Degradation Of Acetylsalicylic Acid Research Articles

Harnessing the potential of cube-like Holmium doped bismuth niobate (Ho–Bi5Nb3O15) amalgamated with rGO sheets for rapid photocatalytic elimination of crystal violet and acetylsalicylic acid

Synthesis of unique morphologies in photocatalytic materials, coupled with utilization of wide-spectrum solar energy through rare earth doping, holds significant promise to maximize the potential of photocatalysts. Herein in, cube-like Holmium (Ho) doped Bi5Nb3O15 was synthesized by the hydrothermal method and integrated with reduced graphene oxide (rGO) sheets. As synthesized Ho–Bi5Nb3O15@rGO composite along its analogs i.e., Bi5Nb3O15 and Ho–Bi5Nb3O15 was characterized by XRD, SEM, FT-IR, TGA, I–V, EIS, Mott-Schottky and photo-current measurements. Phase studies showed that crystallite size for Bi5Nb3O15, Ho–Bi5Nb3O15, and Ho–Bi5Nb3O15@rGO was 27.4, 25.5, and 13.5 nm, respectively. Optical analysis exhibited a reduction in the band gap in consequent to Ho doping from 2.54 to 2.19 eV for Ho–Bi5Nb3O15. Conductivity and photo-current measurements showed a remarkable increase in both electrical conductivity and photo-response of Ho–Bi5Nb3O15 upon its incorporation into rGO matrix, reaching maximum values of 1.72 × 10−2 S/m and 0.66 μA, respectively. The enhanced photocatalytic activity of Ho–Bi5Nb3O15@rGO was ensured through the outstanding photo-degradation efficiency (96.5 %) against crystal violet (CV), greater than Bi5Nb3O15 (49 %) and Ho–Bi5Nb3O15 (63.4 %). Additionally, Ho–Bi5Nb3O15@rGO showed sufficient potential towards the degradation of acetylsalicylic acid (ASA) with 79.1 % photo-degradation. This elevated photocatalytic activity of Ho–Bi5Nb3O15@rGO is believed to be contributed by the collaborative outcomes aroused from the Ho-doping and heterojunction fabrication among cubical Ho–Bi5Nb3O15 and rGO sheets. Hence, our work proposes an efficient strategy for the development of innovative photolytic materials for sustainable wastewater remediation.

Understanding the Roles of Excipients in Moisture Management in Solid Dosage Forms.

Excipients are ubiquitous in pharmaceutical products, and often, they can also play a critical role in maintaining product quality. For a product containing a moisture-sensitive drug, moisture can be deleterious to the product stability during storage. Therefore, using excipients that interact with moisture in situ can potentially alleviate product stability issues. In this study, the interactive behavior of starch with moisture was augmented by coprocessing maize starch with sodium chloride (NaCl) or magnesium nitrate hexahydrate [Mg(NO3)2·6H2O] at different concentrations (5 and 10%, w/w). The effect of the formulation on drug stability was assessed through the degradation of acetylsalicylic acid, which was used as the model drug. The results showed that coprocessing of the starch with either NaCl or Mg(NO3)2·6H2O impacted the number of water molecule binding sites on the starch and how the sorbed moisture was distributed. The coprocessed excipients also resulted in lower drug degradation and lesser changes in tablet tensile strength during post-compaction storage. However, corresponding tablet formulations containing physical mixtures of starch and salts did not yield promising outcomes. This study demonstrated the advantageous concomitant use of common excipients by coprocessing to synergistically mitigate the adverse effects of moisture and promote product stability when formulating a moisture-sensitive drug. In addition, the findings could help to improve the understanding of moisture-excipient interactions and allow for the judicious choice of excipients when designing formulations containing moisture-sensitive drugs.

A magnetite catalysed heterogeneous solar photo electro-Fenton system enhanced with lanthanum doped bismuth ferrite photoanode for the degradation of aspirin in water

The effect of photoanode on a solar photo electro-Fenton system (SPEF) consisting of a magnetite nanoparticle catalyst impregnated carbon felt cathode is studied by coupling the SPEF system to a lanthanum-doped bismuth ferrite (La-BFO) photoanode. The resulting system, referred to as La-BFO /SPEF, was used in the degradation of acetyl salicylic acid in wastewater. The synthesised La-doped/undoped BFO photoanodes and magnetite nanoparticles were characterised with SEM, XRD and FTIR. The heterogeneous electro-Fenton system was prepared by attaching the magnetite nanoparticle to a carbon felt electrode through magnetisation. The effects of La dopant concentration in the photoanode material (doped and undoped BFO on a fluorine doped tin oxide substrate), pH values, current density and anodic oxidation contribution to the SPEF system were explored through parameters such as total organic carbon (TOC) measurements and mineralization current efficiency. A TOC removal of 68 % and 54 % was recorded for the La-doped photoanode (La-BFO/SPEF) and undoped system (BFO/SPEF) respectively, thus reflecting the contribution from the band gap tuning of the photoanode material. The predominant species in the degradation of acetyl salicylic acid were deduced by radical scavenging experiments. The coupling approach and the irradiation with visible light, enhanced the overall performance of the degradation system.

Pharmaceutical compounds photolysis: pH influence

The operating parameters of photolytic and photocatalytic reaction processes directly affect the efficiency in the degradation of compounds. In particular, pH is a variable that needs to be considered as it exerts great influence on adsorption, absorption, solubility, among others. This study describes the application of the photolytic process, at different pHs, in the degradation of different pharmaceutical compounds. Photolytic reactions were performed with the following contaminants: acetylsalicylic acid (ASA), ibuprofen (IBP) and paracetamol (PAR). In addition, a comparison was performed using the commercial catalyst P25. The results indicated a great influence of the pH in the kinetic constant of the photodegradation and in the UV absorbance of the species. In particular, the degradation of ASA and PAR were favored with the reduction of pH, while the degradation of IBU and SA were favored by increasing. Also, the chromatograms indicated that pH may affect the by-products formed. In comparison, the photocatalysis process in the presence of P25 proved to be much more effective, but it was not possible to achieve complete mineralization of the compounds.

Relative Humidity Cycling: Implications on the Stability of Moisture-Sensitive Drugs in Solid Pharmaceutical Products

The stability of a moisture-sensitive drug in tablet formulations depends particularly on the environment's relative humidity (RH) and the products' prior exposure to moisture. This study was designed to understand drug stability in relation to the moisture interaction of the excipients, moisture history of the tablets, and RH of the environment. The stability study was performed on tablets containing acetylsalicylic acid (ASA), formulated with common pharmaceutical excipients like native maize starch, microcrystalline cellulose (MCC), partially pregelatinized maize starch (PGS), dicalcium phosphate dihydrate (DCP), lactose, and mannitol. The tablets were subjected to storage conditions with RH cycling alternating between 53% and 75%. Results were also compared to tablets stored at a constant RH of 53% or 75%. The excipients demonstrated marked differences in their interactions with moisture. They could be broadly grouped as excipients with RH-dependent moisture content (native maize starch, MCC, and PGS) and RH-independent moisture content (DCP, lactose, and mannitol). As each excipient interacted differently with moisture, degradation of ASA in the tablets depended on the excipients' ability to modulate the moisture availability for degradation. The lowest ASA degradation was observed in tablets formulated with low moisture content water-soluble excipients, such as lactose and mannitol. The impact of RH cycling on ASA stability was apparent in tablets containing native maize starch, MCC, PGS, or DCP. These findings suggested that the choice of excipients influences the effect of moisture history on drug stability. The results from studies investigating moisture interaction of excipients and drug stability are valuable to understanding the inter-relationship between excipients, moisture history, and drug stability.

Impact of Amylose-Amylopectin Ratio of Starches on the Mechanical Strength and Stability of Acetylsalicylic Acid Tablets

The two main components of starch — amylose and amylopectin, are responsible for its interaction with moisture. This study investigated how moisture sorption properties of the starches with different amylose-amylopectin ratio impacted tablet properties including drug stability. The starch samples were equilibrated to 33, 53, and 75% relative humidity (RH) and then assessed for tabletability, compactibility, and yield pressure. Effect of humidity on viscoelastic recovery was also evaluated. Tabletability and compactibility of high-amylose starch were better than that of high-amylopectin starch at 33 and 53% RH. However, at 75% RH, the reverse was observed. In terms of yield pressure, high-amylose starch had lower yield pressure than high-amylopectin starch. High-amylose starch tablets also exhibited lower extent of viscoelastic recovery than high-amylopectin starch tablets. The variations in the tableting properties were found to be related to relative locality of the sorbed moisture. Degradation of acetylsalicylic acid in high-amylose starch tablets at 75% RH, 40°C was less than the tablets with high-amylopectin starch. This observation could be attributed to the greater amount of water molecules binding sites in high-amylose starch. Furthermore, most of the sorbed moisture of high-amylose starch was internally absorbed moisture, therefore limiting the availability of diffusible sorbed moisture for degradation reaction. Findings from this study could provide better insights on the influence of amylose-amylopectin ratio on tableting properties and stability of moisture-sensitive drugs. This is of particular importance as starch is a common excipient in solid dosage forms.

Insights into the Moisture Scavenging Properties of Different Types of Starch in Tablets Containing a Moisture-Sensitive Drug.

Starch is a commonly used excipient in the pharmaceutical industry. However, information on the effect of the moisture scavenging properties of starch to protect moisture-sensitive drugs is limited. The interaction between starch and moisture is of particular interest as moisture fugacity can impact drug stability. In this study, the moisture behavior of different starches was examined for an understanding of its role in the degradation of acetylsalicylic acid. The starches were characterized for their dimensional- and moisture-related properties. Stability testing was carried out on tablets containing acetylsalicylic acid and different starches. Although moisture sorption processes were visually comparable for the different starches, quantitative differences were found in their moisture interaction and distribution. From the sorption isotherms, moisture monolayer coverage and area of hysteresis were found to correlate well with the percentage of acetylsalicylic acid degradation. The lowest percentage of acetylsalicylic acid degradation was observed in starch that exhibited high monolayer coverage, large area of hysteresis, and good capacity for internally absorbed moisture. Findings from this study highlighted the value of moisture scavenging excipients when formulating moisture-sensitive drug products. Clearly, the assessment of moisture sorption properties of excipients during the preformulation phase can be an invaluable exercise for identifying the best possible ingredients in formulations where moisture sensitivity is an area of concern.

Rolling-made gas diffusion electrode with carbon nanotube for electro-Fenton degradation of acetylsalicylic acid

H2O2 production plays an important role in electro-Fenton process for pharmaceutical and personal care products (PPCPs) degradation. In this work, carbon nanotube (CNT) was attempted to make a gas diffusion electrode (GDE) by rolling method to achieve a high H2O2 production and current efficiency, and it was further used as electro-Fenton cathode for the degradation of acetylsalicylic acid (ASA) as one kind of PPCPs. The optimal amount of catalyst layer was 0.15 g CNT and 93.75 μL PTFE, obtaining the production of H2O2 of 805 mg L−1 in 0.05 mM Na2SO4 solution at 100 mA after 180 min. The degradation of ASA by electro-Fenton on such a CNT-GDE cathode was studied, and some important parameters such as current, pH as well as the dosage of Fe2+ were optimized. The degradation ratio of ASA could achieve almost 100% after 10 min and the TOC removal ratio was 62% at 1 h under the condition of 100 mA and pH 3, showing a great potential for the treatment of PPCPs.

Raman spectroscopy and capillary zone electrophoresis for the analysis of degradation processes in commercial effervescent tablets containing acetylsalicylic acid and ascorbic acid

In order to ensure the stability of pharmaceutical products appropriate manufacturing and storage conditions are required. In general, the degradation of active pharmaceutical ingredients (APIs) and subsequent formation of degradation products affect the pharmaceutical quality. Thus, a fast and effective detection and characterization of these substances is mandatory. Here, the applicability of Raman spectroscopy and CZE for the characterization of the degradation of effervescent tablets containing acetylsalicylic acid (ASA) and ascorbic acid (AA) was evaluated. Therefore, a degradation study was performed analyzing tablets from two different manufacturers at varying conditions (relative humidity (RH) 33%, 52% and 75% at 30°C). Raman spectroscopy combined with principal component analysis could be successfully applied for the fast and easy discrimination of non-degraded and degraded effervescent tablets after a storage period of approximately 24h (RH 52%). Nevertheless, a clear identification or quantification of APIs and degradation products within the analyzed tablets was not possible, i.a. due to missing reference materials. CZE-UV enabled the quantification of the APIs (ASA, AA) and related degradation products (salicylic acid (SA); semi-quantitative also mono- and diacetylated AA) within the complex tablet mixtures. The higher the RH, the faster the degradation of ASA and AA as well as the formation of the degradation products. Mono- and diacetylated AA are major primary degradation products of AA for the applied effervescent tablets. A significant degradation of the APIs was detected earlier by CZE (6–12h, RH 52%) than by Raman spectroscopy. Summarized, Raman spectroscopy is well-suited as quick test to detect degradation of these tablets and CZE can be utilized for further detailed characterization and quantification of specific APIs and related degradation products.

The stability and degradation kinetics of acetylsalicylic acid in different organic solutions revisited – an UHPLC–ESI-QTOF spectrometry study

Abstract Ultra high performance liquid chromatography (UHPLC), coupled with accurate quadrupole-time-of-flight (Q-TOF) mass spectrometry, was used for the stability study of acetylsalicylic acid within a variety of different organic solutions: methanol, ethanol, propan-2-ol, acetonitrile, tetrahydrofuran and 1,4-dioxane. With the use of gradient elution chromatography and mass spectrometry detection in negative ionization, MS and MS/MS spectra were recorded simultaneously. In addition, quantitative, as well as qualitative analysis was performed during one assay. The stability of acetylsalicylic acid in such solutions was tested at room temperature, in a 12h period. In the work, in all cases, only one main degradation product, salicylic acid, was found. What is more, the work revealed that the degradation of aspirin in the tested organic solutions yields apparent second-order kinetics. The study also demonstrated that acetonitrile and 1,4-dioxane turned out to be the most stable solvents, and an above 80% of initial concentration of acetylsalicylic acid was found in this case. Furthermore, the most popular analytical solvents, methanol and ethanol, were found to be very unstable media. Herein, below 40% of initial concentration of acetylsalicylic acid was seen after 12h. The obtained results were also compared with the degradation of acetylsalicylic acid in a water solution. In this situation, only about 25% of the analyzed compound was resolved to salicylic acid in the same time frame.

Construction and characterization of visible light active Pd nano-crystallite decorated and C-N-S-co-doped TiO2 nanosheet array photoelectrode for enhanced photocatalytic degradation of acetylsalicylic acid

A photo-assisted deposition technique was adopted to construct highly dispersed Pd nano-crystallites on C-N-S-co-doped TiO2 nanosheets (Pd/C-N-S-TiO2 NS) arrays photoelectrodes prepared by one-step hydrothermal synthesis. The morphology, elemental composition, crystal structure, light absorption capability and photoelectrochemical (PECH) property of as-obtained Pd/C-N-S-TiO2 NS electrodes were determined and investigated through the various characterizations. The photocatalytic (PC) and photoelectrocatalytic (PEC) activity of the Pd/C-N-S-TiO2 NS electrode was evaluated through the degradation of acetylsalicylic acid and the formation of OH radicals. Compared with pristine TiO2 NS, Pd/TiO2 NS and C-N-S-TiO2 NS, Pd/C-N-S-TiO2 NS electrode displayed greatly enhanced PC and PEC activity towards the degradation of acetylsalicylic acid under visible light (λ>420nm) or Xenon light irradiation. The synergy effect of interfacial transfer of photoinduced electrons between Pd nanoparticles and TiO2 NS as well as the external potential and intense visible light absorption induced by C, N and S co-doing promoted the effective charge separation and transfer and more visible photons to participate in the catalytic process on obtained Pd/C-N-S-TiO2 NS, which were evidenced by a series of characterizations, resulting in highly efficient and stable PC and PEC activity. Moreover, the probable visible light PEC mechanism was proposed.

Catalytic ozonation for the degradation of acetylsalicylic acid in aqueous solution by magnetic CeO2 nanometer catalyst particles

A magnetic core/shell CeO2 nanometer catalyst particle of Fe3O4@SiO2@CeO2 for ozonation was prepared and the catalytic activity was evaluated by the degradation of acetylsalicylic acid (ASA). The characterizations of the magnetic nanoparticles, such as TEM, XRD and EDX, showed that Fe3O4@SiO2@CeO2 had a ternary structure with a Fe3O4 magnetic core, a silica membrane mid-layer and CeO2 outer layer. The catalysts of Fe3O4@SiO2@CeO2 showed an obviously high efficiency in catalytic ozonation on the degradation of ASA, and thus could also enhance the TOC removal. The ASA removal with Fe3O4@SiO2@CeO2 catalyst at 60min could reach 81.0%, while 67.3% with Fe3O4@SiO2, 66.1% with Fe3O4 and only 64.1% with ozonation alone. Fe3O4@SiO2@CeO2 catalysts could also enhance the ozone utilization during the reaction. The effect of radical scavengers showed that the high removal efficiency of catalytic ozonation over Fe3O4@SiO2@CeO2 may be mainly attributed to surface reactions. According to stability and recyclability test of the Fe3O4@SiO2@CeO2 catalysts, the results showed that the catalysts would be helpful in the separation and magnetic recyclability. In addition, based on the intermediates detected by GC/MS, a possible degradation pathway of ASA was proposed.

Microwave Drying of Granules Containing a Moisture-Sensitive Drug: A Promising Alternative to Fluid Bed and Hot Air Oven Drying

The impact of microwave drying and binders (copolyvidone and povidone) on the degradation of acetylsalicylic acid (ASA) and physical properties of granules were compared with conventional drying methods. Moist granules containing ASA were prepared using a high shear granulator and dried with hot air oven, fluid bed or microwave (static or dynamic bed) dryers. Percent ASA degradation, size and size distribution, friability and flow properties of the granules were determined. Granules dried with the dynamic bed microwave dryer showed the least amount of ASA degradation, followed by fluid bed dryer, static bed microwave oven and hot air oven. The use of microwave drying with a static granular bed adversely affected ASA degradation and drying capability. Dynamic bed microwave dryer had the highest drying capability followed by fluid bed, static bed microwave dryer and conventional hot air oven. The intensity of microwave did not affect ASA degradation, size distribution, friability and flow properties of the granules. Mixing/agitating of granules during drying affected the granular physical properties studied. Copolyvidone resulted in lower amount of granular residual moisture content and ASA degradation on storage than povidone, especially for static bed microwave drying. In conclusion, microwave drying technology has been shown to be a promising alternative for drying granules containing a moisture-sensitive drug.

An investigation about the solid state thermal degradation of acetylsalicylic acid: polymer formation

An investigation about the thermal degradation of acetylsalicylic acid (ASA) is performed. It is verified that the thermal degradation of ASA produces not only salicylic acid (SA) and acetic acid (AA) as products but also an ASA polymer, which is transparent and solid. And also verified that the temperature in which the polymer is obtained influences its physical consistence (solid or semi-solid). Furthermore, the ASA polymer is very stable from a thermic point of view, as verified by TG and DSC analysis. X-ray diffraction patterns obtained for the ASA polymer show that it exhibits a low crystallinity.

The Stability of Drug Adsorbates on Silica

Colloidal and porous silicas are used as carriers in solid, semisolid and liquid dosage forms. Adsorption of active ingredients onto their large surface areas can be used to regulate drug release or for the uniform distribution of drug in single dose units with a very low drug content. In the adsorbates the contact between drug and carrier surface on the molecular level can be of great importance for the chemical stability of drug preparations. This is demonstrated by the following examples:Hydrolytic degradation of acetyl salicylic acid in dry silica adsorbates is mainly determined by alkaline impurities of the carrier and strongly adsorbed water on the silica surface. The “catalytic” action of silicas is, therefore, directly dependent on the preparation technique of the carrier. Propantheline a cationic ester compound is adsorbed on silica from aqueous solution. In aqueous silica suspensions and in dry adsorbates the ester hydrolysis is controlled by the pH, the neutral salt content, and buffer substanc...

Degradation of acetylsalicylic acid by a strain of Acinetobacter lwoffii.

SUMMARY: A strain of Acinetobacter Iwoffii, isolated from a stored sample of distilled water, hydrolysed acetylsalicylic acid to salicylic and acetic acids. It grew in mineral salts medium with either of these compounds as C source and NH4+ as N source. Experiments with whole cells and cell free extracts and the isolation of intermediates showed that acetylsalicylic acid was metabolized through salicylic acid, catechol, cis‐cis‐muconic acid, (+)‐muconolactone and β‐oxoadipic acid. The salicylate hydroxylase required NADH or NADPH as cofactor and 1 mole of O2 was taken up and 1 mole of CO2 evolved for each mole of salicylate oxidized. Catalytic quantities of flavine adenine dinucleotide (FAD) but not flavine mononucleotide (FMN) activated the enzyme. The cis‐cis‐muconate lactonizing enzyme was activated by Mn2+ and inhibited by EDTA.