Regis Technologies

 

Packed with the Ester PC Ligand phase, IAM Fast-Screen Mini columns are a rapid and economically viable screening method for the high throughput estimation of drug permeability. Their benefits include excellent reproducibility, short analysis time and low cost. This can be of great use in characterizing large libraries of compounds.

 

The structure of the ester IAM.PC.C10/C3 packing, selected for the Fast-Screen Mini Column, is shown in Figure 1. This PC analog demonstrates superiority in retention times and stability - essential features for short columns and mass drug screening.

 

The IAM.PC Fast-Screen Mini Column, 1 cm in length by 3.0 mm in internal diameter, was specifically designed by Regis for rapid estimation of drug permeability in high-throughput screening programs. When connected to an HPLC system with an autosampler, a single column can be used in the analysis of hundreds of samples per day with highly reproducible results.

 

The 1 cm Fast-Screen Mini Column is offered not as a separation tool, but rather as a tool for characterizing the chromatographic retention factor (k') of individual analytes. The measured k' of analytes on this column can be used to estimate a value for drug permeability.

 

Column Advantages

Regis Technologies 1 cm Fast-Screen Mini Column for Drug Discovery provides:

The traditional means of predicting permeability includes use of Caco-2 cell line cultures, intestinal tissue or liposome assays. These are laborious and costly to perform. Data obtained from the IAM Fast-Screen Mini Column correlate well to data obtained from taditional assays. This is summarized in Table 1.

 

Table 1. Comparing k'IAM data with other methods for estimating permeability
Method	Number of Compounds Evaluated	Correlation (r) with IAM Fast-Screen Mini Column
Partitioning into liposomes	23	0.831
Intestinal drug permeability	12	0.839
Caco-2 cell permeability	8	0.909

 

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Table 2 shows that drug permeability predicted by inverted Rat Intestines correlates well to drug retention factors, k'IAM measured on the IAM Fast-Screen Mini Columns. Note the short retention times.

 

Chromatographic Conditions:

Caco-2 Cell Correlation

 

Chromatographic Conditions Column: IAM Fast-Screen Mini Column 1 cm x 3.0 mm i.d. Mobile Phase: 0.01 M DPBS Buffer, pH 5.4 Flow Rate: 0.5 mL/min Load: 10 µl Detection: UV 220 nm

Drugs Studied 1. Propranolol 2. Alprenolol 3. Warfarin 4. Metoprolol 5. Hydrocortisone 6. Terbutaline 7. Atenolol 8. (AVP) Arginine-Vasopressin

Figure 1. Drug permeability predicted by Caco-2 cells correlates well to k'IAM measured on the IAM Fast-Screen Mini Columns. 

 

Rapid Indication of Drug Absorption

IAM Chromatography is a more rapid alternative to other methods. In a recent study completed by Regis k'IAMs of 12 compounds were compared with absorption data obtained in situ using rat intestines. Retention times for the compounds tested were between 20 and 180 seconds, while retention factors correlated well to the intestinal absorption data.

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IAM Chromatography is of increasing importance in combinatorial chemistry, where it is used to provide an initial estimate of a drug candidates' membrane permeability. Hundreds of samples can be injected into a single Fast-Screen Mini Column using an automated HPLC system. Recently a group of 12 test analytes was evaluated in 10 runs over the course of eight hours. Total run time for the 12 test analytes was only 42 minutes.

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The measured values for k'IAM show excellent reproducibility, both from run to run and from day to day (Figure 3).

 

Figure 3. Reproducibility of Results

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IAM Fast-Screen Mini Columns are extremely durable. Correlation factors, r, for the original k', and k' after 5000 column volumes were identical.

 

Because the IAM Fast-Screen Mini Column is inexpensive, has a very short analysis time, and provides drug permeability estimates for hundreds of drug candidates in a fraction of the time of conventional methods, the IAM Fast-Screen Mini Column becomes the economical alternative for high throughput screening.

 

Permeability zones can be determined for different analytes when performing large scale drug absorption screening. Thus, rapid IAM analyses can characterize a drug as having low, medium, or high membrane permeability (Figure 4). Regis Technologies manufactures the IAM Fast-Screen Mini Column on-site in its manufacturing facility. This column, as well as all of our other products, must adhere to rigorous manufacturing and quality control specifications before release.

 

Figure 4. Permeability Zone Determination

 

Product	Particle Size	Column Dimensions	Regis Product #
IAM Fast-Screen Mini Column Kit,2 columns, 1 cartridge holder, Care and use booklet	10 µm, 300Å	1 cm x 3.0 mm i.d	775014
IAM Fast-Screen Mini Columns, Pkg. of 12 columns, Care and use booklet	10 µm, 300Å	1 cm x 3.0 mm i.d	775016
IAM Fast-Screen Mini Columns, Pkg. of 6 columns, Care and use booklet	10 µm, 300Å	1 cm x 3.0 mm i.d	775015

 

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