Mercy Amaka Okezue

Dr. Mercy Amaka Okezue

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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 March 2025 in Laboratories
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Adebola Morufu AdekoyaAdebola Morufu Adekoya
Adebola Morufu Adekoya
MOMercy Amaka Okezue
Mercy Amaka Okezue
KMKavitha Menon
Kavitha Menon
Medical laboratories (MLs) are vital in global healthcare delivery, enhancing diagnostic accuracy and supporting clinical decision-making. This systematic review examines the multifaceted contributions of ML, emphasizing their importance in pandemic preparedness, disease surveillance, and the integration of innovative technologies such as artificial intelligence (AI). Medical laboratories are equally crucial to clinical practices, offering essential diagnostic services to identify diseases like infections, metabolic disorders, and malignancies. They monitor treatment effectiveness by analyzing patient samples, enabling healthcare providers to optimize therapies. Additionally, they support personalized medicine by tailoring treatments based on genetic and molecular data and ensure test accuracy through strict quality control measures, thereby enhancing patient care. The methodology for this systematic review follows the PRISMA-ScR guidelines to systematically map evidence and identify key concepts, theories, sources, and knowledge gaps related to the roles and impact of MLs in public health delivery. This review involved systematic searching and filtering of literature from various databases, focusing on studies from 2010 to 2024, primarily in Africa, Asia, and Europe. The selected studies were analyzed to assess their outcomes, strengths, and limitations regarding MLS roles, impacts, and integration within healthcare systems. The goal was to provide comprehensive insights and recommendations based on the gathered data. The article highlights the challenges that laboratories face, especially in low- and middle-income countries (LMICs), where resource constraints hinder effective healthcare delivery. It discusses the potential of AI to improve diagnostic processes and patient outcomes while addressing ethical and infrastructural challenges. This review underscores the necessity for collaborative efforts among stakeholders to enhance laboratory services, ensuring that they are accessible, efficient, and capable of meeting the evolving demands of healthcare systems. Overall, the findings advocate for strengthened laboratory infrastructures and the adoption of advanced technologies to improve health outcomes globally.

23 November 2020 in BMC Health Services Research
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MOMercy Amaka Okezue
Mercy Amaka Okezue
MAMojisola C. Adeyeye
Mojisola C. Adeyeye
SBSteve J. Byrn
Steve J. Byrn
VAVictor O. Abiola
Victor O. Abiola
KCKari L. Clase
Kari L. Clase
Background: The number and severity of nonconformities generated during an audit of a medicine testing laboratory indicates its level of quality compliance. Quality standards are established and maintained to ensure the reliability of laboratory test reports. The National Medicines Regulatory Authority (NMRA) Quality Control laboratories assess the quality of medicines used by the populace as part of their regulatory function. Although countries desire to have reliable medicine testing facilities, accrediting a national laboratory to international standards poses financial and technical challenges for many low-income countries. Sharing the benefits of laboratory accreditation could help more countries within sub-Saharan Africa overcome existing challenges to achieve accreditation and robust quality systems. This study investigated the impact of ISO/IEC 17025 accreditation on the performance of an NMRA Quality Control laboratory to provide evidence of improved quality compliance within a low-resource setting. Methods: Pre- and post- accreditation audits of nonconformities for management and technical requirements of the ISO/IEC17025:2005 standards were evaluated from a Quality Control laboratory in the National Agency for Food and Drug Administration and Control (NAFDAC), located in Nigeria, West Africa. The following research questions were addressed: “does accreditation impact the adherence to quality standards?” and “does accreditation decrease the severity of nonconformities in Quality Control laboratory audits?” Results: Statistical analysis of the pre- to post- accreditation audits from the years 2013 through 2017 revealed a significant decrease in the total number of nonconformities (χ2 = 74, p-value = 9.99e-05, r = 0.67). Further examination of audits from the years 2013 through 2018 audits also revealed a reduction in the number of nonconformities (χ2 = 53, p-value = 9.99e-05, r = 0.62). A reduction in the number of major observations and a decrease in the severity of nonconformities was also observed. Conclusions: A higher level of quality compliance was exhibited for the laboratory during the post-accreditation years. Overall, ISO/IEC 17025 accreditation of the NMRA Quality Control laboratory resulted in improved reliability of test reports and enhancement of the laboratory quality system.

25 August 2021 in AAPS PharmSciTech
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MOMercy Amaka Okezue
Mercy Amaka Okezue
SBSusan Bogdanowich-Knipp
Susan Bogdanowich-Knipp
DSDaniel Smith
Daniel Smith
MZMatthias Zeller
Matthias Zeller
SBStephen Byrn
Stephen Byrn
KCKari Clase
Kari Clase
Bedaquiline is used to treat multi-resistant tuberculosis in adults. The fumarate salt is commercially available and used in the product Sirturo. To provide open access to bedaquiline molecule once the patent on the chemical substance expires, new salts were screened. This work offers additional information on the bedaquiline system, as new salts may present better pharmacokinetic properties. The current studies focus on the attempted isolation of the acetate, benzoate, benzenesulfonate, hydrobromide, succinate, hydrochloride, tartrate, lactate, maleate, malate, and mesylate salts of bedaquiline. Potential salts were screened using a unique combination of conventional screening, and small-scale experiments supplemented by crystallographic analysis and infrared microspectroscopy. Salts were prepared on a larger scale by dissolving 1:1 ratios of the individual salt formers and bedaquiline base (30 mg, 0.055 mmol) in different solvents and allowing the solutions to evaporate or crystallize. X-ray diffraction (XRD) techniques and spectroscopic and thermal analyses were employed to characterize the salts. The benzoate and maleate salts were selected as lead candidates after reviewing preliminary characterization data. To determine the most stable forms for the leads, a polymorph screen was conducted using solvents of various polarities. These salt screens successfully generated five new salts of bedaquiline, namely, benzoate, maleate, hydrochloride, besylate, and mesylate. The existence of these salts was confirmed by powder XRD, proton NMR, and IR spectroscopies. TGA and DSC thermal analysis along with hot-stage optical microscopy were further used to characterize the salts. The polymorph screen conducted on the salts suggested the absence of additional polymorphs at 1 g scale.

4 December 2024 in Scientia Pharmaceutica
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CUChidi Uzoma Uche
Chidi Uzoma Uche
MOMercy Amaka Okezue
Mercy Amaka Okezue
IAIBRAHIM MOHAMMED AMIDU
IBRAHIM MOHAMMED AMIDU
SBStephen Robert Byrn
Stephen Robert Byrn
This study aimed to assess the predictive performance of first- and second-order regression models in optimizing bedaquiline (BQ) solid lipid nanoparticle (SLN) formulations. A three-step central composite design and graphical optimization process was employed. A design of experiments method was used to evaluate the impact of BQ, Tween 80 (T80), polyethylene glycol (PEG), and lecithin on the formulations’ response variables, including Z-average (PSD), polydispersibility index (PdI), and Zeta potential (ZP). Secondly, we quantified the relationship between experimental variables using the regression model coefficients. Lastly, we predicted the responses and verified the models’ adequacies to ensure accurate representation and effective optimization. The first-order polynomial showed poor model adequacy and required further refinement due to its lack of explanatory power and significant predictors. Conversely, the second-order models provided superior fitness, sensitivity to variability, complexity, and prediction consistency. The optimized formulation achieved a desirability value of 0.9998, indicating alignment with the desired criteria. Specifically, the levels of BQ (19.4 mg), T80 (25.2 mg), PEG (39.2 mg), and lecithin (200 mg) corresponded to PdI (0.41), PSD (250.99 nm), and ZP (−25.95 mV). Maintaining a BQ concentration between 10 and 20% and T80 between 15 and 18% is vital for maximizing ZP and minimizing PdI and PSD, ensuring stable SLN formulations. This study underscores the significance of precise model selection and statistical analysis in pharmaceutical formulation optimization for enhanced drug delivery systems.

19 October 2020 in Acta Crystallographica Section C Structural Chemistry
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MOMercy Amaka Okezue
Mercy Amaka Okezue
DSDaniel T. Smith
Daniel T. Smith
MZMatthias Zeller
Matthias Zeller
SBStephen Robert Byrn
Stephen Robert Byrn
PSPamela Anne Smith
Pamela Anne Smith
KCKari L. Clase
Kari L. Clase
Bedaquiline [systematic name: 1-(6-bromo-2-methoxyquinolin-3-yl)-4-(dimethylamino)-2-(naphthalen-1-yl)-1-phenylbutan-2-ol, C32H31BrN2O2] is one of two important new drugs for the treatment of drug-resistant tuberculosis (TB). It is marketed in the US as its fumarate salt {systematic name: [4-(6-bromo-2-methoxyquinolin-3-yl)-3-hydroxy-3-(naphthalen-1-yl)-4-phenylbutyl]dimethylazanium 3-carboxyprop-2-enoate, C32H32BrN2O2 +·C4H3O4 −}, and about a dozen other salts of bedaquiline have been described in patent literature, but none have so far been structurally described. In a first communication, we present the crystal structure of bedaquilinium fumarate and of two new benzoate salts, as well as that of a degradation product of the reaction of bedaquilinium fumarate with sodium ethoxide, 3-benzyl-6-bromo-2-methoxyquinoline, C17H14BrNO. The fumarate and benzoate salts both feature cations monoprotonated at the dimethylamino group. The much less basic quinoline N atom remains unprotonated. Both salts feature a 1:1 cation-to-anion ratio, with the fumarate being present as monoanionic hydrofumarate. The conformations of the cations are compared to that of free base bedaquiline and with each other. The flexible backbone of the bedaquiline structure leads to a landscape of conformations with little commonalities between the bedaquiline entities in the various structures. The conformations are distinctively different for the two independent molecules of the free base, the two independent molecules of the hydrofumarate salt, and the one unique cation of the benzoate salt. Packing of the salts is dominated by hydrogen bonding. Hydrogen-bonding motifs, as well as the larger hydrogen-bonded entities within the salts, are quite similar for the salts, despite the vastly differing conformations of the cations, and both the hydrofumarate and the benzoate structure feature chains of hydrogen-bonded anions that are surrounded by and hydrogen bonded to the larger bedaquilinium cations, leading to infinite broad ribbons of anions, cations, and (for the benzoate salt) water molecules. The benzoate salt was isolated in two forms: as a 1.17-hydrate (C32H32BrN2O2 +·C7H5O2 −·1.166H2O), obtained from acetone or propanol solution, with one fully occupied water molecule tightly integrated into the hydrogen-bonding network of anions and cations, and one partially occupied water molecule [refined occupancy 16.6 (7)%], only loosely hydrogen bonded to the quinoline N atom. The second form is an acetonitrile solvate (C32H32BrN2O2 +·C7H5O2 −·0.742CH3CN·H2O), in which the partially occupied water molecule is replaced by a 74.2 (7)%-occupied acetonitrile molecule. The partial occupancy induces disorder for the benzoate phenyl ring. The acetonitrile solvate is unstable in atmosphere and converts into a form not distinguishable by powder XRD from the 1.17-hydrate.

1 July 2024 in AAPS PharmSciTech
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MOMercy Amaka Okezue
Mercy Amaka Okezue
CUChidi Uche
Chidi Uche
AAAdekoya Adebola
Adekoya Adebola
SBStephen Robert Byrn
Stephen Robert Byrn