scholarly journals PARÂMETROS FÍSICOS NO ESTUDO DA ESTABILIDADE DAS EMULSÕES PHYSICALS PARAMETERS IN THE EMULSION STABILITY STUDY

2001 ◽  
Vol 2 (2) ◽  
Author(s):  
Sandra Maria W. Zanin ◽  
Marilis Dallarmi Miguel ◽  
Márcio Chimelli ◽  
Ana Cláudia Dalmaz
Keyword(s):  
Low Temperature ◽  
Shelf Life ◽  
Emulsion Stability ◽  
Subjective Evaluation ◽  
Stability Study ◽  
Physical Parameters ◽  
Geographic Locations ◽  
Pharmaceutical Manufacturers ◽  
Regulatory Acceptance ◽  
Artificial Stress

A estabilidade de uma emulsão definida pelo consumidor e muitas vezes pelo próprio formulador está baseada inteiramente em parâmetros subjetivos. Por isso, é importante lembrar que o padrão de estabilidade depende em larga escala do observador, e é esta a razão porque as observações subjetivas ou opiniões por si só não são suficientes para definir parâmetros como estabilidade aceitável. O tempo de prateleira de um produto e as condições de estresse artificiais são termos úteis para descrever a avaliação subjetiva da estabilidade de uma emulsão, contudo, e por esta mesma razão, os formuladores devem ser cautelosos para estabelecer a segurança e as condições de regulamentação dos componentes de uma emulsão para uma aplicação particular. O aspecto ou as características organolépticas de uma emulsão como a homogeneidade, brilho, macio, fino e opacidade, bem como o comportamento reológico e a espalhabilidade, estão entre os parâmetros físicos que devem ser avaliados, porque os produtos emulsionados podem ser transportados e utilizados em diversos locais do planeta com diferentes climas e condições de temperatura extremamente altas e baixas. Assim, os farmacêuticos devem possuir conhecimento pré-determinado da estabilidade de suas emulsões antes que elas possam ser comercializadas. PHYSICALS PARAMETERS IN THE EMULSION STABILITY STUDY Abstract Emulsion stability as defined by the consumer or even by the formulator is based entirely in subjective judgments. It is important, therefore, to remember that the standard of stability dependes to a large extent on the observer, since subjective observations or opinions by themselves do not suffice to define such a parameter as acceptable stability. Shelf life and artificial stress conditions are useful terms to describe the subjective evaluation of an emulsion stability, therefore, formulators are cautioned to establish the safety and regulatory acceptance of emulsion ingredients for a particular application. The emulsion aspect such us homogeneity, gloss, smooth, thin and dull, and rheologic behavior and spreadability were among the physical parameters that must be observed because emulsion products may be transported to and used in various geographic locations having varying climates and conditions of extremely high and low temperature. Thus, pharmaceutical manufacturers must have predetermined knowledge of their emulsion stabililty before they may be shipped.

scholarly journals Modified Rhamnogalacturonan-Rich Apple Pectin-Derived Structures: The Relation between Their Structural Characteristics and Emulsifying and Emulsion-Stabilizing Properties

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1586
Author(s):  
Jessika N. Humerez-Flores ◽  
Sarah H. E. Verkempinck ◽  
Clare Kyomugasho ◽  
Paula Moldenaers ◽  
Ann M. Van Loey ◽  
...  
Keyword(s):  
Emulsion Stability ◽  
Structural Characteristics ◽  
Stability Study ◽  
Natural Food ◽  
Apple Pectin ◽  
Oil Droplets ◽  
Food Ingredients ◽  
Acidic Conditions ◽  
Hydrolysis Of ◽  
Subsequent Acid

In the context of the increasing interest in natural food ingredients, the emulsifying and emulsion-stabilizing properties of three rhamnogalacturonan-rich apple pectin-derived samples were assessed by evaluating a range of physicochemical properties. An apple pectin (AP74) was structurally modified by a β-eliminative reaction to obtain a RG-I-rich pectin sample (AP-RG). Subsequent acid hydrolysis of AP-RG led to the generation of pectin material with partially removed side chains (in particular arabinose depleted) (AP-RG-hydrolyzed), thus exhibiting differences in rhamnose, arabinose, and galactose in comparison to AP-RG. All samples exhibited surface activity to some extent, especially under acidic conditions (pH 2.5). Furthermore, the viscosity of the samples was assessed in relation to their emulsion-stabilizing properties. In a stability study, it was observed that the non-degraded AP74 sample at pH 2.5 exhibited the best performance among all the apple pectin-derived samples evaluated. This emulsion presented relatively small oil droplets upon emulsion production and was less prone to creaming than the emulsions stabilized by the (lower molecular weight) RG-I-rich materials. The AP-RG and AP-RG-hydrolyzed samples presented a slightly better emulsion stability at pH 6.0 than at pH 2.5. Yet, neither pectin sample was considered having good emulsifying and emulsion-stabilizing properties, indicated by the presence of coalesced and flocculated oil droplets.

scholarly journals The effect of a novel low temperature-short time (LTST) process to extend the shelf-life of fluid milk

SpringerPlus ◽  
2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Phillip R. Myer ◽  
Kyle R. Parker ◽  
Andrew T. Kanach ◽  
Tengliang Zhu ◽  
Mark T. Morgan ◽  
...  
Keyword(s):  
Low Temperature ◽  
Shelf Life ◽  
Short Time ◽  
Fluid Milk

scholarly journals EVALUATION OF STABILITY OF ROPINIROLE HYDROCHLORIDE AND PRAMIPEXOLE DIHYDROCHLORIDE MICROSPHERES AT ACCELERATED CONDITION

2018 ◽  
Vol 10 (4) ◽  
pp. 82
Author(s):  
Koyel Kar ◽  
R. N. Pal ◽  
Gouranga Nandi
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Surface Morphology ◽  
Shelf Life ◽  
Stability Study ◽  
In Vitro Drug Release ◽  
Drug Content ◽  
Ropinirole Hydrochloride ◽  
Pramipexole Dihydrochloride

Objective: The objective of the present work was to conduct accelerated stability study as per international council for harmonisation (ICH) guidelines and to establish shelf life of controlled release dosage form of ropinirole hydrochloride and pramipexole dihydrochloride microspheres for a period of 6 mo.Methods: Most optimized batch of ropinirole hydrochloride and pramipexole dihydrochloride (F12 and M12 respectively) were selected and subjected to exhaustive stability testing by keeping the sample in stability oven for a period of 3 and 6 mo. Various parameters like surface morphology, particle size, drug content, in vitro drug release and shelf life were evaluated at 3 and 6 mo period. The surface morphology of the formulated microspheres was determined by scanning electron microscopy (SEM). The particle size of the microspheres was estimated by optical microscopy method. The drug content was assayed by the help of ultra-violet spectrophotometer (UV). The in vitro drug release was performed by using Paddle II type dissolution apparatus and the filtrate was analyzed by UV spectrophotometer. The shelf life of the optimized microspheres was calculated by using the rate constant value of the zero-order reaction.Results: A minor change was recorded in average particle size of F12 and M12 microspheres after storage for 6 mo. For F12 and M12, initially the particle size was 130.00 µm and 128.92 µm respectively and after 6 mo it was found to be 130.92 µm and 128.99 µm respectively. There was no change in surface morphology of F12 and M12 microspheres after 6 mo of storage. The shape of microspheres remained spherical and smooth after 6 mo. An insignificant difference of drug content was recorded after 6 mo compared to the freshly prepared formulation. For F12 and M12, 94.50% and 93.77% of the drug was present initially and after 6 mo 94.45% and 93.72% of the drug was recorded. In vitro drug release was recorded after 6 mo for F12 and M12. Initially, 97.99% and 97.69% of the drug was released till 14th hour respectively for F12 and M12. After 6 mo, 98.23% and 97.99% of the drug was released respectively. The percentage residual drug content revealed that the degradation of microspheres was low. Considering the initial percentage residual drug content as 100%, 99.94% of the drug was recorded for both F12 and M12. The shelf life for F12 and M12 was found to be 10 y 52 d and 10 y 70 d respectively which were determined by the zero-order kinetic equation.Conclusion: A more or less similar surface morphology, particle size, drug content and percent of drug release before and after stability study confirmed the stability of F12 and M12 microspheres after storage for 6 mo and prove the efficacy of the microspheres in the site-specific delivery of drugs in Parkinson’s disease.

scholarly journals Limitations and Challenges in the Stability of Cysteamine Eye Drop Compounded Formulations

2021 ◽  
Vol 15 (1) ◽  
pp. 2
Author(s):  
Cristina Martín-Sabroso ◽  
Mario Alonso-González ◽  
Ana Fernández-Carballido ◽  
Juan Aparicio-Blanco ◽  
Damián Córdoba-Díaz ◽  
...  
Keyword(s):  
Shelf Life ◽  
Stability Study ◽  
Eye Drops ◽  
Microbiological Analysis ◽  
Nitrogen Gas ◽  
Long Term Stability ◽  
Main Degradation Product ◽  
The Stability ◽  
Unstable Molecule

Accumulation of cystine crystals in the cornea of patients suffering from cystinosis is considered pathognomonic and can lead to severe ocular complications. Cysteamine eye drop compounded formulations, commonly prepared by hospital pharmacy services, are meant to diminish the build-up of corneal cystine crystals. The objective of this work was to analyze whether the shelf life proposed for six formulations prepared following different protocols used in hospital pharmacies is adequate to guarantee the quality and efficacy of cysteamine eye drops. The long-term and in-use stabilities of these preparations were studied using different parameters: content of cysteamine and its main degradation product cystamine; appearance, color and odor; pH and viscosity; and microbiological analysis. The results obtained show that degradation of cysteamine was between 20% and 50% after one month of storage in the long-term stability study and between 35% and 60% in the in-use study. These data confirm that cysteamine is a very unstable molecule in aqueous solution, the presence of oxygen being the main degradation factor. Saturation with nitrogen gas of the solutions offers a means of reducing cysteamine degradation. Overall, all the formulae studied presented high instability at the end of their shelf life, suggesting that their clinical efficacy might be dramatically compromised.

scholarly journals HYDROCOOLING EFFICIENCY ON POSTHARVEST CONSERVATION AND QUALITY OF ARUGULA

2019 ◽  
Vol 6 (4) ◽  
pp. 36-41
Author(s):  
Elaine Gleice Silva Moreira ◽  
Scarlet Aguiar Basílio ◽  
Mariany Dalila Milan ◽  
Natália Arruda ◽  
Katiane Santiago Silva Benett
Keyword(s):  
Mass Loss ◽  
Respiratory Rate ◽  
Shelf Life ◽  
Water Loss ◽  
Cold Water ◽  
Subjective Evaluation ◽  
Storage Period ◽  
Titratable Acidity ◽  
Fresh Mass ◽  
Soluble Solids

Arugula is mainly cultivated by small producers, being a leafy vegetable susceptible to water loss and wilting after harvest, which may result in changes in appearance, texture, color (yellowing), and nutritional value of the product. Hydrocooling is a cooling method that stands out for being simple, practical and efficient. Its use is to reduce the temperature and respiratory rate of vegetables after harvesting by immersion in ice or cold water, so they can be packed and stored. This study was conducted to evaluate the hydrocooling efficiency when associated with the storage period in the postharvest shelf life of arugula leaves. Arugula leaves were subjected to ten days of storage, and measurements were taken at 0, 2, 4, 6, 8 and 10 days. The experimental design was completely randomized in a 3 × 6 factorial scheme, consisting of three hydrocooling treatments [control (without cooling), and hydrocooling at 0 °C and 10 °C] and for six storage periods (0, 2, 4, 6, 8 and 10 days) with three replicates. Fresh mass loss, soluble solids, titratable acidity, pH and subjective evaluation of product appearance were measured. Hydrocooling at 0 °C proved to be the most appropriate treatment when compared to control, as reported by the values of fresh mass loss, soluble solids, and titratable acidity. Hydrocooling to 0 °C slowed leaf water loss (lower respiratory rate) and resulted in better overall leaf appearance up to the sixth day of storage, thereby increasing shelf life of arugula leaves.

scholarly journals Electrochemical Characterization of Low-Temperature Direct Ethanol Fuel Cells Using Direct and Alternate Current Methods

2019 ◽  
Author(s):  
Paweł Wnuk ◽  
Rafal Jurczakowski ◽  
Adam Lewera
Keyword(s):  
Low Temperature ◽  
Current Density ◽  
Ethanol Concentration ◽  
Physical Parameters ◽  
Impedance Spectra ◽  
Ethanol Fuel ◽  
Cell Temperature ◽  
Faradaic Impedance ◽  
Cell Impedance

Here we report for the first time the results of systematic characterization of a low-temperature polymer electrolyte membrane direct ethanol fuel cell using DC and AC electrochemical methods. Model catalysts (carbon supported Pt nanoparticles) painted on carbon paper are used as anode and cathode. Influence of physical parameters, such as cell temperature, current density, ethanol concentration and anode fuel flow rate on overall cell impedance is studied. Analysis of the obtained impedance spectra in connection with DC measurements allows us to comment on cell properties and to separate different contributions to the overall cell polarization. Our results suggest that the cell impedance is dominated by anode faradaic impedance, with negligible contribution from cathode faradaic impedance. The anode impedance depends strongly on current density and cell temperature, but is not significantly influenced by ethanol concentration. Presence of anode mass-transfer impedance, even when ethanol was fed to the cell in high excess, is confirmed. Based on the results we conclude that changes in ethanol electro-oxidation mechanism might manifest themselves on the impedance spectra in the low-frequency inductive loop. Nonetheless, further studies involving equivalent circuit modelling are needed to determine the exact influence of the cell parameters on the anode kinetics.

scholarly journals Postharvest quality of pepino melon (Solanum muricatum Aiton) as influenced by NPK fertilizer rates, growing environment and storage temperature

2021 ◽  
Vol 35 (1) ◽  
Author(s):  
Carol Mutua ◽  
Joshua Ogweno ◽  
Robert Gesimba
Keyword(s):  
Low Temperature ◽  
Shelf Life ◽  
Room Temperature ◽  
Postharvest Quality ◽  
Solanum Muricatum ◽  
Npk Fertilizer ◽  
And Storage ◽  
Fertilizer Rates ◽  
Storage Temperatures

The present study evaluated the effect of NPK fertilizer (17:17:17) rates (0, 100, 200, 300 and 400 kg ha-1) on the postharvest quality of field and greenhouse grown pepino melons (Solanum muricatum Ait.) stored at room temperature (15-22°C) and at low temperature (7°C). The study was carried out in randomized complete block design with fruits from the field and greenhouse, five NPK fertilizer rates as treatments and the two storage temperatures replicated three times. Data were collected on percentage fruit weight loss (PWL), total soluble solids (TSS), firmness and shelf life. Results indicated that greenhouse and field grown fruits from the control and plants supplied with 100 kg NPK ha-1 had low PWL at both storage temperatures. Field grown fruits from the control stored at room temperature had the highest TSS and were firmer after 28 days of storage. Field grown fruits not supplied with fertilizer and stored at low temperature had a shelf life of 27 and 26 days in trial one and two respectively. Application of 100 kg NPK ha-1 and storage of pepino melon fruits at low temperature can be used to enhance quality and shelf life.

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