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Wavelet Transform-Based UV Spectroscopy for Pharmaceutical Analysis
摘要： In research and development laboratories, chemical or pharmaceutical analysis has been carried out by evaluating sample signals obtained from instruments. However, the qualitative and quantitative determination based on raw signals may not be always possible due to sample complexity. In such cases, there is a need for powerful signal processing methodologies that can effectively process raw signals to get correct results. Wavelet transform is one of the most indispensable and popular signal processing methods currently used for noise removal, background correction, differentiation, data smoothing and filtering, data compression and separation of overlapping signals etc. This review article describes the theoretical aspects of wavelet transform (i.e., discrete, continuous and fractional) and its characteristic applications in UV spectroscopic analysis of pharmaceuticals.
关键词： UV spectroscopy,continuous wavelet transform,discrete wavelet transform,pharmaceutical analysis,fractional wavelet transform
更新于2025-09-10 09:29:36
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Determination of iodide based on dynamic gas extraction and colorimetric detection by paper modified with silver triangular nanoplates
摘要： This paper reports on a new method for sensitive and selective determination of iodide based on dynamic gas extraction with air flow and digital colorimetric detection using paper modified with silver triangular nanoplates (AgTNPs). Iodide is oxidized in a sample by Fe(III) to produce molecular iodine which is extracted in air flow and transferred to a sensitive AgTNPs-containing paper layer. Interaction of AgTNPs with iodine results in optical changes which can be monitored by ordinary scanner. The high selectivity of dynamic gas extraction to volatile compounds ensures successful analysis of such samples as cranberry and kelp with no sample pretreatment, and due to the sensitivity of AgTNPs good analytical performance can be achieved. The limit of detection of iodide was found to be of 0.01 mg L?1 and the determination range of 0.03–0.3 mg L?1. The method can be easily adapted to simultaneous determination of iodide/iodine and iodide/chloride in the same sample.
关键词： Scanner,Silver triangular nanoplates,Colorimetry,Dynamic gas extraction,Plant and pharmaceutical analysis,Iodide
更新于2025-09-10 09:29:36
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Recent advances in the chemical strengthening of glass
摘要： Since its development in the early 1960s till recently, applications of the glass chemical strengthening technology were limited mostly to aircraft cockpit windshields, photocopier transparencies, and hard disks. The interest has been renewed by a need to have stronger and lighter glass products, led mostly by display cover in personal mobile electronic devices, such as cell phones, and glass packaging for safe delivery of medicines in pharmaceutical applications. In this paper, I suggest that the science of the compressive stress development is nearly completely understood. The so-called “dilation anomaly” is resolved. Newer technologies are being developed, for example, thin float-produced flat glasses can be strengthened with reduced warp. Molten salt bath maintenance techniques to avoid discarding of degraded salt have been developed to some extent. In addition to more and more pharmaceutical businesses looking to strengthen the glass packaging to avoid costly recalls, interest is also high in break-resistant automobile and locomotive transparencies. Other miscellaneous topics where the use of chemically strengthened glass could bring value-added premium are also mentioned.
关键词： molten salt bath,pharmaceutical packaging,chemical strengthening,compressive stress,glass,automobile transparencies,dilation anomaly
更新于2025-09-09 09:28:46
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Determination of Ondansetron by Spectrofluorimetry: Application to Forced Degradation Study, Pharmaceuticals and Human Plasma
摘要： The current manuscript describes a validated, responsive and rapid spectrofluorimetric method for quantifying ondansetron (OND) in authentic form, spiked human plasma and dosage forms. This is the first reported fluorescence study of Ondansetron in Triton X 100 system. Various variables affecting fluorescence response were studied precisely and optimised. The described method involved the fluorescence measurement in Triton X 100 system at λem/λex 354/317 nm. The calibration plot attained linearity over concentration range of 0.2 – 2 μg/mL. The developed method has been extensively applied to degradation studies of OND as per International Conference on Harmonisation (ICH) guidelines by exposing to oxidative, thermal, photo, acidic and alkaline conditions and also the degradation pathway has been proposed.
关键词： Pharmaceutical dosage forms,Stability studies,Spiked human plasma,Ondansetron,Spectrofluorimetry
更新于2025-09-09 09:28:46
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Raman Spectroscopy for Process Analytical Technologies of Pharmaceutical Secondary Manufacturing
摘要： As the process analytical technology (PAT) mindset is progressively introduced and adopted by the pharmaceutical companies, there is an increasing demand for effective and versatile real-time analyzers to address the quality assurance challenges of drug manufacturing. In the last decades, Raman spectroscopy has emerged as one of the most promising tools for non-destructive and fast characterization of the pharmaceutical processes. This review summarizes the achieved results of the real-time application of Raman spectroscopy in the field of the secondary manufacturing of pharmaceutical solid dosage forms, covering the most common secondary process steps of a tablet production line. In addition, the feasibility of Raman spectroscopy for real-time control is critically reviewed, and challenges and possible approaches to moving from real-time monitoring to process analytically controlled technologies (PACT) are discussed.
关键词： secondary pharmaceutical manufacturing,process analytical technology,process analytically controlled technology,Raman spectroscopy
更新于2025-09-04 15:30:14
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<i>In Vivo</i> Effects of Preservative-free and Preserved Prostaglandin Analogs: Mouse Ocular Surface Study
摘要： Purpose: Chronic use of topical hypotensive agents induces several side effects caused by preservatives. The purpose of this study was to evaluate the effects of prostaglandin analogs with varying concentrations of benzalkonium chloride (BAC), preservative-free (PF), and alternative preservatives on mouse corneal tissue. Methods: Thirty-five, 8- to 10-week-old female C57BL/6 mice (five mice for each group) were used for this study. To the control group, we applied normal saline, and to each drug-treated group we applied 0.02% BAC, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), travoprost 0.004% (with 0.001% polyquad) or tafluprost 0.0015% with/without 0.001% BAC, once a day (9 p.m.) for 4 weeks. Corneal fluorescein staining was evaluated in all groups. After harvest, the corneal tissues were embedded in paraffin and then Hematoxylin-Eosin stain was performed for histopathological examination. Immunofluorescence staining was done against TNF-α, IL-6, HLA DR, pJNK, and pAkt. Results: In corneal fluorescein staining, severe punctate epithelial keratitis was seen in the groups of 0.02% BAC, 0.02% BAC containing bimatoprost 0.01% and latanoprost 0.005%. The surface desquamation, irregular surface, loss of cell borders, anisocytosis and stromal shrinkage were observed in the groups of BAC-containing eye drops. Moreover, the groups treated with BAC-containing eye drops have high inflammatory markers, significantly decreased cell viability-related signal, pAkt, and higher apoptosis-inducing signal, pJNK, than the control group. On the other hand, travoprost 0.004% and PF tafluprost 0.0015% have less cellular morphologic changes, lower inflammation, and higher cellular viability than BAC-containing formulations. Conclusions: Corneal damage, increased inflammation and apoptosis and low cell viability were observed in BAC-containing groups. PF or alternatively preserved glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.
关键词： Pharmaceutical preservatives,Synthetic prostaglandins,Benzalkonium compounds,Cornea
更新于2025-09-04 15:30:14
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TiO2-catalyzed photodegradation of aromatic compounds: relevance of susceptibility to oxidation and electrophilic attack by hydroxyl radical
摘要： The application of nanostructured titanium dioxide (TiO2) as catalyst for the photodegradation of drugs and dyes is well established. We aimed to evaluate the importance of the reactivity of aromatic compounds submitted to photodegradation. Specifically, we were interested in the correlation between susceptibility to oxidation and/or to electrophilic attack and the efficiency of degradation. We demonstrated that hydroxyl radical (HO˙) is the most relevant species generated in the photodegradation process. Considering that HO˙ has both oxidizing and electrophilic features, the efficiency of degradation of selected aromatic compounds was performed. The choice was based on their susceptibility to oxidation and/or to electrophilic attack. Benzoic acid (C1), salicylic acid (C2), and protocatechuic acid (C3) were compared regarding their oxidability using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and were ranked as follows: C3 ? C2~C1. These compounds were efficiently photodegraded and no significant difference was observed among them. To assess the importance of susceptibility to electrophilic attack, anisole (C4), acetophenone (C5), and nitrobenzene (C6) were selected. Compared to C5 and C6, the higher susceptibility of C4 to electrophilic attack was demonstrated using hypochlorous acid, an electrophilic reagent. The photodegradation showed that C4 was also more susceptible to degradation compared to C5 and C6. In summary, we found that by acting as a powerful oxidant/electrophile agent, HO˙ was able to promote the degradation of aromatic moieties. Considering that the majority of drugs and dyes bear aromatic moieties, our findings explain the great success of photodegradation using metal oxides as catalysts.
关键词： Pharmaceutical drugs,Aromatic compounds,Titanium dioxide,Nanostructured catalysts,Electrophilic susceptibility,Photodegradation
更新于2025-09-04 15:30:14
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Development and validation of a simple spectrophotometric method for the determination of methyldopa in both bulk and marketed dosage formulations
摘要： A simple, precise, sensitive, rapid, specific and economical spectrophotometric method was developed to determine methyldopa (MTD) content in bulk and pharmaceutical dosage formulations. The proposed method was based on the formation of a colored product from the nitrosation reaction of MTD with sodium nitrite in an acid medium. The resultant nitroso derivative species reacts further with sodium hydroxide and is converted it into a more stable compound. This yellow nitrosation product exhibited an absorption maximum at 430 nm. Beer’s Law was obeyed in a concentration range of 6.37 to 82.81 mg mL-1 MTD with an excellent coefficient of determination (R2 = 0.9998). No interference was observed from common excipients in formulations. The results showed the method to be simple, accurate and readily applied for the determination of MTD in pure form and in pharmaceutical preparations. The analytical results obtained for these products using the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at a 95% confidence level.
关键词： Pharmaceutical formulations/quality control,Spectrophotometry/qualitative analysis,Methyldopa/spectrophotometric determination
更新于2025-09-04 15:30:14
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Benzimidazoles in wastewater: Analytical method development, monitoring and degradation by photolysis and ozonation
摘要： Pharmaceutical residues are constantly released into natural waters, mainly from wastewater treatment plants (WWTPs) whose processes are unable to completely eliminate them. Among these drugs, the occurrence of benzimidazoles, a class of antiparasitics for human and veterinary use, has been reported in WWTP e?uents and surface waters. In this study, an SPE-UHPLC-MS/MS method was developed and optimized for extraction and quantitation of benzimidazoles in in?uents and e?uents of a local WWTP and in hospital wastewater. The extraction procedure was optimized using response surface methodology (Box-Behnken design) and the optimal parameters were as follows: 2.0 mL of loading solvent consisting of a mixture of water:methanol (95:5, v/v) and temperature at 43 °C. In hospital wastewater, albendazole (ABZ) and its principal metabolite ricobendazole (RBZ) were the main benzimidazole-related contaminants and were found at concentrations of up to 3810 and 3894 ng L?1, respectively. The WWTP system was able to remove from 46% to 95% of the ABZ quanti?ed in the in?uent, discharging an e?uent with 16–441 ng L?1 of ABZ. The concentrations of other benzimidazoles and metabolites in the WWTP e?uents remained below 350 ng L?1. WWTP e?uents forti?ed with 50 μg L?1 of ABZ and RBZ required 26.7 mgO3 L?1 to remove ABZ and RBZ. After ozonation, the COD and BOD5 of the e?uents were reduced by 27%. Photolysis by UVA radiation was not e?ective to remove ABZ and FBZ from the e?uent samples.
关键词： Antiparasitic,Online SPE-UHPLC-MS/MS,Box-Behnken design,Pharmaceutical residue,Albendazole
更新于2025-09-04 15:30:14