The transition from chlorofluorocarbon (CFC) propellants to hydrofluoroalkane (HFA) alternatives marked a pivotal shift in pharmaceutical aerosol technology. Today, HFA 134a (1,1,1,2-Tetrafluoroethane,Norflurane) dominates the market, but its high global warming potential (GWP) has spurred interest in HFA 152a (1,1-Difluoroethane) as a sustainable alternative.
This article compares these two propellants in terms of regulatory compliance, environmental impact, formulation performance, and cost considerations, helping pharmaceutical manufacturers make informed decisions.
Regulatory Status: Compliance and Approvals
HFA134a: The Established Standard
Global Acceptance: Approved by the FDA, EMA, and other agencies for use in metered-dose inhalers (MDIs).
Pharmacopeia Standards: Complies with USP, EP, and JP monographs for pharmaceutical applications.
Safety Profile: Extensive toxicology data supports its use in respiratory and topical drug delivery.
HFA 152a: The Emerging Contender
Current Approvals:
Europe: Under evaluation for MDIs under the EU F-Gas Regulation.
USA: FDA submissions in progress; used in some OTC aerosol products.
Asia: Increasing adoption in generic inhaler markets.
Challenges:
Requires new stability studies and device compatibility testing.
Not yet universally accepted for all MDI formulations.
Key Takeaway:
While HFA 134a remains the safest choice for immediate regulatory compliance, HFA 152a offers a future-proof solution for companies prioritizing sustainability.
Environmental Impact: GWP and Sustainability
The Carbon Footprint Challenge
HFA 134a propellant:
GWP = 1,430 (per IPCC AR5).
Faces scrutiny under the Kigali Amendment to the Montreal Protocol.
HFA 152a propellant:
GWP = 124 (90% lower than HFA 134a).
Aligns with EU's 2030 F-Gas phase-down targets.
Industry Trends Driving Change
Pharma Sustainability Initiatives: Companies like GSK and AstraZeneca are exploring low-GWP propellants.
Carbon Taxes: Higher levies on high-GWP gases may increase HFA 134a costs over time.
Key Takeaway:
Switching to HFA 152a could reduce environmental liabilities and enhance corporate ESG (Environmental, Social, and Governance) ratings.
Performance in Drug Formulations
Solubility and Stability
| Parameter | HFA 134a | HFA 152a |
|---|---|---|
| API Solubility | Excellent for most drugs | Slightly lower (may require co-solvents) |
| Chemical Stability | Highly stable with common excipients | May need formulation adjustments |
| Vapor Pressure | ~570 kPa at 20°C | ~450 kPa at 20°C (milder spray force) |
Cost and Supply Chain Considerations
Pricing Trends
HFA 134a: Prices are stable but may rise due to carbon taxes.
HFA 152a: Currently 10-15% cheaper in some markets due to lower environmental fees.
Supply Chain Readiness
HFA 134a: Widely available from multiple suppliers.
HFA 152a: Limited pharma-grade sources; secure partnerships early.
Key Takeaway:
Early adopters of HFA 152a could gain long-term cost advantages, but must ensure supply chain reliability.
Which Propellant is Right for You?
Choose HFA 134a If:
✔ You need immediate regulatory approval for MDIs.
✔ Your formulation requires high API solubility.
✔ You prioritize a proven, low-risk option.
Consider HFA 152a If:
✔ Your company has sustainability mandates.
✔ You're developing new inhaler products (not reformulations).
✔ You want to future-proof against carbon regulations.
The choice between HFA 134a and HFA 152a depends on regulatory timelines, environmental goals, and formulation needs. While HFA 134a remains the industry benchmark, HFA 152a is gaining traction as a sustainable, cost-effective alternative.
Partner with Xiamen Juda Chemical & Equipment Co.,Ltd for:
High-purity HFA 134a & HFA 152a compliant with pharmacopeia standards.
Technical support for formulation and regulatory challenges.
Sustainable solutions aligned with global environmental goals.
Visit us at CPHI China 2025, Booth E12D70, or contact us today!
