4-Aminobenzoic Acid

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Inosine pranobex is an antiviral drug. A combination of inosine and dimepranol acedoben (a salt of acetamidobenzoic acid and dimethylaminoisopropanol) has no effect on viral particles itself. Instead, it acts as an immunostimulant. It is most commonly used to treat the rare measles complication subacute sclerosing panencephalitis in conjunction with intrathecal interferon therapy.
Chromatography of these two compounds can be difficult due to their high polarity. But both compounds can be well retained and separated using anhydrous (water-free) conditions using HPLC on SHARC 1 column, which uses hydrogen-bonding as a separation mechanism. The method uses a gradient of acetonitrile (ACN) and methanol (MeOH) mobile phase with volatile buffer containing Formic Acid 0.1% and AmFm – 0.01%, making the method MS-compatible. Both compounds can also be UV detected at 270 nm.
 

Application Notes: Procainamide is a common antiarrhythmic agent used to treat cardiac arrhythmias. According to USP methods procainamide hydrochloride contains not less than 98% and no more than 102% procainamide based on the dried basis. The USP HPLC method for the separation of procainamide and 4-aminobenzoic was developed on Legacy L1 column according to the US Pharmacopeia methodology. L1 classification is assigned to reversed-phase HPLC column containing C18 ligand. Support for the material is spherical silica gel with particles size 3-10 um and pore size of 100-120A. Resolution between critical pairs corresponds to rules and specifications of UPS.

Reference: USP 35- NF30

Application Columns: Legacy L1 C18 HPLC column

Application compounds: Procainamide and 4-aminobenzoic acid

Mobile phase: WAter/MeOH/MeCN (70/70/90) with 7 mM sodium lauryl sulfate and 11mM phosphoric acid

Detection technique: UV

Reference: USP35: NF30

Aminobenzoic Acid is an organic acid that can be found in folic acid vitamins, grains, eggs, milk, and meat. Because it absorbs the UV light, it is used in sunscreen with SPF 15 or greater. The acid can cause damage to DNA and skin irritations in rare cases. Primesep 100, a reverse phase column, contains embedded acidic ionizable groups and can retain aminobenzoic acid. The method is UV compatible and can be used as a general approach for analyzing similar compounds.

Isomers of organic compounds usually have very similar properties. Separation of such isomers by HPLC requires intensive screening of various columns and mobile phase conditions. In case of hydrophilic compounds, this task becomes even more challenging due to the lack of or limited retention on traditional reversed-phase (C18 or C8) HPLC columns. Three isomers of aminobenzoic acid (2-aminobenzoic acid, 3-aminobenzoic acid and 4-aminobenzoic acid) were successfully separated on a Primesep 100 reversed-phase/cation-exchange column. Baseline separation within 10 minutes was achieved and produced a perfect peak shapes for all three analytes. The method can be used a generic approach for separation of ionic hydrophobic and ionic basic isomers by mixed-mode chromatography.