Ultrahigh verapamil-loaded controlled release polymeric beads using superamphiphobic substrate: D-optimal statistical design, in vitro and in vivo performance

Fabrication of polymeric microspheres for biomedical applications

Polymeric microspheres (PMs) have attracted great attention in the field of biomedicine in the last several decades due to their small particle size, special functionalities shown on the surface and high surface-to-volume ratio. However, how to fabricate PMs which can meet the clinical needs and transform laboratory achievements to industrial scale-up still remains a challenge. Therefore, advanced fabrication technologies are pursued. In this review, we summarize the technologies used to fabricate PMs, including emulsion-based methods, microfluidics, spray drying, coacervation, supercritical fluid and superhydrophobic surface-mediated method and their advantages and disadvantages. We also review the different structures, properties and functions of the PMs and their applications in the fields of drug delivery, cell encapsulation and expansion, scaffolds in tissue engineering, transcatheter arterial embolization and artificial cells. Moreover, we discuss existing challenges and future perspectives for advancing fabrication technologies and biomedical applications of PMs.

Superhydrophobic Surface-Assisted Preparation of Microspheres and Supraparticles and Their Applications

Superhydrophobic surface (SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting, and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally, the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.

Preparation of Sustained Release Formulation of Verapamil Hydrochloride Using Ion Exchange Resins

The purpose of this investigation was to formulate and evaluate the interaction between cation exchange resins and verapamil hydrochloride. The uptake studies were conducted using the rotating bottle apparatus. The Langmuir-like equation was applied to the experimental data and the maximum drug loading was determined from the Langmuir-like parameters. The drug-resin complexes were evaluated using XRD, SEM, and particle size analysis. Release studies were performed using USP dissolution apparatus 2. The resin with the lowest percentage of cross-linking had the highest uptake capacity. The percent increase in particle size due to complexation was found to be associated with drug loading; the highest drug loading had the highest increase in particle size. The X-ray diffraction patterns of the resins and the drug-resin complexes showed that they were both amorphous. The maximum drug release was approximately 40% when conventional dissolution testing was used. Results showed that sink conditions could not be maintained using conventional dissolution methods. Maximum drug release increased dramatically by increasing the volume of samples withdrawn and fresh dissolution medium added. Excellent correlation was obtained between sample volume and drug release rate with an R-value of 0.988. Particle diffusion-controlled model and film diffusion-controlled model were both applied to the experimental data. The results indicated that the rate-limiting step is the diffusion of the exchanging cations through the liquid film. The modified release formulation was prepared successfully and correlated very well with the USP monograph for verapamil hydrochloride extended release capsules.

Thin film hydration versus modified spraying technique to fabricate intranasal spanlastic nanovesicles for rasagiline mesylate brain delivery: Characterization, statistical optimization, and in vivo pharmacokinetic evaluation

Rasagiline mesylate (RM) is a monoamine oxidase inhibitor that is commonly used to alleviate the symptoms of Parkinson's disease. However, it suffers from low oral bioavailability due to its extensive hepatic metabolism in addition to its hydrophilic nature which limits its ability to pass through the blood-brain barrier (BBB) and reach the central nervous system where it exerts its pharmacological effect. Thus, this study aims to form RM-loaded spanlastic vesicles for intranasal (IN) administration to overcome its hepatic metabolism and permit its direct delivery to the brain. RM-loaded spanlastics were prepared using thin film hydration (TFH) and modified spraying technique (MST). A 2³ factorial design was constructed to study and optimize the effects of the independent formulation variables, namely, Span type, Span: Brij 35 ratio, and sonication time on the vesicles᾽ characteristics in each preparation technique. The optimized system prepared using MST (MST 2) has shown higher desirability factor with smaller PS and higher EE%; thus, it was selected for further in vivo evaluation where it revealed that the extent of RM distribution from the intranasally administered spanlastics to the brain was comparable to that of the IV drug solution with significantly high brain-targeting efficiency (458.47%). These results suggest that the IN administration of the optimized RM-loaded spanlastics could be a promising, non-invasive alternative for the efficient delivery of RM to brain tissues to exert its pharmacological activities without being dissipated to other body organs which subsequently may result in higher pharmacological efficiency and better safety profile.

In Vitro and In Vivo Studies of a Verapamil-Containing Gastroretentive Solid Foam Capsule

Gastroretentive systems may overcome problems associated with incomplete drug absorption by localized release of the API in the stomach. Low-density drug delivery systems can float in the gastric content and improve the bioavailability of small molecules. The current publication presents verapamil–HCl-containing solid foam prepared by continuous manufacturing. Production runs were validated, and the foam structure was characterized by micro-CT scans and SEM. Dissolution properties, texture changes during dissolution, and floating forces were analyzed. An optimized formulation was chosen and given orally to Beagle dogs to determine the pharmacokinetic parameters of the solid foam capsules. As a result, a 12.5 m/m% stearic acid content was found to be the most effective to reduce the apparent density of capsules. Drug release can be described by the first-order model, where 70% of verapamil dissolved after 10 h from the optimized formulation. The texture analysis proved that the structures of the solid foams are resistant. Additionally, the floating forces of the samples remained constant during their dissolution in acidic media. An in vivo study confirmed the prolonged release of the API, and gastroscopic images verified the retention of the capsule in the stomach.

Effect of co-treatment with doxorubicin and verapamil loaded into chitosan nanoparticles on diethylnitrosamine-induced hepatocellular carcinoma in mice

This study aimed to investigate the potential role of co-treatment with doxorubicin (DOX) and verapamil (VRP) nanoparticles in experimentally induced hepatocellular carcinoma in mice and to investigate the possible mechanisms behind the potential favorable effect of the co-treatment. DOX and VRP were loaded into chitosan nanoparticles (CHNPs), and cytotoxicity of loaded and unloaded drugs against HepG2 cells was evaluated. Male albino mice were divided into eight groups (n = 15): (1) normal control, (2) diethylnitrosamine, (3) CHNPs, (4) free DOX, (5) CHNPs DOX, (6) free VRP, (7) CHNPs VRP, and (8) CHNPs DOX + CHNPs VRP. Either VRP or DOX loaded into CHNPs showed stronger growth inhibition of HepG2 cells than their free forms. DOX or VRP nanoparticles displayed pronounced anticancer activity in vivo through the decline of vascular endothelial growth factor and B cell lymphoma-2 contents in liver tissues, upregulation of antioxidant enzymes, and downregulation of multidrug resistance 1. Moreover, reduced cardiotoxicity was evident from decreased level of tumor necrosis factor-α and malondialdehyde in heart tissues coupled with decreased serum activity of creatine kinase-myocardial band and lactate dehydrogenase. Co-treatment with CHNPs DOX and CHNPs VRP showed superior results versus other treatments. Liver sections from the co-treatment group revealed the absence of necrosis, enhanced apoptosis, and nearly normal hepatic lobule architecture. Co-treatment with CHNPs DOX and CHNPs VRP revealed enhanced anticancer activity and decreased cardiotoxicity versus the corresponding free forms.

Superhydrophobic Substrates for Ultrahigh Encapsulation of Hydrophilic Drug into Controlled-Release Polyelectrolyte Complex Beads: Statistical Optimization and In Vivo Evaluation

: In this work, ultrahigh drug-loaded chitosan (Ch)/K-carrageenan (Kc) polyelectrolyte complex (PEC) beads were formed in situ by cross-linking in a glutaraldehyde-saturated atmosphere and were prepared on superhydrophobic substrates fabricated by spraying glass surfaces with ready-made spray for domestic use (NeverWet^®). Verapamil hydrochloride (VP), a highly hydrophilic drug with a short biological half-life, was incorporated into a series of Ch-based and/or Ch/Kc-PEC-based beads to control its release profile in vivo. The formulation of VP-loaded beads was optimized using stepwise statistical designs based on a prespecified criterion. Several characteristics of the prepared beads, such as entrapment efficiency (EE%), in vitro drug release, swelling ratio, size and surface microstructure as well as molecular interactions between the drug and formulation ingredients, were investigated. In vivo pharmacokinetic (PK) studies were carried out using the rabbit model to study the ability of the optimized VP-loaded beads to control the absorption rate of VP. Results revealed that the prepared superhydrophobic substrates were able to fabricate VP-loaded beads with extremely high EE exceeding 90% w/w compared to only 27.80% when using conventional ionotropic gelation technique. PK results showed that the rate of VP absorption was well controlled following oral administration of the optimized beads to six rabbits compared to a marketed VP immediate release (IR) tablet, as evidenced by a 2.2-fold increase in mean residence time (MRT) and 5.24-fold extension in half value duration (HVD) over the marketed product without any observed reduction in the relative oral bioavailability.