IAM Fast-Screen Mini Columns
The IAM Fast-Screen Mini Column
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 esterIAM.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:
- Excellent Correlation to Traditional Methods
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 |
Intestinal Tissue Correlation
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.
| Table 2. Correlating drug partitioning into IAM with rat intestinal drug absorption |
| Compound | % Absorption of Inverted Rat Intestine | IAM Fast-Screen Mini Column Retention Time
(Sec) | k'
(corrected) |
| m-nitroaniline | 77 | 133.1 | 15.29 |
| p-nitroaniline | 68 | 177.9 | 21.84 |
| salicylic acid | 60 | 93.8 | 9.54 |
| p-toluidine | 59 | 79.7 | 7.48 |
| aniline | 54 | 52.1 | 3.45 |
| m-nitrobenzoic acid | 53 | 68.1 | 5.79 |
| phenol | 51 | 94.6 | 9.66 |
| benzoic acid | 51 | 43.7 | 2.22 |
| acetanilide | 42 | 76.2 | 6.97 |
| antipyrine | 32 | 51.8 | 3.40 |
| theophylline | 29 | 39.3 | 1.58 |
| acetylsalicylic acid | 20 | 36.1 | 1.11 |
r (correlation factor) = 0.8385.
r is calculated by plotting log k' vs. log % absorption of inverted rat intestine. |
Chromatographic Conditions
Column: IAM Fast-Screen Mini Column 1 cm x 3.0 mm i.d.
Mobile Phase: Dulbecco's Phosphate Buffered Saline, pH 5.4
Flow Rate: 0.3 mL/min
Load: 10 µm
Detection: UV 254 nm, 0.1 AUFS
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 11. 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. - High Sample Throughput
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. - Highly Reproducible Results
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 |
- Durability
IAM Fast-Screen Mini Columns are extremely durable. Correlation factors, r, for the original k', and k' after 5000 column volumes were identical. - Cost Effectiveness
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 - Ability to Establish Permeability Zones 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 # | U.S. Price |
|
IAM Fast-Screen Mini Column Kit
• 2 columns, 1 cm x 3 mm
• 1 cartridge holder
• Care and use booklet | 10 µm, 300Å | 1 cm x 3.0 mm i.d | 775014 | $453.65 |  |
IAM Fast-Screen Mini Columns,
Pkg. of 12
• 12 columns, 1 cm x 3 mm
• Care and use booklet | 10 µm, 300Å | 1 cm x 3.0 mm i.d | 775016 | $1,213.25 | |
IAM Fast-Screen Mini Columns,
Pkg. of 6
• 6 columns, 1cm x 3 mm
• Care and use booklet | 10 µm, 300Å | 1 cm x 3.0 mm i.d | 775015 | $696.30 | |