Papers by Adenike Okunlola
DOAJ (DOAJ: Directory of Open Access Journals), May 31, 2022
Journal of pharmaceutics & drug delivery research, 2019
Drug-release characteristics of microspheres can be influenced by the type of coating material us... more Drug-release characteristics of microspheres can be influenced by the type of coating material used in the formulation. The peels of the citrus fruits, Lemon (Citrus limon) and Orange (Citrus sinensis) Family Rutaceae, are sources of pectins, and these were evaluated as sustained release polymers in the formulation of microspheres of metoprolol succinate (MS), an antihypertensive agent. Lemon and Orange pectins were characterized using morphology, Fourier Transform Infra-red (FTIR) analysis, qualitative and quantitative tests. Metoprolol succinate microspheres were prepared by ionic gelation using each pectin, co-blended with sodium alginate. The microspheres were characterized using Scanning Electron Microscope (SEM), FTIR analysis, drug entrapment and quantity of drug released in 12 hours (Q12). The 23 full factorial design was applied to evaluate the individual and interactive effects of three variables: X1, pectin:alginate ratio, X2, Polymer: drug ratio, and X3, type of pectin in polymer blend on size, swelling, drug entrapment and Q12. Yields of pectin from Orange and Lemon were 16.40 and 18.24%, respectively with methoxy content of 4.30 and 5.20%. Spherical microspheres with drug entrapment of 57.71 ± 8.96 to 90.72 ± 9.21% and Q12 of 7.40 to 12.50% were obtained. The FTIR spectra suggested that there were no interactions between metoprolol and polymers. The swelling, entrapment and dissolution time increased with increase in pectin content. The factor X2 had the most influence on microsphere properties while the interactive effects of X2X3 had the most influence. Optimization of the analyzed responses demonstrated that peak conditions for obtaining desired maximum properties was by using Orange pectin at pectin: alginate and polymer: drug ratios of 2:1. Lemon and Orange pectins showed potential as cheaper alternative polymers in sustaining the release of metoprolol succinate from microspheres.
Nigerian Journal of Phamaceutical Research, Jan 30, 2020
Background: Ibuprofen, administered as conventional oral tablets every 4 -6 hours, has some gastr... more Background: Ibuprofen, administered as conventional oral tablets every 4 -6 hours, has some gastrointestinal side effects. Its formulation as sustained and immediate release layers in a compact bilayer tablet avoids the challenge of multiple daily dosing, reducing untoward side effects.Objectives: The objective of the study is to formulate bilayer tablets of ibuprofen using breadfruit (Artocarpus altilis) starches modified by carboxymethylation and acid hydrolysis for immediate and sustained release, respectively, in comparison to sodium starch glycolate (SSG) and hydroxypropyl methyl cellulose (HPMC).Methods: The starches were characterized using Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, viscosity, swelling power, densities and flow properties. Bilayer tablets of ibuprofen were prepared using carboxymethylated Breadfruit starch (5.0 and 7.5%w/w) and acid-hydrolyzed starch (17.0%w/w) and evaluated using crushing strength, friability, disintegration and dissolution times (t80).Results: FTIR and XRD spectra confirmed modification of starches. Carboxymethylation produced starches of higher swelling and flow properties while acid-modification produced higher compressibility. Bilayer tablets containing modified starches had higher crushing strength than the standards. Disintegration time of the fast release layers was 1.00 - 10.37 min. An initial burst release was followed by sustained release (t80 = 4.5 - 9.0 h) with tablets containing the acid modified starch having longer dissolution than HPMC. Drug release fitted the First order, Hixson-Crowell and Hopfenberg kinetic models.Conclusion: Carboxymethylated and acid-modified breadfruit starches were found suitable as cheaper excipients in bilayer tablet formulations for immediate and sustained release of drugs respectively, particularly where high mechanical strength is required.Keywords: Acid-modification, bilayer tablets, breadfruit starch, carboxymethylation, ibuprofen
Nigerian Journal of Pharmaceutical research, 2021
Background: Pregelatinized starches exhibit good swelling and flow properties, imparting fast dis... more Background: Pregelatinized starches exhibit good swelling and flow properties, imparting fast disintegration time but low mechanical strength in tablets. On the other hand, acacia gum acts as a binder in tablets by imparting high mechanical strength but prolonged disintegration time. Development of a co-processed excipient involving combination of the two excipients at sub-particle level will improve the functionality of the final product.Objective: To develop a direct compressible co-processed excipient with pregelatinized cocoyam starch and acacia gum and to evaluate its compaction behavior and tableting properties in metoprolol succinate tablets.Material and Methods: Batches of the co-processed excipient were prepared by co-fusion using different ratios (97.5:2.5; 95:5; 92.5:7.5; 90:10; 85:15; 80:20) of pregelatinized cocoyam starch and acacia gum. Flow and compaction properties and Fourier transform Infrared (FT-IR) analysis were carried out on native and pregelatinized starches...
Tropical Journal of Pharmaceutical Research, Dec 9, 2014
Purpose: To investigate the effectiveness of three natural gums, namely albizia, cissus and khaya... more Purpose: To investigate the effectiveness of three natural gums, namely albizia, cissus and khaya gums, as excipients for the formulation of ibuprofen microbeads. Methods: Ibuprofen microbeads were prepared by the ionotropic gelation method using the natural gums and their blends with sodium alginate at various concentrations using different chelating agents (calcium chloride, zinc chloride, calcium acetate and zinc acetate) at different concentrations. Microbeads were assessed using SEM, swelling characteristics, drug entrapment efficiencies, release properties and drug release kinetics. Results: The natural gums alone could not form stable microbeads in the different chelating agents. Stable small spherical discrete microbeads with particle size of 1.35 ± 0.11 to 1.78 ± 0.11 mm, were obtained using the blends of natural gum: alginate at total polymer concentration of 2 % w/v using 10 % w/v calcium chloride solution at a stirring speed of 300 rpm. The encapsulation efficiencies of the microbeads ranged from 35.3 to 79.8 % and dissolution times, t15 and t80 increased with increase in the concentration of the natural gums present in the blends. Controlled release was obtained for over 4 h and the release was found to be by a combination of diffusion and erosion mechanisms from spherical formulations. Conclusion: The three natural gums would be useful in the formulation of ibuprofen microbeads and the type and concentration of natural gum in the polymer blend can be used to modulate the release properties of the microbeads.
The East and Central African Journal of Pharmaceutical Sciences, 2020
The aim of the study was to use central composite design in formulating theophylline microspheres... more The aim of the study was to use central composite design in formulating theophylline microspheres containing Akidi beans (Vigna unguiculata L Warp) starch as a controlled-release polymer. Theophylline microspheres containing pregelatinized Akidi beans starch, alginate and chitosan were prepared using ionic gelation. A 2 factor, 2 Level central composite design was used with starch:alginate ratio (X1) and polymer:drug ratio (X2) as variables, and size, entrapment efficiency and quantity of drug released in 12 h, Q12, as responses. Regression parameters and response surface plots were generated. The microspheres were spherical with size 1.68 00 ± 0.12 – 1.95 ± 0.03 mm. Optimized formulation containing 4:1 Akidi starch: alginate and 3:1 polymer: drug ratios, prepared according to levels determined by Minitab software using desirability function, showed significant increase in the responses in comparison to those containing alginate alone. Akidi beans starch demonstrated good potential ...
Design of bilayer tablets using modified Dioscorea starches as novel excipients for immediate and... more Design of bilayer tablets using modified Dioscorea starches as novel excipients for immediate and sustained release of aceclofenac sodium
The East and Central African Journal of Pharmaceutical Sciences, 2020
Nigerian Journal of Pharmaceutical Research
Background: Pearl millets (Pennisetum glaucum) are important but underutilized crops found in tro... more Background: Pearl millets (Pennisetum glaucum) are important but underutilized crops found in tropical and semi-arid regions of the world, including Northern Nigeria. A survey report of women in Kaduna, Northern Nigeria, revealed that milk obtained from grains of Pearl millet have been utilized to enhance lactation, even in cases of adoptive nursing.Objectives: The aim of this study is to prepare aqueous slurry of Pearl millet grains, freeze-dry into powders, characterize and then evaluate the powders for galactogogue activity in female Wistar rats, in comparison to domperidone, a dopamine antagonist used as a lactogenic agent.Methods: The aqueous slurry of millets was freeze-dried and characterized for morphology, crystallinity (Fourier Transform Infra-red spectroscopy, FTIR and X-ray diffraction analysis, XRD), viscosity, flow and compaction properties. Animal studies were carried out to evaluate the galactogogue effect and histopathological examination was done on the 15th day of...
The East and Central African Journal of Pharmaceutical Sciences, 2009
The physicochemical equivalence of twenty-two brands of paracetamol and nine brands of ibuprofen ... more The physicochemical equivalence of twenty-two brands of paracetamol and nine brands of ibuprofen tablets sourced from retail Pharmacy outlets in the Nigerian market to their respective innovator brands were investigated. The uniformity of weight, friability, crushing strength, disintegration and dissolution times and assay of active paracetamol ingredient were used as assessment parameters. All the brands of paracetamol and ibuprofen tablets complied with the official specifications for uniformity of weight. However, five brands of paracetamol failed the friability test, one brand of paracetamol and two brands of ibuprofen failed the disintegration test and three brands of paracetamol and four brands of ibuprofen failed the assay of active ingredients. The study shows that not all the brands of paracetamol and ibuprofen tablets are physico-chemically equivalent to their innovator brands. There is therefore the need for constant market surveillance to ascertain their compliance with official standards and equivalence to the innovator products.
Journal of Excipients and Food Chemicals
Chloroquine phosphate (CP) is an antimalarial drug that was popular for its fast onset of action,... more Chloroquine phosphate (CP) is an antimalarial drug that was popular for its fast onset of action, safety in all trimesters of pregnancy, and its beneficial effects in rheumatoid arthritis and lupus erythematosus. CP has poor tableting properties and therefore requires a binder, among other excipients, to form robust tablets. The potential of using Ofada rice (Oryza glaberrina Steud) starch as the binder in tablet formulations of CP was compared to B.P. grade established corn starch. The starches were characterized for morphology (Scanning electron microscopy, SEM), crystallinity (Fourier Transform Infra- Red Spectroscopy, FTIR), swelling, densities, flow, and compressing properties. CP tablets containing the native starches as binders at 5.0 and 10.0% w/w respectively were prepared using wet granulation at compression pressures 56.56 and 113.13 MNm -2 for a period of 15 and 30 seconds. The potential of using Ofada rice starch as a binder was examined using the Taguchi based grey-rel...
Tropical Journal of Pharmaceutical Research, 2014
Purpose: To investigate the effectiveness of three natural gums, namely albizia, cissus and khaya... more Purpose: To investigate the effectiveness of three natural gums, namely albizia, cissus and khaya gums, as excipients for the formulation of ibuprofen microbeads. Methods: Ibuprofen microbeads were prepared by the ionotropic gelation method using the natural gums and their blends with sodium alginate at various concentrations using different chelating agents (calcium chloride, zinc chloride, calcium acetate and zinc acetate) at different concentrations. Microbeads were assessed using SEM, swelling characteristics, drug entrapment efficiencies, release properties and drug release kinetics. Results: The natural gums alone could not form stable microbeads in the different chelating agents. Stable small spherical discrete microbeads with particle size of 1.35 ± 0.11 to 1.78 ± 0.11 mm, were obtained using the blends of natural gum: alginate at total polymer concentration of 2 % w/v using 10 % w/v calcium chloride solution at a stirring speed of 300 rpm. The encapsulation efficiencies of the microbeads ranged from 35.3 to 79.8 % and dissolution times, t15 and t80 increased with increase in the concentration of the natural gums present in the blends. Controlled release was obtained for over 4 h and the release was found to be by a combination of diffusion and erosion mechanisms from spherical formulations. Conclusion: The three natural gums would be useful in the formulation of ibuprofen microbeads and the type and concentration of natural gum in the polymer blend can be used to modulate the release properties of the microbeads.
International Symposium on Photoelectronic Detection and Imaging 2009: Material and Device Technology for Sensors, 2009
In order to increase the species of organic infrared semiconductor, we synthesized organic infrar... more In order to increase the species of organic infrared semiconductor, we synthesized organic infrared semiconductor phthalocyanine gadolinium by using o-phthalodinitrile and GdCl3 as reactants, ammonium molybdate as catalyzer. Under light and dark field modes of microscope, the translucency emerald-like powder of phthalocyanine gadolinium has been observed, the size of the small grain for the sample is around 5μm in diameter, the size of larger grain may reach to several tens of microns. The main vibrational peaks in FT-IR spectrum and Raman spectrum have been assigned. Elementary analysis shows that the experimental data of phthalocyanine gadolinium in the main agree with those of calculated data. The UV-Vis absorption spectrum of the sample indicates the sandwich-like structure of phthalocyanine gadolinium. The organic infrared semiconductor phthalocyanine gadolinium thin film on quartz substrate has been prepared with our synthesized powdered sample by using solution method. The characterizations of XRD and UV-Vis-NIR absorption have been carried out for the phthalocyanine gadolinium thin film on quartz substrate, XRD shows that phthalocyanine gadolinium diffractions occur at 2θ=6.851,8.290 and 8.820 degrees, the corresponding plane spacings (d) for the diffraction peaks are 12.8921, 10.6570, and 10.0176Å.The diffraction peaks locate at low diffraction angle, suggesting that the molecular size of the phthalocyanine gadolinium is big that causes the large spacing of crystal planes. The UV-Vis-NIR absorption of phthalocyanine gadolinium thin film on quartz substrate implies that within near infrared band there is a absorption in the 1.3~2.0μm wavelength range peaked at ca. 1.75μm, indicating the important potential application value of phthalocyanine gadolinium in the field of organic infrared optoelectronics.
SPIE Proceedings, 2009
The study of FT-IR spectrum, Raman spectrum, UV-Vis absorption spectrum as well as photoluminesce... more The study of FT-IR spectrum, Raman spectrum, UV-Vis absorption spectrum as well as photoluminescence spectrum on organic ultraviolet semiconductor KIP-OUVS-1 has been investigated. The main vibrational peaks of organic ultraviolet semiconductor KIP-OUVS-1 in FT-IR spectrum and Raman spectrum have been assigned. The study of UV-Vis solution absorption spectrum on the organic ultraviolet semiconductor KIP-OUVS-1 shows that there is an obvious ultraviolet absorption peak in 210~280nm range, there are several ultraviolet absorption peaks in 290~390nm range too. The photoluminescence spectra of organic ultraviolet semiconductor KIP-OUVS-1 at different excitation wavelengths have also been investigated, the result shows that in the excitation wavelength of 220~360nm range, the shapes for different photoluminescence peaks are similar under different excitation wavelengths, the sole difference among them is strength of the peaks. At 280nm and 300nm excitation wavelengths, the relatively strong peaks have been gotten, at 220nm and 250nm excitation wavelengths, however, the photoluminescence peaks are relatively weak. Furthermore, for organic ultraviolet semiconductor KIP-OUVS-1, the photoluminescence peaks have a stokes' red shift compared with those absorption peaks for the solution samples, and an enantiomorphous symmetry, which is the powerful experimental proof of Franck-Condon theory, between the absorption spectrum and photoluminescence spectrum has been observed too. For the reason that the organic ultraviolet semiconductor KIP-OUVS-1 may be used to prepare large-area thin film and flexible device on low-price, flexible substrates by means of thermal evaporation and solution method, thus, the authors deduce that the organic ultraviolet semiconductor KIP-OUVS-1 may have an important application potential in ultraviolet optoelectronic detecting or lighting field.
International Journal of Biological Macromolecules, 2013
Four natural gums, namely albizia, cissus, irvingia and khaya gums have been characterized and ev... more Four natural gums, namely albizia, cissus, irvingia and khaya gums have been characterized and evaluated as polymers for the formulation of microbeads for controlled delivery of diclofenac sodium. The natural gums were characterized for their material properties using standard methods. Diclofenac microbeads were prepared by ionotropic gelation using gel blends of the natural gums and sodium alginate at different ratios and zinc chloride solution (10%w/v) as the crosslinking agent. The microbeads were assessed using SEM, swelling characteristics, drug entrapment efficiencies and release properties. Data obtained from in vitro dissolution studies were fitted to various kinetic equations to determine the kinetics and mechanisms of drug release, and the similarity factor, f2, was used to compare the different formulations. The results showed that the natural gum polymers varied considerably in their material properties. Spherical and discrete microbeads with particle size of 1.48-2.41 μm were obtained with entrapment efficiencies of 44.0-71.3%w/w. Drug release was found to depend on the type and concentration of polymer gum used with formulations containing gum:alginate ratio of 3:1 showing the highest dissolution times. Controlled release of diclofenac was obtained over for 5h. Drug release from the beads containing the polymer blends of the four gums and sodium alginate fitted the Korsmeyer-Peppas model which appeared to be dependent on the nature of natural gum in the polymer blend while the beads containing alginate alone fitted the Hopfenberg model. Beads containing albizia and cissus had comparable release profiles to those containing khaya (f2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;50). The results suggest that the natural gums could be potentially useful for the formulation controlled release microbeads.
Brazilian Journal of Pharmaceutical Sciences, 2013
Chinese yam (Dioscorea oppositifolia) starch modified by acid hydrolysis was characterized and co... more Chinese yam (Dioscorea oppositifolia) starch modified by acid hydrolysis was characterized and compared with native starch as a binder in chloroquine phosphate tablet formulations. The physicochemical and compressional properties (using density measurements and the Heckel and Kawakita equations) of modified Chinese yam starch were determined, and its quantitative effects as a binder on the mechanical and release properties of chloroquine phosphate were analyzed using a 2³ full factorial design. The nature (X1), concentration of starch (X2) and packing fraction (X3) were taken as independent variables and the crushing strength-friability ratio (CSFR), disintegration time (DT) and dissolution time (t80) as dependent variables. Acid-modified Chinese yam starch showed a marked reduction (p<0.05) in amylose content and viscosity but increased swelling and water-binding properties. The modified starch had a faster onset and greater amount of plastic flow. Changing the binder from nativ...
Research Journal of Applied Sciences, 2010
Saudi Pharmaceutical Journal, 2011
Starches obtained from four Dioscorea species namely Dioscorea dumetorum (Bitter), Dioscorea oppo... more Starches obtained from four Dioscorea species namely Dioscorea dumetorum (Bitter), Dioscorea oppositifolia (Chinese), Dioscorea alata (Water), and Dioscorea rotundata (White) have been evaluated as binding agents in chloroquine phosphate tablet formulations in comparison with official corn starch. The compressional properties of the formulations were analyzed using density measurements and the Heckel and Kawakita equations. The mechanical properties of the tablets were assessed using tensile strength, brittle fracture index (BFI), and friability tests while the drug release properties of the tablets were assessed using disintegration and dissolution times. The results indicate that the four starches vary considerably in their physicochemical properties. The ranking for the tensile strength and the disintegration and dissolution times for the formulations was Chinese > Bitter > Corn > White > Water while the ranking was reversed for BFI and friability. The results suggest that Water, White, and Corn could be useful when faster disintegration time of tablets is desired while Chinese and Bitter could be more useful when bond strength is of concern and in minimizing the problems of lamination and capping in tablet formulation.
Purpose: The aim of the present study was to investigate the pharmaceutical and microbial qualiti... more Purpose: The aim of the present study was to investigate the pharmaceutical and microbial qualities of 21 different (of various dosage forms) Herbal Medicinal Products (HMPs) sourced from some traditional medicine sales outlets and retail pharmacy outlets in south western Nigeria. Method: The pharmaceutical qualities evaluated include tablet crushing strength, friability, disintegration time; density of the solutions and suspensions; particle size and angle of repose of the powders. Phytochemical tests were carried out to assess the class of compounds present in the formulations and the microbial quality of the products was also evaluated. Results: The results show that twelve (57.1%) of the products had their manufacturing and expiry dates stated, nine (42.9%) products have been registered by NAFDAC and ten (47.6%) did not have their content stated but had their therapeutic claims indicated on the container. The tablet formulation (Product A) showed acceptable crushing strength and...
Nigerian Journal of Pharmaceutical research, 2016
Background: Acetylated starches with degrees of substitution (DS) of > 2 have been found suita... more Background: Acetylated starches with degrees of substitution (DS) of > 2 have been found suitable for sustained release applications because of their hydrophobic nature and thermoplasticity. The short half-life and high dosing frequency of repaglinide make it an ideal candidate for sustained release. Objectives: To formulate and evaluate repaglinide microspheres using acetylated starch of the indigenous rice species Oryza glaberrima Steud (Ofada) as polymer. Materials and Methods: Ofada rice starch was acetylated with acetic anhydride in pyridine (DS 2.68) and characterized for morphology (Scanning electron microscope, SEM), Crystallinity (Fourier Transform Infra-Red spectroscopy, FTIR, and X-ray diffraction crystallography, XRD), density and swelling. Microspheres of repaglinide were prepared by emulsification solvent-evaporation method, varying the drug-polymer ratio (1:2, 1:4, 1:8 and 1:10) and polymer type (ethyl cellulose as standard). Microspheres were characterized for par...
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Papers by Adenike Okunlola