Oluwatoyin A Odeku | University of Ibadan (original) (raw)
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Papers by Oluwatoyin A Odeku
Journal of Pharmaceutical Investigation, 2016
Pharmaceutical Development and Technology, Feb 1, 2009
Starches obtained from four different Dioscorea species namely White (D. rotundata), Bitter (D. d... more Starches obtained from four different Dioscorea species namely White (D. rotundata), Bitter (D. dumetorum), Chinese (D. oppositifolia) and Water yam (D. alata), were modified by acid hydrolysis and the physicochemical, material and tablet formation properties of the starches were investigated with the aim of determining their usefulness as a direct compression excipient in pharmaceutical tablets. The results obtained indicate that the physicochemical, material and tablet properties of the acid modified Dioscorea starches varied considerably among the various species. Acid hydrolysis led to an increase in solubility but decrease in swelling of the starches. Acid modification also led to an increase in the compressibility of the starches when compared with the native forms of the starches. Acid modified Water and White formed intact stable tablets only at higher rho(rel,) (max), while acid modified Chinese and Bitter formed tablets at all relative densities which could already be predicted from the deformation behaviour as analyzed by 3-D modeling. The result indicates that acid modified starch tablets showed higher crushing force and acceptable disintegration time and could therefore be useful as directly compressible excipient.
Tropical Journal of Pharmaceutical Research, 2014
ABSTRACT
The authors study the effects of sweet potato and cocoyam starches on the compressional and mecha... more The authors study the effects of sweet potato and cocoyam starches on the compressional and mechanical characteristics of a paracetamol tablet formulation using cornstarch BP.
The individual and interaction effects of nature of binder (N), concentration of binder (C) and t... more The individual and interaction effects of nature of binder (N), concentration of binder (C) and the relative density (D) on the tensile strength and release properties of paracetamol tablets have been studied using a 2 3 factorial experimental design. Methodology: Khaya gum, which represented the "low" level, and polyvinylpyrrolidone (PVP), which represented the "high" level, was used as binding agent at concentrations of 0.5% and 4%w/w in a paracetamol tablet formulation. The tensile strength, which is a measure of the bond strength of tablets, and the release properties of the tablets-measured by the disintegration and the dissolution times, were used as assessment parameters.
Journal of Excipients and Food Chemicals
Two freeze dried pregelatinized Dioscorea starches have been evaluated as directly compressible e... more Two freeze dried pregelatinized Dioscorea starches have been evaluated as directly compressible excipients for sustained release using diclofenac sodium and caffeine as the model drugs. The tableting properties of the binary and ternary mixtures of the drug/starch/excpients were assessed using the 3-D modeling parameters. The crushing force (CF) of the tablets and the drug release properties were evaluated. The effect of dicalcium phosphate dihydrate on the compaction and drug release properties of the matrices was also investigated. The results obtained indicate that the tablet formation properties of the starches depend on the Dioscorea starch used and on the concentration of drug present in the matrix tablets. There appears to be a decrease in the CF of the tablets as the concentration of drug in the matrix is increased. Inclusion of dicalcium phosphate dihydrate in the tablet matrix increased the bonding in the matrix tablets leading to an increase in CF of the tablets. The drug release from the matrices, and the release rates and mechanism were also dependent on the Dioscorea starch used and the drug concentration. Modified Bitter Yam starch matrices provided a controlled release of diclofenac for up to 5 hours while modified Chinese Yam starches provided controlled release for over 24 hours. The release mechanism from modified Chinese Yam starch matrices was found to be Super Case-II transport or time-independent release kinetics. Furthermore, the release rates were dependent on the concentration of the drug present in the matrix. Thus, the modified starch matrices could be used to achieve different drug release profiles depending on the intended use of the tablets. The addition of dicalcium phosphate dihydrate not only improved the mechanical properties of the tablets but also altered the release rates and kinetics. Thus, modified Chinese Yam and Bitter Yam starches could find application as excipients for controlled drug delivery.
The packing and cohesive properties of locally developed cassava, potato and yam starches have be... more The packing and cohesive properties of locally developed cassava, potato and yam starches have been characterised using the maximum volume reduction due to packing as expressed by the Kawakita constant a, and the angle of internal flow, θ, respectively.
Journal of Drug Delivery Science and Technology
ABSTRACT
Journal of Drug Delivery Science and Technology
Acta Pharmaceutica Sciencia
The gum exudates obtained from the incised trunk of Terminalia randii (Family Combretaceae) have ... more The gum exudates obtained from the incised trunk of Terminalia randii (Family Combretaceae) have been evaluated as binding agent in carvedilol tablet formulations in comparison with standard binders -polyvinylpyrrolidone (PVP) and corn starch. The physicochemical properties of the gum was characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray powder diffraction (XRPD), particle size analysis, pH and viscosity determinations. The mechanical properties of the tablets were assessed using the crushing strength and friability tests while drug release properties were assessed using the disintegration and dissolution times. The crushing strength of the tablets increased while the friability decreased with increase in the concentration of the binding agents. The ranking of the crushing strength of the tablet was formulations containing PVP > Terminalia gum > corn starch while the ranking for friability was the reverse. The disintegration and dissolution times of the tablets also increased with increase in the concentration of the binders. The ranking of the disintegration time was PVP > Terminalia gum > corn starch while the ranking of dissolution time was Terminalia gum > PVP > corn starch. The results indicate that the binding properties of Terminalia gum compared favorably with those of the standard binders and could also find application in controlled release tablet formulations.
Acta Pharmaceutica Sciencia
The individual and interaction effects of type or nature of suppository base (N), concentration o... more The individual and interaction effects of type or nature of suppository base (N), concentration of surfactant (C), and storage (S) on the mechanical and release properties of chloroquine phosphate suppositories have been studied using a 2 3 factorial experimental design. Suppositories (1g) containing 100mg chloroquine phosphate each with or without 2%w/v Tween 20 as adjuvant, were prepared in Suppocire® AS2 and Witepsol® H15 bases. The mechanical properties of the suppositories were determined using crushing strength and dissolution properties were assessed using dissolution times (t 50 and t 80 -time for 50% and 80% drug release), and rates. The concentration of surfactant had the highest individual effect on the release properties of the suppository formulations while storage had the lowest effects. Thus, the type of suppository base and concentration of surfactant used in suppository formulations need to be carefully chosen in order to obtain suppositories of desired mechanical and drug release properties.
Background: Talc is used in the pharmaceutical industry as a lubricant in tablet formulations, dr... more Background: Talc is used in the pharmaceutical industry as a lubricant in tablet formulations, dry-coating of oral tablets and as filter medium.
African journal of medicine and medical sciences
To determine the pharmaceutical equivalence and stability of eighteen randomly selected brands of... more To determine the pharmaceutical equivalence and stability of eighteen randomly selected brands of metronidazole suspensions. The tests conducted include ease of redispersibility, sedimentation volume, particle size measurements, viscosity and assay of drug content. The results showed that 16 (88.9%) out of 18 brands including the innovator (SR) were redispersed between 30 seconds to one minute, while 2 (11.1%) took more than two minutes. The sedimentation volume for 15 (83.3%) of the brands was less than 0.50 while the innovator brand had a significantly higher (p < 0.001) value (0.91). The particle size of the brands ranged between 1.942 and 5.92 μm and the sedimentation rate was between 20-50 mL/day. The viscosity of the brands were significantly different (p < 0.05) with SA, SB, SC, SD, SE and SF having 250-400cp, brands SG, SH, SI, SM, SP and SQ had 10-50cp while the remaining six brands had 100-190cp. Four brands including the innovator (SK, SP, SQ and SR) met Pharmacopoeal requirement for metronidazole suspension on drug content. Moreover, colour change, reduced viscosity and significant increase (p < 0.05) in particle sizes were observed for samples stored at 42 degrees C for seven weeks while those stored at 4 degrees C and 25 degrees C maintained stability. Four out of eighteen brands of metronidazole suspensions evaluated in this study were found to be pharmaceutically equivalent. The stability studies showed that there is the need to adhere strictly to storage of metronidazole suspensions in a cool place.
Journal of Excipients and Food Chemicals
ABSTRACT
The compressional characteristics and tableting properties of starches from four yam species name... more The compressional characteristics and tableting properties of starches from four yam species namely Dioscorea dumetorum Pax (Bitter); Dioscorea oppositifolia L (Chinese); Dioscorea alata L.DIAL2 (Water) and Dioscorea rotundata Poir (White) were investigated in comparison with corn starch. The physicochemical properties of the starches were evaluated using established methods while the compressional characteristics were analyzed using density measurements, and the Heckel
Journal of Pharmaceutical Investigation, 2016
Pharmaceutical Development and Technology, Feb 1, 2009
Starches obtained from four different Dioscorea species namely White (D. rotundata), Bitter (D. d... more Starches obtained from four different Dioscorea species namely White (D. rotundata), Bitter (D. dumetorum), Chinese (D. oppositifolia) and Water yam (D. alata), were modified by acid hydrolysis and the physicochemical, material and tablet formation properties of the starches were investigated with the aim of determining their usefulness as a direct compression excipient in pharmaceutical tablets. The results obtained indicate that the physicochemical, material and tablet properties of the acid modified Dioscorea starches varied considerably among the various species. Acid hydrolysis led to an increase in solubility but decrease in swelling of the starches. Acid modification also led to an increase in the compressibility of the starches when compared with the native forms of the starches. Acid modified Water and White formed intact stable tablets only at higher rho(rel,) (max), while acid modified Chinese and Bitter formed tablets at all relative densities which could already be predicted from the deformation behaviour as analyzed by 3-D modeling. The result indicates that acid modified starch tablets showed higher crushing force and acceptable disintegration time and could therefore be useful as directly compressible excipient.
Tropical Journal of Pharmaceutical Research, 2014
ABSTRACT
The authors study the effects of sweet potato and cocoyam starches on the compressional and mecha... more The authors study the effects of sweet potato and cocoyam starches on the compressional and mechanical characteristics of a paracetamol tablet formulation using cornstarch BP.
The individual and interaction effects of nature of binder (N), concentration of binder (C) and t... more The individual and interaction effects of nature of binder (N), concentration of binder (C) and the relative density (D) on the tensile strength and release properties of paracetamol tablets have been studied using a 2 3 factorial experimental design. Methodology: Khaya gum, which represented the "low" level, and polyvinylpyrrolidone (PVP), which represented the "high" level, was used as binding agent at concentrations of 0.5% and 4%w/w in a paracetamol tablet formulation. The tensile strength, which is a measure of the bond strength of tablets, and the release properties of the tablets-measured by the disintegration and the dissolution times, were used as assessment parameters.
Journal of Excipients and Food Chemicals
Two freeze dried pregelatinized Dioscorea starches have been evaluated as directly compressible e... more Two freeze dried pregelatinized Dioscorea starches have been evaluated as directly compressible excipients for sustained release using diclofenac sodium and caffeine as the model drugs. The tableting properties of the binary and ternary mixtures of the drug/starch/excpients were assessed using the 3-D modeling parameters. The crushing force (CF) of the tablets and the drug release properties were evaluated. The effect of dicalcium phosphate dihydrate on the compaction and drug release properties of the matrices was also investigated. The results obtained indicate that the tablet formation properties of the starches depend on the Dioscorea starch used and on the concentration of drug present in the matrix tablets. There appears to be a decrease in the CF of the tablets as the concentration of drug in the matrix is increased. Inclusion of dicalcium phosphate dihydrate in the tablet matrix increased the bonding in the matrix tablets leading to an increase in CF of the tablets. The drug release from the matrices, and the release rates and mechanism were also dependent on the Dioscorea starch used and the drug concentration. Modified Bitter Yam starch matrices provided a controlled release of diclofenac for up to 5 hours while modified Chinese Yam starches provided controlled release for over 24 hours. The release mechanism from modified Chinese Yam starch matrices was found to be Super Case-II transport or time-independent release kinetics. Furthermore, the release rates were dependent on the concentration of the drug present in the matrix. Thus, the modified starch matrices could be used to achieve different drug release profiles depending on the intended use of the tablets. The addition of dicalcium phosphate dihydrate not only improved the mechanical properties of the tablets but also altered the release rates and kinetics. Thus, modified Chinese Yam and Bitter Yam starches could find application as excipients for controlled drug delivery.
The packing and cohesive properties of locally developed cassava, potato and yam starches have be... more The packing and cohesive properties of locally developed cassava, potato and yam starches have been characterised using the maximum volume reduction due to packing as expressed by the Kawakita constant a, and the angle of internal flow, θ, respectively.
Journal of Drug Delivery Science and Technology
ABSTRACT
Journal of Drug Delivery Science and Technology
Acta Pharmaceutica Sciencia
The gum exudates obtained from the incised trunk of Terminalia randii (Family Combretaceae) have ... more The gum exudates obtained from the incised trunk of Terminalia randii (Family Combretaceae) have been evaluated as binding agent in carvedilol tablet formulations in comparison with standard binders -polyvinylpyrrolidone (PVP) and corn starch. The physicochemical properties of the gum was characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray powder diffraction (XRPD), particle size analysis, pH and viscosity determinations. The mechanical properties of the tablets were assessed using the crushing strength and friability tests while drug release properties were assessed using the disintegration and dissolution times. The crushing strength of the tablets increased while the friability decreased with increase in the concentration of the binding agents. The ranking of the crushing strength of the tablet was formulations containing PVP > Terminalia gum > corn starch while the ranking for friability was the reverse. The disintegration and dissolution times of the tablets also increased with increase in the concentration of the binders. The ranking of the disintegration time was PVP > Terminalia gum > corn starch while the ranking of dissolution time was Terminalia gum > PVP > corn starch. The results indicate that the binding properties of Terminalia gum compared favorably with those of the standard binders and could also find application in controlled release tablet formulations.
Acta Pharmaceutica Sciencia
The individual and interaction effects of type or nature of suppository base (N), concentration o... more The individual and interaction effects of type or nature of suppository base (N), concentration of surfactant (C), and storage (S) on the mechanical and release properties of chloroquine phosphate suppositories have been studied using a 2 3 factorial experimental design. Suppositories (1g) containing 100mg chloroquine phosphate each with or without 2%w/v Tween 20 as adjuvant, were prepared in Suppocire® AS2 and Witepsol® H15 bases. The mechanical properties of the suppositories were determined using crushing strength and dissolution properties were assessed using dissolution times (t 50 and t 80 -time for 50% and 80% drug release), and rates. The concentration of surfactant had the highest individual effect on the release properties of the suppository formulations while storage had the lowest effects. Thus, the type of suppository base and concentration of surfactant used in suppository formulations need to be carefully chosen in order to obtain suppositories of desired mechanical and drug release properties.
Background: Talc is used in the pharmaceutical industry as a lubricant in tablet formulations, dr... more Background: Talc is used in the pharmaceutical industry as a lubricant in tablet formulations, dry-coating of oral tablets and as filter medium.
African journal of medicine and medical sciences
To determine the pharmaceutical equivalence and stability of eighteen randomly selected brands of... more To determine the pharmaceutical equivalence and stability of eighteen randomly selected brands of metronidazole suspensions. The tests conducted include ease of redispersibility, sedimentation volume, particle size measurements, viscosity and assay of drug content. The results showed that 16 (88.9%) out of 18 brands including the innovator (SR) were redispersed between 30 seconds to one minute, while 2 (11.1%) took more than two minutes. The sedimentation volume for 15 (83.3%) of the brands was less than 0.50 while the innovator brand had a significantly higher (p < 0.001) value (0.91). The particle size of the brands ranged between 1.942 and 5.92 μm and the sedimentation rate was between 20-50 mL/day. The viscosity of the brands were significantly different (p < 0.05) with SA, SB, SC, SD, SE and SF having 250-400cp, brands SG, SH, SI, SM, SP and SQ had 10-50cp while the remaining six brands had 100-190cp. Four brands including the innovator (SK, SP, SQ and SR) met Pharmacopoeal requirement for metronidazole suspension on drug content. Moreover, colour change, reduced viscosity and significant increase (p < 0.05) in particle sizes were observed for samples stored at 42 degrees C for seven weeks while those stored at 4 degrees C and 25 degrees C maintained stability. Four out of eighteen brands of metronidazole suspensions evaluated in this study were found to be pharmaceutically equivalent. The stability studies showed that there is the need to adhere strictly to storage of metronidazole suspensions in a cool place.
Journal of Excipients and Food Chemicals
ABSTRACT
The compressional characteristics and tableting properties of starches from four yam species name... more The compressional characteristics and tableting properties of starches from four yam species namely Dioscorea dumetorum Pax (Bitter); Dioscorea oppositifolia L (Chinese); Dioscorea alata L.DIAL2 (Water) and Dioscorea rotundata Poir (White) were investigated in comparison with corn starch. The physicochemical properties of the starches were evaluated using established methods while the compressional characteristics were analyzed using density measurements, and the Heckel