Measuring Tablet Dissolution: An Experiment for Teaching Quantitative Ultraviolet Absorption Spectroscopy

Hamad, Mazen L.

doi:10.1021/ed3003622

Cited by 10 publications

(12 citation statements)

References 15 publications

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“…The simulated tablet (522.5 mg) consisted of 4-PMP.3HCl (106.9 mg) and hydroxypropyl methylcellulose (415.6 mg). The tablets were made using an adaptation of the procedure reported by Hamad et al [30] For the analysis of the tablet via SABRE, 30 mg of the tablet (con-taining~6 mg of active pharmaceutical ingredient) was added to 900 μL of CD 3 OD prior to filtering through a through a 0.45-μm polyvinylidene difluoride syringe filter (Whatman). 300 μL of the resulting filtered solution was added to a vial prior to the addition of 3 equivalents of TEA (3 μL), 150-μL catalyst stock solution (6.66 mg mL −1 ) and 147-μL CD 3 OD.…”

Section: Methodsmentioning

confidence: 99%

Benchtop NMR analysis of piperazine‐based drugs hyperpolarised by SABRE

Tennant

Hulme

Robertson

et al. 2020

Magnetic Reson in Chemistry

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Piperazine-based drugs, such as N-benzylpiperazine (BZP), became attractive in the 2000s due to possessing effects similar to amphetamines. Herein, BZP, in addition to its pyridyl analogues, 2-, 3-, and 4-pyridylmethylpiperazine (2-PMP, 3-PMP, and 4-PMP respectively) was subjected to the hyperpolarisation technique Signal Amplification By Reversible Exchange (SABRE) in order to demonstrate the use of this technique to detect these piperazine-based drugs. Although BZP was not hyperpolarised via SABRE, 2-PMP, 3-PMP, and 4-PMP were, with the ortho-and meta-pyridyl protons of 4-PMP showing the largest enhancement of 313-fold and 267-fold, respectively, in a 1.4-T detection field, following polarisation transfer at Earth's magnetic field. In addition to the freebase, 4-PMP.3HCl was also appraised by SABRE and was found not to polarise, however, the addition of increasing equivalents of triethylamine (TEA) produced the freebase, with a maximum enhancement observed upon the addition of 3 equivalents of TEA. Further addition of TEA led to a reduction in the observed enhancement. SABRE was also employed to polarise 4-PMP.3HCl (~20% w/w) in a simulated tablet to demonstrate the forensic application of the technique (138-fold enhancement for the ortho-pyridyl protons). The amount of 4-PMP.3HCl present in the simulated tablet was quantified via NMR using D 2 O as a solvent and compared well to complimentary gas chromatography-mass spectrometry data. Exchanging D 2 O for CD 3 OD as the solvent utilised for analysis resulted in a significantly lower amount of 4-PMP.3HCl being determined, thus highlighting safeguarding issues linked to drug abuse in relation to determining the amount of active pharmaceutical ingredient present.

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Section: Methodsmentioning

confidence: 99%

Benchtop NMR analysis of piperazine‐based drugs hyperpolarised by SABRE

Tennant

Hulme

Robertson

et al. 2020

Magnetic Reson in Chemistry

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“…Students need to think both inductively and deductively in the process of matching the physical and chemical properties of the given chemicals to the reference values that they have found in the literature. The current experiment can be considered as a stepping stone for students to move forward to a more advanced procedure of structural elucidation by spectroscopic techniques. There are usually three approaches to calorimetry experiments, measuring the heat of reaction, − the heat of dissolution, ,− and the heat capacity. ,− Only the first is considered a chemical property due to chemical reactions, but the latter two may be regarded as a physical property of a material. The accuracy of this experiment depends on the magnitude of the temperature change, the precision of the thermometer, and the ability of the calorimeter to insulate heat transfer between the system of interest and the environment.…”

Section: Introductionmentioning

confidence: 99%

Matching Five White Solids to Common Chemicals: A Dissolution Calorimetry and Acid–Base Titration Experiment

Bhukdee

Limpanuparb

2020

J. Chem. Educ.

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An experiment to match five white solids with ascorbic acid, citric acid, potassium hydroxide, sodium chloride, and urea is reported here. This 4 h experiment is an integrated practice of two experimental techniques, calorimetry and titration. Students conduct an extensive literature search on the properties of the five compounds and plan the experiment before the laboratory hours. Calorimetric results are used to identify potassium hydroxide, sodium chloride, and urea out of the five compounds. Acid–base titration is used to differentiate between the two weak acids and confirm the identity of the only base in this experiment. Additional calculations based on titration results can reveal waters of crystallization in citric acid and potassium hydroxide. The experiment helps students to understand concepts of dissolution, stoichiometry, acid–base chemistry, and thermochemistry in the context of common chemicals found in everyday life.

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“…Simplified replication of equipment or research instruments to become a classroom demonstration device has been carried out by many chemistry educators [4][5][6][7][8][9][10][11]. One example is a homemade spectrophotometer that can be made of inexpensive components [4].…”

Section: Introductionmentioning

confidence: 99%

“…To provide photochemical laboratory experiments, an inexpensive and commercially available ultraviolet light device, intended for "drying" gel-type fingernail polish, was developed by a group of researchers [6]. The fundamentals of UV spectroscopy, data handling, calibration, and sampling, can be learned by student to measure dissolution rates of tablets [7].…”

Section: Introductionmentioning

confidence: 99%