Use of Natural Gums and Cellulose Derivatives in Production of Sustained Release Metoprolol Tablets

Influence of Prunus domestica gum on the release profiles of propranolol HCl floating tablets

Propranolol hydrochloride is a beta-blocker used for the management and treatment of hypertension, angina, coronary artery disease, heart failure, fibrillation, tremors, migraine etc. The objective of the present study was to design Propranolol Hydrochloride floating tablets by direct compression method and to explore the role of a new gum as a matrix former. A 2² full factorial design was selected for the present study. Prunus domestica gum and HPMC (K4M) were used as independent variables, swelling index and drug dissolution at 12 hours as dependent variables. Formulations were subjected to pre- and post-compression tests that showed good micromeritics and buoyancy characteristics (Carr’s index 11.76%–14.00%, Hausner’s ratio 1.13°–1.16°, angle of repose 22.67°–25.21°, floating lag time 56–76 seconds, total floating time 18–25 hours and swelling index 59.87%–139.66%). The cumulative drug release in 0.1 N HCl at 12 hours was 72%–90% (p<0.05). Weibull model was found to be the best fit model (R²>0.99) among all other studied models. Multiple regression showed a significant effect of Prunus domestica gum and HPMC K4M on the swelling index and dissolution profiles of propranolol HCl (p<0.05). On the basis of better in-vitro performance and cost-effectiveness, formulation F4 was the best formulation. It is evident from the results that Prunus domestica gum possesses excellent drug release retardant potential for the floating drug delivery system and this new gum should be further explored alone or with other natural and synthetic polymers in future studies.

Spray drying of non-chemically prepared nanofibrillated cellulose: Improving water redispersibility of the dried product

Despite increasing interest in using nanofibrillated cellulose (NFC) as food thickener and emulsifier, poor water redispersibility of dried NFC, which is form suitable for practical utilization, significantly limits such applications. Studies are lacking on preparation of dried NFC with superior redispersibility. The present study therefore proposed and examined strategies to improve water redispersibility of spray dried NFC via the use of selected co-carriers, i.e., gum Arabic with/without xanthan gum, carboxymethyl cellulose or pectin. Synergistic interactions between NFC and co-carriers, as confirmed by X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra, helped prevent NFC agglomeration during spray drying. All reconstituted spray-dried NFC/co-carriers suspensions exhibited shear-thinning and gel-like behaviors, thus supporting the use of such suspensions as thickener and emulsifier. Spray-dried NFC with 80% gum Arabic and 20% xanthan gum (SD-NFC/GA20XG) resulted in suspension with highest viscosity; the suspension also performed best at recovering viscous characteristics of NFC. Water thickened by SD-NFC/GA20XG had strongest shear-thinning behavior, indicating that SD-NFC/GA20XG suspension resulted in smoothest mouth feel and easiest swallowing. Such observations were supported by XRD patterns of SD-NFC/GA20XG, which suggested that its relative crystallinity was the lowest. Its FTIR spectra also showed the highest intensity of -OH bending and carbonyl bands, which are directly related to water adsorption capability of NFC. Use of reconstituted SD-NFC/GA20XG as emulsifier also resulted in highest stability for oil-in-water (O/W) Pickering emulsion during storage for up to 30 days.

Influence of Storage Conditions on the Stability of Gum Arabic and Tragacanth

Storage conditions should be chosen so that they do not affect the action and stability of the active pharmaceutical substance (API), and excipients used in pharmacy. UV irradiation, increased temperature, and relative humidity can decompose storage substances by photolysis, thermolysis, and hydrolysis process, respectively. The effect of physical factors may be the decomposition of pharmaceutical substances or their inappropriate action, including pharmacological effects. Polymers of natural origin are increasingly used in the pharmaceutical industry. With this in mind, we evaluated the effect of storage conditions on the stability of gum arabic (GA) and tragacanth (GT). The influence of higher temperature, UV irradiation, and relative humidity on GA and GT was tested. Thermogravimetry (TG, c-DTA), colorimetric analysis, UV-Vis spectrophotometry, and optical microscopy were used as research methods. The TGA and c-DTA examination indicated that decomposition of GA starts at a higher temperature compared to GT. This indicate that gum arabic is more resistant to higher temperatures compared to tragacanth. However, the conducted analysis showed that gum arabic is more sensitive to the tested storage conditions. Among the tested physical conditions, both polymers were most sensitive to conditions of increased relative humidity in the environment.

Controlled-release granules for the delivery of pymetrozine to roots of transplanted rice seedlings with decreased phytotoxicity and enhanced control efficacy against paddy planthoppers

BACKGROUND

Seedling transplanting is widely used in rice cultivation. Systemic insecticides can be delivered to seedling roots by application through rice seedling boxes before transplanting. The most challenging aspect is to provide long-term control of rice pests and overcome transplanting shock. Precise control of the release rate of insecticide can meet these requirements. Pymetrozine is a promising insecticide used for the control of rice planthoppers resistant to neonicotinoid insecticides.

RESULTS

In this study, four controlled-release granular formulations of pymetrozine were prepared based on a mixture of cost-effective and biodegradable kaolin and xanthan gum or a mixture of calcined kaolin and xanthan gum. Fluorescence images showed that different 3D networks were formed in the four granular formulations. The four granular formulations showed different water uptake rates and release rates of pymetrozine in water. Pymetrozine release rate was positively correlated with the water uptake capacity, rather than the water uptake rate of granules. Diffusion was the dominant mechanism for the release of pymetrozine from granules. Pymetrozine was found to reduce the survival of transplanted rice seedlings suffering from transplanting shock. Incorporating pymetrozine in controlled-release granules alleviated this phytotoxicity. The survival rate of rice seedlings in granular pymetrozine treatments ranged 68.8-85.0%, whereas the survival rate was <50% for powdered pymetrozine treatments. Additionally, four prepared granule formulations had a significant control effect on rice planthopper with efficacies ranging from 76.7% to 98.0% 40 days after seedling box treatment.

CONCLUSIONS

The granule with an intermediate release rate of pymetrozine was shown to be more suitable for seedling box treatment than field application and traditional liquid spraying for the long-term control of paddy planthoppers. © 2021 Society of Chemical Industry.

Khaya grandifoliola C. DC. (Meliaceae: Sapindales): Ethnobotany, phytochemistry, pharmacological properties, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Khaya grandifoliola is a well-known tree species in Africa with a conservation status of 'vulnerable' due to its overexploitation by the wood industry. Several studies have recorded numerous ethnobotanical uses of this plant, as well as the scientific validation of the efficacy of extracts from different plant parts used for the treatment of various ailments. However, this useful information is scattered throughout the literature and thus there is no opportunity to identify the existing knowledge gaps.

AIM OF THE STUDY

This review aims to highlight the medicinal importance of Khaya grandifoliola including its known phytochemistry, biological activities and toxicology, to encourage a refocused conservation strategy since all current efforts are geared towards maintaining its continuous supply to the wood industry.

MATERIALS AND METHODS

Articles on K. grandifoliola were sourced from online databases such as Google Scholar, Medicine, PubMed, Science Direct, Scopus, SciFinder and other science journal websites up to May 2020. The search was conducted using various combinations of keywords such as biotechnological uses, biological activity, ethnobotany, ethnomedicine, indigenous uses, pharmacological activity, phytochemistry, proximate composition, toxicity, and traditional uses of K. grandifoliola. All downloaded articles were screened to determine their relevance to the scope of the review and the selected papers were included.

RESULTS

The review revealed a host of ethnomedicinal uses such as anticancer, antidiabetic, antimicrobial, anti-sickling, anti-ulcerogenic, and hepatoprotective, many of which are supported by scientific data. More importantly, toxicity tests revealed that many of the extracts are safe at various therapeutic doses. Important knowledge gaps that should be explored include phytochemical characterization and validation of some ethnobotanical claims on the folkloric usage of the plant.

CONCLUSIONS

Notwithstanding the importance of K. grandifoliola in the wood industry, this review reveals that its use as a medicine is equally important. Its medicinal uses are also well supported with scientific studies as well as favourable toxicological studies though some scientific knowledge gaps require further studies.

Application of Nanocellulose Derivatives as Drug Carriers; A Novel Approach in Drug Delivery

BACKGROUND

The production of nanocellulose for drug delivery systems has achieved increased attention in the past decade. High capacity for swelling and absorption of the liquid phase, high flexibility in creating different derivatives, economical cost, and ease of access to the primary source, all of these properties have encouraged researchers to use nanocellulose and its derivatives as a high-performance drug carrier.

OBJECTIVE

The recent progress summary of cellulose-based nanocarriers designing and practical approaches in drug delivery.

METHODS

We conducted a literature review on the development of the nanocellulose and its derivatives as a high-performance drug carrier.

RESULTS

In this review, we have attempted to present the latest advances in cellulose modifications for the design of pharmaceutical nanocarriers. At first, cellulose properties and structural classification of nanocellulose were introduced. Then, focusing on medical applications, some efforts and laboratory trials in cellulose-based nano designing were also discussed. The findings demonstrate the benefits of nanocellulose in drug delivery and its potential for modifying by adding functional groups to enhance drug delivery efficiency. Due to the physical and chemical properties of cellulose and its high flexibility to interact with other compounds, a broad perspective can be imagined in the diverse research and novel forms of nanocarriers.

CONCLUSION

The cellulose nanocarriers can be considered as an attractive platform for researchers to design new structures of pharmaceutical carriers and increase the efficiency of these nanocarriers in drug delivery for the treatment of diseases such as cancer.

Evaluation of mucoadhesive property and the effect of Boswellia carteri gum on intranasal vaccination against small ruminant morbillivirus infection (PPR)

A study was conducted to evaluate mucoadhesive property and immunomodulatory effect of phytogenic gums from Boswellia frereana, Boswellia carteri andCommiphora myrrha on intranasal Peste des petits ruminants (PPR) vaccination in goats and sheep in an ex-vivo and in-vivo situations. Plant gums were purified, dried and compressed into 500gm tablets. Modified shear stress measurement technique was used on freshly excised trachea and intestine tissues of goat to measure peak adhesion time. Forty eight animals (24 goats and 24 sheep) were divided into eight groups (of 3 goats and 3 sheep) and immunized intranasally with gum-vaccine combinations in two ratios (1:1, 1:2). Antibody against PPR virus was measured on day 14, 28, 42 and 56 post vaccination using H-based PPR bELISA. The peak adhesion time of the different gums was transient. PPR virus antibodies were detected in all immunized goats and sheep but not in unvaccinated control. The best percentage inhibition was recorded for Boswellia carteri-vaccine combination group at a ratio of 1:1. Administration of Boswellia carteri-PPR vaccine combination through intranasal or subcutaneous route, elicited similar antibody titre, implying that the intranasal route may be used as a non-invasive alternative delivery in PPR vaccination of small ruminants.

Mechanical and release behaviour of theophylline from matrix tablets containing psyllium powder in combination with grewia polysaccharides

This study was aimed at investigating the effect of grewia polysaccharides on the mechanical and release properties of tablet matrices containing binary mixtures of the polysaccharide with psyllium. Two grades of grewia polysaccharides (GG and GDS) were extracted and binary mixtures of the polysaccharides with psyllium were formulated into tablet matrices containing theophylline as the model drug. The true, bulk and tapped densities, Carr's compressibility index of the powders and binary composites were determined before tablet compression. Tablet properties (hardness, porosity, and drug release from the matrices) were investigated. The dissolution test was carried out in 0.1 M HCl (pH 1.2) and phosphate buffer (pH 6.8). The results show that GG and GDS produced tablets with good mechanical strength (108.33 N and 95.70 N, respectively) while psyllium produced softer tablets (7.13 N). The combination of psyllium and grewia polysaccharides in the matrices resulted in a significant increase in the mechanical strength of the matrices when compared to matrices containing psyllium alone as the matrix former. The results also showed that GG and GDS reduced the dissolution rate and effectively eliminated the burst release of theophylline from the psyllium matrices at both pHs. The matrices of GG or GDS and the binary mixtures conform to non-Fickian anomalous diffusion with n > 0.45. When overcoming the burst release of drug from matrices such as psyllium, grewia polysaccharides may provide an effective reduction and a more sustained drug release from such matrices.

Development of Paroxetine Hydrochloride Single Layer Controlled-Release Tablets Based on 3² Factorial Design

Major depressive disorder (MDD) is one of the main contributors to disability and suicide mortality globally. Paroxetine hydrochloride (PHH) is the most potent antidepressant used for MDD treatment. Due to its reduced side effects PAXIL^® CR is a widely-used controlled-release formulation of PHH. However, the complicated double-layer production of PAXIL^® CR faces the risk of layer separation. In this study, PHH enteric coating single layer controlled-release tablets (PHH-EC-SLTs) were designed as a simplified substitution of PAXIL^® CR through a rational formulation screening. The optimized PHH-EC-SLTs showed similar release behaviors in vitro to PAXIL^® CR and the release profiles corresponded to a zero-order release model (R² = 0.9958). Polymer matrix erosion was the main release mechanism, according to the fitting exponents n > 1 in the Korsmeyer-Pappas model. Crucial pharmacokinetic parameters including peak-reaching time (T_max), peak concentration (C_max) and the area under the blood level-time curve (AUC_0-48) of PHH-EC-SLTs and PAXIL^® CR had no significant difference (p > 0.05) and the relative bioavailability (F = 97.97%) of PHH-EC-SLTs demonstrated their similar pharmacokinetic profiles in vivo. In view of avoiding layer separation risk and simplifying the preparation processing, the self-made PHH-EC-SLTs could be considered as a safe and economic alternative to PAXIL^® CR.

Pharmaceutical Applications of Cellulose Ethers and Cellulose Ether Esters

Cellulose ethers have proven to be highly useful natural-based polymers, finding application in areas including food, personal care products, oil field chemicals, construction, paper, adhesives, and textiles. They have particular value in pharmaceutical applications due to characteristics including high glass transition temperatures, high chemical and photochemical stability, solubility, limited crystallinity, hydrogen bonding capability, and low toxicity. With regard to toxicity, cellulose ethers have essentially no ability to permeate through gastrointestinal enterocytes and many are already in formulations approved by the U.S. Food and Drug Administration. We review pharmaceutical applications of these valuable polymers from a structure-property-function perspective, discussing each important commercial cellulose ether class; carboxymethyl cellulose, methyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, and ethyl cellulose, and cellulose ether esters including hydroxypropyl methyl cellulose acetate succinate and carboxymethyl cellulose acetate butyrate. We also summarize their syntheses, basic material properties, and key pharmaceutical applications.

Formulation Development and Evaluation of Diphenhydramine Nasal Nano-Emulgel

The aim of present study is to formulate diphenhydramine nasal nano-emulgels, having lipophilic nano-sized interior droplets, with better penetration for targeted controlled delivery to mucous membrane. Different diphenhydramine (DPH) nasal nano-emulgels were developed having propylene glycol and olive oil (as permeation enhancers) by using RSM for optimization and then evaluated for physico-chemical characteristics and thermal stability. In-vitro drug release through cellophane membrane was conducted and results were analyzed statistically. Further, gelation, mucoadhesive stress, and ex-vivo and histopathological studies were performed on optimized formulation by using goat nasal membrane. Among all formulations, E2 showed maximum DPH release at higher concentration olive oil (4%) and lower concentration propylene glycol (PG) (25%) within 4 h. All formulations have followed first-order kinetics and drug release mechanism was Fickian diffusion. Analysis of variance (ANOVA) and multiple linear regression analysis (MLRA) were used to compare results among formulations and 3D surface plots were constructed also. Optimized formulation showed immediate prolong gelation in artificial nasal mucosa and excellent mucoadhesive property (72.5 ± 1.5 dynes/cm²). Approximately 97.1% optimized formulation was permeated through membrane within 4 h, having a high flux rate (33.19 ± 0.897 μg/cm²/min) with diffusion coefficient (0.000786 ± 4.56 × 10^-5 cm²/min) while drug contents remained on mucosal membrane for 24 h. Histopathologically, change on intra-mucosal surface of excised membrane was observed due to passage of drug through it. In summary, combination of PG and olive oil in nasal DPH nano-emulgel can be utilized successfully for targeted controlled delivery. The optimized formulation has excellent permeability and prolonged residence time on mucosal surface, which prove its good anti-histaminic activity in case of allergic rhinitis.

Extraction, purification and characterization of water soluble galactomannans from Mimosa pudica seeds

Water soluble galactomannans from seed endosperm of Mimosa pudica L. was extracted and characterized (Fig. 1). Nuclear magnetic resonance spectroscopy and Gas Chromatography results revealed the presence of 4-linked mannose backbone with galactose side chains linked at the C6 position. Scanning Electron Micrographs showed smooth, elongated and irregular granular structure of galactomannan. Structural analysis by Attenuated total reflection infrared spectroscopy presented the Mannose to Galactose ratio while the X-ray diffraction studies showed the presences of A-type crystalline pattern of the galactomannan. Thermo Gravitimetric Analysis showed the three steps weight loss event and determined the thermal stability. The results showed that the extracted polysaccharides are typically amorphous, thermally stable and have desirable properties for industrial applications.

Interpenetrating polymer networks as innovative drug delivery systems

Polymers have always been valuable excipients in conventional dosage forms, also have shown excellent performance into the parenteral arena, and are now capable of offering advanced and sophisticated functions such as controlled drug release and drug targeting. Advances in polymer science have led to the development of several novel drug delivery systems. Interpenetrating polymer networks (IPNs) have shown superior performances over the conventional individual polymers and, consequently, the ranges of applications have grown rapidly for such class of materials. The advanced properties of IPNs like swelling capacity, stability, biocompatibility, nontoxicity and biodegradability have attracted considerable attention in pharmaceutical field especially in delivering bioactive molecules to the target site. In the past few years various research reports on the IPN based delivery systems showed that these carriers have emerged as a novel carrier in controlled drug delivery. The present review encompasses IPNs, their types, method of synthesis, factors which affects the morphology of IPNs, extensively studied IPN based drug delivery systems, and some natural polymers widely used for IPNs.

Natural gums as sustained release carriers: development of gastroretentive drug delivery system of ziprasidone HCl

Background

Objective of this study is to show the potential use of natural gums in the development of drug delivery systems. Therefore in this work gastro retentive tablet formulations of ziprasidone HCl were developed using simplex lattice design considering concentration of okra gum, locust bean gum and HPMC K4M as independent variables. A response surface plot and multiple regression equations were used to evaluate the effect of independent variables on hardness, f_lag time, floating time and drug release for 1 h, 2 h, and 8 h and for 24 h. A checkpoint batch was also prepared by considering the constraints and desirability of optimized formulation to improve its in vitro performance. Significance of result was analyzed using ANOVA and p < 0.05 was considered statistically significant.

Results

Formulation chiefly contains locust bean gum found to be favorable for hardness and floatability but combined effect of three variables was responsible for the sustained release of drug. The in vitro drug release data of check point batch (F8) was found to be sustained well compared to the most satisfactory formulation (F7) of 7 runs. The ‘n’ value was found to be between 0.5 and 1 suggesting that release of drug follows anomalous (non-fickian) diffusion mechanism indicating both diffusion and erosion mechanism from these natural gums. Predicted results were almost similar to the observed experimental values indicating the accuracy of the design. In vivo floatability test indicated non adherence to the gastric mucosa and tablets remain buoyant for more than 24 h.

Conclusions

Study showed these eco-friendly natural gums can be considered as promising SR polymers.

Structural and thermal characterization of galactomannans from genus Gleditsia seeds as potential food gum substitutes

BACKGROUND

Seed galactomannans are preferred hydrocolloids since they are comparatively cheap, non-toxic, eco-friendly and non-polluting during production and application. Galactomannans from seeds of three species of Gleditsia, namely G. sinensis, G. microphylla and G. melanacantha, were characterized in terms of structural and thermal properties.

RESULTS

Gleditsia polysaccharides were characterized using both chemical and chromatographic methods, as well as Fourier transform infrared, (1) H nuclear magnetic resonance (NMR) and (13) C NMR spectroscopy, and it was shown that they consist of D-mannopyranose and D-galactopyranose residues. The mannose/galactose (M/G) ratio of galactomannans was 3.25, 3.31 and 2.30, respectively. It was also found that these polysaccharides differ from one another in values of M(w) , M(n) and polydispersity. X-ray diffraction confirmed the amorphous nature of Gleditsia galactomannans, although G. sinensis galactomannan showed a high crystallinity. Thermal analysis of the galactomannans by differential scanning calorimetry illustrated that their endothermic peaks ranged from 290 to 320 °C.

CONCLUSION

Gleditsia polysaccharides are neutral galactomannans. The higher value of M/G ratio from G. sinensis and G. microphylla indicates that their gums offer an excellent alternative for locus bean gum.

Polymeric plant-derived excipients in drug delivery

Drug dosage forms contain many components in addition to the active pharmaceutical ingredient(s) to assist in the manufacturing process as well as to optimise drug delivery. Due to advances in drug delivery technology, excipients are currently included in novel dosage forms to fulfil specific functions and in some cases they directly or indirectly influence the extent and/or rate of drug release and absorption. Since plant polysaccharides comply with many requirements expected of pharmaceutical excipients such as non-toxicity, stability, availability and renewability they are extensively investigated for use in the development of solid oral dosage forms. Furthermore, polysaccharides with varying physicochemical properties can be extracted from plants at relatively low cost and can be chemically modified to suit specific needs. As an example, many polysaccharide-rich plant materials are successfully used as matrix formers in modified release dosage forms. Some natural polysaccharides have even shown environmental-responsive gelation characteristics with the potential to control drug release according to specific therapeutic needs. This review discusses some of the most important plant-derived polymeric compounds that are used or investigated as excipients in drug delivery systems.

Development and release mechanism of diltiazem HCl prolonged release matrix tablets

A coated matrix tablet formulation has been used to develop controlled release diltiazem HCl (DIL) tablets. The developed drug delivery system provided prolonged drug release rates over a defined period of time. DIL tablets prepared using dry mixing and direct compression and the core consisted of hydrophilic and hydrophobic polymers such as hydroxypropylmethylcellulose (HPMC), Eudragits RLPO/RSPO, microcrystalline cellulose, and lactose. Tablets were coated with Eudragit NE 30D, and the influence of varying the inert hydrophobic polymers and the amount of the coating polymer were investigated. The release profile of the developed formulation was described by the Higuchi model. Stability trials up to 6 months displayed excellent reproducibility.

Use of hydrophilic natural gums in formulation of sustained-release matrix tablets of tramadol hydrochloride

The objective of this work was to develop matrix sustained-release tablets of highly water-soluble tramadol HCl using natural gums (xanthan [X gum] and guar [G gum]) as cost-effective, nontoxic, easily available, and suitable hydrophilic matrix systems compared with the extensively investigated hydrophilic matrices (ie, hydroxypropyl methylcellulose [HPMC]/carboxymethyl cellulose [CMC] with respect to in vitro drug release rate) and hydration rate of the polymers. Matrix tablets of tramadol (dose 100 mg) were produced by direct compression method. Different ratios, of 100∶0, 80∶20, 60∶40, 20∶80, 0∶100 of G gum (or X):HPMC, X gum:G gum, and triple mixture of these polymers (G gum, X gum, HPMC) were applied. After evaluation of physical characteristics of tablets, the dissolution test was, performed in the phosphate buffer media (pH 7.4) up to 8 hours. Tablets with only X had the highest mean dissolution time (MDT), the least dissolution efficiency (DE8%), and released the drug following a zero-order model via swelling, diffusion, and erosion mechanisms. Guar gum alone could not efficiently control the drug release, while X and all combinations of natural gums with HPMC could retard tramadol HCl release. However, according to the similarity factor (f 2), pure HPMC and H8G2 were the most similar formulations to Topalgic-LP as the reference standard.