TiO2/graphene composite nanofibers for efficient photocatalytic degradation of pharmaceutical compounds: Rifampin, Phenazopyridine, Azathioprine

Pharmaceutical wastewater treatment is an essential component of environmental protection and sustainable development. In this study, our aim was to investigate the morphology, characterization, and effectiveness of TiO2/graphene composite nanofiber photocatalysts in the treatment of pharmaceutical wastewater containing three different pharmaceutical groups, such as an antibiotic (rifampin), painkiller (phenazopyridine), and immunosuppressant (azathioprine). Various parameters such as pH, salt concentration, and initial pharmaceutical compound concentration were optimized to achieve maximum degradation kinetics and efficiency. The optimum conditions were determined to be 1.5% graphene content, 30 ppm initial concentration of pharmaceutical compound, pH=5, and a 0.5 g/L photocatalyst dose. The presence of salt slightly decreased the degradation kinetics, but it did not significantly affect the performance of the TiO2/graphene composite nanofibers photocatalyst. At optimum condition, TiO2/1.5% graphene composite nanofibers degraded 50% of phenazopyridine, 86.89% of rifampin, and completely azathioprine. Comparing with phenazopyridine, N heteroatom-rich molecule of azathioprine and hydroxyl-rich molecule of rifampin lead to being susceptible to photocatalytic degradation. The reuse of the photocatalyst in multiple cycles showed consistent performance, indicating its potential for practical and economic applications.

Cerium oxide: synthesis, brief characterization, and optimization of the photocatalytic activity against phenazopyridine in an aqueous solution

Water pollution by antibiotics is a global crisis, and its risk is critically more severe due to the explosive use of these drug compounds. A critical effective removal method to diminish this risk is heterogeneous photocatalysis and optimizing the conditions to reach higher mineralization efficiency. CeO₂ anoparticles (NPs) were synthesized and characterized by X-ray diffraction (XRD), UV-Vis diffuse reflection spectroscopy (DRS), and Fourier transform infrared spectroscopy (FTIR) techniques. A cubic structural crystallite phase was detected that had crystallite sizes of 17.9 and 16.7 nm estimated by the Scherrer and Williamson-Hall models. A typical FTIR absorption band for the Ce-O stretching absorption has appeared at 554 cm^-1. Based on DRS data and the Kubelka-Munk and Tauc models, Eg values of 2.80, 3.06, 3.12, and 3.13 eV were obtained for n-values of 1/2, 2, 3/2, and 3, respectively. pHpzc of CeO₂ NPs was about 5.7. The direct photolysis and surface adsorption processes have no critical role in phenazopyridine (PP) removal by appearing with 2.7 and 6.7% removal efficiencies, respectively. Due to the highest photocatalytic activity of CeO₂ NPs toward PP, the effects of the critical operating variable on the activity were evaluated, and the optimal conditions were as catalyst dose, 0.7 g/L; pH, 6; irradiation time, 90 min; and C_PP, 20 ppm. The Hinshelwood kinetics equation plot was y =  - 6.6442 - 0.4677x (r² = 0.9296), in which its slope as the rate constant of the photodegradation process was 0.4677 min^-1 (corresponding to a t_1/2 value of 1.48 min).

Phenazopyridine promotes RPS23RG1/Rps23rg1 transcription and ameliorates Alzheimer-associated phenotypes in mice

Alzheimer's disease (AD) is the most common form of dementia with no effective treatment options. A complete elucidation of its underlying molecular mechanisms, including the transcription regulation of genes critically involved in AD, may shed light on new therapeutic development. RPS23RG1 is a newly identified AD-associated gene, whose expression is decreased in AD and restoration can attenuate AD-like phenotypes in animal models. However, the transcription regulation of RPS23RG1 remains unknown. In this study, we explored the promoter of RPS23RG1 and identified its transcription initiation site (TSS) at 1525 bp upstream of the ATG translation start codon. Progressive deletion analysis determined the presence of a negative regulatory region and a positive regulatory region within nucleotide positions +1127 to +1187 and +732 to +1127 relative to the TSS (+1), respectively. We conducted a reporter system to screen for compounds that increase RPS23RG1 expression through antagonizing its negative regulatory elements and identified phenazopyridine. Importantly, we demonstrated that phenazopyridine not only promoted RPS23RG1/Rps23rg1 expression, but also reduced AD-like pathologies and cognitive impairments in the APP/PS1 AD model mice. We also determined a critical negative regulatory domain of RPS23RG1 within nucleotide positions +1177 to +1187 and found that the transcription factor SMAD3 bound to this domain. Inhibition of SMAD3 promoted RPS23RG1 expression. Moreover, phenazopyridine reduced SMAD3 binding to the RPS23RG1 promoter without affecting SMAD3 phosphorylation and nuclear localization. Taken together, our results determine the transcription regulation mechanism of RPS23RG1 and show that phenazopyridine has potential for AD treatment through regulating RPS23RG1 transcription.

[Phenazopyridine and fosfomycin for the acute cystitis treatment: results of multicenter randomized study]

AIM

To evaluate the analgesic effect, efficacy and tolerability of phenazopyridine in combination with fosfomycin for the treatment of acute uncomplicated cystitis in working-age female.

MATERIAL AND METHODS

A total of 152 women with acute uncomplicated cystitis were included in multicenter, randomized, open-label study which were carried out in 5 polyclinics of the Perm Territory. All the patients were divided into 2 groups of 76 people each, depending on the treatment. In the main group, women received oral phenazopyridine 200 mg 3 times a day for 2 days (a total dose 1200 mg) and fosfomycin trometamol in a dose of 3 g once. In the control group, patients received a single dose of fosfomycin trometamol (3 g) and drotaverin 80 mg 3 times a day for 2 days. A visual analogue scale (VAS) was used for evaluation of pain intensity. The symptoms of cystitis were assessed using the ACSS scale. In addition, urinalysis, urine culture and other methods were done. The results were evaluated after 6, 12, 24, 48 hours, 3 and 6 days.

RESULTS

In the main group, the severity of pain according to the VAS decreased from the initial 7.2+/-0.5 points to 1.6+/-0.2 points after 12 hours, to 0.4 +/- 0.05 points after 24 hours. Pain syndrome completely disappeared in all patients after 48 hours. In the control group, at all time points, a significant less pronounced analgesic effect was seen (p<0.001). The overall ACSS score in the main group decreased from the 12.0+/-0.5 points to 2.1+/-0.3 after 3 days and to 0.28+/-0.04 points after 6 days (p<0.001), which indicated a more rapid resolution of symptoms compared to the control group. The symptomatic effect of phenazopyridine (relief of pain, dysuria and discomfort) provided a more pronounced improvement in the well-being in the main group in comparison to the control group, which was confirmed by Dynamics domain of the ACSS scale (p<0.001). The combination of fosfomycin and phenazopyridine was more effective than the combination of fosfomycin and drotaverine. The clinical and microbiological cure rate in the main group was 97.4% and 96.9%, respectively. Leukocyturia was resolved earlier, and the duration of treatment decreased by 30.1%. An undesirable effect of phenazopyridine (nausea) was detected only in 1 (1.3%) patient.

CONCLUSION

Phenazopyridine has a pronounced analgesic effect and is proved to be an effective and safe drug in patients with acute uncomplicated cystitis.

Case Report: Phenazopyridine-Induced Sulfhemoglobinemia in an 83-Year-Old Presenting with Dyspnea

BACKGROUND

Sulfhemoglobinemia is a rare dyshemoglobinemia that presents similarly to methemoglobinemia.

CASE REPORT

An 83-year-old woman with stage IV ovarian cancer presented to the Emergency Department after a near syncopal spell and was found to be cyanotic with a pulse oximetry reading of 71%. Pulse oximetry improved to only the mid-80s range with administration of high-flow oxygen. Her arterial blood gas on supplemental high-flow oxygen demonstrated a PaO₂ of 413 mm Hg and methemoglobin of 1.2%, but also noted the interference of the co-oximetry with sulfhemoglobinemia. Further history revealed that the patient had recently been started on phenazopyridine. The phenazopyridine was stopped, an exchange transfusion was offered but declined, and the patient was discharged to home hospice. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The diagnosis of sulfhemoglobinemia can be challenging given that routine co-oximetry does not identify it. The clue to the diagnosis is that the cyanotic-appearing patient has a normal or elevated PaO₂ and seems to be less ill than expected, given the degree of cyanosis. Sulfhemoglobinemia does not reverse with the administration of methylene blue.

Simultaneous determination of phenazopyridine HCl and trimethoprim in presence of phenazopyridine HCl impurity by univariate and multivariate spectrophotometric methods - Quantification of phenazopyridine HCl impurity by univariate methods

Three univariate and two multivariate spectrophotometric methods were developed and subsequently validated to determine phenazopyridine HCl (PHZ) and trimethoprim (TMP) in the presence of 2,6-Diaminopyridine (2,6-DAP). The first univariate method depends on direct determination of phenazopyridine by measuring its absorbance at 412 nm and performed in concentration range of 1.00-10.00 μg/mL. Then the contribution of phenazopyridine is removed by dividing the mixture spectrum with PHZ divisor (5 μg/mL) after that the constant is mathematically subtracted and finally the generated spectrum is multiplied with the PHZ divisor. These steps eliminate PHZ contribution and the recovered spectrum is that of TMP and 2,6-DAP only where different methods can be applied to determine TMP and 2,6-DAP through this binary mixture spectrum. The first method to determine both components depends on measuring both TMP and 2,6-DAP through their first derivative (¹DD) spectra at 244.70 and 259.60 nm for TMP and 2,6-DAP, respectively with concentration ranges of 4.00-24.00 μg/mL TMP and 4.00-26.00 μg/mL 2,6-DAP. The second method depends on application of the isoabsorptive method which was used for TMP determination at its isoabsorptive point with 2,6-DAP at 242.64 nm with concentration range 1.00-20.00 μg/mL for TMP. The developed univariate methods were successfully applied to determine PHZ, TMP and PHZ impurity (2,6-DAP). Two multivariate methods were applied for determination of PHZ and TMP in presence of 2,6-DAP namely, Principle Component Regression (PCR) and Partial Least Squares (PLS). The results of the two models show that simultaneous determination of PHZ and TMP in presence of PHZ impurity can be performed in the concentration ranges of 6.00-14.00 μg/mL PHZ and 24.00-56.00 μg/mL TMP. All the proposed methods were successfully applied to analyze PHZ and TMP in pharmaceutical formulations without interference from the dosage form additives and the results were statistically compared with the reported method.

[Efficiency and safety of phenazopyridine for treatment of uncomplicated urinary tract infection: results of multi-center, randomized, placebo-controlled, clinical study]

AIM

to evaluate the efficiency and safety of phenazopyridine for the treatment of patients with uncomplicated lower urinary tract infection, accompanied by pain.

MATERIALS AND METHODS

A multicenter double-blind, randomized, placebo-controlled study with parallel groups to evaluate the efficacy and safety of phenazopyridine in patients with acute uncomplicated cystitis was performed. A total of 60 women were divided into two groups of 30 patients. In the main group (average age 32.6+/-7.4 years) phenazopyridine was prescribed (2 tablets of 100 mg p.o., with a total dose of 200 mg, once). In the control group, patients (mean age 35.53+/-8.79 years) received a placebo according to the same scheme. To evaluate the efficiency of treatment, the severity of the main symptoms 6 hours after taking the drug was analyzed. After that, patients started antibiotic therapy. They were followed-up for the next three days. The tolerance of therapy was evaluated by the presence of adverse events.

RESULTS

All 30 patients taking phenazopyridine had an improvement after 6 hours, and the most frequent response was "significant improvement" (43.3%). The responses of patients in the main group significantly (p<0.05) differed from responses of patients in the control group. Six hours after taking phenazopyridine/placebo, the severity of all values according to VAS score, including the degree of general discomfort, pain during urination and increased frequency of urination improved significantly in the main group compared to the control group. The average assessment of general discomfort in the main group decreased by 53.4% in comparison with 28.8% in the control group, while the severity of pain during urination and urination frequency decreased by 57.4 vs. 35.9% and 39.6 vs. 27.6%, respectively. An analysis of the time before the complete absence of the general discomfort was performed. In the main group this period of time was significantly less than in the control group (p<0.05). There were no serious adverse events while taking phenazopyridine. Rate of adverse events was comparable between two groups.

CONCLUSION

The results of the study showed that phenazopyridine is an effective and well-tolerated drug for symptomatic therapy in patients with acute uncomplicated cystitis and can be recommended in addition to etiological therapy.

Removal of Phenazopyridine from wastewater by merging biological and electrochemical methods via Azolla filiculoides and electro-Fenton process

In the present study, the potential of Azolla filiculoides (A. filiculoides) was first investigated for degradation of Phenazopyridine (PhP), an analgesic drug. The effects of main variables such as initial pharmaceutical concentration, amount of plant, and pH were studied on the efficiency of the biological process. It was observed that A. filiculoides was able to remove pharmaceuticals from contaminated water up to 85.90% during 48 h. Then, the electro-Fenton (EF) method was applied for further removal of PhP yielding a removal rate of about 98.72% under optimum conditions during 2 h. The effects of variables including the current, amount of catalyst, and pH were also studied in this phase. Also, the probability of adsorption was investigated during this step. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were performed for the used magnetite nanoparticles, total organic carbon (TOC) were performed to investigate PhP removal efficiency during the reaction time and Gas chromatography-mass spectrometry (GC-MS) were performed to analyze degradation byproducts of PhP. Based on the results, it was found that a combination of these bioremediation and electrochemical removal steps were capable of PhP removal from contaminated water. Therefore, this approach may be effective for phytoremediation of pharmaceutical-contaminated aquatic ecosystems.

Photocatalytic degradation of phenazopyridine contaminant in soil with direct solar light

Photocatalytic degradation of waste pharmaceutics, with solar radiation, is described here as a feasible method to purify pre-contaminated soils. Phenazopyridine has been used as a model soil contaminant. Two different nano-size powders have been first examined as catalysts, namely commercial TiO₂ (anatase) and commercial ZnO. As the ZnO showed higher catalytic efficiency, the study was then focused on it. The commercial ZnO powder was then compared with lab-prepared ZnO powder, and the latter shows relatively higher efficiency. The ZnO was used in two different ways. In one way, dry ZnO catalyst powder was spread onto the soil, while in the other way the ZnO was sprayed onto the soil surface by a wet spray method. The spray technique shows slightly higher efficiency, in addition to being easier to apply at future large scale. Depending on conditions and type of photocatalyst used, up to 90% contaminant removal can be achieved in 30 min. In case of photocatalysis experiments, the reacted contaminant molecules undergo complete degradation with no detectable side reaction organic products. Possible evaporation or escape of organic contaminant, or other possibly resulting organics, is ruled out by a series of control experiments. Photodegradation process takes place only at the catalytic sites on the soil surface, where contaminant molecules that diffuse from the soil bulk are completely degraded. Other useful organisms inside the soil are not affected as they are kept away from catalyst sites. A plausible mechanism is proposed for the degradation process.

Adsorption of phenazopyridine hydrochloride on pharmaceutical adjuvants

The adsorption of the urinary tract analgesic, phenazopyridine hydrochloride (PN . HCl), on some silicates as pharmaceutical adjuvants was studied. From Langmuir adsorption isotherms the adsorption capacities were determined. The results revealed that the adsorption capacities of veegum and bentonite were comparatively higher than kieselguhr, talc and kaolin. High adsorption capacities of veegum and bentonite were also obtained at pH values ranging between 2 to 4 simulating those of the stomach juice. Bioavailability studies proved that bentonite decreased the rate as well as extent of absorption of PN . HCl from rats.

Single vaginal ectopic ureter: a case report

The seventh case of a female subject with a single, unilateral ectopic ureter draining to the vagina is reported. The renal unit was located in the renal fossa, wheras in 3 of the 7 cases reported it was within the pelvis. Although ectopia with ureteral duplication is not an uncommon anomaly the single ectopic ureter in the female subject is the rarest form of ureteral ectopia. Use of phenazopyridine hydrochloric acid as an excertory marker was most helpful in locating the vaginal orifice.