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In an era dominated by conventional agricultural practices, underutilized legumes termed "Forgotten Gems" represent a reservoir of untapped benefits with the unique opportunity to diversify agricultural landscapes and enhance global food systems. Underutilized crops are resistant to abiotic environmental conditions such as drought and adapt better to harsh soil and climatic conditions. Underutilized legumes are high in protein and secondary metabolites, highlighting their role in providing critical nutrients and correcting nutritional inadequacies. Their ability to increase dietary variety and food security emerges as a critical component of their importance. Compared to mainstream crops, underutilized legumes have been shown to reduce the environmental impact of climate change. Their capacity for nitrogen fixation and positive impact on soil health make them sustainable contributors to biodiversity conservation and environmental balance. This paper identifies challenges and proposes strategic solutions, showcasing the transformative impact of underutilized legumes on agriculture, nutrition, and sustainability. These "Forgotten Gems" should be recognized, integrated into mainstream agricultural practices, and celebrated for their potential to revolutionize global food production while promoting environmental sustainability.

Introduction: Ferulic acid (FA) is a phenolic phytochemical that has garnered the attention of the research community due to its abundant availability in nature. It is a compound that has been explored for its multifaceted therapeutic potential and benefits in modern and contemporary healthcare., Areas Covered: This review furnishes a compilation of the molecular mechanisms underlying the anti-diabetic, anticancer, antioxidant, and anti-inflammatory effects of FA. We also aim to excavate an in-depth analysis of the role of nanoformulations to achieve release control, reduce toxicity, and deliver FA at specified target sites. To corroborate the safety and efficacy of FA, a multitude of pre-clinical studies have also been conducted by researchers and have been discussed comprehensively in this review. The various patented innovations and newer paradigms pertaining to FA have also been presented., Expert Opinion: Enormous research has been conducted and should still be continued to find the best possible novel drug delivery system for FA delivery. The utilization of nanocarriers and nanoformulations has intrigued the scientists for delivery of FA, but before that, it is necessary to shed light upon toxicity, safety, and regulatory concerns of FA.

Legumes are a major food crop in many developing nations. However, orphan or underutilized legumes are domesticated legumes that have valuable properties but are less significant than main legumes due to use and supply restrictions. Compared to other major legumes, they are better suited to harsh soil and climate conditions, and their great tolerance to abiotic environmental circumstances like drought can help to lessen the strains brought on by climate change. Despite this, their economic significance in international markets is relatively minimal. This article is aimed at carrying out a comprehensive review of the nutritional and pharmacological benefits of orphan legumes from eight genera in the sub - family Faboidea, namely Psophocarpus Neck. ex DC. , Tylosema (Schweinf.) Torre Hillc. , Vigna Savi. , Vicia L., Baphia Afzel. ex G. Lodd ., Mucuna Adans, Indigofera L. and Macrotyloma (Wight & Arn.) Verdc, and the phytoconstituents that have been isolated and characterized from these plants. A literature search was conducted using PubMed, Google Scholar, and Science Direct for articles that have previously reported the relevance of underutilized legumes. The International Union for Conservation of Nature (IUCN) red list of threatened species was also conducted for the status of the species. References were scrutinized and citation searches were performed on the study. The review showed that many underutilized legumes have a lot of untapped potential in terms of their nutritional and pharmacological activities. The phytoconstituents from plants in the subfamily Faboideae could serve as lead compounds for drug discovery for the treatment of a variety of disorders, indicating the need to explore these plant species., (© 2023 The Authors.)

Background: Irvingia gabonensis kernel polymer has gained attention in drug delivery systems because of its compatibility and degradation under natural and physiological conditions., Objectives: This study aimed to evaluate Irvingia gabonensis polymer as a matrix system for the controlled delivery of ibuprofen in comparison to xanthan gum and hydroxypropylmethylcellulose (HPMC)., Material and Methods: Irvingia gabonensis polymer was extracted using established methods and dried using the ovenand freeze-drying methods. Ibuprofen tablets were prepared by direct compression and the effects of polymer concentration (10-50%), excipients (lactose, microcrystalline cellulose and dicalcium phosphate dihydrate) and polymers (xanthan gum and HPMC) on the mechanical and drug release properties of the tablets were evaluated. Density measurements and the Heckel and Kawakita equations were used to determine the compression properties of the tablets. Friability, crushing strength and the crushing strength-friability ratio (CSFR) were used to evaluate the mechanical properties of the tablets, while dissolution times were used to evaluate drug release from the matrices. The drug release mechanisms were determined by fitting the dissolution data into classic kinetic equations., Results: Irvingia gabonensis polymer deformed plastically with a fast onset and a high amount of plastic deformation compared with xanthan gum and HPMC. This polymer was directly compressible and formed intact non-disintegrating tablets; the mechanical and dissolution properties of Irvingia gabonensis polymer tablets generally decreased with increasing concentration of ibuprofen. The ranking of dissolution times was xanthan gum > freeze-dried Irvingia gabonensis > HPMC > oven-dried Irvingia gabonensis. The addition of the excipients improved the mechanical properties of the tablets, aided ibuprofen release, and altered the release kinetics, which was largely defined by the Korsmeyer-Peppas model. Increasing the proportion of xanthan gum and HPMC in the matrices resulted in a decreased amount of ibuprofen released after 9 h, with xanthan gum having a greater effect., Conclusions: Irvingia gabonensis polymer matrices may be effective in the preparation of controlled release tablets, and their right combination with xanthan gum or HPMC could provide a time-independent release for longer durations.

Background: Mucilage and pectin are both natural polymers with the advantages of availability and biodegradability. Microspheres made from biodegradable polymers can break down naturally after performing their tasks., Objectives: The study aimed to use mucilage and pectin from the leaves of Talinum triangulare (Jacq.) Willd. as polymer matrices for the formulation of microspheres, with ibuprofen as the model drug., Material and Methods: Both polymers were examined under a microscope and evaluated using measurements of viscosity, density, flow properties, swelling power, elemental analysis, Fourier-transform infrared spectroscopy (FTIR), and the degree of esterification (DE) for pectin. The microspheres were prepared using the ionotropic gelation method and alginate:mucilage/pectin at ratios of 1:1 and 1:2. They were assessed for swellability, drug entrapment effectiveness and drug release profile., Results: The mucilage particles were ovoid while pectin particles were irregularly shaped. Pectin had higher particle, bulk and tapped densities than mucilage, while mucilage had a higher swelling power and a better flow than pectin. Talinum triangulare pectin is a low-methoxyl pectin with a DE of 7.14%. The FTIR spectra showed no interaction between the polymers and ibuprofen. The surface morphology of the microspheres without ibuprofen was smooth, while those with ibuprofen revealed a spongy-like mesh. The swelling power of the microspheres was higher in phosphate buffer with a pH of 7.2 than in distilled water. The entrapment efficiency ranged within 39.57-60.43% w/w, with microspheres containing alginate:mucilage/pectin ratio of 1:1 having higher entrapment efficiency. Microspheres with polymer at a ratio of 1:1 provided a longer release (>2 h), while microspheres with polymer blend of 1:2 provided an immediate release of ibuprofen., Conclusions: The polymers of T. triangulare could be used as matrices in microsphere formulations.

In the present study, microcrystallinecellulose-colloidal silicon dioxide (MCC-SiO 2 ) and carboxymethylcellulose-colloidal silicon dioxide (CMC-SiO 2 ) conjugates have been investigated as superdisintegrants in fast dissolving tablets (FDTs). MCC-SiO 2 and CMC-SiO 2 conjugates were prepared and micromeritic studies, FTIR, SEM and XRD methods were utilized for characterizing the powdered conjugates. The conjugates were used for the preparation of domperidone FDTs by direct compression and the wetting time, water absorption ratio, disintegration time and in vitro drug release were evaluated. Effective pore radius of MCC-SiO 2 and CMC-SiO 2 conjugates for 1:1, 1:2.5 and 1:5 was found to be 13.35 ± 0.31 µm, 15.66 ± 0.17 µm and 18.38 ± 0.44 µm, and 16.81 ± 0.24 µm, 20.12 ± 0.39 µm and 26.37 ± 0.24 µm, respectively, compared to 12.21 ± 0.23 µm for MCC and 13.65 ± 0.21 µm for CMC. The results of effective pore radius indicate the wicking capability as well as the disintegration potential of MCC-SiO 2 and CMC-SiO 2 conjugates over pure MCC and CMC. The results of wetting time, water absorption ratio and disintegration time for MCC-SiO 2 conjugates were found to be in the range of 19 ± 1.21 to 30 ± 1.33 s, 42 ± 0.28 to 49 ± 0.47% and 15 ± 2 to 40 ± 1 s, and for CMC-SiO 2 conjugates were found to be in the range of 21 ± 1.13 to 40 ± 1.17 s, 42 ± 0.94 to 49 ± 0.57% and 12 ± 2 to 20 ± 3 s, respectively. Conjugation of MCC and CMC with SiO 2 led to the formation of a complex with remarkable tablet superdisintegrant potential that could be used in preparing fast disintegrating tablets.

Background: Co-processing starch with clay nanocomposite has been shown to yield a new class of materials, potentially with better properties than pristine starch, that could be used as directly compressible excipients in tablet formulations., Objectives: In this study, starches from 3 botanical sources, i.e., millet starch from Pennistum glaucum (L) RBr grains, sorghum starch from Sorghum bicolor L. Moench grains and cocoyam starch from Colocasia esculenta L. Schott tubers, were co-processed with montmorillonite clay (MMT) and evaluated as a directly compressible excipient in tramadol tablet formulations. The effects of different starch-to-clay ratios on the material and drug release properties of the resulting tablets were evaluated., Material and Methods: The starch-clay composites were prepared by heating a dispersion of the starch in distilled water, then precipitating the dispersion with an equal volume of 95% ethanol. The starch-clay composites were characterized and used as direct compression excipients for the preparation of tramadol tablets. The mechanical and drug release properties of the tablets were evaluated., Results: Co-processing MMT with the starches yielded starch-clay composites with different material and tablet properties than the pristine starches. The co-processed starch-MMT biocomposites exhibited improved flowability and compressibility over the pristine starches. The mechanical and drug release properties of tramadol tablets containing starch-clay composites were significantly better than those containing only pristine starches. The properties of the starch-clay composites were not related to the botanical source of the starches., Conclusions: The study showed that starch-clay biocomposites could be used in the controlled release of tramadol.

Background: Natural polymers such as gums have gained attention in drug delivery systems due to their availability, compatibility and degradation under natural and physiological conditions., Objectives: The aim of the present study was to investigate the film forming properties of gums obtained from the stem of Cissus polpunea (Guill and Perr) and the seed of Irvingia gabonensis (O'Rorke)., Material and Methods: Gums were extracted from the relevant plant parts and characterized using functional, proximate and elemental properties. Films were prepared by the casting method using gum concentrations of 1-4% w/v and varied with propylene glycol (PG). The films were assessed through physical observation, thickness, swelling power and moisture sorption effects using the relative humidity of 0, 27, 43, 57, 75 and 90%. The gum yielding optimal film properties was used as coating material in ibuprofen tablet formulations. The mechanical and release properties of the tablets were determined., Results: The functional and proximate properties of gums showed a similarity in the majority of the parameters, but significant (p < 0.05) variation existed in their solubility, while elemental assessment revealed the absence of toxic metals. Generally, the films were homogenous, opaque and demonstrated high swelling power in phosphate buffer, which was pH-dependent. Moisture sorption properties of the gums increased with the increase in relative humidity in the order HPMC < Cissus < Irvingia. Film-coated ibuprofen tablets showed higher mechanical properties and disintegration and dissolution times compared with uncoated tablets., Conclusions: Cissus and irvingia gums have demonstrated acceptable functional, proximate and elemental properties. Film-coated ibuprofen tablets showed higher mechanical and release properties than was the case in uncoated tablets.

Cissus gum has been employed as polymer with sodium alginate in the formulation of diclofenac microbeads and the in vivo mucoprotective properties of the polymer in anti-inflammatory therapy assessed in rats with carrageenan-induced paw edema in comparison to diclofenac powder and commercial diclofenac tablet. A full 2(3) factorial experimental design has been used to investigate the influence of concentration of cissus gum (X1); concentration of calcium acetate (X2) and stirring speed (X3) on properties of the microbeads. Optimized small discrete microbeads with size of 1.22±0.10 mm, entrapment efficiency of 84.6% and t80 of 15.2±3.5 h were obtained at ratio of cissus gum:alginate (1:1), low concentration of calcium acetate (5% w/v) and high stirring speed (400 rpm). In vivo studies showed that the ranking of percent inhibition of inflammation after 3h was diclofenac powder>commercial tablet=cissus>alginate. Histological damage score and parietal cell density were lower while crypt depth and mucosal width were significantly higher (p<0.05) in the groups administered with the diclofenac microbeads than those administered with diclofenac powder and commercial tablet, suggesting the mucoprotective property of the gum. Thus, cissus gum could be suitable as polymer in the formulation of non-steroidal anti-inflammatory drugs ensuring sustained release while reducing gastric side effects., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: To determine the pharmaceutical equivalence and stability of eighteen randomly selected brands of metronidazole suspensions., Methods: The tests conducted include ease of redispersibility, sedimentation volume, particle size measurements, viscosity and assay of drug content., Results: The results showed that 16 (88.9%) out of 18 brands including the innovator (SR) were redispersed between 30 seconds to one minute, while 2 (11.1%) took more than two minutes. The sedimentation volume for 15 (83.3%) of the brands was less than 0.50 while the innovator brand had a significantly higher (p < 0.001) value (0.91). The particle size of the brands ranged between 1.942 and 5.92 μm and the sedimentation rate was between 20-50 mL/day. The viscosity of the brands were significantly different (p < 0.05) with SA, SB, SC, SD, SE and SF having 250-400cp, brands SG, SH, SI, SM, SP and SQ had 10-50cp while the remaining six brands had 100-190cp. Four brands including the innovator (SK, SP, SQ and SR) met Pharmacopoeal requirement for metronidazole suspension on drug content. Moreover, colour change, reduced viscosity and significant increase (p < 0.05) in particle sizes were observed for samples stored at 42 degrees C for seven weeks while those stored at 4 degrees C and 25 degrees C maintained stability., Conclusion: Four out of eighteen brands of metronidazole suspensions evaluated in this study were found to be pharmaceutically equivalent. The stability studies showed that there is the need to adhere strictly to storage of metronidazole suspensions in a cool place.

In the present study, corn Starch-Neusilin UFL2 conjugates were prepared by physical, chemical, and microwave methods with the aim of using the conjugates as tablet superdisintegrant. Various powder tests, namely, angle of repose, bulk density, tapped density, Hausner's ratio, Carr's index, swelling index, and powder porosity were conducted on the samples. The conjugates were characterized by ATR-FTIR, XRD, DSC, and SEM techniques. Heckel and Kawakita models were applied to carry out compression studies for the prepared conjugates. Fast disintegrating tablets of domperidone were prepared using corn starch and corn Starch-Neusilin UFL2 conjugates as tablet superdisintegrants in different concentrations. Conjugates were found to possess good powder flow and tabletting properties. Heckel analysis indicated that the conjugates prepared by microwave method showed the slowest onset of plastic deformation while Kawakita analysis indicated that the conjugates prepared by microwave method exhibited the highest amount of total plastic deformation. The study revealed that the corn Starch-Neusilin UFL2 conjugates possess improved powder flow properties and could be a promising superdisintegrant for preparing fast disintegrating tablet. Also, the results sugessted that the microwave method was found to be most effective for the preparation of corn Starch-Neusilin UFL2 conjugates.

Four natural gums, namely albizia, cissus, irvingia and khaya gums have been characterized and evaluated as polymers for the formulation of microbeads for controlled delivery of diclofenac sodium. The natural gums were characterized for their material properties using standard methods. Diclofenac microbeads were prepared by ionotropic gelation using gel blends of the natural gums and sodium alginate at different ratios and zinc chloride solution (10%w/v) as the crosslinking agent. The microbeads were assessed using SEM, swelling characteristics, drug entrapment efficiencies and release properties. Data obtained from in vitro dissolution studies were fitted to various kinetic equations to determine the kinetics and mechanisms of drug release, and the similarity factor, f2, was used to compare the different formulations. The results showed that the natural gum polymers varied considerably in their material properties. Spherical and discrete microbeads with particle size of 1.48-2.41 μm were obtained with entrapment efficiencies of 44.0-71.3%w/w. Drug release was found to depend on the type and concentration of polymer gum used with formulations containing gum:alginate ratio of 3:1 showing the highest dissolution times. Controlled release of diclofenac was obtained over for 5h. Drug release from the beads containing the polymer blends of the four gums and sodium alginate fitted the Korsmeyer-Peppas model which appeared to be dependent on the nature of natural gum in the polymer blend while the beads containing alginate alone fitted the Hopfenberg model. Beads containing albizia and cissus had comparable release profiles to those containing khaya (f2>50). The results suggest that the natural gums could be potentially useful for the formulation controlled release microbeads., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Acid modified starches obtained from two species of yam tubers namely white yam - Dioscorea rotundata L. and water yam - D. alata L. DIAL2 have been investigated as intra- and extra-granular disintegrants in paracetamol tablet formulations. The native starches were modified by acid hydrolysis and employed as disintegrant at concentrations of 5 and 10% w/w and their disintegrant properties compared with those of corn starch BP. The tensile strength and drug release properties of the tablets, assessed using the disintegration and dissolution (t 50 and t 80 - time required for 50% and 80% of paracetamol to be released) times, were evaluated. The results showed that the tensile strength and the disintegration and dissolution times of the tablets decreased with increase in the concentration of the starch disintegrants. The acid modified yam starches showed better disintegrant efficiency than corn starch in the tablet formulations. Acid modification appeared to improve the disintegrant efficiency of the yam starches. Furthermore, tablets containing starches incorporated extragranularly showed faster disintegration but lower tensile strength than those containing starches incorporated intragranularly. This emphasizes the importance of the mode of incorporation of starch disintegrant.

The exudates from the incised trunk of Terminalia randii has been evaluated as controlled release excipient in comparison with xanthan gum and hydroxypropylmethylcellulose (HPMC) using carvedilol (water insoluble) and theophylline (water soluble) as model drugs. Matrix tablets were prepared by direct compression and the effects of polymer concentration and excipients-spray dried lactose, microcrystalline cellulose and dicalcium phosphate dihydrate on the mechanical (crushing strength (CS) friability (F) and crushing strength-friability ratio (CSFR)) and drug release properties of the matrix tablets were evaluated. The drug release data were fitted into different release kinetics equations to determine the drug release mechanism(s) from the matrix tablets. The results showed that the CS and CSFR increased with increase in polymer concentration while F decreased. The ranking of CS and CSFR was HPMC > terminalia > xanthan while the ranking was reverse for F. The ranking for t(25) (i.e. time for 25% drug release) at a polymer concentration of 60% was xanthan > terminalia = HPMC. The dissolution time, t(25), of theophylline matrices was significantly lower (p < 0.001) than those of carvedilol matrix tablets. Drug release from the matrices was by swelling, diffusion and erosion. The mechanical and drug release properties of the tablets were significantly (p < 0.05) dependent on the type and concentration of polymer and excipients used with the release mechanisms varying from Fickian to anomalous. Terminalia gum compared favourably with standard polymers when used in controlled release matrices and could serve as a suitable alternative to the standard polymers in drug delivery.

Objective: To explore the antidiabetic properties of Mucuna pruriens(M. pruriens)., Methods: Diabetes was induced in Wistar rats by single intravenous injection of 120 mg/kg of alloxan monohydrate and different doses of the extract were administered to diabetic rats. The blood glucose level was determined using a glucometer and results were compared with normal and untreated diabetic rats. The acute toxicity was also determined in albino mice., Results: Results showed that the administration of 5, 10, 20, 30, 40, 50, and 100 mg/kg of the crude ethanolic extract of M. pruriens seeds to alloxan-induced diabetic rats (plasma glucose > 450 mg/dL) resulted in 18.6%, 24.9%, 30.8%, 41.4%, 49.7%, 53.1% and 55.4% reduction, respectively in blood glucose level of the diabetic rats after 8h of treatment while the administration of glibenclamide (5 mg/kg/day) resulted in 59.7% reduction. Chronic administration of the extract resulted in a significant dose dependent reduction in the blood glucose level (P<0.001). It also showed that the antidiabetic activity of M. pruriens seeds resides in the methanolic and ethanolic fractions of the extract. Acute toxicity studies indicated that the extract was relatively safe at low doses, although some adverse reactions were observed at higher doses (8-32 mg/kg body weight), no death was recorded. Furthermore, oral administration of M. pruriens seed extract also significantly reduced the weight loss associated with diabetes., Conclusions: The study clearly supports the traditional use of M. pruriens for the treatment of diabetes and indicates that the plant could be a good source of potent antidiabetic drug., (Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.)

Objective: To investigate the antiplasmodial activity of the extracts of Phyllanthus amarus (P. amarus) on Plasmodium yoelii (P. yoelii) (a resistant malaria parasite strain used in animal studies) infection in mice., Methods: The aqueous and ethanol extracts of the whole plant of Phyllanthus amarus was administered to Swiss albino mice at doses of 200 mg/kg/day, 400 mg/kg/day, 800 mg/kg/day and 1600 mg/kg/day and the prophylactic and chemotherapeutic effect of the extracts against P. yoelii infection in mice was investigated and compared with those of standard antimalaria drugs used in the treatment of malaria parasite infection. Acute toxicity test was carried out in mice to determine the safety of the plant extract when administered orally., Results: The results showed that the extracts demonstrated a dose-dependent prophylactic and chemotherapeutic activity with the aqueous extracts showing slightly higher effect than the ethanol extract. The antiplasmodial effects of the extracts were comparable to the standard prophylactic and chemotherapeutic drugs used in chloroquine resistant Plasmodium infection although the activity depended on the dose of the extract administered. The extracts showed prophylactic effect by significantly delaying the onset of infection with the suppression of 79% at a dose of 1600 mg/kg/day., Conclusions: The results obtained indicate that the extracts of the whole plant of P. amarus possess repository and chemotherapeutic effects against resistant strains of P. yoelii in Swiss albino mice. The findings justify the use of the extract of P. amarus in traditional medicine practice, for the treatment of malaria infections., (Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.)

Starches 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.

Grandifotane A (1), a limonoid with an unprecedented carbon skeleton, was isolated from the stem bark of Khaya grandifoliola. The structure of 1 with the absolute configuration was determined by spectroscopic data, X-ray crystallography, and ECD calculation. A biogenetic route for grandifotane A (1) involving an enzymatic Baeyer-Villiger oxidation as the key step is proposed.

Starches obtained from four different Dioscorea species-namely, White yam (Dioscorea rotundata), Bitter yam (Dioscorea dumetorum), Chinese yam (Dioscorea oppositifolia), and Water yam (Dioscorea alata)-were modified by cross-linking, hydroxypropylation, and dual modification-cross-linking followed by hydroxypropylation. The physicochemical, material, and tablet properties of the modified starches were investigated with the aim of understanding their properties to determine their potential use for different applications. The tablet formation properties were assessed using 3D modeling, the Heckel equation, and force-displacement profiles. The analyzed tablet properties were elastic recovery, compactibility, and disintegration. The result indicates that the modifications generally increased the swelling power for all the starches in the rank order hydroxypropyl > hydroxypropylated cross-linked > cross-linked (CL) while the solubility did not show a clear-cut pattern. This indicates that hydroxypropylation generally showed the strongest effects on swelling. Furthermore, hydroxypropylation improved the hot water swelling of the CL starches. The modifications did not cause any detectable morphological change in the starch granules shape or size although slight rupture was observed in some granules. CL starch had the lowest water sorption capacity and hydroxypropylation increased the sorption capacity of the CL starches. The material property results indicate that hydroxypropylation and cross-linking did not significantly improve the flowability and compressibility but improved bonding, which resulted in an increased compaction and higher tablet crushing force even though they all disintegrated rapidly. Thus, the modified Dioscorea starches showed potentials for development as new excipients in solid dosage form design, and they could be useful as disintegrants or for Soft tableting.

Starches obtained from four different Dioscorea species namely White (D. rotundata), Bitter (D. dumetorum), Chinese (D. oppositifolia) and Water yam (D. alata), were modified by acid hydrolysis and the physicochemical, material and tablet formation properties of the starches were investigated with the aim of determining their usefulness as a direct compression excipient in pharmaceutical tablets. The results obtained indicate that the physicochemical, material and tablet properties of the acid modified Dioscorea starches varied considerably among the various species. Acid hydrolysis led to an increase in solubility but decrease in swelling of the starches. Acid modification also led to an increase in the compressibility of the starches when compared with the native forms of the starches. Acid modified Water and White formed intact stable tablets only at higher rho(rel,) (max), while acid modified Chinese and Bitter formed tablets at all relative densities which could already be predicted from the deformation behaviour as analyzed by 3-D modeling. The result indicates that acid modified starch tablets showed higher crushing force and acceptable disintegration time and could therefore be useful as directly compressible excipient.

The material and tablet formation properties of pregelatinized (thermally modified) forms of four Dioscorea starches have been investigated. Dioscorea starches were pregelatinized followed by either oven drying (PS) or freeze drying (FD) and used as excipient in direct compression. The physicochemical, morphological and material properties of the pregelatinized starches have been investigated. The tablet formation properties were assessed using the 3-D modeling parameters, the Heckel equation and the force-displacement profiles. The tablet properties were evaluated using the elastic recovery, compactibility plots and the disintegration test. The results indicate that pregelatinization improved the compressibility and flowability of the Dioscorea starches. The high bulk and tap densities of PS coupled with their good flowability offer a unique possibility of the starches being used as filler in capsule formulations. The modified starches generally showed differences in their time and pressure dependent deformation behaviour. PS exhibited higher elasticity during tableting. FD Chinese and FD Bitter showed higher plasticity and low fast elastic deformation than the PS forms of the starches indicating that the FD starches undergo the highest plastic deformation. However, FD starches generally showed higher compactibility compared to the PS forms of the Dioscorea starches. While FD White and FD Water showed fast disintegration time and high compactibility, FD Chinese and FD Bitter were non-disintegrating and showed high compactibility. The high compactibility observed with the FD starches appears to be as a result of material change occurring during tableting probably due to the effect of temperature or pressure or a combination of both factors. Thus, FD White and FD Water starches could be useful when high crushing force and fast disintegration are of concern while FD Chinese and FD Bitter, which were non-disintegrating, could find application as excipients for controlled drug delivery.

A study was made of the comparative effects of polymers obtained from two species of khaya tree - Khaya senegalensis and Khaya grandifoliola - as binding agents in a paracetamol tablet formulation. The mechanical properties of the tablets were assessed using the tensile strength (T), brittle fracture index (BFI) and friability (F) of the tablets while the drug release properties of the tablets were assessed using disintegration and dissolution times. The tensile strength, disintegration and the dissolution times of tablets increased with the increase in binder concentration while F and BFI decreased. K. senegalensis gum produced tablets with stronger mechanical properties with less tendency to laminate, and longer disintegration and dissolution times than K. grandifoliola gum. The results suggest that the polymer gum from K. senegalensis will be more appropriate as a binding agent than the gum from K. grandifoliola when higher mechanical strength and slower release profiles of tablets are desired.

Three limonoids, deacetylkhayanolide E (1), 6S-hydroxykhayalactone (2), and grandifolide A (3), along with three known ones, were isolated from stem bark of the Nigerian medicinal plant Khaya grandifoliola. Their structures were characterized on the basis of the application of spectroscopic methods. In vitro antimicrobial and cytotoxic activities of the isolates were also tested, but were all found to be inactive.

A study has been made of the effects of pigeon pea starch obtained from the plant Cajanus cajan (L) Millisp. (family Fabaceae) and plantain starch obtained from the unripe fruit of Musa paradisiaca L. (family Musaceae) on the compressional, mechanical, and disintegration properties of paracetamol tablets in comparison with official corn starch BP. Analysis of compressional properties was done by using density measurements, and the Heckel and Kawakita equations, whereas the mechanical properties of the tablets were evaluated by using tensile strength (T--a measure of bond strength) and brittle fracture index (BFI--a measure of lamination tendency). The ranking for the mean yield pressure, P(y), for the formulations containing the different starches was generally corn < pigeon pea < plantain starch while the ranking for P(k), an inverse measure of the amount of plasticity, was pigeon pea < plantain < corn starch, which indicated that formulations containing corn starch generally exhibited the fastest onset of plastic deformation, whereas those formulations containing pigeon pea starch exhibited the highest amount of plastic deformation during tableting. The tensile strength of the tablets increased with increase in concentration of the starches while the Brittle Fracture Index decreased. The ranking for T was pigeon pea > plantain > corn starch while the ranking for BFI was corn > plantain > pigeon pea starch. The bonding capacity of the formulations was in general agreement with the tensile strength results. The disintegration time (DT) of the formulation increased with concentration of plantain and corn starches but decreased with concentration of pigeon pea starch. The general ranking of DT values was plantain < pigeon pea < corn starch. Notably, formulations containing pigeon pea starch exhibited the highest bond strength and lowest brittleness, suggesting the usefulness of pigeon pea starch in producing strong tablets with minimal lamination tendency. Plantain starch, on the other hand, would be more useful where faster disintegration of tablet is desired. The results show that the starches could be useful in various formulations depending on the intended use of the tablets with the implication that the experimental starches can be developed for commercial purposes.

A study has been made of the compression properties of khaya gum matrices and the effects of drug concentration and method of preparation of the material on the compression, mechanical and the drug release characteristics of the matrices. Khaya gum matrix tablets were prepared by direct compression and wet granulation methods. The compression properties of the formulations were assessed using the equations of Heckel and Kawakita. The mechanical properties of the tablets were evaluated using crushing strength and friability of the tablets, whereas the release properties of the tablets were evaluated by using the disintegration and dissolution times. The results obtained show that khaya gum deformed mainly by plastic deformation. The compression properties of the formulations were affected by the concentration of the drug and the method of preparation of the materials for compression. Tablets prepared by wet granulation showed faster onset and higher amount of plastic deformation during compression than those prepared by direct compression. Tablets containing dicalcium phosphate showed higher mechanical strength and disintegration and dissolution times. Wet granulation also increased the mechanical strength of the tablet without significantly affecting the drug release characteristics from the matrix tablets. Thus, the wet granulation method could be useful in the preparation of khaya gum matrix tablet with acceptable mechanical properties and drug release properties.

The effects of plantain starch obtained from the unripe fruit of the plant Musa paradisiaca L. (Musaceae) on the mechanical and disintegration properties of paracetamol tablets have been investigated in comparison with the effects of corn starch BP using a 2(3) factorial experimental design. The individual and combined effects of nature of starch binder (N), concentration of starch binder (C), and the relative density of tablet (RD) on the tensile strength (TS), brittle fracture index (BFI), and disintegration time (DT) of the tablets were investigated. The ranking of the individual effects on TS was RD > C >> N, on BFI was C >> RD > N and on DT was N > C > RD. The ranking for the interaction effects on TS and DT was N-C >> N-RD > C-RD, while that on BFI was N-C >> C-RD > N-RD. Changing nature of starch from a "low" (plantain starch) to a "high" (corn starch) level, increasing the concentration of starch binding agent from 2.5% to 10.0% wt/wt, and increasing relative density of the tablet from 0.80 to 0.90, led to increase in the values of TS and DT, but a decrease in BFI. Thus, tablets containing plantain starch had lower tensile strength and disintegration time values than those containing corn starch, but showed better ability to reduce the lamination and capping tendency in paracetamol tablet formulation. The interaction between N and C was significantly (P < .001) higher than those between N and RD and between C and RD. There is therefore the need to carefully choose the nature (N) and concentration (C) of starch used as binding agent in tablet formulations to obtain tablets of desired bond strength and disintegration properties. Furthermore, plantain starch could be useful as an alternative binding agent to cornstarch, especially where faster disintegration is required and the problems of lamination and capping are of particular concern.

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.

Khaya and albizia gums were evaluated as compression coatings for target drug delivery to the colon using indometacin (a water insoluble drug) and paracetamol (a water soluble drug) as model drugs. The core tablets were compression-coated with 300 and 400 mg of 100% khaya gum, 100% albizia gum and a mixture of khaya and albizia gum (1:1). Drug release studies were carried out in 0.1(M) HCl (pH 1.2) for 2 h, Sorensen's buffer (pH 7.4) for 3 h and then in phosphate-buffered saline (pH 6.8) or in simulated colonic fluid for the rest of the experiment to mimic the physiological conditions from the mouth to colon. The results indicated that khaya and albizia gums were capable of protecting the core tablet in the physiological environment of the stomach and small intestine, with albizia gum showing greater ability than khaya gum. The release from tablets coated with the mixture of khaya and albizia gums was midway between the two individual gums, indicating that there was no interaction between the gums. Studies carried out using rat caecal matter in phosphate-buffered saline at pH 6.8 (simulated colonic fluid) showed that the gums were susceptible to degradation by the colonic bacterial enzymes, leading to release of the drug. The results demonstrate that khaya gum and albizia gum have potential for drug targeting to the colon.

Dika nut mucilage obtained from the nuts of Irvingia gabonensis (O'Rorke) Bail (family Irvingiaceae) has been evaluated as a binding agent in metronidazole tablet formulations in comparison with gelatin BP. The compressional properties of metronidazole formulations were analyzed using density measurements and the Heckel equations as assessment parameters, whereas the mechanical properties of the tablets were assessed using the tensile strength (T), brittle fracture index (BFI), and the friability of the tablets. The drug release properties of the tablets were assessed using disintegration and dissolution times of the tablets. The results obtained indicate that formulations containing dika nut mucilage as binding agent show faster onset of plastic deformation under compression pressure than those containing gelatin. The tensile strength of the tablets increased with increase in concentration of the binding agents, whereas the BFI and friability values decreased. Furthermore, tablets containing dika nut mucilage generally showed lower tensile strength but higher brittleness and friability than those containing gelatin. The results also showed that tablets containing dika nut mucilage generally showed higher disintegration and dissolution times than those containing gelatin BP. The results suggest that dika nut mucilage could be useful in achieving various tablet strength and drug release properties.

Khaya gum has been evaluated as a controlled release agent in modified release matrices in comparison with hydroxypropylmethylcellulose (HPMC) using paracetamol (water soluble) and indometacin (water insoluble) as model drugs. Tablets were produced by direct compression and the in-vitro drug release was assessed in conditions mimicking the gastrointestinal system. Khaya gum matrices provided a controlled release of paracetamol for up to 5 h. The release of paracetamol from khaya gum matrices followed time-independent kinetics (n = 1.042) and release rates were dependent on the concentration of the drug present in the matrix. The addition of tablet excipients not only improved the mechanical properties of the tablet, but also altered the dissolution profile, except for dicalcium phosphate where the profile remained unchanged. HPMC could be used to control the drug release rates from khaya gum matrices and a combination of khaya gum and HPMC gave zero-order time-independent release kinetics. Indometacin exhibited a lag time in excess of 2 h, due to its insolubility at low pH, before the zero-order release was observed. Thus khaya gum matrices could be useful in the formulation of sustained release tablets for up to 5 h and the appropriate combination of khaya gum and HPMC could be used to provide a time-independent release for longer periods.

A study of the comparative effects of khaya gum and two standard binding agents-polyvinylpyrrolidone (PVP) and gelatin--on crushing strength and friability, and the disintegration and dissolution characteristics of paracetamol tablets was made. The crushing strength-friability ratio (CSFR), the disintegration times, D, and the dissolution times t50, t90, and t1 (derived from the equation of Noyes and Whitney), all increased with an increase in binder concentration; however, the dissolution rate constants, k1 and k2, decreased. The ranking for the values of CSFR for tablets containing the different binders was PVP > gelatin > khaya gum. The ranking for D and the dissolution times was gelatin > khaya gum > PVP, whereas the ranking for the dissolution rate constants was PVP > khaya gum > gelatin. There were significant linear correlations between CSFR, D, t50, t90, and t1 for the tablets. There were also significant correlations between k1 and D, t50, t90, and t1, and between k2 and t90. The results suggest that khaya gum could be useful as an alternative binding agent to produce tablets with particular mechanical strength and drug release profiles.

The influence of khaya gum, a binding agent obtained from Khaya grandifolia (Meliaceae family), on the bulk, compressional, and tabletting characteristics of a paracetamol tablet formulation was studied in comparison with the effects of two standard binders: polyvinylpyrrolidone (PVP; molecular weight 40,000) and gelatin. The relative ability of khaya gum to destroy any residual microbial contamination in the binder or in the formulation during tabletting was also studied using Bacillus subtilis spores as a model. Formulations containing khaya gum exhibited more densification than formulations containing PVP and gelatin during die filling, but less densification due to rearrangement at low pressures. The mean yield pressure of the formulation particles obtained from Heckel plots, and another pressure term, also inversely related to plasticity, obtained from Kawakita plots, showed dependence on the nature and concentration of the binder, with formulations containing khaya gum exhibiting the lowest and highest values respectively. The values of the pressure terms suggest that the yield pressure relates to the onset of plastic deformation during compression, while the Kawakita pressure relates to the total amount of plastic deformation occurring during the compression process. Tablets made from formulations containing khaya gum had the lowest tensile strength values but also the lowest tendency to laminate or cap, as indicated by their lowest brittleness. All the tablets had friability values < 1% at higher concentrations of the three binders. In addition, khaya gum demonstrated a comparable ability to destroy microorganisms in the formulation during tabletting as the two binders. The characterization of the formulations suggests that khaya gum can be developed into a commercial binding agent for particular tablets.

The destructive effect of khaya gum used as a binding agent in a paracetamol formulation on Bacillus subtilis spores during tableting has been investigated, in comparison with the effects of two standard binders-polyvinylpyrrolidone and gelatin. The destructive effect of khaya gum was generally similar to those of the standard binders. Significant (p < 0.001 in each case) inverse linear relationships of log % survival of the B. subtilis spores with compression pressure and with concentration of binder, were established. The effect of the binding agent was significantly dependent (p < 0.001 in each case) on both compression pressure and the binder concentration. However, there was no significant interaction (p > 0.05) between the destructive effects of compression pressure and binder concentration. The results suggest that khaya gum and the standard binders would be useful in the destruction of microorganisms during tableting.