Automated Dissolution Sampler with Media Replacement

What is the Automated Dissolution Sampler with Media Replacement?

This sampler withdraws each sample and immediately replaces the same volume with fresh pre-heated medium, keeping vessel volume constant. It is used for long profiles with many pull points, where volume loss would otherwise distort concentrations. It keeps concentrations and temperature stable.

Overview

For extended-release products and profile studies, pulling 10 mL at each of 10 time points from 900 mL removes over 10% of the medium. USP <711> allows either replacement with fresh medium or volume correction in calculation. This sampler adds a heated medium reservoir and a second pump channel that refills each vessel with the same volume, at 37 ± 0.5 °C, right after sampling. Replacement reduces the need for correction factors and avoids temperature dips. Replacement dilutes the dissolved drug, so the software applies cumulative dilution corrections to compute percent released. It also handles timing, cannula flushing, vial labeling and logging of replacement lot. The added complexity requires validation of replacement accuracy, typically ±2% by volume, and periodic verification of medium temperature and degassing.

How does it work?

A sampling system places a filtered probe in the compendial sampling zone of each vessel and moves a defined volume of medium by syringe pump, peristaltic pump or vacuum to the destination. Valves select the channel, timers trigger sampling at preset times, and flush steps clear the lines. Probes are fitted with filters, typically 10 µm full-flow or 0.45 µm, which stop dissolution by removing undissolved particles. In-situ fibre-optic probes skip withdrawal entirely and measure absorbance in the vessel. Data such as time, volume and vial position are logged. Performance depends on timing accuracy, volume accuracy, dead volume, adsorption to tubing and filters, and the effect of the probe on hydrodynamics. Replacement of sampled volume with fresh medium can keep vessel volume constant.

What are the key features?

• Heated medium reservoir refilling vessels after each pull
• Replacement volume accuracy about ±2%
• Automatic cumulative dilution correction in software
• Degassed and preheated replacement medium at 37 °C
• Vial labeling and medium lot logging
• Suitable for profiles of 12 or more time points

What are the technical specifications?

A typical automated dissolution sampler with media replacement configuration offers sampling channels of 6 or 8, sample volume of 1–20 mL, replacement accuracy of ±2%, replacement temperature of 37.0 ± 0.5 °C, reservoir capacity of 5–10 L and timing accuracy of ±2 s. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Automated Dissolution Sampler with Media Replacement is used in extended-release profiling, many-time-point studies, low-volume vessel tests and bioequivalence dissolution. Across the wider Sampling Systems class, laboratories also deploy it for dissolution profile automation, regulated QC testing and extended-release studies.

Which standards and certifications apply?

Relevant standards and methods include USP <711>, USP <1092>, Ph. Eur. 2.9.3, JP 6.10, ChP 0931, ASTM E2503 and 21 CFR Part 11. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Validate automated sampling against manual pulls during OQ and method transfer, checking timing, volume accuracy and carry-over. Clean and inspect probes and cannulas regularly, since blockage and film build-up affect recovery. Replace pump tubing and filters per schedule, and evaluate drug adsorption on tubing and filters. Keep cannula position within the compendial zone and avoid contact with paddles or baskets. Ensure software provides audit trail, user access control and time-stamped records. Include samplers in preventive maintenance and calibration programs alongside the dissolution tester.

How do I select the right Automated Dissolution Sampler with Media Replacement?

Choose replacement when profiles have many time points or when vessel volume is small, such as 250 mL mini-vessels, so that volume correction is significant. Specify replacement accuracy, reservoir capacity, temperature control and software dilution correction. For short immediate-release tests, simple sampling is sufficient. Confirm the maximum number of pull points needed.

How does it compare with other Sampling Systems variants?

Match the system to the number of time points, unattended operation needs and analytical method. Syringe-pump samplers give accurate aliquots and suit vial-based HPLC analysis. Peristaltic online systems suit continuous UV profiles and fraction collection. Fibre-optic probes give the fastest time resolution without withdrawal but need UV-active, non-interfering analytes. Media replacement is worth having when withdrawn volume exceeds a few percent of vessel volume. Manual kits suit single-point QC and backup. Key specifications are timing accuracy, volume accuracy, channel count, filter options, carry-over, compatibility with the existing tester and software data integrity. Validate against manual sampling before replacing it in a regulated method.