Evaluation of starches obtained from four Dioscorea species as binding agent in chloroquine phosphate tablet formulations

AbstractStarches 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

Effects of interacting variables on the tensile strength and the release properties of paracetamol tablets

Purpose: 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 23 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. Results: Changing the concentration of binder and the relative density of the tablets from “low” to “high” led to an increase in the tensile strength and the disintegration and dissolution times of the tablets. The ranking of the individual coefficient values for the formulations was D > N > C for T and C >> N > D for the disintegration and dissolution parameters while the ranking for the interaction effects was N - D >> N - C > C – D for T and t50, N - C >> N – D> C - D for DT and C - D > N - C >> N - D for t90. Conclusion: The results suggest that khaya gum could be useful as an alternative binding agent to produce tablets with particular tensile strength and drug release profiles and there was considerable interaction between the variables employed on the tablet properties. Keywords: Binding agent, khaya gum, release properties, paracetamol tablets, tensile strength Tropical Journal of Pharmaceutical Research 2003; 2(1): 147-15

Evaluacija Albizia zygia gume kao veziva u tabletama

Albizia gum has been evaluated as a binding agent in tablet formulations in comparison with gelatin BP. Compressional properties were analyzed using density measurements and the compression equations of Heckel and Kawakita as assessment parameters, while the mechanical properties of the tablets were assessed using the crushing strength and friability of the tablets. Drug release properties of the tablets were assessed using disintegration time and dissolution time as assessment parameters. Formulations containing Albizia gum as a binding agent show a faster onset and higher amount of plastic deformation under compression pressure than those containing gelatin. The crushing strength, disintegration and dissolution times of the tablets increased with increased binder concentration while their friability decreased. Albizia gum produced tablets with better mechanical properties and longer disintegration and dissolution times than those containing gelatin BP. This suggests that Albizia gum could be useful as a binding agent especially when high mechanical strength and slower release rates are desired.Albizia guma je evaluirana kao vezivo u tabletama i uspoređivana sa želatinom BP. Svojstva stlačivosti analizirana su mjerenjem gustoće i uporabom Heckelove i Kawakitine jednadžbe, dok su mehanička svojstva tableta evaluirana mjerenjem lomljivosti. Sposobnost oslobađanja lijeka iz tableta procijenjena je mjereći vrijeme dezintegracije i otapanja. Pripravci s Albizia gumom kao vezivom manje se plastično deformiraju uslijed tlaka kompresije nego pripravci sa želatinom. Jačina loma, vrijeme dezintegracije i otapanja povećalo se s povećanjem udjela veziva, dok se lomlljivost smanjila. Tablete s Albizia gumom imaju bolja mehanička svojstva i dulje vrijeme dezintegracije i otapanja od tableta sa želatinom. Zbog toga se Albizia guma može uporabiti kao vezivo, posebice kada je poželjna bolja mehanička svojstva i polaganije oslobađanje lijeka

Formulation optimization of floating microbeads containing modified Chinese yam starch using factorial design

Controlled release floating metformin hydrochloride microbeads have been prepared and optimized using a blend of varying concentrations of freeze-dried pregelatinized Chinese yam (Dioscorea oppositifolia) starch and sodium alginate. Floating microbeads were prepared by the ionotropic gelation method using 10% w/v calcium chloride as the cross-linking agent and sodium bicarbonate as the gas releasing agent. A full 32 factorial design was used to investigate the influence of two variables: concentrations of starch (X1) and sodium bicarbonate (X2) on the swelling, floating lag time and amount of drug released after 1 hour (Q1) and 10 hours (Q10). Potential variables such as the concentrations of drug and total polymer were kept constant. The results showed that the properties of the floating microbeads were significantly (

Assessment of Suspending Properties of Katira Gum: Formulation and Evaluation of Nimesulide Suspension

There are several hydrophilic polymers that have been employed as suspending agents in pharmaceutical suspensions due to their ability to form colloidal gel in aqueous medium. In the present study, katira gum obtained from the bark of Cochlospermum religiosum has been evaluated as suspending agent in nimesulide suspension and compared with acacia gum at concentration of 1-5%. Sedimentation volume, rheology, particle size, degree of flocculation and in-vitro drug release were employed as assessment parameters. The result showed that at all concentrations, katira gum higher suspending capability compared acacia gum. The sedimentation volume was found to increase from 0.36 to 1 (A1-A3) and 0.26 to 0.56 (B1-B3). The viscosity of suspensions (A1 and A2) containing gum katira as suspending agent was found to be 1.35 and 2.4 centipoise and 0.63- 1.05 centipoise (B1- B3). Plots between shear stress and rate of shear were plotted using different concentrations indicates the obedience to newtonian behaviour. Degree of flocculation of gum katira and gum acacia suspension was established to be 1.69 and 1.05 respectively

Formulation optimization of floating microbeads containing modified Chinese yam starch using factorial design

Controlled release floating metformin hydrochloride microbeads were prepared and optimized using a blend of varying concentrations of freeze-dried pregelatinized Chinese yam starch (Dioscorea oppositifolia L) and sodium alginate. Floating microbeads were prepared by the ionotropic gelation method using 10% w/v calcium chloride as the cross-linking agent and sodium bicarbonate as the gas releasing agent. A full 32 factorial design was used to investigate the influence of two variables: concentrations of starch (X1) and sodium bicarbonate (X2) on the swelling, floating lag time and amount of drug released after 1 hour (Q1) and 10 hours (Q10). Potential variables such as the concentrations of drug and total polymer were kept constant. The results showed that the properties of the floating microbeads were significantly (p<0.01) affected by the concentration of the modified Chinese yam starch. Buoyancy and drug release appeared to be facilitated by increased concentrations of both starch and sodium bicarbonate in the formulation. The results also show that an optimized formulation of metformin hydrochloride could be obtained with the potential for gastroretentive controlled drug delivery using a blend of freeze-dried pregelatinized Chinese yam starch and sodium alginate

Comparative analysis of eight brands of sulfadoxine-pyrimethamine tablets

Purpose: The aim of the present study is to investigate the physicochemical equivalence of eight brands of tablets containing sulfadoxine-pyrimethamine (antimalarial drug combination) sourced from different retail Pharmacy outlets in the Nigerian market. Method: The quality and physicochemical equivalence of eight different brands of sulfadoxine-pyrimethamine combination tablets were assessed. The assessment included the evaluation of uniformity of weight, friability, crushing strength, disintegration and dissolution tests as well as chemical assay of the tablets. Results: All the eight brands of the tablets passed the British Pharmacopoeia (BP) standards for uniformity of weight, disintegration and crushing strength. Three of the eight brands failed the friability test. One of the brands did not comply with the standard assay of content of active ingredients while another brand did not comply with the USP specifications for dissolution test for sulfadoxine-pyrimethamine tablets. There were no significant differences in the amounts of pyrimethamine and sulfadoxine released from the different brands (P>0.05). Conclusion: Only three brands (registered by NAFDAC) out of the eight brands of sulfadoxine-pyrimethamine tablets that were analysed passed all the BP quality specifications and were physically and chemically equivalent. This study highlights the need for constant market monitoring of new products to ascertain their equivalency to the innovator product. Keywords: Chemical equivalence, comparative study, pyrimethamine-sulfadoxine tablets Tropical Journal of Pharmaceutical Research 2003; 2(1): 161-16

Research Article - Effects of interacting variables on the tensile strength and the release properties of paracetamol tablets

Purpose: 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 23 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. Results: Changing the concentration of binder and the relative density of the tablets from "low"to "high"led to an increase in the tensile strength and the disintegration and dissolution times of the tablets. The ranking of the individual coefficient values for the formulations was D > N > C for T and C >> N > D for the disintegration and dissolution parameters while the ranking for the interaction effects was N -D >> N -C > C - D for T and t50, N -C >> N - D> C -D for DT and C -D > N -C >> N -D for t90. Conclusion: The results suggest that khaya gum could be useful as an alternative binding agent to produce tablets with particular tensile strength and drug release profiles and there was considerable interaction between the variables employed on the tablet properties