Development of Floating-Mucoadhesive Microsphere for Site Specific Release of Metronidazole

Biodegradable Guar-Gum-Based Super-Porous Matrices for Gastroretentive Controlled Drug Release in the Treatment of Helicobacter pylori: A Proof of Concept

An increase in resistance to key antibiotics has made the need for novel treatments for the gastric colonization of Helicobacter pylori (H. pylori) a matter of the utmost urgency. Recent studies tackling this topic have focused either on the discovery of new compounds to ameliorate therapeutic regimes (such as vonoprazan) or the synthesis of gastroretentive drug delivery systems (GRDDSs) to improve the pharmacokinetics of oral formulations. The use of semi-interpenetrating polymer networks (semi-IPNs) that can act as super-porous hydrogels for this purpose is proposed in the present work, specifically those displaying low ecological footprint, easy synthesis, self-floating properties, high encapsulation efficiency for drugs such as amoxicillin (AMOX), great mucoadhesiveness, and optimal mechanical strength when exposed to stomach-like fluids. To achieve such systems, biodegradable synthetic copolymers containing acid-labile monomers were prepared and interpenetrated with guar gum (GG) in a one-pot polymerization process based on thiol-ene click reactions. The resulting matrices were characterized by SEM, GPC, TGA, NMR, and rheology studies, and the acidic hydrolysis of the acid-sensitive polymers was also studied. Results confirm that some of the obtained matrices are expected to perform optimally as GRDDSs for the sustained release of active pharmaceutical ingredients at the gastrointestinal level, being a priori facilitated by its disaggregation. Therefore, the optimal performance of these systems is assessed by varying the molar ratio of the labile monomer in the matrices.

Utilizing 4D Printing to Design Smart Gastroretentive, Esophageal, and Intravesical Drug Delivery Systems

The breakthrough of 3D printing in biomedical research has paved the way for the next evolutionary step referred to as four dimensional (4D) printing. This new concept utilizes the time as the fourth dimension in addition to the x, y, and z axes with the idea to change the configuration of a printed construct with time usually in response to an external stimulus. This can be attained through the incorporation of smart materials or through a preset smart design. The 4D printed constructs may be designed to exhibit expandability, flexibility, self-folding, self-repair or deformability. This review focuses on 4D printed devices for gastroretentive, esophageal, and intravesical delivery. The currently unmet needs and challenges for these application sites are tried to be defined and reported on published solution concepts involving 4D printing. In addition, other promising application sites that may similarly benefit from 4D printing approaches such as tracheal and intrauterine drug delivery are proposed.

Formulation, optimization, and in-vitro-ex-vivo evaluation of dual-crosslinked zinc pectinate-neem gum-interpenetrating polymer network mediated lansoprazole loaded floating microbeads

Low methoxy pectin (LM pectin) suffers from burst release owing to its high swellability and solubility in water. Consequently, in ways to design an ideal drug delivery system, these obstacles must be surmounted. Therefore, the work aimed to design dual crosslinked LM pectin -neem gum (NG) mediated interpenetrating polymer network (IPN) floating mucoadhesive microbeads for lansoprazole (LNZ) gastro-retentive delivery. In short, LNZ-loaded floating microbeads were achieved by using the ionic gelation method wherein zinc acetate was preferred as a crosslinking agent. The optimization of IPN microbeads was performed employing a 3²-factorial design wherein concentration of pectin and NG was considered as independent factors whereas dependant factors are entrapment efficiency and drug release. Importantly, carboxylic functionality of low methoxy (LM) pectin and hydroxylic functionality NG cross-linked with Zn⁺² forms a 3D network. Diffractogram and thermogram revealed that conversion of drug from crystalline to amorphous form because of entrapment of drug within polymeric network. Anticipated floating microbeads showed that polymer concentration had considerable effect on drug encapsulation efficiency and drug release. Briefly, optimizing floating microbeads (Batch B:5) showed maximum drug entrapment (87.47 %) with a delayed drug release (69.20 %, at 8 h) due to formation of strong IPN. Moreover, it showed good mucoadhesive aptitude with goat stomach mucosa because of entanglement between gum and mucus layer. In addition, use of calcium silicate assists to modulate floating profile of IPN microbeads. Therefore, designing dual crosslinked zinc-pectinate-NG mediated IPN floating mucoadhesive microbeads will offer a new substitute for floating delivery.

Scope and Limitations of Current Antibiotic Therapies against Helicobacter pylori: Reviewing Amoxicillin Gastroretentive Formulations

Even though general improvement of quality of life has happened around the globe, statistics show that gastric cancer is still a very serious medical concern in some regions of the world. A big portion of malignant neoplasms that develop inside the stomach are linked to an infection of Helicobacter pylori; in fact, this pathogen has already been categorized as a group 1 carcinogen by the World Health Organization (WHO). Still, the efficacy of current anti-H. pylori therapeutic approaches is insufficient and follows a worrying decreasing trend, mainly due to an exponential increase in resistance to key antibiotics. This work analyzes the clinical and biological characteristics of this pathogen, especially its link to gastric cancer, and provides a comprehensive review of current formulation trends for H. pylori eradication. Research effort has focused both on the discovery of new combinations of chemicals that function as optimized antibiotic regimens, and on the preparation of gastroretentive drug delivery systems (GRDDSs) to improve overall pharmacokinetics. Regarding the last topic, this review aims to summarize the latest trend in amoxicillin-loaded GRDDS, since this is the antibiotic that has shown the least bacterial resistance worldwide. It is expected that the current work could provide some insight into the importance of innovative options to combat this microorganism. Therefore, this review can inspire new research strategies in the development of efficient formulations for the treatment of this infection and the consequent prevention of gastric cancer.

Mucoadhesive gastroretentive microparticulate system for programmed delivery of famotidine and clarithromycin

AIM

The present research was aimed to develop thiolated polyacrylic acid (TPA) based microspheres (MSPs) containing famotidine (FX) and clarithromycin (CLX).

METHODS

TPA was synthesised from polyacrylic acid and l-cysteine in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC). The prepared TPA was characterised using FT-IR (Fourier transform-infra red), ¹H-NMR (proton nuclear magnetic resonance) spectroscopy, P-XRD (powder X ray diffraction) method, and zeta potential. The analytical tools have supported the formation of TPA. The thiolated microspheres were prepared by emulsion solvent evaporation method using 0.75% w/v polymer concentration and stirring at 400 rpm for 8 hr.

RESULTS

The average particle size and zeta potential of optimised formulation was found to be 25.2 ± 1.87 μm and -26.68 mV, respectively. The entrapment efficiency of the optimised formulation was obtained 67.20% for FX and 70.20% for CLX. The developed microspheres were swelled only in 4 h from 0.5 to 0.9. The in vitro mucoadhesive study and in vitro drug release studies demonstrated that microspheres showed mucoadhesive property. In in vitro drug release studies, the release of FX and CLX were observed to be 58.68% and 60.48%, respectively from microspheres in 8 h. The thiolated microspheres showed higher adhesion time (7.0 ± 0.8 h) in comparison to the plain microspheres (2.6 ± 0.4 h).

CONCLUSION

The prepared TPA based mucoadhesive microspheres can be utilised as carriers for the treatment of peptic ulcer caused by Helicobacter pylori which will offer enhanced residence time for the rational drug combination in the gastric region.

Guar Gum-Based Floating Microspheres of Repaglinide Using 32 Factorial Design: Fabrication, Optimization, Characterization, and In Vivo Buoyancy Behavior in Albino Rats

In this present study, floating microspheres of repaglinide were successfully fabricated by the solvent evaporation technique with varying ratios of guar gum, hydroxypropyl methylcellulose, and ethylcellulose with polyvinyl alcohol. Microspheres were characterized by production yield, particle size, in vitro buoyancy, entrapment efficiency, in vitro drug release, and in vivo floating behavior in albino rats. The formulation process was optimized for stirring speed (X₁) and concentration of polymer ratio (X₂) on dependent variables such as percentage entrapment efficiency, percentage yield, in vitro buoyancy, and percentage of drug release by the 3² factorial Design-Expert^® 12, trial version, software. The optimized formulation was characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy and was successfully formulated with the highest percentage of cumulative drug release (94.26 ± 3.10), entrapment efficiency (74.70% ± 2.16%), and particle size (50.34 ± 3.67 μm) and remains buoyant for 24 h in simulated gastric fluid (0.1N HCL) with high in vitro buoyancy percent (84.90 ± 2.88). When the drug-polymer solution of dichloromethane and ethanol is dropped in polyvinyl alcohol solution, it leads to the formation of a shell and produces cavities, creating the buoyant nature of floating microspheres. X-ray imaging indicates the uniform distribution and buoyant nature of microspheres in the gastric fluid for a 10-h period.

Improved Stability of Rifampicin in the Presence of Gastric-Resistant Isoniazid Microspheres in Acidic Media

The degradation of rifampicin (RIF) in an acidic medium to form 3-formyl rifamycin SV, a poorly absorbed compound, is accelerated in the presence of isoniazid, contributing to the poor bioavailability of rifampicin. This manuscript presents a novel approach in which isoniazid is formulated into gastric-resistant sustained-release microspheres and RIF into microporous floating sustained-release microspheres to reduce the potential for interaction between RIF and isoniazid (INH) in an acidic environment. Hydroxypropyl methylcellulose acetate succinate and Eudragit^® L100 polymers were used for the manufacture of isoniazid-loaded gastric-resistant sustained-release microspheres using an o/o solvent emulsification evaporation approach. Microporous floating sustained-release microspheres for the delivery of rifampicin in the stomach were manufactured using emulsification and a diffusion/evaporation process. The design of experiments was used to evaluate the impact of input variables on predefined responses or quality attributes of the microspheres. The percent degradation of rifampicin following 12 h dissolution testing in 0.1 M HCl pH 1.2 in the presence of isoniazid gastric-resistant sustained-release microspheres was only 4.44%. These results indicate that the degradation of rifampicin in the presence of isoniazid in acidic media can be reduced by encapsulation of both active pharmaceutical ingredients to ensure release in different segments of the gastrointestinal tract, potentially improving the bioavailability of rifampicin.

Repka M. Novel Gastroretentive Floating Pulsatile Drug Delivery System Produced via Hot-Melt Extrusion and Fused Deposition Modeling 3D Printing

This study was performed to develop novel core-shell gastroretentive floating pulsatile drug delivery systems using a hot-melt extrusion-paired fused deposition modeling (FDM) 3D printing and direct compression method. Hydroxypropyl cellulose (HPC) and ethyl cellulose (EC)-based filaments were fabricated using hot-melt extrusion technology and were utilized as feedstock material for printing shells in FDM 3D printing. The directly compressed theophylline tablet was used as the core. The tablet shell to form pulsatile floating dosage forms with different geometries (shell thickness: 0.8, 1.2, 1.6, and 2.0 mm; wall thickness: 0, 0.8, and 1.6 mm; and % infill density: 50, 75, and 100) were designed, printed, and evaluated. All core-shell tablets floated without any lag time and exhibited good floating behavior throughout the dissolution study. The lag time for the pulsatile release of the drug was 30 min to 6 h. The proportion of ethyl cellulose in the filament composition had a significant (p < 0.05) effect on the lag time. The formulation (2 mm shell thickness, 1.6 mm wall thickness, 100% infill density, 0.5% EC) with the desired lag time of 6 h was selected as an optimized formulation. Thus, FDM 3D printing is a potential technique for the development of complex customized drug delivery systems for personalized pharmacotherapy.

Mucoadhesive Multiparticulate Drug Delivery Systems: An Extensive Review of Patents

Innovations in pharmaceutical research are striving for designing newer drug therapies to eradicate deadly diseases. Strategies for such inventions always flourish with keys and objectives of minimal adverse effects and effective treatment. Recent trends in pharmaceutical technology specify that mucoadhesive drug delivery system is particularly appropriate than oral control release, for getting local systematic delivery of drugs in GIT for an extended interval of time at a predetermined rate. However, it is somehow expensive and unpleasant sensation for some patients, but still it is needful for getting short enzymatic activity, simple administration without pain and evasion of fast pass metabolism. Usually the vehicles employed in drug delivery of mucoadhesive system have a significant impact that draws further attention to potential benefits like improved bioavailability of therapeutic agents, extensive drug residence time at the site of administration and a comparatively faster drug uptake into the systemic circulation. The drug release from mucoadhesive multiparticulates is contingent on several types of factors comprising carrier need to produce the multiparticles and quantity of medication drug contained in them. Mucoadhesion is characterized by selected theories and mechanisms. Various strategies emergent in mucoadhesive multiparticulate drug delivery system (MMDDS) by in-vitro as well as ex-vivo description and characterization are also critically discussed. Apart from these, the primary focus during this review is to highlight current patents, clinical status, and regulatory policy for enhancement of mucoadhesive multi-particulate drug delivery system in the present scenario.