What is the RWD Mini Osmotic Pump?

The RWD Mini Osmotic Pump is a small, fully implantable drug delivery system designed for precise, continuous long-term dosing in laboratory mice and rats. Driven by an osmotic gradient — rather than mechanical or battery-powered components — each pump delivers compounds at a stable, predictable rate for durations ranging from 3 days up to 4 weeks. This frees researchers from the burden of repeated injections, night and weekend dosing, and the experimental variability that comes with manual handling.

The pump is built around a robust semi-permeable membrane and a high-pressure salt interlayer that absorbs surrounding body fluids, expanding to squeeze the drug reservoir at a constant pre-defined flow rate. The pump can be implanted subcutaneously or intraperitoneally for systemic delivery, or connected to a catheter for targeted delivery to blood vessels, the brain, the spinal cord, or other specific tissues.

Key Features

• Stable pumping rate: Predictable dosing minimises experimental variability and ensures reproducible, consistent results across animals.
• Reduced animal stress: Continuous administration eliminates the stress response and physiological artefacts associated with repeated injections or frequent handling — improving animal welfare and data quality.
• Systemic or targeted delivery: Implant directly for subcutaneous or intraperitoneal dosing, or connect a catheter to reach the brain, spinal cord, blood vessels, liver, or other organs.
• Three reservoir sizes: 100 µL, 200 µL, and 2 mL — covering a wide range of dose volumes and durations.
• Multiple flow rates and durations: Models delivering between 0.125 µL/hr and 5 µL/hr, with durations of 3 days, 1 week, 2 weeks, or 4 weeks.
• Biocompatible and sterile: Built from biocompatible materials to avoid immune rejection, with each pump irradiation-sterilised to prevent inflammatory reaction.
• No external hardware: No batteries, controllers, or external connections — the pump operates entirely on the osmotic gradient.

Research Applications

Mini osmotic pumps are widely used wherever continuous, slow, or pulsatile delivery of a compound is essential to the experimental design. Typical applications include:

• Cardiovascular disease models: Chronic infusion of vasoactive compounds (e.g. angiotensin II) to induce hypertension or cardiac hypertrophy.
• Addiction and behavioural research: Sustained delivery of agonists, antagonists, or test compounds to study reward, dependence, and withdrawal.
• Anxiety, fear, and emotion-based research: Stable plasma or CNS drug levels for behavioural pharmacology paradigms where injection-induced stress would confound results.
• Diabetes and metabolic disease research: Long-term infusion of insulin, hormones, or candidate metabolic drugs.
• Pain, injury, and therapeutic infusions: Targeted analgesic or neurotrophic-factor delivery directly to lesion sites or the spinal cord.
• Oncology and cancer drug screening: Continuous tumour-targeted or systemic delivery of candidate anti-cancer compounds in xenograft and syngeneic models.

How the Pump Works

The osmotic pump consists of a robust semi-permeable membrane that surrounds a high-pressure salt interlayer. As body fluids permeate through the membrane, the salt layer expands and compresses the inner drug reservoir, expelling the contents at a precisely controlled rate through a flow regulator. Because the driving force is biological — the animal's own body fluid — the pump requires no batteries, no external wiring, and no maintenance once implanted.

Why Researchers Choose RWD

RWD Mini Osmotic Pumps offer the same proven implantable design that the scientific community has relied on for decades — now at a competitive price point. Sterilised, biocompatible, and shipped ready for surgical implantation, the pumps integrate seamlessly with standard rodent stereotaxic, catheterisation, and subcutaneous implant workflows.