Acid decomposition of omeprazole in the absence of thiol: A differential pulse polarographic study at the static mercury drop electrode (SMDE)

Qaisi, Ali M.; Tutunji, Maha F.; Tutunji, Lara

doi:10.1002/jps.20546

Cited by 38 publications

(29 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reduction potentials of the three PPIs at pH 7.5 are shown in table 1, and they are comparable with previous works [29][30]. Similarly to omeprazole , it was observed that the reduction potential(s) of lansoprazole and pantoprazole shift cathodically, as the solution pH increases from 3 to 7.5.…”

Section: Acid Decomposition Of Ppissupporting

confidence: 87%

“…Shine et al investigated only the rate of degradation of PPIs using UV spectroscopy; no attempt was made to quantitatively evaluate or monitor the formation of degradation products. , worked on the acid degradation of omeprazole and investigated the mechanism for the inhibition of gastric (H+, K+)-adenosine triphosphate by omeprazole [29] . , investigated acid degradation of omeprazole, lansoprazole and pantoprazole under the same experimental conditions using differential pulse polarography (DPP) at the static mercury drop electrode (SMDE) in phosphate buffer of pH 2.0-8.0 [30], and results were compared with previous techniques, which employed HPLC and UV spectroscopy, alone or in combination.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Study of Acid Catalyzed Reactions of Proton Pump Inhibitors at D.M.E.

Gupta¹,

Saini²,

Dhingra³

et al. 2007

Port. Electrochim. Acta

View full text Add to dashboard Cite

Acid catalyzed reactions of three proton pump inhibitors (PPIs), namely omeprazole, lansoprazole and pantoprazole, have been investigated and monitored by direct current polarography at dropping mercury electrode (D.M.E) in phosphate buffer (0.1 M) of pH 3-7.5. This gives well defined current-time profiles of individual electroactive degradation products along with their starting materials. The investigation shows that the order of stability of three PPIs can be written as: pantoprazole > omeprazole > lansoprazole. The rate of degradation of PPIs decreases with decreasing the basicity of the corresponding benzimidazole nitrogen of PPIs, as predicted by the effect of individual substituents on each of the benzimidazole rings. At pH 7.5 all three PPIs are almost stable and the observed half wave potentials (E 1/2 ) are -1.07 V for omeprazole, -1.25 V for lansoprazole and -1.32 V for pantoprazole. On decreasing the pH from 7.5 to 3.0 the anodic shift in E 1/2 values were observed along with degradation of the PPIs and simultaneous appearance of degradation products. The present study may provide an insight for designing more potent new proton pump inhibitors.

show abstract

Section: Acid Decomposition Of Ppissupporting

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Study of Acid Catalyzed Reactions of Proton Pump Inhibitors at D.M.E.

Gupta¹,

Saini²,

Dhingra³

et al. 2007

Port. Electrochim. Acta

View full text Add to dashboard Cite

show abstract

“…After 30 min, the band at 370 nm disappeared and a peak at 293 nm was formed (curve 2) and remained so for the next 4 days (curve 3). It is well established that OMZ is stable at high pH but degrades under acidic conditions to produce the corresponding sulfenamide, sulfide, dimer and other products, which reduce at DME [18,20]. Therefore, the degradation products may be due to omeprazole sulfenamide, which can suffer further degradation, and omeprazole sulfide [20].…”

Section: Spectrophotometric Experimentsmentioning

confidence: 96%

“…Several polarographic techniques and supporting electrolytes for determining OMZ were reported and the best results were obtained with differential pulse polarography (DPP) in borate buffer solution (pH9.0) [17]. The reactions of OMZ, in the absence of a nucleophile, were monitored using DPP at the static mercury drop electrode (SMDE) [18]. Experiments carried out in solutions buffered to pH values ranging from 2.0 to 8.0 showed that the DPP signals of OMZ and its degradation products are highly dependent on pH.…”

Section: Omeprazole (Omz) 5-methoxy-2-[[(4-methoxy-35-dimethyl-2-pymentioning

confidence: 99%

Electrochemical Redox Behavior of Omeprazole Using a Glassy Carbon Electrode

2010

View full text Add to dashboard Cite

The electrochemical redox behavior of omeprazole (OMZ), a gastric acid pump inhibitor, was investigated at a glassy carbon electrode using cyclic, differential pulse and square-wave voltammetry over a wide pH range. The pHdependent oxidation occurs in two irreversible consecutive charge transfer reactions. Adsorption of the nonelectroactive product was also observed. The first oxidation involves removal of one electron, followed by deprotonation and leads to the formation of a hydroxylated species. The second oxidation process is related to the hydroxyl and amino groups in the benzimidazole moiety. The reduction is irreversible, also pH-dependent, and occurs in a single step at the sulfoxide group in a diffusion-controlled mechanism. The diffusion coefficient of omeprazole was calculated to be D OMZ ¼ 2.31 Â 10 À6 cm 2 s À1 .

show abstract

“…A strong peak was assigned to the dimer hypothesized to be the major product from the acid decomposition of omeprazole. 10 Therefore, we decided to investigate the stable thiosulfinate degradation product of omeprazole, i.e., the omeprazole dimer 11 ( Fig. 1), as a potential ionophore for heavy metal cations.…”

Section: Introductionmentioning

confidence: 99%

A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

Abbas¹,

Amer²

2013

Bulletin of the Korean Chemical Society

View full text Add to dashboard Cite

A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 × 10 −7 to 1 × 10 −2 M and a lower detection limit (LDL) of 1 × 10 −7 M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

show abstract

Acid decomposition of omeprazole in the absence of thiol: A differential pulse polarographic study at the static mercury drop electrode (SMDE)

Cited by 38 publications

References 12 publications

Study of Acid Catalyzed Reactions of Proton Pump Inhibitors at D.M.E.

Study of Acid Catalyzed Reactions of Proton Pump Inhibitors at D.M.E.

Electrochemical Redox Behavior of Omeprazole Using a Glassy Carbon Electrode

A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

Contact Info

Product

Resources

About