Gastroretentive Matrix Tablets of Boswellia Oleogum Resin: Preparation, Optimization, In Vitro Evaluation, and Cytoprotective Effect on Indomethacin-Induced Gastric Ulcer in Rabbits

FDM 3D-Printed Sustained-Release Gastric-Floating Verapamil Hydrochloride Formulations with Cylinder, Capsule and Hemisphere Shapes, and Low Infill Percentage

The aim of this work was to design and fabricate fused deposition modeling (FDM) 3D-printed sustained-release gastric-floating formulations with different shapes (cylinder, capsule and hemisphere) and infill percentages (0% and 15%), and to investigate the influence of shape and infill percentage on the properties of the printed formulations. Drug-loaded filaments containing HPMC, Soluplus^® and verapamil hydrochloride were prepared via hot-melt extrusion (HME) and then used to print the following gastric-floating formulations: cylinder-15, capsule-0, capsule-15, hemisphere-0 and hemisphere-15. The morphology of the filaments and the printed formulations were observed by scanning electron microscopy (SEM). The physical state of the drugs in the filaments and the printed formulations were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The printed formulations were evaluated in vitro, including the weight variation, hardness, floating time, drug content and drug release. The results showed that the drug-loaded filament prepared was successful in printing the gastric floating formulations. Verapamil hydrochloride was proved thermally stable during HME and FDM, and in an amorphous state in the filament and the printed formulations. The shape and infill percentage of the printed formulations effected the hardness, floating time and in vitro drug release.

Review of the Chemical Composition, Pharmacological Effects, Pharmacokinetics, and Quality Control of Boswellia carterii

OBJECTIVE

This review aimed to systematically summarize studies that investigated the bioactivities of compounds and extracts from Boswellia.

METHODS

A literature review on the pharmacological properties and phytochemicals of B. carterii was performed. The information was retrieved from secondary databases such as PubMed, Chemical Abstracts Services (SciFinder), Google Scholar, and ScienceDirect.

RESULTS

The various Boswellia extracts and compounds demonstrated pharmacological properties, such as anti-inflammatory, antitumour, and antioxidant activities. B. carterii exhibited a positive effect on the treatment and prevention of many ageing diseases, such as diabetes, cancer, cardiovascular disease, and neurodegenerative diseases.

CONCLUSION

Here, we highlight the pharmacological properties and phytochemicals of B. carterii and propose further evidence-based research on plant-derived remedies and compounds.

Glutaraldehyde-crosslinked chitosan-polyethylene oxide nanofibers as a potential gastroretentive delivery system of nizatidine for augmented gastroprotective activity

Nizatidine (NIZ), a histamine H₂-receptor antagonist, is soluble and stable in the stomach, however, it exhibits a short half-life and a rapid clearance. Therefore, chitosan (CS) and polyethylene oxide (PEO) nanofibers (NFs) at different weight ratios were prepared by electrospinning and characterized. The selected uncrosslinked and glutaraldehyde-crosslinked NFs were investigated regarding floating, solid-state characteristics, in vitro release, and in vitro cytotoxicity. The cytoprotective activity against ethanol-induced gastric injury in rats was evaluated through macroscopical, histopathological, immunohistochemical, and oxidative stress examinations. NFs based on 8:2 CS:PEO exhibited the smallest diameter (119.17 ± 22.05 nm) and the greatest mucoadhesion (22.82 ± 3.21 g/cm²), so they were crosslinked with glutaraldehyde. Solid-state characterization indicated polymers interaction, a successful crosslinking, and NIZ dispersion in NFs. Crosslinking maintained swollen mats at pH 1.2 (swelling% = 29.47 ± 3.50% at 24 h), retarded their erosion at pH 6.8 (swelling%= 84.64 ± 4.91% vs. 25.40 ± 0.79% for the uncrosslinked NFs at 24 h), augmented the floating up to 24 h vs. 10 min for the uncrosslinked NFs at pH 1.2 and prolonged the drug release (%drug released ≥ 93% at 24 h vs. 4 and 5 h for the uncrosslinked NFs at pHs 1.2 and 6.8, respectively). The viability of Caco-2 cells ≥ 86.87 ± 6.86% revealed NFs biocompatibility and unreacted glutaraldehyde removal. Crosslinking of 8:2 CS:PEO NFs potentiated the antiulcer activity (38.98 vs. 8.67 for the uncrosslinked NFs) as well as it preserved the gastric wall architecture, COX-2 expression, and oxidative stress markers levels of the normal rats.

Formulation of Nanospanlastics as a Promising Approach for ‎Improving the Topical Delivery of a Natural Leukotriene Inhibitor (3-‎Acetyl-11-Keto-β-Boswellic Acid): Statistical Optimization, in vitro ‎Characterization, and ex vivo Permeation Study

Purpose

The current study aimed to discuss the potential of nanospanlastics as a surfactant-based vesicular system for improving the topical delivery of 3-acetyl-11-keto-β-boswellic acid (AKBA). AKBA is a potent anti-inflammatory drug, but it has poor oral bioavailability due to its poor aqueous solubility. Moreover, the topical delivery of AKBA is difficult due to its high lipophilicity. To overcome these drawbacks, AKBA was formulated as deformable elastic nanovesicles and nanospanlastics, for improving its topical delivery.

Materials and Methods

AKBA-loaded spanlastic nanovesicles (SNVs) were formulated by ethanol injection technique according to 2³ factorial design using Span 60 as a non-ionic surfactant and Tween 80 as edge activator (EA) to investigate the effect of different independent variables on entrapment efficiency (EE%), % drug released after 8 hr (Q_8h) and particle size (PS) using Design-Expert software. In vitro characterization, stability test and ex vivo permeation study of the optimized formula were performed.

Results

The choice of the optimized formula was based on the desirability criteria.‎ F7 was selected as the optimized formula because it has the highest desirability value of 0.648. F7 exhibited EE% of 90.04±0.58%, Q_8h of 96.87±2.67%, PS of 255.8±2.67 nm, and zeta potential of −49.56 mV. F7 appeared as spherical well-defined vesicles in both scanning electron microscope (SEM) and transmission electron microscope (TEM). The Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) studies investigated the absence of interaction between AKBA and ‎different excipients and good encapsulation of AKBA within SNVs. F7 retained both physical and chemical stability after storage for 3 months at 4–8 °C. Ex vivo permeation test exhibited significant enhancement of permeability of F7 across rat skin than the free drug.

Conclusion

Nanospanlastics could be a promising approach for improving the permeability and topical delivery of AKBA.

Repeated 28-DAY oral dose study on Boswellia sacra oleo gum resin extract for testicular toxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Frankincense (Boswellia sacra Fluck.,) is a widely used herbal drug and household medicine for treatment of several diseases. Earlier toxicological studies revealed its proulcerogenic effect and no significant hepatotoxic or nephrotoxic effects in rats. However, some other members of Boswellia species such as Boswellia papyrifera (Caill. ex Delile) Hochst and Boswellia carterii have been reported for testicular toxicity in rats.

AIM OF THE STUDY

Testicular toxicity of standardized methanolic extract of B. sacra oleo gum resin was determined through repeated oral dose administration for 28 days. Biochemical, histological and genetic changes in rat testes were evaluated.

MATERIALS AND METHODS

B. sacra extract was analyzed for its boswellic acid content by high performance liquid chromatography (HPLC) method. The extract was administered at three different doses to rats. Effect on behavior, weight, food and water consumption along with changes in serum testosterone levels and cytoarchitecture of testis, epididymis and adrenal gland were determined. Gene expression of GSTPi, IGFBP3 and HSP70 in testis was also studied.

RESULTS

Boswellic acids (α and β) were present in highest concentration whereas acetyl-11-keto beta boswellic acid was present in relatively smaller amounts. The extract did not produce any significant change in the behavior of the animals, food/water consumption or weight gain. Serum testosterone levels were significantly decreased only by highest tested dose of Boswellia extract (1000 mg/kg, p.o). Histological examination did not reveal any variation in the structure of testis, adrenal gland and epididymis after administration of the extract while the expression of all three studied genes was significantly decreased.

CONCLUSION

The results indicate that B. sacra extract does not possess any toxic effect on testis. On the contrary, decrease in gene expression of GSTPi, IGFBP3 and HSP70 revealed its antioxidant potential that may protect testes against effect of toxicants. However, a significant reduction in serum testosterone levels point to mechanisms other than direct testicular toxicity.

Promising Swellable Floating Bupropion Tablets: Formulation, in vitro/in vivo Evaluation and Comparative Pharmacokinetic Study in Human Volunteers

Purpose

Bupropion is an antidepressant drug that facilitates weight loss. It is a highly water-soluble drug that needs multiple dosing, so it is considered a potential candidate for oral controlled-release dosage form. The aim of this research was to formulate and evaluate satiety-inducing swellable floating bupropion tablets by direct compression targeting depression associated with eating disorders. Various combinations of natural and semi-synthetic hydrogels were selected to achieve maximum swelling and remaining buoyant in the stomach. This synergistically enhances weight loss by increasing satiety.

Methods

An I-optimal mixture design was conducted to establish the optimal quantitative composition of tablets. Friability, floating lag time, swelling index after 4 and 8 hours, along with the percent of bupropion released at 1 and 8 hours were selected as dependent variables. The optimized formulation was characterized by physicochemical properties, thermal stability, and chemical interaction. In vivo radiographic evaluation of gastric residence besides, the oral bioavailability relative to marketed Wellbutrin^® sustained-release tablets were investigated using human volunteers.

Results

The optimized formulation (73.3 mg xanthan, 120 mg glucomannan, 8.4 mg tamarind kernel powder, 78.3 mg HPMC K15M) was achieved with the overall desirability equals 0.782. In vivo radiographic study showed that formulation was retained for >8 hours in the stomach. Compared with the marketed BUP tablets, the C_max was almost the same with a significant increase (p =0.004) for T_max.

Conclusion

Using combinations of these hydrogels would be promising gastroretentive delivery systems in the control of bupropion rate release with enhanced floating and swelling features.

Colon Targeting of Naringin for Enhanced Cytoprotection Against Indomethacin-Induced Colitis in Rabbits

Background

Naringin is a promising anti-inflammatory drug against various disorders including ulcerative colitis. However, its oral bioavailability is low (8%) possibly due to cleavage at the upper gut. Consequently, colon targeting would be necessary for drug protection at the upper gut, enhanced oral bioavailability and potentiated cytoprotection against colitis.

Methodology

This study involved the formulation of compression-coated tablets of naringin employing mixtures of pH-sensitive Eudragit L100-55 (EUD-L100-55) and different time-dependent polymers including ethyl cellulose (EC), sodium alginate (ALG) and sodium carboxymethyl cellulose (SCMC). Drug-polymer interaction during release was assessed using Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Tablets were evaluated in vitro. Surface morphology of the optimized tablets either before or after exposure to the different release media was examined employing scanning electron microscopy (SEM). Cytoprotection potential of the optimized tablets against indomethacin-induced colitis in rabbits was screened and compared to core tablets through a histopathological examination of colon, measurement of serum perinuclear antineutrophil cytoplasmic antibodies (pANCA) and immunohistochemical localization of tumor necrosis factor-alpha (TNF-α).

Results

FT-IR and DSC results may indicate drug-polymers interaction during release. Release retardation could be related to polymer swelling that was in the order of SCMC > ALG > EC. SEM examination indicated more porous coats at the buffers relative to the acidic medium. Colon targeting was expected in case of coats of 5% ALG, 5% SCMC and 10% EC (w/w) in combination with EUD-L100-55; thus, they were selected for in vivo evaluation. Effective cytoprotection of selected tablets against indomethacin-induced colitis was indicated by a significant (P<0.05) reduction in mucosal damage, serum levels of pANCA and TNF-α expression compared to untreated colitis and core-pretreated groups. Compared to EC, higher cytoprotection potential of ALG- and SCMC-based tablets was reflected by lower concentration (5% w/w) to provide cytoprotection against indomethacin-induced colitis.

Anti-inflammatory and anti-cancer activities of frankincense: Targets, treatments and toxicities

The oleogum resins of Boswellia species known as frankincense have been used for ages in traditional medicine in India, China and the Arabian world independent of its use for cultural and religious rituals in Europe. During the past two decades, scientific investigations provided mounting evidence for the therapeutic potential of frankincense. We conducted a systematic review on the anti-inflammatory and anti-cancer activities of Boswellia species and their chemical ingredients (e.g. 3-O-acetyl-11-keto-β boswellic acid, α- and β-boswellic acids, 11-keto-β-boswellic acid and other boswellic acids, lupeolic acids, incensole, cembrenes, triterpenediol, tirucallic acids, and olibanumols). Frankincense acts by multiple mechanisms, e.g. by the inhibition of leukotriene synthesis, of cyclooxygenase 1/2 and 5-lipoxygenase, of oxidative stress, and by regulation of immune cells from the innate and acquired immune systems. Furthermore, frankincense modulates signaling transduction responsible for cell cycle arrest and inhibition of proliferation, angiogenesis, invasion and metastasis. Clinical trials showed the efficacy of frankincense and its phytochemicals against osteoarthritis, multiple sclerosis, asthma, psoriasis and erythematous eczema, plaque-induced gingivitis and pain. Frankincense revealed beneficial effects towards brain tumor-related edema, but did not reduce glioma size. Even if there is no treatment effect on brain tumors itself, the management of glioma-associated edema may represent a desirable improvement. The therapeutic potential against other tumor types is still speculative. Experimental toxicology and clinical trials revealed only mild adverse side effects. More randomized clinical trials are required to estimate the full clinical potential of frankincense for cancer therapy.

Plant-derived bioadhesives for wound dressing and drug delivery system

Synthetic polymers have been widely used in various biomedical applications like drug delivery, wound dressing, etc. They pose a question of bio-compatibility and bio-accumulation, limiting to a minimum class of synthetic polymers to be efficient and versatile. Hence, one cheap and reliant replacement is the use of natural adhesives over the synthetic adhesive polymeric system. The pluripotency of plant could be exploit, making it a perfect candidate for extraction of plant-derived adhesives component for wound dressing and drug delivery system in large-scale production. Current advancement use excipients which influence, the rate of drug release and absorption. Properties like matrix formation and environment responsive gelation can be exploited through these plant-derived components for controlled drug release according to specific therapeutic requirement. This review explores such plant-derived bioactive component: Mucilage and gums, their isolation, and characterization which can be exploited as excipients in the formulation of drug delivery system as well as a wound dressing.

Design and optimization of gastric floating sustained-release mini-tablets of alfuzosin hydrochloride based on a factorial design: in vitro/in vivo evaluation

The purpose of this research was to develop multiple-unit gastric floating mini-tablets and to evaluate the possibility of using these mini-tablets as a delivery system to improve the drug absorption for drugs with a narrow absorption window. Mini-tablets were prepared using hydroxypropyl methylcellulose (HPMC K100M) and carbopol 971P as release retarding agents and sodium bicarbonate (NaHCO₃) as gas-forming agent. The properties of the prepared mini-tablets in terms of floating characteristic parameters and in vitro release were evaluated. Furthermore, in vivo gastric retention study in rats and in vivo pharmacokinetic study in rabbits of the optimized formulation were performed. The optimized mini-tablets containing 45% HPMC K100M, 15% stearyl alcohol, 13% carbopol 971P, and 12% NaHCO₃ were found to float immediately within 1 min and duration more than 9 h. The in vivo gastric retention study results indicated that the mini-tablets could retain in the stomach for more than 6.67 h. Furthermore, the AUC_0-t of the floating mini-tablets (6849.83 ± 753.80 h ng·mL^-1) was significantly higher than that of marketed sustained-release tablets XATRAL®XL (4970.16 ± 924.60 h ng·mL^-1). All these results illustrated that the gastric floating mini-tablets might be a promising drug delivery system for drugs with a narrow absorption window.

Design and optimization of gastro-floating sustained-release tablet of pregabalin: In vitro and in vivo evaluation

Pregabalin is a promising drug for the treatment of neuropathic pain, a chronic disease affecting a large population needing long-term treatment. However, due to its short half-life, the commercial tablet has to be administered 2-3 times per day, with inconvenience for patient and fluctuations of plasma concentration. In this study, a gastro-floating drug delivery system of pregabalin was developed to prolong the gastric retention of drugs absorbed or act in stomach or upper gastrointestinal tract. First of all, it was proved that the drug was mainly absorbed in stomach and upper gastrointestinal tract. The final formulation was optimized in consideration of buoyancy and drug release profile. The gastro-floating tablet was prepared with hydroxypropyl methylcellulose (HPMC) as sustained-release matrix, lipophilic cetyl alcohol as floating-assistance agent and other excipients to achieve satisfying buoyancy and sustained release performance with mechanisms of diffusion and matrix erosion. Food exhibited significant effect on the pharmacokinetics of gastro-floating tablet and conventional capsule. Compared with conventional capsules, the relative bioavailability of gastro-floating tablet in fasted conditions or in fed conditions was only 62.47 ± 10.80% and 100.98 ± 17.25% respectively, even though the gastro-floating tablet obtained decreased C_max and prolonged T_max in fasted and fed conditions. Besides, good in vivo-in vitro correlation of the gastro-floating tablet was established. In summary, a gastro-floating tablet of pregabalin exhibiting desired buoyancy and release profiles was designed, and the tablet expressed significantly sustained-release behavior in fed conditions with good in vivo-in vitro correlation. The designed gastro-floating system is a promising choice for the patients to relieve neuropathic pain.

Polymeric micelles for potentiated antiulcer and anticancer activities of naringin

Naringin is one of the most interesting phytopharmaceuticals that has been widely investigated for various biological actions. Yet, its low water solubility, limited permeability, and suboptimal bioavailability limited its use. Therefore, in this study, polymeric micelles of naringin based on pluronic F68 (PF68) were developed, fully characterized, and optimized. The optimized formula was investigated regarding in vitro release, storage stability, and in vitro cytotoxicity vs different cell lines. Also, cytoprotection against ethanol-induced ulcer in rats and antitumor activity against Ehrlich ascites carcinoma in mice were investigated. Nanoscopic and nearly spherical 1:50 micelles with the mean diameter of 74.80±6.56 nm and narrow size distribution were obtained. These micelles showed the highest entrapment efficiency (EE%; 96.14±2.29). The micelles exhibited prolonged release up to 48 vs 10 h for free naringin. The stability of micelles was confirmed by insignificant changes in drug entrapment, particle size, and retention (%) (91.99±3.24). At lower dose than free naringin, effective cytoprotection of 1:50 micelles against ethanol-induced ulcer in rat model has been indicated by significant reduction in mucosal damage, gastric level of malondialdehyde, gastric expression of tumor necrosis factor-alpha, caspase-3, nuclear factor kappa-light-chain-enhancer of activated B cells, and interleukin-6 with the elevation of gastric reduced glutathione and superoxide dismutase when compared with the positive control group. As well, these micelles provoked pronounced antitumor activity assessed by potentiated in vitro cytotoxicity particularly against colorectal carcinoma cells and tumor growth inhibition when compared with free naringin. In conclusion, 1:50 naringin-PF68 micelles can be represented as a potential stable nanodrug delivery system with prolonged release and enhanced antiulcer as well as antitumor activities.

The In vitro/vivo Evaluation of Prepared Gastric Floating Tablets of Berberine Hydrochloride

Currently available antiulcer drugs suffered from serious side effects which limited their uses and prompted the need for a safe and efficient new antiulcer agent. The objective of this project work was to retain the drug in the stomach for better antiulcer activity and less side effects. Hence, the aim of our present work was to prepare a gastric floating tablet of Berberine hydrochloride (Ber) with suitable in vitro/vivo properties. In this study, different Ber gastric floating tablets were prepared by simple direct compression using various amounts of HPMCK15M and Carbopol 971PNF combined with other tablet excipients. The properties of the tablets including hardness, buoyancy, swelling ability, in vitro drug release, and in vivo pharmacokinetic study were evaluated. The obtained results disclosed that hardness, floating, swelling, and in vitro drug release of the Ber tablets depended mainly on the ratio of polymer combinations. Moreover, among six formulations, F3 exhibited desirable floating, swelling, and extended drug release. In addition, in vivo pharmacokinetic study suggested that prepared gastric floating tablets had significantly sustained-releasing effects compared with market tablets. Therefore, the developed gastric floating tablets of Ber could be an alternative dosage form for treatment of gastrointestinal disease.

Development and Evaluation of Buccal Films Based on Chitosan for the Potential Treatment of Oral Candidiasis

In this work, chitosan films were prepared by a casting/solvent evaporation methodology using pectin or hydroxypropylmethyl cellulose to form polymeric matrices. Miconazole nitrate, as a model drug, was loaded into such formulations. These polymeric films were characterized in terms of mechanical properties, adhesiveness, and swelling as well as drug release. Besides, the morphology of raw materials and films was investigated by scanning electron microscopy; interactions between polymers were analyzed by infrared spectroscopy and drug crystallinity studied by differential scanning calorimetry and X-ray diffraction. In addition, antifungal activity against cultures of the five most important fungal opportunistic pathogens belonging to Candida genus was investigated. Chitosan:hydroxypropylmethyl cellulose films were found to be the most appropriate formulations in terms of folding endurance, mechanical properties, and adhesiveness. Also, an improvement in the dissolution rate of miconazole nitrate from the films up to 90% compared to the non-loaded drug was observed. The in vitro antifungal activity showed a significant activity of the model drug when it is loaded into chitosan films. These findings suggest that chitosan-based films are a promising approach to deliver miconazole nitrate for the treatment of candidiasis.

Overview on gastroretentive drug delivery systems for improving drug bioavailability

In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems.