Piroxicam Benzoate—Synthesis, HPLC Determination, and Hydrolysis

Abstract

An improved method of piroxicam benzoate synthesis was described, and an isocratic reversed-phase high-performance liquid chromatography method for its determination was developed and fully validated. The method was found to be specific, precise (relative standard deviation 0.3%), accurate (mean recovery 99.9%), and robust. Limit of detection was estimated at 0.055 microg mL(-1) and limit of quantification at 0.185 microg mL(-1). The kinetics of piroxicam benzoate hydrolysis in aqueous buffer solutions (pH 1.1 and 10), simulated gastric and intestinal fluids was studied. The hydrolysis followed first-order kinetics. The following rate constants were obtained at pH 10: k = 1.8 x 10(-3) hr(-1) at 37 degrees C and k = 3.4 x 10(-2) hr(-1) at 60 degrees C. In acidic media, no significant hydrolysis was observed after 24 hr. During the 24-hr period in simulated intestinal fluid, only 10.9% of the starting ester was hydrolyzed.

4-Benzoyloxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide

“…The product was recrystallized from ethyl acetate to give pure (I) [m.p. 421±423 K; literature 418±421 K (Boneschans et al, 2003)]. o + 2F 2 c )/3 (Á/') max < 0.001 Á& max = 0.17 e A Ê À3 Á& min = À0.25 e A Ê À3…”

“…Besides great therapeutic potential, oxicams are very interesting polyfunctional chemical compounds by virtue of their dynamic structural features, which include tautomeric switches and their possible polymorphism (Banerjee & Sarkar, 2002). Piroxicam benzoate, (I), was synthesized by an acylation reaction from piroxicam and benzoyl chloride (Boneschans et al, 2003). This acyl piroxicam derivative proved to be useful in therapy as a non-steroidal anti-in¯ammatory agent (Lombardino, 1982).…”

“…This acyl piroxicam derivative proved to be useful in therapy as a non-steroidal anti-in¯ammatory agent (Lombardino, 1982). Compound (I) has been characterized by elemental analysis, IR spectroscopy, high-performance liquid chromatography (HPLC) and thermal analysis (melting point) (Boneschans et al, 2003;Lombardino, 1982), but its crystal structure has not been solved until now. The structure of a compound of similar composition, namely 4-ethoxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, (II), which contains an ethoxy group instead of the benzoyloxy group, was solved by Hammen et al (1989).…”

Solvent-Free Mechanochemical Modification of Lappaconitine and Piroxicam

“…However, due to acidic properties of this compound, a long-term medical treatment with piroxicam may cause gastric irritation and ulceration. It was also shown that some acyl derivatives of piroxicam possess improved therapeutic properties and exhibit substantial antiinflammatory activity [15,16].…”

Desenvolvimento de sensores utilizando hidróxidos metálicos mistos nanoestruturados e sua aplicação em sistemas BIA

“…Vários métodos têm sido empregados para a determinação de piroxicam, sendo os mais recorrentes a cromatografia líquida [90], cromatografia líquida de alta eficiência (HPLC) [91], espectrofotometria [92], espectrofluorimetria [93], eletroforeses capilar [94], fluorescência [95] entre outros. Além dos mencionados anteriormente, os métodos eletroquímicos têm sido uma atrativa alternativa para a análise de fármacos, pois os baixos custos e maior frequência de análise são vantagens importantes que fornecem estes métodos.…”