Multifaceted role of clay minerals in pharmaceuticals

Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 μm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

ROS generation and p-38 activation contribute to montmorillonite-induced corneal toxicity in vitro and in vivo

BACKGROUND

Montmorillonite (Mt) and its derivatives are now widely used in industrial and biomedical fields. Therefore, safety assessments of these materials are critical to protect human health after exposure; however, studies on the ocular toxicity of Mt are lacking. In particular, varying physicochemical characteristics of Mt may greatly alter their toxicological potential. To explore the effects of such characteristics on the eyes, five types of Mt were investigated in vitro and in vivo for the first time, and their underlying mechanisms studied.

RESULTS

The different types of Mt caused cytotoxicity in human HCEC-B4G12 corneal cells based on analyses of ATP content, lactate dehydrogenase (LDH) leakage, cell morphology, and the distribution of Mt in cells. Among the five Mt types, Na-Mt exhibited the highest cytotoxicity. Notably, Na-Mt and chitosan-modified acidic Na-Mt (C-H-Na-Mt) induced ocular toxicity in vivo, as demonstrated by increases corneal injury area and the number of apoptotic cells. Na-Mt and C-H-Na-Mt also induced reactive oxygen species (ROS) generation in vitro and in vivo, as indicated by 2',7'-dichlorofluorescin diacetate and dihydroethidium staining. In addition, Na-Mt activated the mitogen-activated protein kinase signaling pathway. The pretreatment of HCEC-B4G12 cells with N-acetylcysteine, an ROS scavenger, attenuated the Na-Mt-induced cytotoxicity and suppressed p38 activation, while inhibiting p38 activation with a p38-specific inhibitor decreased Na-Mt-induced cytotoxicity.

CONCLUSIONS

The results indicate that Mt induces corneal toxicity in vitro and in vivo. The physicochemical properties of Mt greatly affect its toxicological potential. Furthermore, ROS generation and p38 activation contribute at least in part to Na-Mt-induced toxicity.

Sustainable sepiolite-based composites for fast clotting and wound healing

Uncontrolled bleeding and bacterial coinfection are the major causes of death after an injury. Fast hemostatic capacity, good biocompatibility, and bacterial coinfection inhibition pose great challenges to hemostatic agent development. A prospective sepiolite/Ag nanoparticles (sepiolite@AgNPs) composite has been prepared by using natural clay sepiolite as template. A tail vein hemorrhage mouse model and a rabbit hemorrhage model were used to evaluate the hemostatic properties of the composite. The sepiolite@AgNPs composite can quickly absorb fluid to subsequently stop bleeding due to the natural fibrous crystal structure of sepiolite, and inhibit bacterial growth with the antibacterial ability of AgNPs. Compared with commercially-available zeolite material, the as-prepared composite exhibits competitive hemostatic properties without exothermic reaction in the rabbit model of femoral and carotid artery injury. The rapid hemostatic effect was due to the efficient absorption of erythrocyte and activation of the coagulation cascade factors and platelets. Besides, after heat-treatment, the composites can be recycled without significant reduction of hemostatic performance. Our results also prove that sepiolite@AgNPs nanocomposites can stimulate wound healing. The sustainability, lower-cost, higher bioavailability, and stronger hemostatic efficacy of sepiolite@AgNPs composite render these nanocomposites as more favorable hemostatic agents for hemostasis and wound healing.

A Review of Pickering Emulsions: Perspectives and Applications

Pickering emulsions are systems composed of two immiscible fluids stabilized by organic or inorganic solid particles. These solid particles of certain dimensions (micro- or nano-particles), and desired wettability, have been shown to be an alternative to conventional emulsifiers. The use of biodegradable and biocompatible stabilizers of natural origin, such as clay minerals, presents a promising future for the development of Pickering emulsions and, with this, they deliver some advantages, especially in the area of biomedicine. In this review, the effects and characteristics of microparticles in the preparation and properties of Pickering emulsions are presented. The objective of this review is to provide a theoretical basis for a broader type of emulsion, in addition to reviewing the main aspects related to the mechanisms and applications to promote its stability. Through this review, we highlight the use of this type of emulsion and its excellent properties as permeability promoters of solid particles, providing ideal results for local drug delivery and use in Pickering emulsions.

MgAl and ZnAl-Hydrotalcites as Materials for Cosmetic and Pharmaceutical Formulations: Study of Their Cytotoxicity on Different Cell Lines

The knowledge about the effect of hydrotalcites (HTlcs), largely used in pharmaceutics, on non-malignant cell lines is limited. The effect of MgAl-HTlc-and ZnAl-HTlc- (NO3−/Cl−/CO32−) on the cell viability of HaCat, fibroblasts and HepG2 was studied by MTT assay. Cells were incubated either with HTlc suspensions in the culture media and with the supernatant obtained from the suspension being centrifuged. MgAl-HTlcs suspensions resulted in being cytotoxic. As SEM and TEM analyses showed the presence of sub-micrometric particles in all the MgAl-HTlc examined, it could be hypothesized that this fraction can be internalized into cells reducing the viability. MgAl-HTlc-NO3 is the most cytotoxic probably due to the additional effect of NO3− anions. ZnAl-HTlcs are cytotoxic, especially for HaCat and HepG2 cells (viability <60% at all the concentrations assayed). The effect is attributable both to the sub-micrometric fraction (identified by TEM) and to the high Zn2+ levels found in the culture medium by ICP-OES analysis, suggesting that ZnAl-HTlcs are less stable than MgAl-HTlc in the used media. The obtained results suggest that it is very important to perform ad hoc studies in order to evaluate HTlc safety before to be introduced in a formulation.

Multifaceted synergistic electron transfer mechanism for enhancing denitrification by clay minerals

The performance and mechanism of denitrification enhanced by three clay minerals, montmorillonite (Mmt), illite and kaolinite, were first studied. Batch experiments indicated that clay minerals significantly enhanced denitrification at certain concentrations (0.1-1 g/L). The denitrification rate with 1 g/L Mmt was increased by 5.0-fold. The mechanism of clay minerals promoting denitrification was analyzed from three aspects: electron transfer characteristics, interfacial interaction and metabolism activity. Electrochemical tests showed that the clay minerals promoted electron transfer rate by improving current efficiency and electronic accommodation capacity. The biofilm formation on the clay minerals interface indicated that micro-domain catalytic phases were formed, which was beneficial to improve the nitrate reduction rate. In addition, nicotinamide adenine dinucleotide, nitrate reductase and nitrite reductase activities in Mmt-supplemented system were increased by 283.3%, 128.1% and 126.2%, respectively; and extracellular polymeric substance secretion was enhanced, indicating that the addition of clay minerals promoted microbial metabolic activity. Higher microbial diversity and enrichment of electroactive bacteria were observed in the Mmt-supplemented system. Based on the above exploration, the multifaceted synergistic mechanism was proposed to account for the enhanced denitrification performance on clay minerals. Overall, this study expanded understanding of the roles of clay minerals on denitrification and provided strategies for accelerating the biological transformation process.

Copper/Zinc-Modified Palygorskite Protects Against Salmonella Typhimurium Infection and Modulates the Intestinal Microbiota in Chickens

Palygorskite (Pal), a clay nanoparticle, has been demonstrated to be a vehicle for drug delivery. Copper has antibacterial properties, and zinc is an essential micronutrient for intestinal health in animals and humans. However, whether copper/zinc-modified Pal (Cu/Zn-Pal) can protect chickens from Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) infection remains unclear. In this study, three complexes (Cu/Zn-Pal-1, Cu/Zn-Pal-2, and Cu/Zn-Pal-3) were prepared, and Cu/Zn-Pal-1 was shown to be the most effective at inhibiting the growth of S. Typhimurium in vitro, whereas natural Pal alone had no inhibitory effect. In vivo, Cu/Zn-Pal-1 reduced S. Typhimurium colonization in the intestine of infected chickens and relieved S. Typhimurium-induced organ and intestinal mucosal barrier damage. Moreover, this reduction in Salmonella load attenuated intestinal inflammation and the oxidative stress response in challenged chickens. Additionally, Cu/Zn-Pal-1 modulated the intestinal microbiota in infected chickens, which was characterized by the reduced abundance of Firmicutes and the increased abundance of Proteobacteria and Bacteroidetes. Our results indicated that the Cu/Zn-Pal-1 complex may be an effective feed supplement for reducing S. Typhimurium colonization of the gut.

The Antimicrobial Properties of Modified Pharmaceutical Bentonite with Zinc and Copper

Pharmaceutical grade bentonite, containing a high amount of montmorillonite, enriched with zinc (Zn) or copper (Cu) (ZnBent and CuBent, respectively) was used as the main component for the creation of formulations for cutaneous use and tested for their antimicrobial capacity. Bentonite (Bent) with added phenoxyethanol (PH) as a preservative and unmodified bentonite were used as control groups. The mineralogical composition, structural state, and physical or chemical properties, before and after the modification of the samples, were characterized utilizing X-ray Diffraction Analysis (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Fluorescence (XRF) techniques, and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM, SEM-EDS) analyses. In addition, the profile of zinc and copper concentration from two types of surfaces ZnBent and CuBent, and into Phosphate-Buffered Saline (PBS) are discussed. Finally, the formulations in the form of basic pastes were challenged against bacteria, molds, and yeasts, and their performance was evaluated based on the European Pharmacopeia criteria. The Cu-modified bentonite performed excellently against bacteria and yeasts, while the Zn-modified bentonite only showed great results against yeasts. Therefore, Cu-modified bentonite formulations could offer antimicrobial protection without the use of preservatives.

Nanoclay-based drug delivery systems and their therapeutic potentials

Safe, therapeutically effective, and patient-compliant drug delivery systems are needed to design novel tools and strategies to combat the deadliest of diseases such as cancer, SARS, H7N9 avian influenza, and dengue infection. The major challenges in drug delivery are cytotoxicity, poor biodistribution, insufficient functionality, ineffective drug incorporation in delivery devices, and subsequent drug release. Clay minerals are a class of nanolayered silicates that have good biocompatibility, high specific surface area, chemical inertness, colloid, and thixotropy, and are attractive practical and potential nanomaterials in medicine. These properties enable the usage of nanoclays as drug carriers for the delivery of antibiotics, antihypertensive drugs, anti-psychotic, and anticancer drugs. The review examines the latest advances in nanoclay-based drug delivery systems and related applications in gene therapy and tissue engineering. Clay minerals, particularly montmorillonite, kaolinite, and halloysite are used to delay and/or target drug release or even improve drug dissolution due to their surface charge. Chemical modification of clay minerals such as intercalation of ions into the interlayer space of clay minerals or surface modification of clay minerals is a strategy to tune the properties of nanoclays for the loading and release of a drug. The modified nanoclay can take up drugs by encapsulation, immobilization, ion exchange reaction, or electrostatic interactions. Controlled drug release from the drug-clay originates from the incorporation and interactions between the drug and inorganic layers, including electrostatic interactions and hydrogen bonding. Montmorillonite has proven non-toxic through hematological, biochemical, and histopathological analyses in rat. Montmorillonite can also act as a potent detoxifier. Halloysite nanotubes can bind synthetic and biological components such as chitosan, gelatin, and alginate innate nanocarriers for the improved loading and controlled release of drugs, proteins, and DNA. The peculiar properties of clay nanoparticles lead to promising applications in drug delivery, gene delivery, tissue engineering, cancer and stem cell isolation, and bioimaging.

Recent advances in the design of inorganic and nano-clay particles for the treatment of brain disorders

Inorganic materials, in particular nanoclays and silica nanoparticles, have attracted enormous attention due to their versatile and tuneable properties, making them ideal candidates for a wide range of biomedical applications, such as drug delivery. This review aims at overviewing recent developments of inorganic nanoparticles (like porous or mesoporous silica particles) and different nano-clay materials (like montmorillonite, laponites or halloysite nanotubes) employed for overcoming the blood brain barrier (BBB) in the treatment and therapy of major brain diseases such as Alzheimer's, Parkinson's, glioma or amyotrophic lateral sclerosis. Recent strategies of crossing the BBB through invasive and not invasive administration routes by using different types of nanoparticles compared to nano-clays and inorganic particles are overviewed.

Electrospun, sepiolite-loaded poly(vinyl alcohol)/soy protein isolate nanofibers: Preparation, characterization, and their drug release behavior

Wound management and drug release are important applications for electrospun nanofibers. In this study, poly(vinyl alcohol)/soy protein isolate (PVA/SPI) nanofiber mats were produced by electrospinning and used as drug carriers. The mats were loaded with ketoprofen by dissolving the drug in the solutions for nanofiber electrospinning. To improve drug release control of the nanofiber mats, a natural tubular nanoparticle, sepiolite, was used as a secondary release control tool. Three types of nanofiber mats were fabricated by electrospinning the solutions prepared by 1) direct mixing of PVA, SPI, and ketoprofen, 2) direct mixing of PVA, SPI, sepiolite, and ketoprofen, and 3) mixing PVA, SPI, and ketoprofen-preloaded sepiolite. The drug release behavior of the mats was studied using UV-vis spectroscopy and the mechanical properties of the mats were investigated by tensile testing. The results showed that sepiolite had a high impact on the release of ketoprofen, with the drug-loaded sepiolite leading to the slowest release. The incorporation of SPI and sepiolite into the PVA nanofibers also increased the mechanical strength of the mats, making them easier to handle and potentially longer-lasting. This study demonstrated the potential of using natural biomaterials and nanomaterials as the components of controlled-release drug delivery vehicles.

Broad-Spectrum Antimicrobial and Antibiofilm Activity of a Natural Clay Mineral from British Columbia, Canada

Worldwide increases in antibiotic resistance and the dearth of new antibiotics have created a global crisis in the treatment of infectious diseases. These concerns highlight the pressing need for novel antimicrobial agents. Natural clay minerals have a long history of therapeutic and biomedical applications and have lately received specific attention for their potent antimicrobial properties. In particular, Kisameet clay (KC) has strong antibacterial activity against a variety of multidrug-resistant (MDR) bacterial pathogens in vitro Here, we have extended the known spectrum of activity of KC by demonstrating its efficacy against two major fungal pathogens, Candida albicans and Cryptococcus neoformans In addition, KC also exhibits potent activity against the opportunistic bacterial pathogen Mycobacterium marinum, a model organism for M. ulcerans infection. Moreover, aqueous KC leachates (KC-L) exhibited broad-spectrum antibacterial activity, eradicated Gram-negative and Gram-positive biofilms, and prevented their formation. The mechanism(s) underlying KC antibacterial activity appears to be complex. Adjusting KC-L to neutral pH rendered it inactive, indicating a contribution of pH, although low pH alone was insufficient for its antibacterial activity. Treatment of KC minerals with cation-chelating agents such as EDTA, 2,2'-bipyridyl, and deferoxamine reduced the antibacterial activity, while supplementation of KC-L with these chelating agents eliminated the inhibitory activity. Together, the data suggest a positive role for divalent and trivalent cations, including iron and aluminum, in bacterial inhibition by KC. Collectively, these studies demonstrate the range of KC bioactivity and provide a better understanding of the mechanism underlying its antibacterial effects.IMPORTANCE The escalating emergence of multidrug-resistant (MDR) bacteria, together with the paucity of novel antimicrobial agents in antibiotic development, is recognized as a worldwide public health crisis. Kisameet clay (KC), found in British Columbia (BC), Canada, is a clay mineral with a long history of therapeutic applications among people of the First Nations. We previously reported the antibacterial activity of KC against a group of MDR clinical pathogens. Here, we demonstrate its activity against two major human-pathogenic fungal species, as well as against bacterial biofilms, which underlie many recalcitrant bacterial infections. In these studies, we also identified several geochemical characteristics of KC, such as metal ions and low pH, which are involved in its antibacterial activity. These findings provide a better understanding of the components of KC antibacterial activity and a basis for developing defined preparations of this clay mineral for therapeutic applications.

New Technological Approach for Glycyrrethic Acid Oral and Topical Administration

Background:

18β- glycyrrhetinic acid (Gly) is the major bioactive component of licorice roots and rhizomes of the Glycyrrhiza glabra species. It shows many activities such as antiviral, anti-inflammatory, antioxidant, antimicrobial, and antifungal, however, its use in the health field is very limited due to the low water solubility.

Methods:

This paper deals with the development of a new technological approach for Gly dissolution rate enhancement. It consists of Gly intercalation (guest) in the interlamellar spaces between the inorganic spaces (host) of the anionic clays “hydrotalcites” (HTlc) to obtain hybrids MgAl-HTlc-Gly and ZnAl-HTlc-Gly. Gly can find applications in both systemic and local therapies, thus advantages of the use of the hybrids in these two fields were investigated.

Results:

Gly dissolution rate from hybrids in the intestinal environment, site in which it is preferentially absorbed, resulted enhanced (ZnAl-HTlc-Gly > MgAl-HTlc-Gly) compared to the crystalline form, thereby, making them suitable for oral administration as dry powder in hard capsules.

:

For a local therapy, bioadhesive, vaginal emulgels loaded with the hybrids were developed. These showed suitable mucoadhesive property to the vaginal mucosa, necessary to prolong the residence time in the application site. The emulgel containing ZnAl-HTlc-Gly showed a faster and higher release profile than that containing MgAl- HTlc-Gly.

Conclusions:

The obtained results suggest that Gly intercalation into HTlc, especially in ZnAl-HTlc, allows to enhance Gly dissolution when the hybrids are formulated both as oral or topical products.

Elevated Arsenic and Lead Concentrations in Natural Healing Clay Applied Topically as a Treatment for Ulcerative Dermatitis in Mice

Ulcerative dermatitis in laboratory mice remains an ongoing clinical problem and animal welfare issue. Many products have been used to treat dermatitis in mice, with varying success. Recently, the topical administration of healing clays, such as bentonite and green clays, has been explored as a viable, natural treatment. We found high concentrations of arsenic and lead in experimental samples of therapeutic clay. Given the known toxic effects of these environmental heavy metals, we sought to determine whether the topical administration of a clay product containing bioavailable arsenic and lead exerted a biologic effect in mice that potentially could introduce unwanted research variability. Two cohorts of 20 singly housed, shaved, dermatitis free, adult male CD1 mice were dosed daily for 2 wk by topical application of saline or green clay paste. Samples of liver, kidney and whole blood were collected and analyzed for total arsenic and lead concentrations. Hepatic and renal concentrations of arsenic were not different between treated and control mice in either cohort; however, hepatic and renal concentrations of lead were elevated in clay treated mice compared to controls in both cohorts. In addition, in both cohorts, the activity of δ-aminolevulinate acid dehydratase, an enzyme involved with heme biosynthesis and a marker of lead toxicity, did not differ significantly between the clay-treated mice and controls. We have demonstrated that these clay products contain high concentrations of arsenic and lead and that topical application can result in the accumulation of lead in the liver and kidneys; however, these concentrations did not result in measurable biologic effects. These products should be used with caution, especially in studies of lead toxicity, heme biosynthesis, and renal α2 microglobulin function.

Exploration of a New Source of Sustainable Nanomaterial from the Koh-e-Suleiman Mountain Range of Pakistan for Industrial Applications

The present study aimed to explore a new source of montmorillonite and to develop an extraction and purification protocol for its isolation from raw clay samples acquired from the Koh-e-Suleiman mountain range in Pakistan. The process involved the collection of raw clay from the source, identification and quantification of montmorillonite. Granulometric extraction and purification protocols increased the montmorillonite content from 21.8-25.1% in the raw clay to 90.1-93.9% after small-scale extraction and 85.33-89.33% on a larger scale. A techno-economic analysis highlighted the practicality and economic benefits of large-scale extraction for industrial applications. This study highlights the existence of a substantial new source of this valuable clay which is currently used across multiple industries including construction, pottery making, pharmaceuticals, cosmetics and engineering. It is intuitively expected that the large-scale extraction of the material will improve the economic condition of the region by providing employment opportunities to locals and may be a valuable resource for export.

Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

The present work aimed at assessing the pharmaceutical tableting properties of some Egyptian kaolin samples belong to the Abu Zenima kaolin deposits (estimated at 120 million tons). Four representative samples were selected based on kaolinite richness and their structural order-disorder degree, and after purification, they were dried at 70 °C and heated from room temperature up to 400 °C (10 °C/min). Mineralogy, micromorphology, microtexture, granulometry, porosimetry, moisture content, bulk and tapped density, direct and indirect flowability, and tableting characteristics are studied. Results indicated that purified kaolin samples were made up of 95–99% kaolinite, <3% illite, 1% quartz and 1% anatase. The powder showed mesoporous character (pore diameters from 2 to 38 nm and total pore volume from 0.064 to 0.136 cm3/g) with dominance of fine nanosized particles (<1 μm–10 nm). The powder flow characteristics of both the ordered (Hinckley Index HI > 0.7, crystallite size D001 > 30 nm) and disordered (HI < 0.7, D001 < 30 nm) kaolinite-rich samples have been improved (Hausner ratio between 1.24 and 1.09) as their densities were influenced by thermal treatment (with some observed changes in the kaolinite XRD reflection profiles) and by moisture content (variable between 2.98% and 5.82%). The obtained tablets exhibited hardness between 33 and 44 N only from the dehydrated powders at 400 °C, with elastic recovery (ER) between 21.74% and 25.61%, ejection stress (ES) between 7.85 and 11.45 MPa and tensile fracture stress (TFS) between 1.85 and 2.32 MPa, which are strongly correlated with crystallinity (HI) and flowability (HR) parameters. These findings on quality indicators showed the promising pharmaceutical tabletability of the studied Egyptian kaolin powders and the optimization factors for their manufacturability and compactability.

Effect of Pressure Treatment on the Specific Surface Area in Kaolin Group Minerals

Pressure can tailor the properties of a material by changing its atomistic arrangements and/or crystal morphology. We have investigated the changes in the adsorption properties of kaolin group minerals as a function of pressure treatment in the gigapascal range. External pressures have been applied using a large volume press (LVP) to kaolinite (Al2Si2O5(OH)4) and halloysite (H4Al2O9Si2·2H2O), which represent natural 2D layered and 1D nanowire structures, respectively. Powdered samples have been compressed up to 3 GPa in 1 GPa steps at room temperature and recovered by up to ca. 0.35 g from each pressure step. Brunauer–Emmett–Teller (BET) measurements were conducted using N2 gas to measure the specific surface area, pore size distribution, and pore volume of the pressure-treated samples. As the treatment pressure increased, kaolinite showed an increase in the adsorption behavior from nonpores to mesopores, whereas halloysite responded in an opposite manner to show a decrease in its adsorption capability. We discuss the contrasting effects of pressure-treatment on the two morphologically distinct kaolin group minerals based on field-emission scanning electron microscope (FE-SEM) images measured on each recovered material. We observed that the layers in kaolinite separate into smaller units upon increasing pressure treatment, whereas the tubes in halloysite become flattened, which led to the contrasting changes in surface area. Further study is in progress to compare this effect to when water is used as the pressure-transmitting medium.

Synthesis of Saponite Based Nanocomposites to Improve the Controlled Oral Drug Release of Model Drug Quinine Hydrochloride Dihydrate

In the present research study, a 2:1 type of smectite clay minerals, namely natural saponite (NSAP) and synthetic saponite (SSAP), was demonstrated for the first time to be controlled drug release host materials for the model drug quinine hydrochloride dihydrate (QU). The popular sol-gel hydrothermal technique was followed for the synthesis of saponite. The QU was ion exchanged and intercalated into an interlayered gallery of synthetic as well as natural saponite matrices. The developed QU-loaded hybrid composite materials along with the pristine materials were characterized by powder X-ray diffraction (PXRD), Fourier transformed infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), the Brunauer-Emmett-Teller method (BET) for surface area (SA), and scanning electron microscopy (SEM). The characterization of material results using DSC, FTIR and PXRD confirmed the presence of saponite clay mineral phases in the original and the synthesized saponite samples. Similarly, the drug-loaded composites confirmed the successful intercalation of QU drug on the natural and synthesized saponite matrices. The oral drug release performance of both nanocomposites along with pure quinine drug was monitored in sequential buffer environments at 37 ± 0.5 °C. These composite hybrid materials showed the superior controlled release of QU in gastric fluid (pH = 1.2) and intestinal fluid (pH = 7.4). QU release was best fitted in the Korsmeyer-Peppas kinetic model and demonstrated a diffusion-controlled release from nanocomposite layered materials. The observed controlled drug release results suggest that the applied natural/synthetic saponite matrices have the potential to provide critical design parameters for the development of bioengineered materials for controlled drug release.

The Use of Some Clay Minerals as Natural Resources for Drug Carrier Applications

The goal of modern research is to use environmentally preferable materials. In this context, clay minerals are emerging candidates for their bio- and ecocompatibility, low cost and natural availability. Clay minerals present different morphologies according to their layer arrangements. The use of clay minerals, especially in biomedical applications is known from ancient times and they are regaining attention in recent years. The most representative clay minerals are kaolinit, montmorillonite, sepiolites and halloysite. This review summarizes some clay minerals and their derivatives for application as nanocontainer for biologically active species.

Preparation and characterization of biocomposite films of carrageenan/locust bean gum/montmorrillonite for transdermal delivery of curcumin

Introduction: Skin can be used as a site for local and systemic drug administration. Diffusion of drugs through the skin has led to the development of different transdermal drug delivery systems. Curcumin is a wound healing and anti-inflammatory agent. Curcumin was incorporated into biocomposite films of carrageenan (κC)/locust bean gum (LBG)/ montmorillonite (MMT) prepared by a solvent casting method. Methods: Film-forming solutions were prepared by adding and 2.5% v/v of propylene glycol and MMT (30% w/w). The curcumin loaded polymer composite transdermal films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Mechanical properties in terms of tensile strength and extensibility were studied. Films were also evaluated for moisture content, moisture uptake, thickness, folding endurance, swelling ratio and water vapor transmission rate (WVTR). Results: κC and κC/L40 showed the highest percent cumulative release of 80.42±1.61% and 69.38±1.26% among all of the polymer composite transdermal films in 8 hours and 24 hours respectively. Conclusion: In vitro release profiles showed that increasing concentration of LBG and MMT sustained the release of the drug from the polymer composite transdermal films. Decreased percent cumulative release as the concentration of LBG and MMT increases in polymer composite transdermal film.