Kolawole T Jaiyeoba’s research while affiliated with University of Ibadan and other places

The growing demand for polymers to improve drug delivery profiles (particularly for poorly aqueous soluble drugs) has prompted a global search for new polymers. The drug loading, dissolution, and release characteristics of trifoliate yam (Dioscorea dumetorum) starch, a biodegradable polymer, were evaluated using naproxen as the model drug. Trifoliate starch nanoparticles (TSNP) were created by acid hydrolysis of trifoliate native starch (TNS) with H2SO4. In contrast, carboxymethylated trifoliate starch nanoparticles (CTSNP) were created by reacting the TSNP with sodium hydroxide and monochloroacetic acid. Scanning electron microscopy analysis revealed that TSNP were formed by acid hydrolysis. Modification of the TSNP resulted in a significant particle size reduction (86.5 ± 5.60 nm) and changes in the morphology of these starch forms compared to the native trifoliate starch (1616.0 ± 0.54 nm). The addition of a carboxylate functional group to the TSNP molecule as a means of modification was confirmed by significant peaks in the Fourier transform Infrared spectroscopy's 1600-1300 cm-1 absorption band region. All of the starch forms, TNS, TNSP and CTNSP demonstrated significant drug loading capacity and efficiency (86.7%, 86.4%, and 84.9%), respectively. The TNS demonstrated delayed naproxen release, whereas the TSNP and CTSNP demonstrated a biphasic release profile (immediate and sustained release). Naproxen release kinetics from most formulations followed the Korsmeyer-Peppas model of non-Fickian diffusion through the polymeric matrix. A loading time of one hour was found to optimize loading efficiency. The starch nanocarriers developed in this study can be used as vehicles to enhance, control, and prolong the release of poorly soluble drugs.

Acha (Digitaria exilis) starches were investigated as nanocrystal carriers for the controlled release of naproxen. Starch nanocrystals (SNC) were prepared by acid hydrolysis using H2SO4 and the modified form (carboxymethylated SNC) were obtained by reaction of the SNC with Monochloroacetic acid and Sodium hydroxide. Physicochemical properties, degree of substitution, SEM and FTIR analyses, loading and release studies including in‐vitro release kinetics of the drug‐loaded starch nanocrystals were determined. FTIR analysis confirmed the introduction of the hydrophilic carboxylate functional group into the starch molecule of the modified starches with strong peaks in the region 1300‐1650cm−1. SEM images revealed the disruption of the granular structure of the starch particles due to hydrolysis conferring crystallinity on the granules. The drug release kinetics of all the starch polymers followed Korsemeyer‐Peppas model indicating that the drug release was by non‐Fickian diffusion. The native starch, starch nanocrystals and carboxymethylated nanocrystal forms had drug loading content that were above 50% and loading efficiency above 75% and produced a steady and sustained release of naproxen. The release studies of native Acha starch and the modified trifoliate SNC showed that their formulations can function as carriers/polymers that can achieve sustained and/or delayed drug release of poorly soluble drugs.

The uptake and specificity of drugs and the bioavailability of poorly soluble drugs has been improved by means of targeted drug delivery using nanoparticles. Many platforms have been used for nanoparticulate drug delivery and these include liposomes, polymer conjugates, metallic nanoparticles, polymeric micelles, dendrimers, nanoshells, and protein and nucleic acid-based nanoparticles. Starch is the 2nd most abundant natural polymer and has found wide use in drug delivery systems as binder, disintegrant and filler. However, its application is limited by the poor functional properties of native starch. Starch nanocrystals of different shapes and sizes can be obtained based on the starch origin and isolation process involved. Nanocrystals with varying morphology have been reported; from nanocrystals of platelet-like shaped waxy maize starch with 5–7 nm thickness and 15–40 nm diameters, to those with round and grape-like shape from potato starch granules, with sizes ranging from 40 nm to 100 nm. This review describes different methods of obtaining starch nanoparticles, their modification and application in drug delivery.

The paper present a study regarding the binding properties of Cissus gum, obtained from Cissus populnea (Vitaceae), in paracetamol tablet formulations in comparison with official gelatin. Compressional properties were analyzed using density measurements and compression equations of Heckel. The mechanical properties of the tablets were assessed using the crushing strength and friability of the tablets, while drug release properties were assessed using disintegration and dissolution times. Formulations containing Cissus gum exhibited faster onset and higher amount of plastic deformation during compression when compared with those of gelatin. The crushing strength, disintegration and dissolution times of the tablets increased with binder concentration while friability values decreased. Cissus gum tablets presented faster disintegration and higher crushing strength-friability ratio (CSFR) values than those containing gelatin. The dissolution profiles of formulations containing the two binders showed similarity factors above 50. Cissus gum would be a better alternative to gelatin in producing uncoated tablets for which the fast release is essential. Rezumat Articolul prezintă un studiu privind proprietăţile gumei Cissus, obţinute din specia Cissus populnea (Vitaceae), utilizată ca liant în formularea comprimatelor cu paracetamol. Studiul a fost efectuat comparativ cu gelatina. Au fost studiate proprietăţile mecanice de compactare şi de eliberare a substanţei active pentru cele două formulări. Rezultatele obţinute confirmă faptul că guma Cissus ar putea fi o alternativă mai bună a gelatinei, ca liant în formulările tabletelor cu eliberare rapidă.

The quantitative effects of a new gum, used as a binder, on the mechanical and release properties of paracetamol tablet formulations were analyzed in a 2 3 full factorial experiment. Cissus gum extracted from Cissus populnea Guill. & Perr. (Vitaceae) was compared with official gelatin. The individual and interaction effects of type of binder, concentration of binder and packing fraction on the friability, tensile strength, brittle fracture index, disintegration time and drug release profile of tablets were determined. Changing the binder from gelatin to cissus gum led to an increase in friability and a decrease in tensile strength, brittle fracture index (BFI) and drug release variables. Increasing binder concentration from 2.0w/w to 4.0%w/w, and increasing relative density from 0.80 to 0.90, led to increases in lamination tendency and release rate of the formulations. Tablets containing gelatin had higher tensile strength, lower friability, longer disintegration time and a greater tendency to laminate than those with cissus gum. Hence, care must be taken in choosing a suitable binder for tablet formulations, with respect to their mechanical and release characteristics. The study suggests that cissus gum should be preferred to gelatin in tablet formulations that tend to cap or laminate or in formulations meant for rapid drug release.

Os efeitos quantitativos de uma goma nova como a pasta nas propriedades mecânicas e da liberação de formulações da tabuleta do paracetamol foram avaliados usando um projeto 23 experimental factorial cheio. Goma de Cissus obtida do populnea Guill de Cissus. & Perr. (Vitaceae) foi comparado com o gelatin oficial. Os efeitos do indivíduo e da interação do tipo de pasta, da concentração de fração da pasta e de embalagem na friabilidade, da força elástica, do índice da fratura frágil, do tempo da desintegração e da liberação da droga das tabuletas eram determinados. Mudar a pasta do gelatin à goma de Cissus conduziu a um aumento na friabilidade e a uma diminuição na força elástica, no BFI e nos parâmetros da liberação da droga. Concentração crescente da pasta de 2.0w/w a 4.0%w/w, e densidade relativa crescente de 0.80 a 0.90, conduzido para aumentar na tendência da laminação e na taxa de liberação das formulações. As tabuletas que contêm o gelatin tiveram uma força elástica mais elevada com mais baixa friabilidade, e uns tempos mais elevados da desintegração e da dissolução com mais tendência laminar quando comparadas com a goma de Cissus. Daqui, o cuidado deve ser recolhido escolhendo uma pasta apropriada para formulações da tabuleta no que diz respeito às características mecânicas e da liberação. O estudo sugere que a goma de Cissus seja preferida ao gelatin nas formulações da tabuleta que exibem a tendência tampar ou laminar ou nas formulações significadas para a liberação rápida da droga. The quantitative effects of a new gum, used as a binder, on the mechanical and release properties of paracetamol tablet formulations were analyzed in a 23 full factorial experiment. Cissus gum extracted from Cissus populnea Guill. & Perr. (Vitaceae) was compared with official gelatin. The individual and interaction effects of type of binder, concentration of binder and packing fraction on the friability, tensile strength, brittle fracture index, disintegration time and drug release profile of tablets were determined. Changing the binder from gelatin to cissus gum led to an increase in friability and a decrease in tensile strength, brittle fracture index (BFI) and drug release variables. Increasing binder concentration from 2.0w/w to 4.0%w/w, and increasing relative density from 0.80 to 0.90, led to increases in lamination tendency and release rate of the formulations. Tablets containing gelatin had higher tensile strength, lower friability, longer disintegration time and a greater tendency to laminate than those with cissus gum. Hence, care must be taken in choosing a suitable binder for tablet formulations, with respect to their mechanical and release characteristics. The study suggests that cissus gum should be preferred to gelatin in tablet formulations that tend to cap or laminate or in formulations meant for rapid drug release. Keywords: Cissus gum, paracetamol, factorial analysis, mechanical / release properties RESUMO A influência da goma de Cissus nas propriedades mecânicas e de liberação de comprimidos de paracetamol - uma análise fatorial Os efeitos quantitativos de uma nova goma como agente agregante nas propriedades mecânicas e de liberação de formulações de comprimidos de paracetamol foram avaliados utilizando um modelo fatorial 23 experimental. A goma foi obtida de Cissus populnea Guill. & Perr. (Vitaceae) e comparada com a gelatina oficial. Os efeitos individuais e de interação do tipo de agregante, concentração de agregante, porcentagem de friabilidade, resistência à tração, índice de fratura e tempo de desintegração e liberação do fármaco dos comprimidos foram determinados. A mudança do agente agregante de gelatina para goma de cissus levou a um aumento da friabilidade e a uma diminuição na resistência à tração, no índice de fratura e nos parâmetros de liberação do fármaco. O aumento da concentração do agregante de 2,0% p/p para 4,0% p/p e da densidade relativa de 0,80 a 0,90 levou a um aumento na tendência de laminação e na taxa de liberação das formulações. Comprimidos contendo gelatina apresentaram maior resistência à tração com menor friabilidade e maior tempo de desintegração e dissolução com maior tendência para laminado, quando comparados com a goma de cissus. Por isso, cuidados devem ser tomados na escolha de um agente agregante para formulações de comprimidos no que diz respeito às características mecânicas e de liberação. O estudo sugere que a goma de cissus pode ser empregada ao invés de gelatina em formulações de comprimidos que apresentam tendência de formar laminado ou decapeamento ou em formulações para liberação controlada de fármacos. Palavras-chaves: Goma de cissus; paracetamol; análise fatorial; propriedades mecânicas e de liberação.

The disintegrant property of dried pods of Okra was investigated in metronidazole tablet formulations using physicochemical properties of relevance to tableting, disintegration times and dissolution rates as assessment parameters. X-ray fluorescence spectrometric analysis of the elemental constituents of the pods was determined and the comparative effects of the Okra powder and two standard disintegrants - corn starch B.P and microcrystalline cellulose-on crushing strength, friability, disintegration time (D) and dissolution characteristics of metronidazole tablet formulation made by direct compression method were studied. Okra powder contained potassium, sodium and calcium while heavy metals like lead and mercury were absent. Okra powder exhibited good flow and had superior hydration (p<0.05) and moisture sorption (p<0.01) capacities compared to corn starch B.P and microcrystalline cellulose. Ranking for the values of the crushing strength - friability ratio for the tablet formulation was corn starch B.P > microcrystalline cellulose > Okra powder. Tablets formulated with Okra powder passed the official disintegration test. Okra powder produced a more significant reduction in the disintegration time of formulated metronidazole tablets than microcrystalline cellulose but less than corn starch. Tablets containing Okra powder showed good dissolution profile with T50 and T90 values comparable to those of corn starch B.P and microcrystalline cellulose. The result shows the potentials of Okra powder as tablet disintegrant and suggests that it could be further developed for commercial purposes.

A study has been made of the effects of sun and oven drying methods on the physicochemical characteristics and compressibility of Okra powder and the release properties of its metronidazole tablet formulation. Corn starch was used as the reference standard. The mechanical properties of the tablets were evaluated using crushing strength and friability, while the release properties were determined using the disintegration times and dissolution rates. The results obtained showed that sun-dried Okra powder had smaller particle size, exhibited good flow and possessed higher hydration and swelling capacities compared to the oven dried samples. The compressibility of Okra powders assessed by the indices of plasticity from Heckel (Py) and Kawakita plots (Pk) showed that sun dried Okra powders had higher Py but lower Pk values than the oven-dried Okra powder. Metronidazole tablets formulated with oven dried Okra powder formed stronger tablets than tablets containing sun dried Okra powder. Generally, tablets containing sun dried Okra powders had faster disintegration and dissolution than tablets formulated with oven-dried powder. The results suggest that the choice of drying method during the processing of pharmaceutical raw materials is critical to its physicochemical properties and the release properties of its tablet formulations.

The aim of this study was to identify the most significant factors in the formulation of ascorbic acid tablets with hydrophilic polymers used as stabilizers against oxidative degradation. The study involved the use of a factorial experimental design with the use of regression analysis to derive equations in order to predict the optimum parameters in terms of tensile strength and release properties for the formulations. The results have shown that pharmaceutical characteristics of ascorbic acid tablets are significantly affected by the polymer type and polymer concentration. The study also showed that ascorbic acid tablets with good mechanical, release and stability profiles could be obtained using hydrophilic polymers. The study showed that with factorial experimental design and regression analysis, it is possible to derive regression equations and contour plots that allow the ranking of each variable according to its significance on the responses studied and hence with reduced time and experimental effort, it may be possible to predict if formulation composition will produce the desired response.

The effects of magnesium stearate, sodium lauryl sulphate (SLS) and talc as lubricants on some powder and tablet properties of silicified microcrystalline cellulose (SMCC) were studied. Single and binary blends of talc, magnesium stearate and SLS at 1% concentration were evaluated as flow modulators on SMCC. Influence of the lubricants on the powder and tablet properties of metronidazole was also investigated. A similar grade of regular microcrystalline Cellulose (MCC) was used as control. The bulk and tapped densities, Hausner factor (Hf), and angle of repose (θ) were the basis for evaluation of the powders. Compacts of the powder blends were made at fixed compression force of 25 KN and evaluated on the basis of crushing strength. Magnesium stearate, SLS or talc did not have an adverse impact on the powder fluidity and crushing strength of SMCC except that loss of crushing strength of about 20% was recorded in the batch containing 1% w/w magnesium stearate. The binary blends of talc + SLS or talc + magnesium stearate enhanced the fluidity of MCC as Hf was reduced to 1.2 while θ was below 24° compared to 33.9° in the control. The results indicate that SMCC possesses some inherent lubricating properties. However, in tabletting a highly cohesive drug, a limited concentration of an external lubricant may be useful.