Taro starch (Colocasia esculenta) and citric acid modified taro starch as tablet disintegrating agents

Preparation and characterization of starch carbamate modified natural sodium alginate composite hydrogel blend formulation and its application for slow-release fertilizer

The exploration of environmentally friendly slow-release fertilizer (SRF) based on natural bio-polymers is of great importance in the development of modern agriculture and horticulture. Herein, a novel starch carbamate (SC) modified sodium alginate (SA) hydrogel (SC/SAH) was prepared utilizing as-synthesized SC and natural SA through the cationic ions crosslinking method and ultimately the corresponding slow-release fertilizer (SC/SAH-SRF) was successfully developed by immersing the dried SC/SAH matrix into saturated urea solution. Due to the low gelation temperature and high viscosity of the synthesized SC, the formed SC/SAH exhibits significantly enhanced properties including excellent water absorbency up to 8.02 g/g with considerable repeatability, abundant pore structure and high hydrophilicity compared with the neat SAH and natural starch based hydrogel (NS/SAH). Accordingly, the SC/SAH leads to higher urea loading amount ∼ 1.28 g/g. Importantly, the resultant SC/SAH-SRF also shows superior slow-release performance, yielding a cumulative urea release of only 61.6 % within 10 h and almost completely release >16 h in water, what's more, only 58.5 % of the urea releases within 25 days and exceeding 50 days for complete release in soil column assays. The slow-release of urea from SC/SAH-SRF well complies for the first-order kinetics and accomplishes via a non-Fickian diffusion process. Moreover, the pot experiment demonstrates that the SC/SAH-SRF has higher growth promotion role for the maize seedlings than those of others. Consequently, this work provides a novel strategy for preparing environmentally friendly SRF by blending modified starch and hydrogel.

Effect of dry heat and its combination with vacuum heat on physicochemical, rheological and release characteristics of Alocasia macrorrhizos retrograded starches

Retrograded starches have received increasing attention due to their potential excipient properties in pharmaceutical formulations. However, to evade its application-oriented challenges, modification of retrograded starch is required. The study emphasizes influence of dry heating and the dual heat treatment by dry heating amalgamation with the vacuum heat treatment on quality parameters of retrograded starch. The starch was isolated by using two different extraction media (0.05 % w/v NaOH and 0.03 % citric acid) from Alocasia macrorrhizos and then retrograded separately. Further, retrograded starches were first modified by dry heating and afterwards modified with combination of dry and vacuum heating. Modification decreased moisture, ash content and increased solubility. Modified Samples from NaOH media had higher water holding capacity and amylose content. X-ray diffraction revealed type A and B crystals with increasing crystallinity of retrograded heat-modified samples from NaOH media. Thermogravimetric analysis, differential scanning calorimetry confirmed thermal stability. Shear tests showed shear-thinning behavior whereas dominant storage modulus (G/) over loss modulus (G//), depicting gel-like behavior. Storage, loss, and complex viscosity initially increased, then decreased with temperature. In-vitro release reflects, modified retrograded starches offers versatile drug release profiles, from controlled to rapid. Tailoring starch properties enables precise drug delivery, enhancing pharmaceutical formulation flexibility and efficacy.

Synthesis and characterization of citrate soft rice starch: A new strategy of producing disintegrating agent for design drug and resistant starch

Assam soft rice starch (ASRS) and Citric acid-esterified Assam soft rice starch (c-ASRS) were studied extensively. FTIR, CHN, DSC, XRD, SEM, TEM and optical microscope studies were performed for native and modified starches. Powder rearrangements, cohesiveness and flowability were studied by the Kawakita plot. Moisture and ash content was around 9 % and 0.5 %. In vitro digestibility of ASRS and c-ASRS produced functional RS. Paracetamol tablets were prepared using ASRS and c-ASRS as granulating-disintegrating agents through wet granulation methods. The prepared tablets' physical properties, disintegrant properties, in vitro dissolution and dissolution efficiency (DE) were performed. The average particle size was obtained at 6.59 ± 0.355 μm and 8.15 ± 0.168 μm for ASRS and c-ASRS, respectively. All the results were statistically significant at p < 0.05, p < 0.01 and p < 0.001. The amylose content was 6.78 %, classifying it as a low amylose type of starch. The disintegration time was reduced with the increasing concentration of ASRS and c-ASRS and facilitated the immediate release of the model drug from the tablet compact to improve its bioavailability. Therefore, the current investigation concludes that ASRS and c-ASRS can be used as novel and functional materials in pharmaceutical industries due to their unique physicochemical attributes. HYPOTHESIS: The central hypothesis of the current work was to develop citrated starch through a one-step reactive extrusion method and investigate its disintegrants property for pharmaceutical tablets. Extrusion is a continuous, simple, high-speed, low-cost, producing very limited wastewater and gas. Characterization was done through different instrumental techniques to confirm successful esterification. The flow properties were evaluated, and tablets were prepared at a different level of ASRS and c-ASRS (disintegrating agent), followed by the evaluation of tablets to confirm the model drug's dissolution and disintegration efficiency. Finally, in vitro digestibility of both ASRS and c-ASRS was analyzed to establish their potential nutritional benefits.

A comprehensive review on pharmaceutical uses of plant-derived biopolysaccharides

Biopolysaccharides extracted from plants are mainly photosynthetic byproducts found in leaves, pods, stems, fruits, grains, seeds, corms, rhizomes, roots, bark exudates, and other plant parts. Recently, these plant-derived biopolysaccharides have received a great deal of attention as pharmaceutical excipients in a range of different dosage forms because of several key advantages, such as widespread accessibility from nature as plant-based sources are readily available, sustainable production, availability of easy and cost-effective extraction methodologies, aqueous solubility, swelling capability in the aqueous medium, non-toxicity, biodegradability, etc. The current review presents a comprehensive overview of the uses of plant-derived biopolysaccharides as effective pharmaceutical excipients in the formulations of different kinds of dosage forms, for example gels, pastes, films, emulsions, suspensions, capsules, tablets, nanoparticles, microparticles, beads, buccal formulations, transdermal formulations, ocular formulations, nasal formulations, etc.

Citric acid esterified Glutinous Assam bora rice starch enhances disintegration and dissolution efficiency of model drug

The current work was designed to study the starch's physicochemical attributes, tablet disintegration and dissolution efficiency and its derivatives obtained from the glutinous Assam bora rice (G-ABR) variety of Assam, Northeast India. Starch was isolated by a simple protein denaturation method, and a starch derivative was prepared through citric acid modification. G-ABRS and citrated G-ABRS were characterized through FTIR, DSC, XRD and SEM. The rate of consolidation, consolidation index, angle of internal friction, packing rearrangement and cohesive properties were determined to investigate their applications as functional excipients in pharmaceutical industries. G-ABRS and citrated G-ABRS exhibited better packing rearrangement and cohesive properties than standard corn starch. Furthermore, immediate release of API from the tablet compact was observed when the starch concentration increased from 1 to 5 %, indicating facilitation of the tablet compact disintegration. Therefore, G-ABRS and citrated G-ABRS are potentially functional and sustainable materials for pharmaceutical industries.

A Prospective Review on the Research Progress of Citric Acid Modified Starch

Citric acid (CA) treatment is a convenient, mild and environmentally friendly strategy to modify the composition, structure and function of starch through hydrolysis and esterification, which expands the application of starch in industry. In this paper, the effects of CA modification on amylose content, amylopectin chain length distribution, microscopic morphology, solubility and swelling ability, thermodynamic properties, gelatinization properties, digestibility properties, texture properties and the film-forming properties of starch were summarized. The application status and development trend of CA modified starch were reviewed, which has important implications for the targeted utilization of CA modified starch in the future.

Isolation, characterization, modification and uses of taro starch: A review

Taro is a major root crop utilized widely for diverse food and non-food applications. Taro corms are processed into various forms before consumption, which makes them digestible and palatable, extends the shelf life and reduces post-harvest losses. Taro corm contains starch as the major carbohydrate, accounting up to 70-80% of the whole dry matter. The starches obtained from different cultivars and sources significantly differ in physical, chemical, thermal, morphological, and functional properties, which can be explored for varied applications. Starch quality also controls the end-quality of food and industrial products. Several starch modification methods have been studied to improve its positive attributes and to eliminate deficiencies in its native characteristics. These modification methods, which can be categorised into physical, chemical and enzymatic, have proved to improve the characteristics and applications of starch. This review aims to compile the information about the chemical composition, characterization, isolation and modification methods, with an objective of its increased use in food or non-food industries. In addition, challenges and issues in the small-scale processing of taro are discussed. The information available in this review may help in a better understanding and utilization of taro starch.

Talipot palm (Corypha umbraculifera L.) a nonconventional source of starch: Effect of citric acid on structural, rheological, thermal properties and in vitro digestibility

Starch from talipot palm trunk (Corypha umbraculifera L.), a new starch source, was treated with different citric acid concentrations (5%, 10%, 20%, and 40% of the dry weight of starch) to produce citrate starch. The influence of citric acid treatment on physicochemical, pasting, structural, thermal, rheological, and digestibility properties of talipot palm starch were studied. A new peak at 1728 cm^-1 was observed in the Fourier-transform infrared spectroscopy (FTIR) spectra of citric acid-treated starches, which confirmed the formation of an ester bond between starch molecule and citric acid. The crystalline pattern of talipot palm starch was unaffected by citric acid treatment, whereas the relative crystallinity decreased from 16.35% to 3.06%. The Rapid Visco Analysis of starch treated with citric acid did not show any characteristic peaks, however, the untreated starch showed a peak viscosity of 3646 cP. The gelatinization parameters decreased with an increase in the degree of substitution, and the enthalpy of gelatinization (ΔH_gel) decreased from 11.19 J/g to 6.37 J/g. The in-vitro digestibility of talipot palm starch was decreased by citric acid treatment, and that of the slowly digestible starch (SDS) and resistant starches (RS) increased significantly (p ≤ 0.05) from 31.71% to 39.43% and 37.55% to 53.38%, respectively.

Pharmaceutical applications of citric acid

Background

Citric acid (CA) is a universal plant and animal-metabolism intermediate. It is a commodity chemical processed and widely used around the world as an excellent pharmaceutical excipient. Notably, CA is offering assorted significant properties viz. biodegradability, biocompatibility, hydrophilicity, safety, etc. Therefore, CA is broadly employed in many sectors including foodstuffs, beverages, pharmaceuticals, nutraceuticals, and cosmetics as a flavoring agent, sequestering agent, buffering agent, etc. From the beginning, CA is a regular ingredient for cosmetic pH-adjustment and as a metallic ion chelator in antioxidant systems. In addition, it is used to improve the taste of pharmaceuticals such as syrups, solutions, elixirs, etc. Furthermore, free CA is also employed as an acidulant in mild astringent preparations.

Main text

In essence, it is estimated that the functionality present in CA provides excellent assets in pharmaceutical applications such as cross-linking, release-modifying capacity, interaction with molecules, capping and coating agent, branched polymer nanoconjugates, gas generating agent, etc. Mainly, the center of attention of the review is to deliver an impression of the CA-based pharmaceutical applications.

Conclusion

In conclusion, CA is reconnoitered for multiple novels pharmaceutical and biomedical/applications including as a green crosslinker, release modifier, monomer/branched polymer, capping and coating agent, novel disintegrant, absorption enhancer, etc. In the future, CA can be utilized as an excellent substitute for pharmaceutical and biomedical applications.

Graphical abstract

Mung bean (Vigna radiata) porous starch for solubility and dissolution enhancement of poorly soluble drug by solid dispersion

In this study, a novel Vigna radiata based porous starch (PS) is prepared by solvent exchange technique and explored as a solubilizer for model drug albendazole (ABZ). PS carrier was investigated for different chemical, functional, and micromeritic properties. Solubilizing potential of PS is evaluated by formulating ABZ-PS solid dispersion (1:0.5-1:2) based tablets (SDT). ABZ-PS solid dispersions were evaluated for micromeritic properties, dissolution studies, and anthelmintic activity. Direct compression suitability and susceptibility of mung bean starch were studied by SeDem diagram, Heckel, and Kawakita analysis respectively. PS had an A-type crystallinity pattern and evinced functional properties similar to other legume starches. PS was determined to be suitable for direct compression (good compressibility index = 5.50). SD (1:2) manifested 36.18 fold and 1.6-3.04 fold improvement in the % dissolution and anthelmintic activity of ABZ respectively. All SD batches (R² = 0.949-0.996) and ABZ (R² = 0.168) followed the Higuchi-matrix release kinetic model. DSC and P-XRD analysis corroborated the amorphous form of ABZ. SDT showed ≈ a 1.90 fold improvement in dissolution rate than the marketed formulation. Conclusively, Vigna radiata PS could be explored as an alternative to reduce the large burden on the established starches.

Synthesis of novel superdisintegrants for pharmaceutical tableting based on functionalized nanocellulose hydrogels

Superdisintegrants have an important function in Fast dissolving tablets (FDT). It's believed that an increase in surface to the mass (size reduction) can enhance their performance. Due to the obligation of pharmaceutical excipients being in GRAS (generally recognized as safe) list, we've devoted our research to modify one of the routinely used and important natural polymer, cellulose, as superdisintegrant. Nanocrystalline cellulose (NCC) was extracted from microcrystalline cellulose (MCC) via the sulfuric acid hydrolysis process. NCC derivatives have been synthesized by Itaconic acid/Hydroxyethyl methacrylate (IA/HEMA) via maleic anhydride (MA) to acquire unique swellability properties in to achieve superabsorbent cellulose-based nano hydrogel with the cross-linking system. The disintegration performance of prepared tablets was compared with tablets composed of sodium starch glycolate (SSG) and MCC as positive and negative controls. The results show that the disintegration time of tablets formulated with synthesized modified NCC (m-NCC) decreased dramatically compared to other disintegrants. The dissolution analysis showed suitable condition for complete drug release in a shorter time. The in vitro cytotoxic experiments proved the biocompatibility of newly synthesized superdisintegrant. The dissolution Analysis findings suggest that our developed novel superdisintegrant paves the way for the formulation of fast dissolving tablets containing rapidly acting medicines such as zolpidem.

Production and Properties of Starch Citrates-Current Research

Starch modification by chemical reaction is widely used to improve the properties of native starch. Modified by citric acid, starch is characterized by specific properties resulting from the presence of citrate residues and as a result of cross-linking starch. The chemicals used for preparing starch citrates are safe for human health and the natural environment compared to the harsh chemicals used for conventional modifications. Starch citrates are traditionally produced by heating starch-citric acid mixtures in semi-dry conditions or by a heat moisture treatment. The conditions of the modification process (roasting temperature, heating time, citric acid dose) and the botanic source or genotype of starch determine the degree of substitution and the properties of the obtained preparations. Changes of starch properties occurring during esterification lead to reduced relative crystallinity, resulting in a decrease in the affinity for water, the gelatinization parameters, and the viscosity of starch citrate. However, one of the most important outcome of the modification is the formation of resistant starch (RS), which has increased resistance to the action of amylolytic enzymes. Currently, new methods for producing starch citrates with improved functional and rheological properties while maintaining the highest possible content of resistant starch are being sought. The article presents an overview of recent studies on the production, properties. And applicability of starch citrates with special attention paid to their role as preparations of resistant starch (RS). The use of citric acid for modification of starch is better for the technology process, while using cross-linking is better than simply using esterification.

Mechanical strength, structural and hydration properties of ethanol-treated starch tablets and their impact on the release of active ingredients

Ethanol-treated starch (ETS) shows potentiality to be used for binder of pharmaceutical tablets. This study was aimed to evaluate the mechanical strength, structural and hydration properties of ETS tablets and ETS tablets containing lauric acid and ascorbic acid and their release behavior. ETS was prepared from cassava starch at the temperatures of 80, 90, and 100 °C. The active compounds were entrapped within the ETS tablets by two methods, including dry mixing and ethanol solubilisation. The results indicated that ETS tablets from temperatures of 80 °C showed granular shapes, had high friability and low crushing strength indexes, and dispersed and released active ingredients rapidly upon contact with water. Meanwhile, ETS tablets from temperatures of 90 and 100 °C exhibited non-granular particles, had low friability and high crushing strength indexes. Upon hydration, the tablets of non-granular ETS containing lauric acid eroded gradually and released active ingredients during tablet's erosion, meanwhile ascorbic acid diffused out gradually from the swelled tablets.

Monpa, memory, and change: an ethnobotanical study of plant use in Mêdog County, South-east Tibet, China

BACKGROUND

Due to their relative isolation, the previous studies of Monpa plant use were only conducted in north-east India. In October 2013, Mêdog County was no longer remote, thanks to completion of a highway into the county. This study of plant species used by the Monpa had three research objectives. These were (i) to identify and record local names and uses of plants in Mêdog County, (ii) to assess which of these were uses of endemic or near-endemic species within this part of the Indo-Burma biodiversity hotspot, and (iii) to assess how plant uses reflect socio-economic change in Mêdog County?

METHODS

Field surveys were conducted in 12 villages of four townships in Mêdog County, Tibet, China. Two field visits were made. The first field trip was in November 2017 and the second field trip was in May 2018. We interviewed 64 key informants between 21 and 84 years old. Most of them were the village leaders and other local people who are knowledgeable about plants. After transect walks with knowledgeable local people, we used free listing, key informant interviews, and semi-structured interviews during the field work. Plants traditionally used by the Monpa were documented. Utilization frequency was used to assess the significance of each species, and the Cultural Importance index was used to estimate the cultural significance of the species in common. We also used the informant consensus factor (FIC) to determine the homogeneity of the informants' knowledge of medicinal plants.

RESULTS

One hundred ninety-four plant species belonging to 82 families and 158 genera were recorded and collected. One hundred twenty-two species, primarily fruits, were food plants. Forty-five species were used as traditional medicines. This included highly valued species collected in alpine areas (Paris polyphylla) and brought to villages in Mêdog, which are at a lower altitude (between 728 and 1759 m a.s.l). Seven edible plant species were also used as herbal medicines. We also recorded 39 species used for other purposes in Monpa daily life. These included nine species that were used to make agricultural tools, five species for dyes and mordants, four species for timber, three species for fuelwood, four species for religious ritual use, three species for washing, two species for incense, two species for thatching, two species for fiber (rope and paper), two "calendar plants" were used to indicate seasons for agricultural purposes, two fish poison plant species, and one species were used as a tobacco substitute. Based on taxonomic insights and from studies elsewhere, we suggested that fiber species were under-reported (c. 14 species were used vs. one species reported used). Even though these plant species are rich and diverse, the use of endemic or near-endemic species was rarely recorded in previous studies. These species included Arenga micrantha (used for starch), Hornstedtia tibetica (fruits), Castanopsis clarkei (edible nuts) and Gnetum pendulum (edible nuts), Ophiorrhiza medogensis (vegetables), Derris scabricaulis (fish poison), Radermachera yunnanensis (agricultural tools), Litsea tibetana (seed oil), Dendrocalamus tibeticus (wine strainers and implements for administering medicine), Zanthoxylum motuoense (spices), Cinnamomum contractum (tobacco substitutes), Morus wittiorum (medicines), and Garcinia nujiangensis (funeral rituals). Despite the absence of roads until 2013 and the impression of "isolation," Monpa knowledge of plant use reflects three categories of change. Firstly, oral histories of plants used in Bhutan were also encountered by Monpa people after their migration from Bhutan to south-eastern Tibet. Secondly, a "slow change" through centuries of exchange of knowledge (for example of Chinese and Tibetan medical systems), seeds of introduced crops (finger millet (indigenous to Africa), maize (from Meso-America)), and experimentation and use of introduced medicinal plants (such as Datura stramonium, which originates from North America). Thirdly, "fast change" over the past decade. This is reflected in changes in traditional architecture and in rising commercial trade in selected plant resources such as Dendrobium orchid stems and Paris polyphylla rhizomes which are in demand in China's Traditional Chinese Medicine (TCM) markets).

CONCLUSIONS

Monpa people in the south-eastern Tibet have detailed knowledge of the diverse plant resources. But that traditional knowledge is now faced with a crisis because of the modern socio-economic change. In addition, Monpa knowledge of plants reflects slower changes in knowledge as well. For example, Monpa ethnomedicine has been influenced by traditional Tibetan and Chinese medicine over a longer period in time. Overall, this study provides a deeper understanding of the Monpa peoples' knowledge on wild plants, including endemic and near-endemic species whose uses have not been previously recorded. Several of these narrowly distributed species, such as the fish poison Derris scabricaulis, could be the focus of further studies. Some wild edible plants may also have interesting dietary constituents which need in-depth studies. These detailed studies could enable the Monpa people to benefit from the use of their traditional plant-derived culture and therefore support the biodiversity conservation.