including biodegradation, bioaccumulation, aquatic toxicity, PNEC derivation and PEC/PNEC risk characterisation.
OECD & International Testing Principles
Where laboratory studies are required, testing strategies are designed with consideration of relevant OECD Test Guidelines, GLP expectations and applicable regulatory requirements.
Risk-Based Environmental Assessment
Integration of physicochemical data, environmental fate information, ecotoxicological data, existing literature, published studies, regulatory databases, usage data, and environmental monitoring data.
Weight-of-Evidence (WoE) Approach
A scientifically justified WoE approach integrates existing data and avoids unnecessary testing wherever scientifically and regulatorily justified.
ERA Assessment Pathway
Phase I → Phase II → Risk Characterization
Each phase builds on the prior tier — screening first, escalating only when the evidence demands it.
Phase I Screening
Environmental Exposure Assessment
Initial screening to determine whether the substance requires progression to Phase II.
- Product and substance information review
- Indication, dose and usage assessment
- PEC calculation and environmental exposure estimation
- Physicochemical property review
- Initial environmental risk screening
- Determination of Phase II requirement
Phase II Evaluation
Environmental Fate & Effects
Detailed evaluation when Phase I triggers further assessment.
- Biodegradation, hydrolysis & photolysis
- Adsorption/desorption behaviour
- Bioaccumulation potential
- Algal, Daphnia and fish toxicity
- Chronic ecotoxicity, where required
- PEC/PNEC risk characterisation
Consortium Testing Model
Laboratory Coordination & Study Execution
When regulatory testing is mandatory, Masuu coordinates with qualified GLP/appropriate testing laboratories and specialized scientific partners — giving clients a single point of contact across the full testing lifecycle.
Study Selection→
Protocol Development→
Lab Coordination→
Sample Management→
Study Execution→
Data Review→
Regulatory Interpretation→
ERA Integration
Final ERA Report — Contents
- Executive summary
- Substance & product information
- Environmental exposure assessment
- Phase I evaluation
- Phase II assessment (where applicable)
- Environmental fate assessment
- Ecotoxicological assessment
- PEC/PNEC calculations
- Risk characterisation
- Data gap evaluation
- Testing rationale
- Risk mitigation considerations
- References and supporting scientific evidence
How We Work
Report Preparation Process
Every ERA follows a structured, tiered workflow designed to deliver scientifically defensible and regulator-ready assessments.
01
Comprehensive Data Collection
Product, substance, usage, physicochemical, toxicological, environmental and regulatory information collected and reviewed.
02
Phase I Environmental Screening
Environmental exposure assessment and determination of whether the assessment can conclude at Phase I or requires progression.
03
Phase II Evaluation
Detailed environmental fate and ecotoxicological assessment when Phase II is triggered.
04
Data Gap & Testing Strategy
Missing information identified and available alternatives evaluated before recommending additional testing.
05
Consortium Testing Support
Where testing is mandatory, Masuu coordinates with qualified testing partners through its Consortium Model.
06
Scientific & Regulatory Review
Integration and critical review of generated and existing data by experienced scientific and regulatory experts.
07
Final ERA Delivery
Comprehensive ERA report with transparent methodology, scientific rationale, calculations, conclusions and regulatory recommendations.
Ex-Agency Advantage
Why Masuu Global?
Our experienced regulatory and scientific experts bring a practical regulatory perspective — helping clients understand not only what data are required, but why they are required and how regulators may evaluate them.
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Regulatory expectation-driven assessmentsAligned with applicable global ERA requirements.
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Tiered assessment strategyPhase I screening followed by Phase II only when scientifically and regulatorily justified.
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Data gap optimisationLiterature, databases, read-across and in-silico information evaluated before recommending new testing.
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Consortium testing coordinationManaged laboratory engagement when mandatory studies are required.
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Integrated scientific interpretationEnvironmental fate, ecotoxicity and risk characterisation connected into one coherent assessment.
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Regulatory-ready documentationDesigned to support submissions, authority queries and technical reviews.
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Reduced testing burdenStructured data-gap and weight-of-evidence approach minimises unnecessary study requirements.
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Single-point coordinationAssessment, testing strategy, laboratory engagement and final ERA integration — one team.
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Global regulatory supportERA services spanning pharmaceutical and healthcare products across multiple markets.
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