DSpace Community: PHARMACEUTICS AND INDUSTRIAL PHARMACY

Evaluation of freeze-dried pregelatinized Chinese yam (Dioscorea oppositifolia) starch as a polymer in floating gastroretenive metformin microbeads.

2010-01-01T00:00:00Z

Title: Evaluation of freeze-dried pregelatinized Chinese yam (Dioscorea oppositifolia) starch as a polymer in floating gastroretenive metformin microbeads. Authors: Okunlola, A.; Patel, R. P.; Odeku, O. A. Abstract: Pregelatinized Chinese yam (Dioscorea oppositifolia) starch has been evaluated as a polymer for the formulation of floating gastroretentive beads for the controlled delivery of metformin hydrochloride. Floating microbeads were prepared by the ionotropic gelation method using a blend of modified Chinese yam starch and sodium alginate at different ratios. Sodium bicarbonate was added as a gas-generating agent. The floating microbeads were characterized by SEM, DSC, FTIR analyses and the drug entrapment efficiency and floating ability was evaluated. Drug release was investigated using in vitro dissolution test and the results were fitted to various kinetic models to determine the mechanism(s) of release. Spherical, discrete and free flowing microbeads were obtained from the modified starch-alginate blends. Minimum lag time (< 20 s) was observed for the floating microbeads containing starch and buoyancy was maintained for 12 h. The release of MET from the floating microbeads appeared to be controlled by varying the starch to alginate polymer ratio. In general, the formulations followed diffusion and erosion mechanisms of drug release. The results suggest that modified Chinese yam starch-sodium alginate blend can be useful for the formulation of floating gastroretentive system for metformin hydrochloride

Flow, compaction and tabletting properties of co-processed excipients using pregelatinized ofada rice starch and HPMC

2018-01-01T00:00:00Z

Title: Flow, compaction and tabletting properties of co-processed excipients using pregelatinized ofada rice starch and HPMC Authors: Okunlola, A. Abstract: The growing popularity of direct-compression process necessitates an ideal filler–binder that can substitute two or more excipients. Pregelatinization of starches significantly improves swelling and flow properties but produces tablets with low mechanical strength. When used as a binder in many tablet formulations, hydroxyl propyl methyl cellulose (HPMC) imparts mechanical strength but because of its poor flow during high speed tablet manufacturing, granulation of HPMC-based formulations is required prior to compaction. Directly-compressible co-processed excipients were developed utilizing pregelatinized starch of the indigenous Ofada rice starch (Oryza glaberrima Steud Family Poaceae) and HPMC. Co-processed excipients of various combinations of pregelatinized Ofada rice starch and HPMC K15M (15cps) were prepared using a co-fusion method (97.5:2.5; 95:5; 92.5:7.5; 90:10; 85:15; 80:20). The flow and compaction properties of the co-processed excipients, as well as, individual excipients were evaluated using density, Hausner ratio, Carr’s index, angle of repose, angle of internal friction, the Kawakita model, consolidation index and rate. Aceclofenac tablets were formulated using direct compression with starch, HPMC and specific co-processed excipients as filler-binders. Pregelatinization produced starch with larger granules and improved flow characteristics. FTIR spectra of the co-processed excipients confirmed absence of any chemical interaction. The angle of repose, Hausner ratio, Carr’s index, angle of internal friction indicated that flow properties improved with increasing starch content of the co-processed excipients. Kawakita plots, consolidation index and consolidation rate demonstrated cohesiveness while compressibility and rate of packing were enhanced. Aceclofenac tablets containing co-processed excipients exhibited a crushing strength ≥ 66.03 ± 1.58 MNm-2; friability ≤ 1%; disintegration time ≤ 10.75 ±3.10 minutes and dissolution time (t80) ≤ 30.00 ± 3.07 minutes. The co-processed excipients of pregelatinized Ofada rice starch and HPMC could be cheaper alternatives to other synthetic excipients used in direct compression of tablets assuming the starch would meet all compendial specifications.

Formulation of metronidazole tablets using hydroxypropylated white yam (dioscorea rotundata) starch as the binding agent

2017-01-01T00:00:00Z

Title: Formulation of metronidazole tablets using hydroxypropylated white yam (dioscorea rotundata) starch as the binding agent Authors: Okunlola, A.; Alade, O. O.; Odeku, O. A. Abstract: White yam starch obtained from the tubers of Dioscorea rotundata Poir was modified by hydroxypropylation and used as a binding agent in a metronidazole tablet formulation and compared with corn starch BP. The quantitative effects of the novel starch binder on the mechanical (tensile strength and friability) and release properties (disintegration and dissolution times) of the metronidazole tablet was analyzed using a full 23 factorial experimental design. The individual and interaction effects of type of starch binder (X1), concentration of binder (X2) and relative density (X3) on tensile strength, friability, disintegration time and dissolution time (t90) were determined. The ranking of the coefficients was X3 > X2 > X1 on T, X1 > X3 > X2 on F and X3 > X1 > X2 on DT and t90 (time for 90% drug release) indicating that the formulation variables influence the properties of metronidazole tablets to varying degrees. This indicates that the type and concentration of starch binder as well as the compression pressure employed in table formulation need to be carefully selected to obtain tablets with the desired mechanical and drug release properties. Hydroxypropyl white yam starch could be more useful as a binder especially when tablets require high mechanical strength and faster drug release are desired.

Development of ibuprofen microspheres using acetylated plantain starches as polymer for sustained release

2018-01-01T00:00:00Z

Title: Development of ibuprofen microspheres using acetylated plantain starches as polymer for sustained release Authors: Okunlola, A.; Ghomorai, T. Abstract: 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.