Identification of Two Novel Hydroperoxide Impurities in Fluocinolone Acetonide Topical Solution by Liquid Chromatography Mass Spectrometry.

Fluocinolone acetonide topical is used to treat skin discomforts such as swelling, itching and redness by activating the natural substances in the skin. Several process-related impurities and degradation products are identified and reported. But hydroperoxide impurities in Fluocinolone acetonide topical solution are not reported anywhere. In this study, we identify two potential genotoxic isomeric hydroperoxide impurities in Fluocinolone acetonide topical solution by Liquid Chromatography Mass Spectrometry analysis. A possible mechanism for the formation of these two novel hydroperoxide impurities is based on the neighboring group participation effect of adjacent hydroxyl group (Internal SN2) which results in the loss of fluorine atom and formation of epoxide intermediate followed by the addition of the HOOH group. Since most of the hydroperoxide impurities are genotoxic in nature, one should eliminate these impurities from Active Pharmaceutical Ingredient (API) or protect the formulation product from these oxidative impurities.

Trace Level Quantification of the (-)2-(2-amino-5-chlorophenyl)-4-cyclopropyl-1,1,1-trifluoro-3-butyn-2-ol Genotoxic Impurity in Efavirenz Drug Substance and Drug Product Using LC-MS/MS.

Efavirenz is a non-nucleoside reverse transcriptase inhibitor used in the treatment of human immunodeficiency virus type-1 (HIV). (2S)-(2-Amino-5-chlorophenyl)-4-cyclopropyl-1,1,1-trifluoro-3-butyn-2-ol (AMCOL), used as an intermediate in the synthesis of efavirenz and a degradation impurity, has an aminoaryl derivative which is a well-known alerting function for genotoxic activity. Upon request from a regulatory agency, a selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for trace level quantitative determination of AMCOL related compound of efavirenz, for a risk assessment and comparison of impurity levels with the commercially available innovator product (brand name: Sustiva). The method provided excellent sensitivity at a typical target analyte level of <2.5 ppm, an established threshold of toxicological concern (TTC), when the drug substance and drug product samples were prepared at 15.0 mg/mL. The AMCOL sample was analyzed on a Luna C18 (2) (100 mm × 4.6 mm, 3 µm) column interfaced with a triple quadrupole tandem mass spectrometer operated in a multiple reaction monitoring (MRM) mode. Positive electrospray ionization (ESI) was employed as the ionization source and the mobile phase used was 5.0 mM ammonium acetate-methanol (35:65, v/v). The calibration curve showed good linearity over the concentration range of 0.2-5.0 ppm with a correlation coefficient of >0.999. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.07 and 0.2 ppm, respectively. The developed method was validated as per international council on harmonization (ICH) guidelines in terms of LOD, LOQ, linearity, precision, accuracy, specificity, and robustness.