Comparative evaluation of the binding properties of okra gum and other hydrocolloids in the formulation of erythromycin stearate tablet

Abstract

Binders constitute a major class of excipients that are used to hold the active pharmaceutical ingredients and other inactive ingredients together in a cohesive mass during granulation. The type and concentration of a binder influences the physicochemical characteristics of a compressed tablet. The aim of this study therefore is to examine and compare the binding and release properties of okra gum with those of microcrystalline cellulose (Avicel) and acacia gum in erythromycin stearate tablet dosage form. Okra gum was extracted from the pods of locally cultivated Hibiscus esculentus in Okada Town. Unripe okra fruits were purchased from Edo State, Nigeria. The dried okra gum was then milled and sieved into fine powder form and evaluated for angle of repose, flow rate, solubility, pH and viscosity. The gum powder was used as a binder in the formulation of tablets using wet granulation and compression methods. Erythromycin stearate was used as a model drug and the efficiency of okra gum as a binder was determined by comparing with microcrystalline cellulose (Avicel) and acacia gum. The tablets were evaluated for hardness, friability, disintegration and dissolution rate. The okra gum had a moisture content of 15.21%, was slightly soluble in water and insoluble in organic solvents, had pH 6.63 and viscosities of 61.45 cP for 0.5 %w/v concentration and 232.3 cP for 1%w/v. The hardness of all the tablets was satisfactory (4.2 – 4.5 kgf. All the tablet batches passed the friability test with values ranging from 0.30 – 0.68. The mean disintegration time (min) of the tablets was within the Pharmacopoeial acceptable time limit of 15 min for uncoated tablets. The tablets formulated with Avicel and acacia gum released ≥ 70% of the drug at 45 min, while those of okra gum demonstrated a slow release profile for the concentration range as none released up to 70% at 45 min. From the release profile, Abelmoschus esculentus (okra) gum may be effective as a controlled release polymer for delayed release erythromycin stearate tablets and other oral solid dosage forms.

Keywords: okro, gum, binder, Avicel, acacia, erythromycin

Journal of Pharmaceutical and Allied Sciences, Vol. 16 No.4 (2019)