scholarly works

Permanent URI for this collectionhttps://repository.ui.edu.ng/handle/123456789/391

Browse

End date: 2019Subject: search.filters.subject.Chloranilic acid

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Spectrophotometric and thermodynamic studies of the charge-transfer complexation of Tranexamic Acid with Chloranilic Acid
    (Nigeria Association of Pharmacists in Academia, 2018) Thomas, O. E.; Adedoyin, O.
    Background: Tranexamic acid is a synthetic analogue of lysine that is clinically useful as an antifibrinolytic agent. Due to its lack of chromophores and aromaticity, chemical derivatization is necessitated and outcomes are often poor and/or associated with low sensitivity and poor stability. Objective: To develop a colorimetric method for the determination of tranexamic acid (TXA) following the optimization and parameterization of the charge-transfer (CT) complexation of the drug with chloranilic acid (CAA). Method: The method involved the utilization of TXA as n-electron donor and CAA as π-acceptor in methanol to generate a CT complex. Factors contributory to the formation and stabilization of the complex were optimized. The Benesi-Hilderbrand equation was used to estimate the molar absorptivity and formation constant of the CT band before its application to dosage form analysis. Results: The CT band which absorbed maximally at 520 nm was associated with molar absorptivity of 807 Lmol- 1cm-1 and a large formation constant (1.14x104). The calculated physicochemical properties including transition energy (2.303eV), oscillator strength (0.267), transition dipole moment (5.455 Debye), resonance energy (1.159 eV), ionization potential (8.679 eV) and dissociation energy (5.276 eV) as well as the thermodynamic parameters were indicative of a highly stable charge-transfer complex. Under optimal conditions, the assays of the drug were linear over the range 10-100 μg/mL and the method was accurate and reproducible (inter-day relative errors and standard deviations not greater than 2.92% and 3.40% respectively). When applied to dosage forms, there was no statistical difference in the mean recoveries of the new method when compared to reference method. Conclusion: The new method is rapid, accurate and precise. It can serve as alternative to the routine analysis of tranexamic acid in bulk and dosage forms.
  • Thumbnail Image
    Item
    Colorimetric determination of Olanzapine via charge-transfer complexation with Chloranilic Acid.
    (Elsevier B.V., 2016) Adegoke, O. A.; Thomas, O. E.; Emmanuel, S. N.
    The charge-transfer complexation (CTC) formed between olanzapine and chloranilic acid have been studied and used as a sensitive colorimetric method for the determination of olanzapine. Evidence for the formation of the CTC between chloranilic acid (CAA) and olanzapine (OLP) was established by spot tests and TLC. Method development was carried out through selection of analytical wavelength, optimization and validation studies. Physicochemical parameters such as energy of transition, transition dipole, oscillator frequency and ionization energies were estimated and related to the stability of the formed CT band. Thermodynamic properties of the CT band at four temperature levels were also estimated and their inter-relationship established. The reaction was completed at room temperature within 10 min with the evidence of formation of purple-coloured solution with CAA that absorbed maximally at 520 nm. Linearity was obtained in the concentration range of 2–40 µg/mL for OLP (r = 0.9977) with a limit of detection of 1.57 µg/mL. Estimates of accuracies and precisions gave error values less than 2% for both intra- and inter-day assessments. The transition energies were of the order of 2.303 eV. The Gibbs energy varied with the temperature and room temperature values favoured formation of stable complexes. The thermodynamic studies revealed small positive entropy for slightly negative enthalpy change. The method was successfully applied to estimate OLP in tablets and the method was found to be of equivalent accuracy with the Indian Pharmacopoeia’s HPLC method (p > 0.05). The method could find application as a rapid and sensitive determination technique for olanzapine.