Characterization and evaluation of acid-modified starch of Dioscorea oppositifolia (Chinese yam) as a binder in chloroquine phosphate tablets

Abstract

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 2 3 full factorial design. The nature (X 1 ), concentration of starch (X 2 ) and packing fraction (X 3 ) were taken as independent variables and the crushing strength-friability ratio (CSFR), disintegration time (DT) and dissolution time (t 80 ) 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 t 80. 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. Amido de inhame chinês (Dioscorea oppositifolia), modificado por meio de hidrólise ácida, foi caracterizado e avaliado como aglutinante em formulações de comprimidos de fosfato de cloroquina, em comparação com o amido nativo. Determinaram-se as propriedades físico-químicas e de compressão (utilizando medidas de densidade e as equações de Heckel e Kawakita). Os efeitos quantitativos do amido modificado como ligante sobre as propriedades mecânicas e de liberação de fosfato de cloroquina foram analisados por meio de um planejamento fatorial completo 2 3 . Tomaram-se a natureza (X 1 ), a concentração de amido (X 2 ) e a fração de empacotamento (X 3 ) como variáveis independentes e relação força de compressão-friabilidade (RFCE), tempo de desintegração (DT) e tempo de dissolução (t 80 ), como variáveis dependentes. O amido de inhame chinês modificado mostrou redução marcante (p<0,05) no teor de amilose e da viscosidade, mas aumento no inchamento e nas propriedades de ligação de água. O amido modificado teve início rápido e maior quantidade de fluxo plástico. A alteração do aglomerante da forma nativa para a modificada com ácido conduziu a aumento significativo (p <0,05) em CSFR e DT, mas diminuição da t 80 . O aumento da concentração do aglutinante e da fração de empacotamento deu origem a resultados semelhantes apenas para RFCE e DT. Os resultados sugerem que os amidos modificados com ácido do inhame chinês podem ser mais úteis como aglutinantes de comprimidos, quando se necessitam de força de ligação alta e de dissolução rápida..

Modified Starches as Direct Compression Excipients – Effect of Physical and Chemical Modifications on Tablet Properties: A Review

“…Acid hydrolysis selectively affects the amorphous regions of the starch granule while the crystalline region remains intact, thereby producing starch with a more crystalline structure . The resultant starch retains its granular structure but exhibits reduced viscosity, swelling capacity, and increased solubility and gel strength …”

“…[56] The resultant starch retains its granular structure but exhibits reduced viscosity, swelling capacity, and increased solubility and gel strength. [57,58] The acid catalyst, for example, hydrochloric or sulfuric acid is added to a starch slurry under agitation at a temperature ranging from ambient (25 C) to a few degrees below the typical starch gelatinization temperature until the appropriate degree of hydrolysis is achieved. The acid is then neutralized before recovering the converted starch granules by filtration, washing, and drying.…”

Isolation, Composition, Structure, Properties, Modifications, and Uses of Yam Starch

“…Several studies have used yam starches from diverse species for tablet formulation (Riley and others , ; Zuluaga and others ; Odeku and Picker‐Freyer , , ; Odeku and others ; Nattapulwat and others ; Okunlola and Odeku ; Odeku and Akinwande ; Okunlola and Akingbala ). Comparative studies employing starches from D. alata , D. dumetorum , D. oppositifolia , D. cayenensis , D. esculenta , D. polygonoides , and D. rotundata revealed the structural basis for the tableting properties of native starches (Riley and others , ; Odekua and Picker‐Freyer ; Okunlola and Odeku ).…”

“…Modified starches in various forms (cross‐linked, hydroxypropylated, acid‐thinned, carboxymethylated, and pre‐gelatinized) have been used to give the tablets a range of properties. For example, acid‐thinned starch was suggested to be useful to improve the disintegrant efficiency (Odeku and Akinwande ), as binders when high bond strength and fast dissolution are desired (Okunlola and Akingbala ), and as directly compressible excipient to improve the crushing force of tablets (Odeku and Picker‐Freyer ). Incorporation of carboxymethyl starch (1.0% to 4.0%) made the disintegration of tablets fast (Nattapulwat and others ).…”

An investigation of the direct compression properties of pre-gelatinized African bitter yam and cassava starches in acetylsalicylic acid tablet formulations

“…Native forms of starches are modified physically, enzymatically or chemically to improve the utility properties of the starch powder (Gotlieb and Capelle, 2005). Modified starches have been reported to improve tablet properties such as compressibility and dissolution characteristics in pharmaceutical preparations (Mostafa, 2004;Okunlola and Akingbala, 2013;Lawal et al, 2015;Akin-Ajani et al, 2016).…”