A thermal analysis study of ascorbic acid and its pharmaceutical formulations

Lerdkanchanaporn, Supaporn; Dollimore, D.; Alexander, Kenneth S.

doi:10.1007/bf01996774

Cited by 24 publications

(11 citation statements)

References 2 publications

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“…However, high values for activation entropy confirm that the reagent is far from its own thermodynamic equilibrium; therefore, the reactivity of the compound is high, and the system can react faster to form the activated complex, and hence, gives shorter reaction times. Furthermore, prediction of the shelf life (i.e., the maximum length of time that the drug preserves its activity) or half-life (i.e., length of required time for isothermal decomposition the half of compound) at a given temperature is possible via heating the sample and facilitating its decomposition process by the aid of thermal analysis techniques (18)(19)(20)(21)(22)(23)(24).…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability and Decomposition Kinetic Studies of Acyclovir and Zidovudine Drug Compounds

Shamsipur

Pourmortazavi

Beigi³

et al. 2013

AAPS PharmSciTech

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Investigations on thermal behavior of drug samples such as acyclovir and zidovudine are interesting not only for obtaining stability information for their processing in pharmaceutical industry but also for predicting their shelf lives and suitable storage conditions. The present work describes thermal behaviors and decomposition kinetics of acyclovir and zidovudine in solid state, studied by some thermal analysis techniques including differential scanning calorimetry (DSC) and simultaneous thermogravimetry-differential thermal analysis (TG/DTA). TG analysis revealed that thermal degradation of the acyclovir and zidovudine is started at the temperatures of 400°C and 190°C, respectively. Meanwhile, TG-DTA analysis of acyclovir indicated that this drug melts at about 256°C. However, melting of zidovudine occurred at 142°C, which is 100°C before starting its decomposition (242°C). Different heating rates were applied to study the DSC behavior of drug samples in order to compute their thermokinetic and thermodynamic parameters by non-isothermal kinetic methods. Thermokinetic data showed that both drugs at the room temperature have slow degradation reaction rates and long shelf lives. However, acyclovir is considerably more thermally stable than zidovudine.

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Section: Introductionmentioning

confidence: 99%

Thermal Stability and Decomposition Kinetic Studies of Acyclovir and Zidovudine Drug Compounds

Shamsipur

Pourmortazavi

Beigi³

et al. 2013

AAPS PharmSciTech

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“…In general, rapid drying retains a greater amount of ascorbic acid than slow drying (Goula and Adamopoulos 2006). The above observation might be due to time-temperature regimes used in combined drying (Guadagni and Kelly 1958;Lerdkanchanaporn et al 1997). Drying time in hot air drying alone was too long, whereas temperature in microwave drying alone was too high, the product of time and temperature may be an adequate index for preservation of ascorbic acid in drying process.…”

Section: Quality Aspectmentioning

confidence: 99%

“…In general, rapid drying retains a greater amount of ascorbic acid than slow drying (Goula and Adamopoulos 2006). The above observation might be due to time‐temperature regimes used in combined drying (Guadagni and Kelly 1958; Lerdkanchanaporn et al. 1997).…”

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confidence: 98%

ENERGY REQUIREMENT AND QUALITY ASPECTS OF CHINESE JUJUBE (ZIZYPHUS JUJUBA MILLER) IN HOT AIR DRYING FOLLOWED BY MICROWAVE DRYING

Fang

Wang

et al. 2011

J Food Process Engineering

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Chinese jujube samples were dried in hot air at 60C, and then switched into microwave drying of 45, 65 and 90 W at moisture contents of 50, 40 and 30%, respectively. Results indicated that the energy consumptions of combined drying at a transition point of 50% were all lower than that of microwave drying by itself at three power levels, which might be ascribed to the reduction of initial heat‐up region in microwave drying of combined drying. As compared with hot air drying alone, the combined drying can save energy consumption up to about 55%. Combined drying was higher in the rehydration capacity of the dried products than microwave drying alone or hot air drying alone, and is also beneficial to the preservation of vitamin C and less browning. Hot air drying followed by microwave drying of 45 W at transition point of 50% was best in terms of higher product quality with less energy consumption. PRACTICAL APPLICATIONS Jujube is a fruit distributed to over 30 countries around the world. Drying of jujube is energy intensive. Hot air drying alone takes too much time, requires more energy consumption and degrades the product quality, and microwave drying alone will result in more browning of the product. The combined drying – hot air drying followed by microwave drying – is a promising way to lower energy consumption and to raise product quality.

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“…Numerous analytical procedures have been developed, including spectrometry [9], fluorimetry [10], enzymatic methods [11], chromatography [12], titrimetry [13,14], chemiluminescence [15], spectrophotometry [16,17,18], calorimetry [19], oscillator reaction method [20], optical sensor [21], and thermal analysis [22]. Each technique has its advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

et al. 2003

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A carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin (CuP-Poly) is proposed for voltammetric determination of L-ascorbic acid in pharmaceutical formulations. The modified electrode allows the detection of L-ascorbic acid at lower anodic potentials than observed at unmodified electrodes. Several parameters that can influence the voltammetric response of the proposed electrode such as carbon paste composition, pH, scan rate, and possible interference were investigated. The peak current was proportional to the concentration of ascorbic acid in the range 2.0 x 10(-5) to 3.2 x 10(-3) mol L(-1) with a detection limit of 1.0 x 10(-5) mol L(-1). The stability and repeatability of the electrode for the determination of L-ascorbic acid are also discussed. Amperometric response was also recorded for electrocatalytic oxidation of the L-ascorbic acid. Concentrations of the vitamin C in pharmaceutical formulations (tablets) measured using the modified electrode and a titrimetric method are in agreement at the 95% confidence level and within an acceptable range of error.

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A thermal analysis study of ascorbic acid and its pharmaceutical formulations

Cited by 24 publications

References 2 publications

Thermal Stability and Decomposition Kinetic Studies of Acyclovir and Zidovudine Drug Compounds

Thermal Stability and Decomposition Kinetic Studies of Acyclovir and Zidovudine Drug Compounds

ENERGY REQUIREMENT AND QUALITY ASPECTS OF CHINESE JUJUBE (ZIZYPHUS JUJUBA MILLER) IN HOT AIR DRYING FOLLOWED BY MICROWAVE DRYING

Carbon paste electrode modified with copper(II) phosphate immobilized in a polyester resin for voltammetric determination of l -ascorbic acid in pharmaceutical formulations

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