Dynamic Vapor Sorption Analyzer - DVS Wetability Tester

DVST – 5 /11 /23 - A

Dynamic Vapor Sorption (DVS) Analyzer - DVST Series

Functions

Measure moisture adsorption and desorption isotherms​ of materials under controlled temperature and humidity conditions.

Generate adsorption-desorption kinetic curves​ to evaluate the rate and extent of water uptake/release.

Determine moisture absorption rate​ and other critical hygroscopic performance parameters.

Essential for pharmaceutical formulation, excipient screening, packaging development, and stability prediction.

Working Principle

The instrument controls temperature, relative humidity (RH), and gas flow rate​ within a sealed test chamber. A sample-loaded cup gains weight by adsorbing moisture when humidity increases and loses weight by desorbing moisture when humidity decreases. A built-in ultra-microbalance​ periodically weighs the sample cup to derive hygroscopic parameters and generate corresponding graphs in real time. The system automatically adjusts humidity steps to construct complete sorption isotherms and kinetic profiles.

Compliant Standards

USP <1241>​ - Water-Solid Interactions in Pharmaceutical Systems(moisture sorption isotherms for solid dosage forms)

USP <701>​ - Disintegration(reference for moisture interaction context)

ICH Q1A(R2)​ - Stability Testing of New Drug Substances and Products(moisture sensitivity evaluation)

European Pharmacopoeia (Ph. Eur.)​ - 2.2.32. Water – Solid Interactions(sorption-desorption isotherms)

ChP 2025 Edition​ - General Chapter: Dynamic Vapor Sorption Method(equivalent methodology)

Key Features

Built-in Humidity Control:​ Gas flows directly into the measurement chamber, ensuring high humidity stability​ and rapid response without external humidifiers.

Precision Temperature & Humidity Regulation:​ Automatic humidity control with water auto-refill; semiconductor-based bidirectional cooling/heating​ for accurate temperature control from ambient to elevated temperatures.

Patented Balance Protection:​ Proprietary thermal insulation and moisture-proof technology​ safeguards the ultra-microbalance, ensuring long-term stability and extended service life.

Adjustable Flow Rate:​ Flow rate adjustable from 0.02 to 2 m/s, ensuring uniform temperature and humidity fields throughout the test chamber for consistent results.

Full Automation:​ One-click testing with automatic termination, data saving, and dryer/desiccant regeneration cycle. Minimal operator intervention required.

No Special Room Required:​ Designed for indoor use without a constant-temperature/humidity environment​ - significantly reduces operating costs while maintaining data integrity unaffected by ambient fluctuations.

Data Security & Continuity:​ Graphical, full-process, multi-parameter recording; data retention during power outages; optional GMP Computerized System software module​ with user management, access control, and audit trail.

Technical Specifications

Test host (main unit)

Computer with professional testing software

Air dryer

Sample cups (quantity per workstation)

Calibration weights

Sample handler

Optional Configuration

GMP Computerized System software module (user management, access control, audit trail)

User-Provided Items

Compressed air source (>0.3 MPa)

Distilled water

Desiccant

Application Industries & Scenarios

Pharmaceutical & Biotech

Excipient Screening:​ Determine moisture sorption isotherms of lactose, microcrystalline cellulose, and HPMC to predict caking and flow issues.

API Stability:​ Evaluate hygroscopicity of Active Pharmaceutical Ingredients per ICH Q1A(R2) for packaging and storage recommendations.

Solid Dosage Forms:​ Generate moisture absorption kinetics for tablets and capsules to optimize blister packaging and desiccant selection.

Amorphous Solid Dispersions:​ Monitor water uptake to detect crystallization tendencies in spray-dried dispersions.

Food & Nutraceuticals

Powdered Ingredients:​ Test hygroscopicity of protein powders, vitamins, and probiotics to determine shelf-life and packaging requirements.

Instant Beverages:​ Evaluate moisture adsorption of coffee, tea, and soup mixes to prevent clumping during storage.

Confectionery:​ Assess water vapor interactions in gummy candies and chewy snacks for texture stability.

Polymers & Advanced Materials

Hygroscopic Polymers:​ Measure water uptake in polyamides (PA), polycarbonates (PC), and polyurethanes (PU) for automotive and electronics applications.

Biodegradable Films:​ Evaluate moisture sorption of PLA, PHA, and starch-based films for compostability and shelf-life predictions.

Adhesives & Sealants:​ Test moisture curing kinetics and storage stability.

Chemical & Catalyst Industries

Desiccants & Molecular Sieves:​ Characterize water adsorption capacity and regeneration efficiency.

Catalyst Pellets:​ Evaluate moisture-induced deactivation and structural changes.

Research & Third-Party Testing

CNAS/CMA-Compliant Testing:​ Issue sorption isotherm reports referencing ChP 2025 or equivalent international methods.

New Material Development:​ Compare moisture barrier properties of novel polymers and composites.

Failure Analysis:​ Investigate moisture-related degradation in field-returned products.

Frequently Asked Questions (FAQ)

Q1: What is the difference between Dynamic Vapor Sorption (DVS) and static gravimetric methods?

A: Static gravimetric methods​ place samples in desiccators with saturated salt solutions at fixed RH levels - they require weeks to reach equilibrium and offer limited kinetic data. DVS​ dynamically controls humidity and continuously weighs the sample, generating complete isotherms and kinetic curves in days rather than weeks, with far greater precision and automation.

Q2: Which international standards apply to this instrument?

A: The instrument supports methodologies referenced in USP <1241> (Water-Solid Interactions), ICH Q1A(R2) (Stability Testing), and European Pharmacopoeia 2.2.32. The Chinese Pharmacopoeia 2025 Edition also specifies the "Dynamic Vapor Sorption Method" as an equivalent approach.

Q3: How many samples can be tested simultaneously?

A: The DVST series offers three models: DVST-5-A (5 samples), DVST-11-A (11 samples), and DVST-23-A (23 samples). Each workstation operates independently, allowing different humidity profiles on different samples concurrently.

Q4: Is a constant-temperature/humidity room required?

A: No. The instrument is designed for standard indoor use​ without a dedicated environmental room. Its internal temperature and humidity control system compensates for ambient fluctuations, reducing facility costs while maintaining data integrity.

Q5: What is the balance readability and why does it matter?

A: The standard balance offers 10 µg (0.00001 g) readability, with an optional 1 µg (0.000001 g)​ upgrade. For hygroscopic materials with low moisture uptake (<1%), this ultra-high resolution is essential to detect meaningful weight changes and construct accurate isotherms.

Q6: Can the instrument regenerate the desiccant automatically?

A: Yes. The system includes an automatic dryer and desiccant regeneration cycle, eliminating the need for manual oven drying and ensuring continuous operation.

Q7: Is the software GMP-compliant?

A: The standard software provides full data recording and graphical analysis. For regulated pharmaceutical environments, the optional GMP Computerized System module​ adds user role management, access control, electronic signatures, and audit trails to meet 21 CFR Part 11 and NMPA requirements.