Formulation and Evaluation of Conventional Metronidazole Tablets using Natural Gum Extracted from Grewia species

Aims: The pharmaceutical world has been paying increasing attention to the extraction, development and use of natural gums as binders in the formulation of solid dosage forms. The use of natural gums as binders is more advantageous than the use of synthetic ones due to availability, low cost, biodegradability and biocompatibility. In this study, gum extracted from Grewia species was compared with that fromAcacia in metronidazole tablets. Study Design: Ten batches of metronidazole tablets were formulated with varied concentration of Grewiaspp gum and Acacia gum. Place and Duration of Study: The study was carried out in Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Delta State University, Abraka, Nigeria; between January and December 2019. Methodology: Five batches of metronidazole tablets containing 0.5, 0.75, 1.0, 1.25 and 1.5% w/w of Grewia gum were preparedby wet granulation. Resulting granules were characterised by measuring flow and packing properties. In other experiments, five batches of tablets were formulated using same concentration of gum, with Acacia gum substituted for Grewia gum. Both sets of granules were compressed into tablets using tableting machine at a load of 27 arbitrary units. Tablets so formed were evaluated for hardness, friability, disintegration time, drug content and drug release profiles. Drug – excipient interaction was investigated with FTIR. Results: The resulting metronidazole tablets showed hardness of 5.46 kgF to 7.87 kgF (Grewiagum) and 6.06 kgF-8.20 kgF (Acacia gum). Friability percentages of all the batches were above 1% except for A3-A5 and B5 which are less than 1%. All formulations released more than 75 % of the drug content within 60 min. The FTIR analysis revealed no interaction between the metronidazole and Grewia species gum. Conclusion: Metronidazole granules and tablets were successfully prepared using Grewiagum and showed comparable pre-compression and post-compression properties with those formulated with Acacia.

Evaluation of some important physicochemical properties of starch free grewia gum

© 2015 Elsevier Ltd. Gums obtained by extraction from the inner bark of stems can be found in association with starch, which must be digested in order to obtain a refined polysaccharide isolate. In the present study, grewia gum obtained from the inner bark of the stems of Grewia mollis was shown to co-exist with starch and the effect of starch digestion on the physicochemical properties of the resultant polysaccharide was evaluated. The gum was extracted by maceration of the inner bark in deionised water and isolated by a combination of filtration, centrifugation and finally precipitation with absolute ethanol to produce the crude grewia gum extract (GG). The presence and content of starch in the gum sample was determined followed by enzymatic digestion of the starch using a-amylase (Termamyl 120L) to give a starch-free extract (GGDS). Physicochemical properties of the extracts such as total carbohydrates, total protein, differential sugar composition, NMR, intrinsic viscosity and rheological behaviour of the samples were evaluated. The GG extract had total carbohydrate content of ~60% out of which 11.8% was starch, and a protein content of 2.3%. Samples also contained galacturonic and glucuronic acid which were highly acetylated. Both samples had a higher proportion of galacturonic acid than glucuronic acid and contained rhamnose, arabinose, galactose, glucose and xylose as neutral sugars in varying proportions. Rheological measurements on 2%w/w dispersions of the extracts show minor differences between both the original extract and the de-starched material but were influenced by changes in pH.

Evaluation of some important physicochemical properties of starch free grewia gum

© 2015 Elsevier Ltd. Gums obtained by extraction from the inner bark of stems can be found in association with starch, which must be digested in order to obtain a refined polysaccharide isolate. In the present study, grewia gum obtained from the inner bark of the stems of Grewia mollis was shown to co-exist with starch and the effect of starch digestion on the physicochemical properties of the resultant polysaccharide was evaluated. The gum was extracted by maceration of the inner bark in deionised water and isolated by a combination of filtration, centrifugation and finally precipitation with absolute ethanol to produce the crude grewia gum extract (GG). The presence and content of starch in the gum sample was determined followed by enzymatic digestion of the starch using a-amylase (Termamyl 120L) to give a starch-free extract (GGDS). Physicochemical properties of the extracts such as total carbohydrates, total protein, differential sugar composition, NMR, intrinsic viscosity and rheological behaviour of the samples were evaluated. The GG extract had total carbohydrate content of ~60% out of which 11.8% was starch, and a protein content of 2.3%. Samples also contained galacturonic and glucuronic acid which were highly acetylated. Both samples had a higher proportion of galacturonic acid than glucuronic acid and contained rhamnose, arabinose, galactose, glucose and xylose as neutral sugars in varying proportions. Rheological measurements on 2%w/w dispersions of the extracts show minor differences between both the original extract and the de-starched material but were influenced by changes in pH.

Investigating potential wound healing properties of polysaccharides extracted from Grewia mollis Juss. and Hoheria populnea A. Cunn. (Malvaceae)

© 2019 Elsevier Ltd The Malvaceae family is a group of flowering plants that include approximately 244 genera, and 4225 species. Grewia mollis, and Hoheria populnea (lacebark), are examples of the Malvaceae family that are used in traditional medicine. For this study polysaccharide samples were extracted from the inner bark of Grewia mollis (unmodified (GG) and destarched grewia gum (GGDS)) and from the leaves of Hoheria populnea (lacebark polysaccharide (LB)). Wound healing properties of grewia gum and lacebark polysaccharides were investigated using 3T3 fibroblast cells cultured in supplemented DMEM. Deposition of collagen using van Gieson's stain, expression of the COL1A1 gene which encodes type I collagen using quantitative PCR, and chemotaxis using a scratch plate assay were analysed following treatment of cells with the test polysaccharides. Quantitative PCR results indicated that all three polysaccharides increased the levels of COL1A1 mRNA, with GG showing the greatest fold change. Histological staining also indicated that the fibroblasts treated with GG deposited more collagen than control cells. Additionally, scratch assay data indicated that simulated cell ‘wounds’ treated with each polysaccharide showed increased wound closure rate over a 36 h period post treatment, with GG exhibiting the greatest effect on wound closure. Analysis of the Malvaceae derived polysaccharides indicates that they could have a positive effect on mechanisms that are integral to wound healing, potentially providing greater scientific understanding behind their use in traditional medicine.

Investigating potential wound healing properties of polysaccharides extracted from Grewia mollis Juss. and Hoheria populnea A. Cunn. (Malvaceae)

© 2019 Elsevier Ltd The Malvaceae family is a group of flowering plants that include approximately 244 genera, and 4225 species. Grewia mollis, and Hoheria populnea (lacebark), are examples of the Malvaceae family that are used in traditional medicine. For this study polysaccharide samples were extracted from the inner bark of Grewia mollis (unmodified (GG) and destarched grewia gum (GGDS)) and from the leaves of Hoheria populnea (lacebark polysaccharide (LB)). Wound healing properties of grewia gum and lacebark polysaccharides were investigated using 3T3 fibroblast cells cultured in supplemented DMEM. Deposition of collagen using van Gieson's stain, expression of the COL1A1 gene which encodes type I collagen using quantitative PCR, and chemotaxis using a scratch plate assay were analysed following treatment of cells with the test polysaccharides. Quantitative PCR results indicated that all three polysaccharides increased the levels of COL1A1 mRNA, with GG showing the greatest fold change. Histological staining also indicated that the fibroblasts treated with GG deposited more collagen than control cells. Additionally, scratch assay data indicated that simulated cell ‘wounds’ treated with each polysaccharide showed increased wound closure rate over a 36 h period post treatment, with GG exhibiting the greatest effect on wound closure. Analysis of the Malvaceae derived polysaccharides indicates that they could have a positive effect on mechanisms that are integral to wound healing, potentially providing greater scientific understanding behind their use in traditional medicine.

Evaluation of diclofenac niosomal gel formulated with Grewia gum for topical delivery

The purpose of this study was to formulate niosomal gel for topical delivery of diclofenac using Grewia gum as gelling agent. Niosomes containing 1g of diclofenac were formed using the thin film hydration (TFH) method. Niosomal gels were then formulated using a semi-synthetic polymer, hydroxypropylmethylcellulose (HPMC) and a natural polymer, Grewia gum as gelling agents. The formulated gels were evaluated for spreadability, viscosity, extrudability, homogeneity, clarity and pH. Results show that gels having pH and viscosity ranges of 6.8-7.3 and 265-490 Poise respectively were formed. The gels were homogenous, clear and showed good spreadability and extrudability except for batches F7 and F8. The gels formulated using the test gum, Grewia gum compared favourably with those of the standard polymer, HPMC as well as with the marketed gel. Formulation F5 containing 2% w/w Grewia gum, the optimized batch, showed viscosity of 265 poise, pH of 6.9, spreadability and extrudability values of 5.55 cm and 5.00 g/s respectively. In conclusion, Grewia gum at a concentration of 2% w/w could be used in the formulation niosomal gel for the delivery of diclofenac, which would help to circumvent the potential gastric irritation of diclofenac when used orally. Keywords: Niosomes; Grewia gum; Diclofenac; Lipid hydration; Topical delivery