Physicochemical properties of various alginate-based raft-forming antacid products: a comparative study

Background: Alginate-based, raft-forming antacid products with reflux suppressant activity are complex formulations expected to achieve effective raft formation and cause elimination or displacement of the acid pocket, which is typically manifested in gastroesophageal reflux disease (GERD).Methods: In the present study, six alginate-based raft-forming products commercially available in the Indian market were compared in terms of their acid neutralization properties, strength, resilience and structural and thermal properties of their rafts. Percent alginate content was also determined.Results: Rafts of products containing calcium-based antacids formed voluminous, porous and floating rafts within seconds of addition to the simulated gastric fluid (SGF) compared with the products that contained aluminium and magnesium-based antacids. Marked differences were not evident in the ANC (acid neutralization capacity) values of the various products. No correlation was observed between ANC and raft-forming capacity or duration of neutralization. Raft structures affected their neutralization profiles. Rafts of porous and absorbent nature could retain their ANC probably due to release of trapped antacids. Further, raft strengths of only two products were above the British Pharmacopoeia specification of not less than 7.5 g. Sodium alginate content was within specifications (85-115%) for three of the six products.Conclusions: Raft-forming formulations with higher alginate content and calcium-based antacids have better physicochemical properties such as ANC, neutralization profiles, raft strength and raft resilience than those with lower alginate content or those containing aluminium or magnesium-based antacids.

Tissue Conditioner Incorporating a Nano-Sized Surface Pre-Reacted Glass-Ionomer (S-PRG) Filler

We aimed to evaluate the properties of a novel tissue conditioner containing a surface pre-reacted glass-ionomer (S-PRG) nanofiller. Tissue conditioners containing 0 (control), 2.5, 5, 10, 20, or 30 wt% S-PRG nanofiller or 10 or 20 wt% S-PRG microfiller were prepared. The S-PRG nanofillers and microfillers were observed using scanning electron microscopy. The ion release, acid buffering capacity, detail reproduction, consistency, Shore A0 hardness, surface roughness, and Candida albicans adhesion of the tissue conditioners were examined. The results indicated that the nanofiller particles were smaller and more homogeneous in size than the microfiller particles. In addition, Al, B, F, and Sr ions eluted from S-PRG were generally found to decrease after 1 day. Acid neutralization was confirmed in a concentration-dependent manner. The mechanical properties of tissue conditioners containing S-PRG nanofiller were clinically acceptable according to ISO standard 10139-1:2018, although the surface roughness increased with increasing filler content. Conditioners with 5–30 wt% nanofiller had a sublethal effect on C. albicans and reduced fungal adhesion in vitro. In summary, tissue conditioner containing at least 5 wt% S-PRG nanofiller can reduce C. albicans adhesion and has potential as an alternative soft lining material.

Development of Acid-Neutralization and in Vitro Dissolution to Evaluate the Overall Quality of Compound Aluminum Hydroxide Tablets

Background: Compound aluminum hydroxide tablets (CAHTs) are widely used in the Chinese domestic market, and strict quality control is required to ensure their clinical efficacy. Purpose: In this study, we established a comprehensive strategy of acid-neutralization, in vitro dissolution and an assay of magnesium trisilicate to evaluate the overall quality and monitor the consistency of CAHTs. Methods: The acid-neutralization profiles of 38 batches of CAHTs were generated using the dissolution and release method III (the cup method, the Chinese pharmacopeia) combined with potentiometric titration. To directly reflect the disintegration and release process of the preparation, we optimized the sample pretreatment method by omitting the grinding step to determine the profiles of complete tablets. In addition, in vitro dissolution was conducted in the hydrochloric acid medium at pH 1.0 by using the assay of magnesium trisilicate through a validated approach of flame atomic absorption spectrophotometry (FAAS) to evaluate the similarity of the dissolution profiles. Results: Acid-neutralization tests showed that the quality of the samples from manufacturers B and F was poor. In vitro dissolution experiments showed that the samples from manufacturer A had the highest similarity with the reference preparation, which indicated their good quality consistency. Besides, the optimized acid-neutralization method had the advantage of simple operation and enabled direct characterization of pharmacodynamics in the quality consistency evaluation of antacids. Conclusion: A successful synthetic evaluation strategy was established to assess the overall quality of CAHTs, which demonstrated that the improvement in the quality of this formulation is imperative.

Study on Acidity and Neutralizing Ability of Ions in the Chemical Composition of Rainwater

The acidity in rainwater is mainly controlled by the presence of H2SO4, HNO3 in combination with the ability to neutralize cations in rainwater. pH is an important value in the evaluation of acidity in rainwater. The research used a series of rainwater quality monitoring data from 2005 to 2018 in Vietnam. The research showed that the average pH distribution at 23 stations ranged from 5.83 ± 0.62. The rains with pH <5.6 appear in all years at the research stations. Considering the ability of acid neutralizing to various ions shows that Ca2+ is the main contributor to acid neutralization processes in rainwater, followed by Mg2 +, NH4+, and K+. While Ca2+ always play the highest acid neutralizing role at all stations; Depending on each station, Mg2+ and NH4+ ions play a role in neutralizing acidity in rainwater. The research also shows a match between the trend of H+ concentration and the tendency of cations to contribute to acid neutralization in rainwater.

The Physico-Chemical and Mineralogical Characterization of Mg-Rich Synthetic Gypsum Produced in a Rare Earth Refining Plant

The physical, chemical and mineralogical characterization of the constituents of magnesium-rich synthetic gypsum produced in a rare earth-refining plant located in Gebeng, Pahang, Malaysia was conducted through elemental chemical analysis, scanning electron microscopy with Energy Dispersive X-ray (EDX)-analyzer, thermal analysis, X-ray fluorescence and X-ray diffraction. The crystalline nature of the by-product was studied using FTIR spectroscopy. Elemental analysis confirmed the presence of Ca and Mg, which are essential macronutrients required by plants and this Ca alongside the high pH (9.17) of MRSG may confer on the material a high acid neutralization capacity. From the result, it was observed that the studied by-product is a heterogeneous crystalline material comprising of gypsum (CaSO4.2H2O) and other major components such as calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate) and sulfur. These aggregates may contribute to give an acid neutralization capacity to MRSG. The XRD study of MRSG indicated a high content of gypsum (45.4%), shown by the d-spacing of 7.609 Å (2-theta 11.63) in the diffractogram. The infrared absorption spectra of MRSG indicate close similarities to mined gypsum. The results of the characterization indicated that MRSG has valuable properties that can promote its use in amending soil fertility constraints on nutrient-deficient tropical acid soils.

EFFECT ON DEGREE OF PHOSPHORIC ACID NEUTRALIZATION ON PROPERTIES OF NITRATE-CONTAINING NITROGEN-PHOSPHORUS-POTASSIUM FERTILIZERS

Основной задачей данной работы является обоснование оптимального технологического режима производства нитроаммофоски с уравновешенным содержанием питательных веществ. В статье на примере азотно-фосфорно-калийного удобрения марки 17:17:17 представлены результаты исследования зависимости химического и фазового состава, а также структуры и физико-механических характеристик гранулированных образцов от степени нейтрализации промышленной экстракционной фосфорной кислоты аммиаком, выраженной значением мольного отношения [NH3]:[H3PO4]. Приведены методики синтеза, гранулирования и изучения свойств образцов удобрений. Отмечены особенности процесса гранулирования удобрений, полученных с различной степенью нейтрализации: образцы с мольным отношением от 1,0 до 1,2 налипают на стенки гранулятора, образуя крупные агломераты из отдельных гранул; при увеличении мольного отношения более 1,2 и выше наблюдается стабилизация процесса гранулирования, образуются гранулы близкой к сферичной формы; при значениях мольного отношения более 1,6 полученные гранулы начинают интенсивно истираться между собой в тарелке гранулятора. Определены значения статической прочности и среднего диаметра гранул, слеживаемости и коэффициента гигроскопичности образцов удобрений. Предложено объяснение полиэкстремального характера зависимостей свойств удобрений от степени нейтрализации. Выполнен количественный рентгенофазовый анализ кристаллической фазы при различной степени нейтрализации. Описана зависимость изменения фазового состава кристаллической части удобрений при увеличении степени нейтрализации. Показано влияние примесей, вносимых с экстракционной фосфорной кислотой, на коэффициент гигроскопичности удобрений, измельченных до состояния порошка. Представлены микрофотографии сколов гранул. Предложены оптимальные значения мольного отношения [NH3]:[H3PO4] при получении наиболее востребованных удобрений марки 17:17:17.

Strengthening Regenerated Cellulose Fibers Sourced from Recycled Cotton T-Shirt Using Glucaric Acid for Antiplasticization

The recycling of cellulose from cotton textiles would minimize the use of virgin crop fibers, but recycled polymers are generally inferior in mechanical performance to those made from virgin resins. This challenge prompted the investigation of biobased additives that were capable of improving the mechanical properties of fibers by means of antiplasticizing additives. In this study, regenerated cellulose (RC) fibers were spun from cellulose found in cotton T-shirts, and fibers were mechanically strengthened with glucaric acid (GA), a nontoxic product of fermentation. The recycled pulp was activated using aqueous sodium hydroxide and then followed by acid neutralization, prior to the direct dissolution in lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) at 3 wt.% cellulose. At 10% (w/w) GA, the tensile modulus and strength of regenerated cellulose from recycled cotton fibers increased five-fold in contrast to neat fibers without GA. The highest modulus and tenacity values of 664 cN/dtex and of 9.7 cN/dtex were reported for RC fibers containing GA.