Controlled release formulation of ranitidine-containing montmorillonite and Eudragit® E-100

Interactions between Active Ingredient Ranitidine and Clay Mineral Excipients in Pharmaceutical Formulations

Excipients play an important role in pharmaceutical formulations. Many clay minerals, because of their large specific surface area and inert behaviour in reactions with active ingredients, are commonly used as excipients. In this study, the uptake of ranitidine (RT), the active ingredient of Zantac, on and released from palygorskite (Pal), kaolinite (Kao), and talc was evaluated under different physicochemical conditions. The results showed that the uptake of RT on these minerals was limited to the external surface areas only. Cation exchange and electrostatic interactions were responsible for the RT uptake on Pal and Kao, resulting in a monolayer sorption. In contrast, multilayer RT uptake was found on the talc surfaces. Under different desorbing conditions, significant amounts of sorbed RT remained on the solid surface after 5 h of desorption. The results suggest that the sorptive interactions between the active ingredients and the excipients may not be neglected in pharmaceutical formulations, should these minerals be used as additives and/or excipients.

Polymer Selection for Hot-Melt Extrusion Coupled to Fused Deposition Modelling in Pharmaceutics

Three-dimensional (3D) printing offers the greatest potential to revolutionize the future of pharmaceutical manufacturing by overcoming challenges of conventional pharmaceutical operations and focusing design and production of dosage forms on the patient’s needs. Of the many technologies available, fusion deposition modelling (FDM) is considered of the lowest cost and higher reproducibility and accessibility, offering clear advantages in drug delivery. FDM requires in-house production of filaments of drug-containing thermoplastic polymers by hot-melt extrusion (HME), and the prospect of connecting the two technologies has been under investigation. The ability to integrate HME and FDM and predict and tailor the filaments’ properties will extend the range of printable polymers/formulations. Hence, this work revises the properties of the most common pharmaceutical-grade polymers used and their effect on extrudability, printability, and printing outcome, providing suitable processing windows for different raw materials. As a result, formulation selection will be more straightforward (considering the characteristics of drug and desired dosage form or release profile) and the processes setup will be more expedite (avoiding or mitigating typical processing issues), thus guaranteeing the success of both HME and FDM. Relevant techniques used to characterize filaments and 3D-printed dosage forms as an essential component for the evaluation of the quality output are also presented.

Electrophoretic Deposition and Characterization of Chitosan/Eudragit E 100 Coatings on Titanium Substrate

Currently, a significant problem is the production of coatings for titanium implants, which will be characterized by mechanical properties comparable to those of a human bone, high corrosion resistance, and low degradation rate in the body fluids. This paper aims to describe the properties of novel chitosan/Eudragit E 100 (chit/EE100) coatings deposited on titanium grade 2 substrate by the electrophoretic technique (EPD). The deposition was carried out for different parameters like the content of EE100, time of deposition, and applied voltage. The microstructure, surface roughness, chemical and phase composition, wettability, mechanical and electrochemical properties, and degradation rate at different pH were examined in comparison to chitosan coating without the addition of Eudragit E 100. The applied deposition parameters significantly influenced the morphology of the coatings. The chit/EE100 coating with the highest homogeneity was obtained for Eudragit content of 0.25 g, at 10 V, and for 1 min. Young’s modulus of this sample (24.77 ± 5.50 GPa) was most comparable to that of human cortical bone. The introduction of Eudragit E 100 into chitosan coatings significantly reduced their degradation rate in artificial saliva at neutral pH while maintaining high sensitivity to pH changes. The chit/EE100 coatings showed a slightly lower corrosion resistance compared to the chitosan coating, however, significantly exceeding the substrate corrosion resistance. All prepared coatings were characterized by hydrophilicity.

Layered Silicates as a Possible Drug Carrier

The potential of layered silicates as drug carrier is overviewed. Due to their large surface area and expandable interlayer space to accommodate drug molecules, layered silicates have a potential as carrier of various molecules. In addition to the electrostatic interactions between negatively charged layered silicates and positively charged drug molecules, the organic modification of the surface of layered silicates has been applied to accommodate a variety of drug molecules not only cationic ones. The in vitro release experiment of the accommodated drug molecules has been reported under the acidic conditions. In order to discuss the future direction of layered silicates as drug carrier, materials' variation of layered silicates and their modification, and the reported stimuli-responsive hybrids based on layered silicates were introduced.

Investigation of the potential application of sodium bentonite as an excipient in formulation of sustained release tablets

In this study, the application of sodium bentonite (SB) in formulation of tablets prepared by direct compression for oral administration was tested. Three different model drugs with different solubilities: paracetamol, diclofenac sodium and metformin HCl were tested. Each drug was mixed with SB at ratio of 50% and the mixtures were subsequently compressed. Compatibility studies were conducted using both Deferential Scanning Calorimeter (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). The dissolution profile for each drug was determined in USP-buffers at different time intervals. Diclofenac sodium in pH 6.8 buffer and paracetamol in both pH 6.8 and pH 4.5 buffers showed extended release. However, metformin HCl showed immediate release at the different pH values. The study showed that using SB was possible to prepare tablets with different release profiles. However, these profiles differ depending on dissolution media and drug type.

A novel ion-exchange carrier based upon liposome-encapsulated montmorillonite for ophthalmic delivery of betaxolol hydrochloride

As a novel ion-exchange carrier with high surface area and excellent exchangeability, montmorillonite (Mt) was intercalated with betaxolol hydrochloride (BH) to form a nanocomposite and then encapsulated by liposomes (Mt-BH-LPs) for an ophthalmic drug-delivery system. The Mt-BH and Mt-BH-LPs were prepared by an acidification process and ethanol injection combined with ammonium sulfate gradient methods. The successful formation of Mt-BH and Mt-BH-LPs was verified by thermogravimetric analysis, X-ray diffraction, Fourier-transform infrared spectra, and transmission electron microscopy. Mt-BH-LPs possessed the favorable physical characteristics of encapsulation efficiency, drug loading, mean particle size, and ζ-potential. In vitro release studies indicated Mt-BH-LPs effectively maintained a relatively sustained slow release. Immortalized human corneal epithelial cell cytotoxicity, in vivo rabbit eye-irritation tests, and chorioallantoic membrane–trypan blue staining all revealed that Mt-BH-LPs had no obvious irritation on ocular tissues. A new in vitro tear-turnover model, including inserts containing human corneal epithelial cells, was designed to evaluate the precorneal retention time of Mt-BH-LPs. The results showed that Mt-BH-LPs maintained a certain BH concentration in tear fluid for a longer period than the BH solution. In vivo precorneal retention studies also indicated Mt-BH-LPs prolonged drug retention on the ocular surface more than the BH solution. Furthermore, pharmacodynamic studies showed that Mt-BH-LPs had a prolonged effect on decreasing intraocular optical pressure in rabbits. Our results demonstrated that Mt-BH-LPs have potential as an ophthalmic delivery system.

Interference of 1:1 and 2:1 layered phyllosilicates as excipients with ranitidine

As natural ingredients and excipients, kaolinite and talc were frequently studied for their interactions with drugs in pharmaceutical formulations. In this study, the uptake of ranitidine (RT) on these two minerals was studied under different physic-chemical conditions and the mechanism of RT uptake on these two minerals contrasted. Although the thermodynamic and kinetic RT uptake on these two minerals was similar and the RT uptake on both minerals were limited to the external surfaces only, drastic difference in RT uptake was found under different equilibrium solution pH and ionic strength conditions. As cation exchange process was strongly affected by solution pH and ionic strength, the RT uptake on kaolinite was dominated by cation exchange and electrostatic interactions, while the RT uptake on talc was more controlled by inter- and intra- molecular hydrogen bonding interactions. For kaolinite, the limiting factor for RT uptake was the specific surface area due to monolayer RT adsorption. In contract, multilayer RT uptake was found on talc surfaces. No matter which mechanism dominated RT uptake on these minerals, the interaction should not be neglected in pharmaceutical formulations should these minerals be used as additives and/or excipients.

Biomedical applications of cationic clay minerals

Different types of cationic clay minerals and their applications in various biological systems.

Effect of dinitolmide intercalated into Montmorillonite on E. tenella infection in chickens

To enhance the anti-coccidial effect of dinitolmide and reduce its residual, the dinitolmide/MMT compounds were synthesized by the method of solution intercalation via dinitolmide intercalated into Na + -montmorillonite (Na + -MMT). The structure of compounds was characterized by X-ray diffraction and Fourier transformed infrared. Its anti-coccidial effect was examined by Eimeria tenella infection experiment. One hundred fifty AA broiler chickens were divided into five groups. Chickens were orally inoculated with 5 × 10(4) E. tenella oocysts after dinitolmide was given. Their curative effects were observed. The results showed that intercalated dinitolmide expanded the basal spacing (d 001) of MMT from 12.6 to 15.2 Å. The IR bands of amide group in dinitolmide/MMT were detected at 1,533 cm(-1) which showed that dinitolmide was successfully intercalated into the interlayer spaces of MMT. The dinitolmide/MMT showed higher anti-coccidian oocyst activity compared with dinitolmide (p < 0.05). The dinitolmide/MMT compound can significantly increase body weight gains and reduce bloody diarrhea, lesion score, and oocyst excretion. The anti-coccidia index of dinitolmide/MMT group (165.21) is much higher than dinitolmide group (88.84). The dinitolmide/MMT hybrid systems can be more effective in control of coccidiosis in comparison to dinitolmide.

The Layered Silicate, Montmorillonite (MMT) as a Drug Delivery Carrier

Controlled drug delivery system is a protocol to develop nanostructures and materials that can efficiently encapsulate drugs at high concentration, cross the cell membrane, and release the drug at the target site in a controlled manner for a prescribed period of time. This system can reduces the patient expenses, and risks of toxicity, while it can increase the drug efficacy, specificity, tolerability and therapeutic index of corresponding drugs. Therefore, construction of stimuli-responsive controlled-release systems is of crucial importance for the development of both fundamental science and clinical medicine. Both natural and synthetic materials have been tested and proposed as components of controlled drug delivery. Clay minerals, synthetic or natural, are an important, widely abundant, and low-cost class of materials with unique swelling, intercalation, adsorption, and ion-exchange properties. The safety proof data of clay minerals clearly suggest them to be non-toxic for transdermal application and oral administration. To accomplish controlled-release systems based on layered clay minerals, one of the best ways is to intercalate organic molecules into the interlayer gallery of clay minerals. Intercalation of organic molecules within the gallery of layered silicates offers a novel route to prepare organic and inorganic hybrids that contain properties of both the inorganic host and organic guest in a single material. In this article we will highlight the applications of clay in pharmaceutics as controlled drug delivery carrier.