scholarly works Pharmaceutics and Industrial Pharmacy

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Acetylated starch of ofada rice as a sustained release polymer in microsphere formulations of repaglinide
(Pharmaceutical Society of Nigeria, 2015) Okunlola, A.; Ogunkoya, T. O.
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 particle size, wall thickness, swelling, entrapment efficiency, time taken for 80% drug release (t80) and permeability. Data obtained from in-vitro drug release studies were fitted to various kinetic models. Results: Repaglinide microspheres were near spherical, discrete and of size range 23.45 ± 4.25 to 44.55±3.85 μm. FTIR spectra revealed the absence of drug–polymer interaction and complete drug entrapment. Particle size, swelling, entrapment and wall thickness increased with drug: polymer ratio and were generally higher in microspheres containing acetylated Ofada rice starch while t80 (195±6.60 - 395± 24.75 min) was lower. Drug release fitted the Hixson-Crowell kinetic model. Conclusions: The acetylated starch of Ofada rice was found suitable as a polymer to sustain the release of repaglinide in microsphere formulations.
Application of the Gurnham equation in characterizing the compressibility of fonio and sweet potato starches and their paracetamol tablet formulations
(Nigeria Association of Pharmacists in Academia, 2018-02) Akin-Ajani, O. D.; Itiola, O. A.; Odeku, O. A.
Background: A number of empirical relationships have been proposed to describe the compaction of pharmaceutical materials, among them are the Heckel, Kawakita and Gurnham equations. Objective: To characterize the compressibility of fonio, sweet potato and corn starches and their paracetamol formulations using the Gurnham and Kawakita equations, and to determine the complementarity of these equations. Materials and Methods: Starches were extracted from fonio (Digitaria exilis) grains and sweet potato (Ipomea batatas) tubers and modified by acid hydrolysis for 96 h. Paracetamol formulations containing 2.5–10.0 %w/w starch binders were prepared by wet granulation. Packing and compaction properties of native and modified starches and their formulations were determined using tapping procedures. The data obtained was analyzed using the Gurnham and Kawakita equations. Results: The ranking for Gurnham compressibility, c, for the starches was sweet potatocornfonio, which was inversely related to the ranking for Kawakita maximum volume reduction, a and angle of internal flow, θ. There was no clear-cut pattern in the Gurnham compressibility of paracetamol formulation probably due to its multicomponent nature. There was correlation between c, a and θ for all the starches with the modified starches exhibiting higher compressibility than native starches. There appeared to be no correlation between c and Kawakita compressibility index, b. Conclusion: The Gurnham equation appeared useful in characterising compressibility in single component systems and could be used along with Kawakita functions, to gain a better understanding of the deformation of powdered materials under pressure.
Characterization and evaluation of acid-modified starch of Dioscorea oppositifolia (Chinese yam) as a binder in chloroquine phosphate tablets
(2013) Okunlola, A.; Akingbala, O.
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 native to acid-modified form led to significant increases (p<0.05) in CSFR and DT but a decrease in t80. An increase in binder concentration and packing fraction gave similar results for CSFR and DT only. These results suggest that acid-modified Chinese yam starches may be useful as tablet binders when high bond strength and fast dissolution are required.
Chrysophyllum albidum mucilage as a binding agent in paracetamol tablet formulations.
(Springer, 2016-05) Ajala, T. O; Akin-Ajani, O. D; Ihuoma-Chidi, C.; Odeku, O. A
Chrysophyllum mucilage obtained from the fruit of Chrysophyllum albidum (Family Sapotaceae) hasbeen characterised and evaluated as a binding agent in comparison with methylcellulose in paracetamol tabletformulations. Chrysophyllum mucilage was characterized using elemental and proximate analyses as well as material properties. The Heckel and Kawakita plots were used to assess the compressional properties and the tablet properties were evaluated using tensile strength, friability, disintegration and dissolution times. The results showed the presence of calcium, magnesium, potassium, sodium, manganese, iron, copper, zinc and absence of heavy metals from the mucilage. The mucilage exhibited excellent flow and swelling properties, but poor water solubility. The viscosity of chrysophyllum mucilage increased with decrease in temperature in a similar manner with methylcellulose. C. albidum mucilage when used as a binder in paracetamol tablet formulation induced faster onset of plastic deformation and higher amount of total plastic deformation than methylcellulose. The results of the tablet properties showed that the tensile strength, disintegration and dissolution times, increased with increase in binder concentration while friability decreased. Tablets containing chrysophyllum mucilage as binder also had lower tensile strength, disintegration and dissolution times but higher friability values than those containing methylcellulose. However, tablets containing chrysophyllum mucilage at low concentrations conformed to pharmacopeial standard on disintegration indicating its potential usefulness as binder for immediate release tablets. Thus, C. albidum mucilage could be used as an alternative binding agent in pharmaceutical tablets
Comparative evaluation of starches obtained from dioscore species as intragranular tablet disintegrant
(Editions de Sante, 2008) Okunlola, A.; Odeku, O. A.
Starches from four Dioscorea species namely Dioscorea dumetorum (bitter yam), D. oppositifolia (Chinese yam), D. alata (water yam) and D. rotundata (white yam) have been evaluated as disintegrants in chloroquine phosphate tablet formulations in comparison with official corn starch. The mechanical and drug release properties of the tablets were assessed. The results showed that the ranking of the effectiveness of the starches as intragranular disintegrant was water > white > corn > Chinese> bitter. The disintegrant concentration had significant (p < 0.001) effects on the disintegrant efficiency. The four experimental starches compared favorably and in some cases showed better efficiency as intragranular disintegrant than corn starch and could be further developed for use in commercial tablet formulation.
Comparative Evaluation of the Disintegrant Properties of Starches from Three Cultivars of Dioscorea rotundata (Poir)
(University of Huddersfield Press, 2022) Akin-Ajani, O. D.; Agbomeji, O. I.; Odeku, O. A.; Ahmadu, U.
Dioscorea rotundata Poir starches from three cultivars (Lagos, Giwa, and Sule) were evaluated as exo-disintegrants (5 and 10%w/w) in paracetamol tablet formulations to determine whether the similarity in their physicochemical and material properties translates to performance in tablet formulation. The tablets were prepared by wet granulation and were evaluated for compressional properties (Heckel equation), mechanical strength (crushing strength and friability), and drug release (disintegration and dissolution times). Plastic deformation occurred in all tablets with rank order for the onset of plastic deformation Lagos>Giwa>Sule. An increase in the concentration of disintegrants in the tablets led to a decrease in mean yield pressure, total relative precompression density, and relative density at low pressure, but an increase in relative density at zero pressure. The crushing strength and disintegration times of the tablets were dependent on the disintegrants' concentration. All tablets passed the disintegration test (≤15min) with tablets containing the Sule cultivar producing the fastest disintegration (p<0.05). Tablets containing 10% of the Sule cultivar had the fastest release of paracetamol (t80=32.1min), though it failed the compendial standard for immediate release tablets (t80≤30min). Starches from the three cultivars despite their similar physicochemical and material properties exhibited different disintegrant properties and could find different applications as excipients in tablet formulations.
comparative photostability study of fancimef tablet and it's active ingredients
(1999) Oke, J. M.
fancimef tablet is one of the multi-component drugs recently introduced into malaria theraphy to combat the resistent strains of plasmodium parasite. Like most complex organic compounds, it is expectesd that the organic compounds in Fancimf tablet will absorb light spectra leading to its photodecomposition and all its attendant problems. In this study, a comparative photostability study of the Fancimf tablet and its active components was undertaken. The results obtained showed that the active ingredients of Fancimf tablet undergo photodecomposition in buffer solutions while the dry Fancimf tablet (powder) is photostable. Thus suggesting that Fancimf tablet is not susceptible to photodecomposition.
Compressional characteristics and tableting properties of starches obtained from four dioscorea species
(2009) Okunlola, A; Odeku, O. A
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 and Kawakita equations. The properties of the tablets were assessed using Tensile strength (T), Brittle Fracture Index (BFI), Friability (F) and Disintegration Time (DT). The physicochemical properties of the starches varied considerably among the various species. The ranking for the mean yield pressure (Py) obtained from Heckel plots was Chinese > Bitter>Corn > White>Water while the ranking was the reverse for another pressure term, Pk, obtained from Kawakita plots. The ranking for T was Chinese > Bitter>Corn > White>Water. The T values were inversely related to Pk values. The ranking of DT was Bitter>Chinese>Corn>White> Water, while the ranking was reverse for BFI and F. Water and White yam starch tablets did not conform to the Pharmacopoeia requirements on friability (≤1%) while all the starch tablets except Bitter yam starch conformed to the requirements on disintegration (≤15minutes). Thus, the starches could be useful as excipients in tablet formulations.
Date Mucilage as Co-Polymer in Metformin-loaded Microbeads for Controlled Release
(Natural Product Research Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria, 2019) Akin-Ajani, O. D; Odeku O. A.; Babalola Y.
The World Health Organization (WHO) has recognized the use of rectal preparations for certain indications in children as an alternative to parenteral. However, challenges of stability in tropical countries have limited its application. Furthermore, adverse effects arise in the use of some excipients in infants and neonates. In this study, paediatric paracetamol suppositories using two plant-derived fats - shea butter and dika fat - and their combination as suppository bases in comparison with cocoa butter were formulated. Shea butter and dika fat were purified and characterised using acid, iodine and saponification values, refractive index and relative density. Paracetamol suppositories were formulated by fusion method and evaluated using appearance, weight uniformity, melting point range, solidification point, crushing strength, disintegration time and dissolution test. Physicochemical properties showed shea butter and dika fat as stable with minimal susceptibility to oxidation with melting point ranges of 32 - 35C and 37 - 39C respectively. Base mixtures yielded melting point ranges of 32 - 39C. The suppositories had crushing strengths  31 N and disintegration times ranged between 3 - 21 min. Paracetamol release from the single bases ranked cocoa butter >dika fat > shea butter. Paediatric paracetamol suppositories using these plant-derived fats compared well with cocoa butter. Paracetamol suppositories with mixtures of either shea butter or dika fat with cocoa butter had superior release properties compared to cocoa butter alone. Thus, could serve as an alternative to cocoa butter in the formulation of suppositories.
Date Mucilage as Co-Polymer in Metformin-loaded Microbeads for Controlled Release
(International Pharmaceutical Excipients Council (IPEC), 2019-03) Akin-Ajani O. D.; Ajala T. O.; Ikehin, M.
Mucilage from the fruit of the date palm (Phoenix dactylifera) was characterized and evaluated for use as a polymer in controlled release metformin-loaded microbeads. Metformin-loaded (1% w/w) microbeads were formed by the ionotropic gelation method using blends (2% w/v) of date mucilage: sodium alginate in varying concentrations (20:80 C4, 25:75 C3, 33:67 C2, 50:50 C1) using zinc chloride (10% w/v) as a crosslinking agent. Bead size and morphology, swelling index, entrapment efficiency and release properties were then measured. The dissolution profiles were fitted to kinetic equations to determine the kinetics and mechanisms of drug release while the similarity factor, ƒ2 was used to determine formulations with similar drug release patterns. The results showed that the date mucilage had crude fat content of 2.5%. The microbeads formed were spherical with bead sizes ranging from 0.44 to 1.99 mm except for the one prepared using blend C4 which was ellipsoidal. Drug entrapment efficiency ranged between 25.0 and 91.1%w/w with alginate alone giving the least entrapment. Microbeads formulated with blends C2 and C3 had the slowest dissolution rates at t15 < 9% in 240 minutes. C3, however, had a higher entrapment efficiency and was considered the optimum formulation. All microbead formulations fitted the Korsmeyer-Peppas’ model with super case II transport mechanism except for the one made of sodium alginate alone, which had an anomalous (non-Fickian) diffusion. Secondary parameters of the Korsmeyer-Peppas’ model showed that microbead formulations C2 and C3 provided controlled release for longer than 24 hours. Similarity factor, ƒ2 showed comparable release profiles between C2 and C3 (ƒ2=94.2). This study shows that mucilage from the date fruit could potentially be used as a polymer in the formulation of controlled release metformin-loaded microbeads.
Design of bilayer tablets using modified dioscorea starches as novel excipients for immediate and sustained release of aceclofenac soduim
(Frontiers in Pharmacology, 2015-01) Okunlola, A.
Bilayer tablets of aceclofenac sodium were developed using carboxymethylated white yam (Discorearotundata) starch (CWY)for a fast release layer (2.5, 5.0, and 7.5% w/w), and acid hydrolyzed bitter yam (Dioscoreadumetorum) starch (ABY) for a sustaining layer(27% w/w). Sodium starch glycolate (SSG) and hydroxypropyl methyl cellulose (HPMC) were used as standards. The starches were characterized using Fourier Transform Infrareds pectroscopy(FT- IR), particle size, swelling power, densities and flow analyses. Mechanical properties of the tablets were evaluated using crushing strength and friability while release properties were evaluated using disintegration and dissolution times. Distinctive fingerprint differences between the native and modified starches were revealed by FT-IR. Carboxymethylation produced starches of significantly (p<0.05) higher swelling and flow properties while acid- modification produced starches of higher compressibility. Bilayer tablets containing ABY had significantly higher crushing strength and lower friability values (p<0.05) than those containing HPMC. Crushing strength increased while friability values decreased with increase in CWY. Generally tablets containing the modified Dioscorea starches gave faster (p<0.05) disintegration times and produced an initial burst release to provide the loading dose of the drug from the immediate-release layer followed by sustained release (300±7.56– 450±11.55min). The correlation coefficient (R2) and chi- square (χ2) test were employed as error analysis methods to determine the best- fitting drug release kinetic equations. Invitro dissolution kinetics generally followed the Higuchi and Hixson- Crowell models via a non-Fickian diffusion-controlled release. Carboxymethylated white yam starch anda cid- modified bitter yam starch could serve as cheaper alternative excipients in bilayer tablet formulations for immediate and sustained release of drugs respectively, particularly where high mechanical strength is required.
Design of cissus–alginate microbeads revealing mucoprotection properties in anti-inflammatory therapy
(Elsevier B.V., 2015) Okunlola, A.; Odeku, O. A.; Lamprech, A.; Oyagbemi, A. A.; Oridupa, O. A.; Aina, O. O.
Cissus gum has been employed as polymer with sodium alginate in the formulation of diclofenac microbeads and the in vivo mucoprotective properties of the polymer in anti-inflammatory therapy assessed in rats with carrageenan-induced paw edema in comparison to diclofenac powder and commercial diclofenac tablet. A full 23 factorial experimental design has been used to investigate the influence of concentration of cissus gum (X1); concentration of calcium acetate (X2) and stirring speed (X3) on properties of the microbeads. Optimized small discrete microbeads with size of 1.22 ± 0.10 mm, entrapment efficiency of 84.6% and t80 of 15.2 ± 3.5 h were obtained at ratio of cissus gum:alginate (1:1), low concentration of calcium acetate (5% w/v) and high stirring speed (400 rpm). In vivo studies showed that the ranking of percent inhibition of inflammation after 3 h was diclofenac powder > commercial tablet = cissus > alginate. Histological damage score and parietal cell density were lower while crypt depthand mucosal width were significantly higher (p < 0.05) in the groups administered with the diclofenac microbeads than those administered with diclofenac powder and commercial tablet, suggesting the mucoprotective property of the gum. Thus, cissus gum could be suitable as polymer in the formulation of non-steroidal anti-inflammatory drugs ensuring sustained release while reducing gastric side effects.
Development of directly compressible excipients from Phoenix dactylifera (Date) mucilage and microcrystalline cellulose using co-processing techniques
(2018) Akin-Ajani, O. D; Ajala, T. O; Okoli, U. M.; Okonta, O
The objective of this study was to harness the excipient potential of date mucilage by co-grinding and co-fusing with avicel for enhanced performance in the directcompression of metronidazole. Co-grinding and co-fusing of parent polymers were done using established methods and excipients were used in the direct-compression of metronidazole tablets. The shape and surface morphology of the particles of date mucilage (DAM) and co-processed excipients were generally granular, rough and irregular. There was a significant improvement in the disintegration of tablets prepared using the coprocessed excipients in comparison to that prepared using DAM alone. The disintegration time for tablets prepared using co-fused excipients was lower than that of co-grinded additives although the differences were not significant (p > 0.05). Generally, the co-processed excipients improved the mechanical and disintegration properties of the tablets produced compared to tablets prepared using DAM alone and could be further developed as direct compression excipients
Development of ibuprofen microspheres using acetylated plantain starches as polymer for sustained release
(Springer Publications, 2018) Okunlola, A.; Ghomorai, T.
Ibuprofen has a short half-life (1–3 h) and istypically administered 3–4 times daily with subsequent adverse side effects. A good approach to reduce these effects is the preparation of sustained-release formulations of ibuprofen. Acetylated starches form water-insoluble, acid-resistant films that can substantially retard drug release. Ibuprofen microspheres were prepared using acetylated plantain starch as sustained-release polymer. Starch obtained from unripe plantain (Musa Paradisiaca normalis) were acetylated using acetic anhydride with pyridine (degrees of substitution, DS 1.5 ± 0.05 and 2.20 ± 0.10). The starches were characterized using morphology, crystallinity, swelling, density and flow properties. Ibuprofen microspheres were prepared by quasi-emulsion solvent diffusion method, using acetylated plantain starches DS 1.5 and 2.20 in comparison to Eudragit S100. Full 32 factorial experimental design was performed with polymer type (X1), polymer: drug ratio (X2) as independent factors; microsphere size, entrapment, and quantity of drug released in 12 h (Q12) were dependent variables. The data from in vitro drug release were fitted to various kinetic models. Acetylation resulted in larger starch aggregates with disruption in crystalline order. Ibuprofen microspheres were spherical with size 5.50 ± 4.00–129.90 ± 12.97μm. Drug entrapment was 43.92 ± 4.00–79.91 ± 6.15%. Values of Q12 ranged from 20.10 ± 0.55 to 54.00 ± 5.71%. Interaction between variables X1 and X2 had positive effects on size and entrapment. Drug release fitted zero order, first order and Baker-Lonsdale kinetic models. Acetylated starch of plantain with DS 2.20 was suitable as a polymer at polymer:drug ratio 4:1 for the formulation of ibuprofen microspheres with prolonged drug release.
Development of repaglinide microspheres using novel acetylatedstarches of bitter and Chinese yams as polymers
(Elsevier B.V., 2016) Okunlola, A.; Adebayo, A. S.; Adeyeye, M. C.
Tropical starches from Dioscorea dumetorum (bitter) and Dioscorea oppositifolia (Chinese) yams were acetylated with acetic anhydride in pyridine medium and utilized as polymers for the delivery of repaglinide in microsphere formulations in comparison to ethyl cellulose. Acetylated starches of bitter and Chinese yams with degrees of substitution of 2.56 and 2.70 respectively were obtained. Acetylation was confirmed by FTIR, 1 H NMR spectroscopy. A 32 factorial experimental design was performed using polymer type and drug-polymer ratio as independent variables. Particle size, swelling, entrapment and time for 50% drug release (t50) were dependent variables. Contour plots showed the relationship between the independent factors and the response variables. All variables except swelling increased with drug: polymer ratio. Entrapment efficiency was generally in the rank of Bitter yam > Ethyl cellulose > Chinese yam. Repaglinide microspheres had size 50 ± 4.00 to 350 ± 18.10μm, entrapment efficiency 75.30 ± 3.03 to 93.10 ± 2.75% and t50 3.20 ± 0.42 to 7.20 ± 0.55h. Bitter yam starch gave longer dissolution times than Chinese yam starch at all drug-polymer ratios. Drug release fitted Korsmeyer-Peppas and Hopfenberg models. Acety-lated bitter and Chinese yam starches were found suitable as polymers to prolong release of repaglinidein microsphere formulations.
Disintegrant properties of native and modified polymers in metronidazole tablet formulations
(2014-09) Ayorinde, J. O.; Odeniyi, M. A.
Natural polymers may be modified in order to improve desired properties in tablet formulations. Granule incorporation techniques have different effects on the disintegrant properties of tablets. Disintegrant properties of two new plant polymers, extracted from Pigeon pea (Cajanus cajan) and Khaya senegalensis tree, were investigated in metronidazole tablet formulations. Native and microwave irradiated forms of the starch and gum were incorporated into the tablet formulations using a 3-factor general full factorial design. Type of disintegrants (X1) was at two levels (Starch or Gum), effect of modification (X2) was also investigated at two levels (Native or Irradiated), while the mode of incorporation (X3) of the disintegrants was at three levels (Intragranular (IG), Extragranular (EG) or Intra-extragranular (IG/EG). Sodium starch glycolate was the standard. Tablets were evaluated for disintegration, dissolution and physical qualities using British Pharmacopoeia methods. The native and modified gum showed higher hydration capacity than the starches. The rank order of the disintegrant properties of the polymers was MG (modified gum)>NG (native gum)>MS (modified starch)>NS (native starch) (p<0.05). The crushing strength for tablets from both native and modified polymers was similar but differs with the mode of incorporation. In starch, the rank orders were IG/EG > IG > EG; and EG > IG/EG > IG for the gums. However, IG/EG incorporation of native and modified starches and gums gave a longer t80 (time taken for 80% of the drug to dissolve) than both IG and EG (p<0.05). The effect of the variables on the disintegrant properties of the polymers was in the order: X3 > X1 > X2 and the effect on t80 was X1 > X3 > X2. The gums and starches were better disintegrants than sodium starch glycolate, with the gums exhibiting better properties than the starches. Microwave irradiation had no significant effect on the disintegrant properties of both polymers but increased the crushing strength of the tablets. Intragranular incorporation proved to be the best method for optimum disintegrant property.
Effect of acid modification on the material and compaction properties of fonio and sweet potato starches
(Wiley Online Library, 2014-03) Akin-Ajani, O. D.; Itiola, O. A.; Odeku, O. A
Starches obtained from the grains of white fonio (Digitaria exilis) and tubers of sweet potato (Ipomea batatas) have been modified by acid hydrolysis at different steeping times – (0, 24 and 96 h) and the physicochemical, material and compaction properties of the modified starches have been evaluated in comparison with official corn starch. The effect of acid modification on the compaction properties of the starches were evaluated with the aim of determining their usefulness as excipients in direct compression. The results showed that the physicochemical and material properties of the starches varied considerably depending on their botanical source. Acid modification led to an increase in solubility and relative crystallinity but decrease in swelling and viscosity of the starches. The effects were found to depend on the steeping time during acid hydrolysis. The results of the compressional properties indicated that the starches formed intact tablets at relatively low compression pressure with acid modified starches forming tablets with higher tensile strength than the natural starches. The results indicate that the physicochemical and compaction properties of white fonio and sweet potato starches were improved by acidmodification yielding starches that could be suitable as directly compressible excipient.
Effects of pigeon pea and plantain starches on the compressional, mechanical and disintegration properties of paracetamol tablets
(Taylor & Francis Group, 2006-09) Dare, K.; Akin-Ajani, D. O; Odeku, O. A; Odusote, O. M; Itiola, O. A.
A study has been made of the effects of pigeon pea starch obtained from the plant Cajanus cajan (L) Millisp. (family Fabaceae) and plantain starch obtained from the unripe fruit of Musa paradisiaca L. (family Musaceae) on the compressional, mechanical, and disintegration properties of paracetamol tablets in comparison with official corn starch BP. Analysis of compressional properties was done by using density measurements, and the Heckel and Kawakita equations, whereas the mechanical properties of the tablets were evaluated by using tensile strength (T-a measure of bond strength) and brittle fracture index (BFI-a measure of lamination tendency). The ranking for the mean yield pressure, Py, for the formulations containing the different starches was generally corn < pigeon pea < plantain starch while the ranking for Pk, an inverse measure of the amount of plasticity, was pigeon pea < plantain < corn starch, which indicated that formulations containing corn starch generally exhibited the fastest onset of plastic deformation, whereas those formulations containing pigeon pea starch exhibited the highest amount of plastic deformation during tableting. The tensile strength of the tablets increased with increase in concentration of the starches while the Brittle Fracture Index decreased. The ranking for T was pigeon pea > plantain > corn starch while the ranking for BFI was corn > plantain > pigeon pea starch. The bonding capacity of the formulations was in general agreement with the tensile strength results. The disintegration time (DT) of the formulation increased with concentration of plantain and corn starches but decreased with concentration of pigeon pea starch. The general ranking of DT values was plantain < pigeon pea < corn starch. Notably, formulations containing pigeon pea starch exhibited the highest bond strength and lowest brittleness, suggesting the usefulness of pigeon pea starch in producing strong tablets with minimal lamination tendency. Plantain starch, on the other hand, would be more useful where faster disintegration of tablet is desired. The results show that the starches could be useful in various formulations depending on the intended use of the tablets with the implication that the experimental starches can be developed for commercial purposes
Effects of water yam and corn starches on the interacting variables influencing the disintegration of chloroquine phosphate tablets
(Medwell Journals, 2010) Okunlola, A.; Odeku, O. A.
The individual and interaction effects of nature (X) and concentration (Y) of disintegrant and the relative density (Z) on the mechanical and release properties of chlor-oquine phosphate tablets were studied using a 23 factorial experiment design. Water yam starch (low level) and corn starch (high level) were used as disintegrants at concentrations of 5.0 and 20.0% w/w .The mechanical properties were assessed using the Crushing Strength (CS) and Friability (F) and the release properties by the Disintegration Time (DT) and dissolution time (t80). Increasing the concentration of disintegrants and the relative density of tablets resulted in increase in CS but decrease in F, DT and t80. The ranking of the individual coefficient values was Z>X>Y for CS, Z>X>Y for F and DT and Y>X>Z for t80, while that for the interaction coefficient was X-Z>Y-Z>X-Y for CS, Y-Z>X-Z>X-Y for F, Y-Z>X-Y>X-Z for DT and t80. Changing the disintegrant from corn starch to water yam starch resulted in decrease in CS, DT and t80 but increase in F. The results show considerable interaction between the variables employed and suggest that water yam could be an alternative disintegrant to corn starch particularly where with faster disintegration and release are required.
Entandophragma angolense (WELW) CDC GUM AS A NOVEL BINDER AND MUCOADHESIVE COMPONENT IN ORAL TABLETS
(2013-05) ADETUNJI, O. A.
Mucoadhesive drug delivery systems are designed to prolong drug retention, thus offering advantages over conventional dosages through reduced dosage regimen and improved patient compliance. Natural polymers have gained importance over synthetic materials as excipients in such systems because they are less expensive, biocompatible and biodegradable. Entandophragma angolense gum (ENTA) is used in traditional medicine as a febrifuge, but its excipient properties have not been exploited. This study was carried out to evaluate ENTA as a novel polymer-binder and mucoadhesive component in oral tablets. Entandophragma angolense gum, obtained as dried exudates from the incised trunk of the tree, was characterised using material properties, rheological studies, Fourier-Transform Infrared spectrometer and X-ray diffractometer. Tablets were prepared by Wet Granulation (WG) and Direct Compression (DC) techniques using 2.5 - 10.0 %w/w polymer as binder and 60.0 - 90.0 %w/w polymer as matrix system for controlled release tablets containing ENTA (or official gelatin or hydroxypropylcellulose) with chlorpheniramine maleate (CPM) and ibuprofen as model drugs. Compressional characteristics of the tablets were determined using density measurements, and the Heckel and Kawakita plots. Mechanical and release properties of the tablet formulations were determined by standard methods. Mucoadhesive time (MT) of the tablets were determined ex-vivo in phosphate buffer (pH 7.4) and 0.1M hydrochloric acid (HCl, pH 1.2) using the rotating cylinder method containing excised pig ileum. Data were analysed using descriptive statistics, ANOVA and regression at p = 0.05. The ENTA consisted of irregularly shaped particles with a swelling index of 51.3 %. Rheological studies showed that the final viscosity of 5.0 %w/v ENTA was 258.17 poise. The gum contained hydroxyl groups and was amorphous with some degree of crystallinity. When used as a binder, the ranking of yield pressure was hydroxypropylcellulose > ENTA > gelatin, while the ranking was the reverse for plasticity index. Tablets formulated by WG had higher Tensile Strength (TS) and lower Brittle Fracture Index (BFI) and friability. The ranking of TS was hydroxypropylcellulose > ENTA > gelatin, while those of BFI and friability were the reverse. There was strong correlation(r > 0.98) between binder concentration and dissolution times. When used as polymer for controlled release matrices, the TS increased with binder concentration with tablets prepared by DC technique giving better release profiles than WG technique. The ranking of the disintegration and dissolution times was hydroxypropylcellulose > ENTA > gelatin (p < 0.05). The MT increased with polymer concentration with ibuprofen matrices showing significantly higher MT values than CPM matrices. Generally, the tablets adhered longer in 0.1M HCl, with a ranking of hydroxypropylcellulose (313.00 ± 0.18mins) > ENTA (300.01 ± 0.06mins) > gelatin (207.03 ± 0.11 mins). The polymer matrices provided zero-order drug release for over 14 hours. Entandophragma angolense gum could serve as an alternative binder to official polymers when high mechanical strength is desired. The gum could also serve as a mucoadhesive component in the controlled release of compressed tablets and matrices.