Co-Determination of Two Antiparasitics Drugs by Derivative Spectrophotometry and Its Photodegradation Studies

Abstract

This work proposes a method for the co-determination of praziquantel and fenbendazole in veterinary pharmaceutical formulations (VPF) by second-derivative spectrophotometry at 226.4 nm (Zero-crossing method) and 324.6 nm (Graphic method), respectively. The excipients commonly used in VPF do not interfere. To obtain the optimal determination conditions, studies of solvent and light effects, were performed. The results of the light effects show that the expose of both drugs to indirect light and darkness does not produce any chemical change, since their zero-order spectra remained unchanged during the experiment. However, the exposition to the direct light only affects the fenbendazole. The zero order spectrum of FBZ in EtOH-HCl, present two broad bands (200 to 240 nm and 260 to 330 nm), these signals disappear and appear others totally different, at 230 nm and other with two peaks (285 and 295 nm). The FT-IR spectrum shows characteristics signals of the FBZ structure as the amide-NH group (3336.3 cm -1 ), this signal disappear indicating the bond break of the amide group caused by the exposition to sunlight for a time. These spectral changes evidenced a structural transformation as a result of photochemical decomposition in acid medium.

Formulation and Evaluation of Fenbendazole Extended-Release Extrudes Processed by Hot-Melt Extrusion

“…Figure 3 a displays the IR spectra corresponding to raw materials and melt-extruded formulations. Fen spectrum was confirmed by comparison with SpectraBase TM /Wiley (CAS #43210-67-9), identifying its relevant signals at 3336 cm −1 attributed to stretching mode of (N-H) from the carbamate group, 1708 cm −1 attributed to the (C=O) stretching vibrations of the carbamate carbonyl, 1630 cm −1 attributed to the (N-H) bending and the (C-N) stretching modes, 1442 cm −1 assigned to the (C-N), 1222 cm −1 attributed to the (C-O), 1099 cm −1 attributed to the phenyl-(o), 742 cm −1 characteristic of phenyl group, and 685 cm −1 identified as benzenethiol moiety [ 18 , 26 , 27 , 28 ].…”

Comparative study on the selectivity of various spectrophotometric techniques for the determination of binary mixture of fenbendazole and rafoxanide

“…These include High performance and ultra-high performance liquid chromatography [1,[4][5][6], densitometry [7], electrophoresis [8][9][10], voltammetry [11,12], potentiometry [1], colorimetry via ion pair complex formation with bromothymol blue [13] and derivative spectrophotometry [14].…”

Development of a Dissolution Test for Fenbendazole-Praziquantel Capsules Using UV-PLS Method

“…6, 2017 methods for the simultaneous determination of both drugs in pharmaceutical dosage forms are scarce. This association has been determined in dog plasma by the HPLC method 18 and UHPLC-QqLIT-MS [19][20][21] and there is not dissolution test conditions developed to evaluate formulations containing both.…”