Accelerate your DMPK work with Automated Blood Sampling and the AccuSampler

The pressures on pharmaceutical companies bring high demands for speeding up the time to market. Every day the time can be shortened can mean millions in advantage sales for a block buster compound. A simple way to cut this time is to eliminate a bottleneck in the preclinical work. The sampling of blood in both discovery and development trials takes time, but with a new technique where the blood sampling is done automatically instead of manually, it is possible to increase throughput and provide other benefits. This article will highlight the general concept and the AccuSampler® from DiLab.

Blood sampling is time consuming
Blood sampling is an important step prior to the analysis in many trials. In DMPK- or toxicology research for example, the time for sampling blood is extensive and time consuming for the personnel. The planning of the sampling must also be adjusted to the working time of the staff and have limitations over weekends and over nights. Because of this, the pharmaceutical company Novo Nordisk in Denmark started a project with DiLabs founder Hans-Axel Hansson. The aim was to build an instrument that automatically could handle the collection of blood instead of manual sampling. The result became the AccuSampler and with this the first step was taken in the ABS business (Automated Blood Sampling). Blood samples can now be automatically taken without staff supervision over prolonged periods, including overnight collections. 

Animal welfare
In addition to the increased throughput, automated sampling also improves the animals’ welfare. Today most of the pharmaceutical companies work actively to reduce, replace, and to refine the work with test animals – the 3R guidelines. Several studies have shown that the animals are less stressed, and that levels of corticosteroids are less affected when using AccuSampler compared to manual sampling (Royo, Björk et al. in J Endocrinology 2004). Since blood is drawn from the animals without handling, the animals are not even aware of the sampling and can continue to sleep or maintain normal behavior. With the ABS technique it is also possible to use the same animal for longer study periods and also to use mice instead of rats thanks to smaller sample sizes that can be taken. Both these possibilities are highly attractive arguments for improving the work within the 3R concept. 

Areas of use
The AccuSampler has been successfully applied to many species ranging from mice through primates, in application areas such as DMPK, Safety Pharmacology, Toxicology, Biomarkers, as well as in Cardiovascular, Diabetes, and other therapeutic groups. Furthermore, the idea where to use automated blood sampling has just begun. 

Technical description
The animal is linked to the AccuSampler via a catheter. The catheter can be placed in either the vein or artery of choice for the protocol. The catheter is connected to the AccuSampler tubing system which easily can manage a wide volume range with great accuracy – from more than 1ml down only 5µl!

The idea behind AccuSampler is to use an air bubble between the blood and the saline solution when transporting the sample in the tubing system. By this unique technique the two fluids do not mix and minimal volumes can be taken.

The blood not needed for the sample is given back to the animal and cleaning of catheters also compensates for the animal’s loss of blood to prevent dehydration.

The AccuSampler compensates for the amount of blood sampled with the same volume of saline solution.

Thanks to this minimal waste of blood, it is possible to use the same animal for more samples or for longer periods, including cross-over studies that require a wash out period. 

The AccuSamplers
Because not all applications are the same, DiLab offers unique AccuSampler systems for mice, rats and larger rodents, and a system optimized for larger species like dogs and pigs.

There are basically two different versions of the AccuSampler instrument, AccuSampler Standard and AccuSampler µ. The major difference between them is the volume capacity. If samples above 50µl are needed the Standard version is preferred. The Micro instrument is uniquely adapted for low volume sampling typically over the range of 5 to 50 µL. For the first time, a 6-8 point mouse PK study can be done in one animal whereas manual methods typically require 3 animals for one data point. In addition to using pressure sensors to verify catheter patency, the AccuSampler Micro individually weighs each sample with an integrated balance. This not only confirms that the sample was taken accurately, but can provide additional information to improve analytical data. The system is also ideal for experiments where many samples need to be taken from one animal, such as in Biomarker studies, as there is virtually only a minimal waste volume.

Until recently the AccuSampler µ was mainly seen as an instrument for mice only, compared to AccuSampler Standard where the major use is for rats, but the future for AccuSampler µ seems to be broader. Thanks to the possibility to take smaller amounts of blood more samples can be taken before reaching the upper limit of the maximal volume of blood taken per animal. Hence, rats can also be used in a totally new way thanks to ABS. 

Larger Animals
For other species than rodents, the AccuSampler Standard is used and if more blood than 500µl is needed a special application called Large Animal (LA) is implemented. With this technique automated blood sampling is possible also for pigs, dogs, primates or other larger species. The AccuSampler LA is able to handle larger sample volumes, automated infusions, connection to vascular access ports, as well as interface with telemetry systems. The system may be programmed with a delayed starting time, and the computer can be located outside the animal room to minimize disruption of physiological parameters during sampling. By selecting variable withdrawal and injection speeds, the AccuSampler LA can be easily optimized for various vessels, access port volumes, and a variety of harnessing and caging systems. Periodic measurement of the animal’s blood pressure can alert the operator to a disconnected access port before sampling takes place. The system can also be customized to use the vial of the volume and type required by the customer.

Quality results
The AccuSampler bridges the gap between the blood sampling and the analysis of the blood with the most advanced capabilities available. The system allows the user to program future experimental start times to facilitate delayed studies. The ability to run trials over night is seen as one of the best features for users. All AccuSampler systems require no calibration and use syringe pumps with accuracy and precision of less than one percent. The systems may be used with the caging choice of the customer including metabolic and telemetry capable arrangements.

The AccuSampler can be used to automatically dose animals by bolus or continuous infusion, to collect samples from 2 vessels simultaneously to assess hepatic clearance, to split samples into multiple vials, add reagents and more. By monitoring pressure in the catheter during sample withdrawal, the system can alert the operator to potential catheter issues and confirm sample integrity. In the event of a missed sample, the user can program the number of retries to be made before sending a notification. Catheter patency is maintained by delivering small volumes of heparinized saline through the catheter at user defined intervals.

The individual samples are stored in cooled vials kept at 4°C and are collected into standard 96 well tubes, or other customer specified vials including EDTA or heparinized containers. The systems are computer controlled (typically 8 units to one PC) by a Windows based software that has been verified to 21 CFR part 11. The software allows the user to specify sampling times, volumes, injections/infusions and can also provide the user with e-mail or other types of alerts in the event of a sampling issue. All sampling events, studies, protocols, treatments, etc. are stored in log files for easy access and study documentation.

Best practice
The most efficient way to use the AccuSampler is to use the instruments “24/7”. This is best accomplished if a smaller team or a Super User is pinpointed to supervise the trials, to co-ordinate the micro surgery of the animals and to manage support from DiLab. If there is space, another benefit is to install instruments in rooms next to each other. The more instruments controlled by one person, the more efficient the throughput will be.

DiLab
DiLab is a Swedish biomedical company totally dedicated to automated blood sampling. Manufacturing and R&D is located in Lund, while sales are managed from both Lund and Boston. DiLab’s mission is to be the Life Science industry’s preferred partner for ABS. The AccuSampler is used world-wide primarily by pharmaceutical companies within various preclinical research areas.

Furthermore, the AccuSampler is just one part of a whole blood-collecting concept. To complete the concept, DiLab offers a complete package of instrument training, training in microsurgery, software education to optimize documentation, and instruction in how to use options such as infusion and dosing capabilities.

For a continuous and smooth performance, DiLab also offers preventive maintenance service. A service visit from a service engineer twice yearly is a good check up to insure trouble-free operations. All consumables needed in the sampling can also be ordered from DiLab.

In summary
Automated Blood Sampling in freely moving animals using the AccuSampler® family of instruments has been shown to improve the quality of data, reduce animal usage, result in less stress to the animal, and increase throughput versus manual blood sampling (data available on request). Sample sizes from 5 µL to 3+ ml can be routinely collected over a 4-5 minute interval.

For more information about automated blood sampling and AccuSampler®, please send a mail to info@dilab.com or call +46 46 37 69 90 or visit www.dilab.com