A nanohybrid system for taste masking of sildenafil

Formulation and evaluation of taste-masked oral disintegrating tablet containing tolterodine-loaded montmorillonite

Background and purpose

The present study aimed to obtain a taste-masked oral disintegrating tablet (ODT) containing tolterodine tartrate (TT) intercalated into montmorillonite (MMT).

Experimental approach

The TT-MMT hybrid was prepared by ion exchange reaction. The effect of the initial concentration of TT, MMT, temperature, and pH on the encapsulation efficiency (EE) % of the drug in MMT was evaluated. The selected TT-MMT hybrid was characterized by X-ray diffraction (XRD), Fourier transforms infrared (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Then, the optimized TT-MMT hybrid was incorporated in the ODT prepared by direct compression method and taste-masking assessment performed by a human test panel.

Findings/Results

The EE% of TT was in the range of 22.67 to 71.06% in different formulations. It was found that increases in MMT concentration significantly increased EE%. DSC and XRD studies indicated that the TT was intercalated in the MMT interlayer space in an amorphous or molecular state. In-vitro release studies at pH 6.8 showed that the amount of the drug released from the TT-MMT hybrid was negligible for the first 3 min. The post-compression of ODT also showed satisfactory results in terms of friability, hardness, disintegration time, and taste.

Conclusion and implications

MMT-ODT could be a suitable vehicle for the taste masking of TT, with the potential for use in patients with swallowing problems.

Self-nanoemulsifying formulation for oral delivery of sildenafil: effect on physicochemical attributes and in vivo pharmacokinetics

Sildenafil (SLD) is employed for the management of erectile dysfunction and pulmonary arterial hypertension. It exhibits meagre water solubility and is available in the form of citrate salt hydrate to improve the solubility. However, it still exhibits moderate solubility, high first-pass metabolism, resulting in very less oral bioavailability. The present study demonstrates the preparation of self-nanoemulsifying drug delivery system for augmenting the oral bioavailability of SLD. Oleic acid and Capmul MCM C8 blend (oil phase), Cremophor^® RH40 (surfactant), and Labrafil^® M1944 CS (cosurfactant) were selected as main constituents for making liquid preconcentrate based on the solubility and emulsification study. The preconcentrate upon dilution and emulsification showed droplet size 52.03 ± 13.03 nm, PDI 0.143 ± 0.028, and % transmittance was 99.77 ± 1.86% with SLD load of 40 mg/g of formulation. The prepared formulation was further assessed for stability, in vitro release, Caco-2 cell uptake, and in vivo pharmacokinetic performance. SLD-SNEDDS formulation was found to be robust in terms of stability against several folds dilution in the gastrointestinal tract (GIT), freeze-thaw cycles, and had a storage stability of 3 months at 4 °C and 25 °C. SLD-SNEDDS showed ~4.7-fold and ~5-fold increase in time- and concentration-dependent cellular uptake as against SLD cultured with Caco-2 cells. In vivo pharmacokinetic study revealed ~5.8- and ~2.5-fold increase in AUC_0-∞ values in case of SLD-SNEDDS as against SLD suspension and SLD citrate solution, respectively.

Strategies for Taste Masking of Orodispersible Dosage Forms: Time, Concentration, and Perception

Orodispersible dosage forms, characterized as quick dissolving and swallowing without water, have recently gained great attention from the pharmaceutical industry, as these forms can satisfy the needs of children, the elderly, and patients suffering from mental illnesses. However, poor taste by thorough exposure of the drugs' dissolution in the oral cavity hinders the effectiveness of the orodispersible dosage forms. To bridge this gap, we put forward three taste-masking strategies with respect to the intensity of time, concentration, and perception. We further investigated the raw material processing, the composition of auxiliary material, formulation techniques, and process control in each strategy and drew conclusions about their effects on taste masking.

Nanocarrier Systems in Taste Masking

Taste is the most crucial organoleptic parameter affecting patient compliance in the case of drugs with poor palatability. Taste masking is a major challenge for the development of orally ingested active pharmaceutical constituents in the pharmaceutical industry. Numerous conventional taste-masking techniques have been extensively studied. In parallel, affecting the drug solubility or release is a major concern of conventional taste-masking techniques. Recently, many nanocarrier systems have been introduced, claiming the advantage of effective taste masking without affecting either the drug solubility or its release. In this review, we will present new techniques for taste masking, including taste-masking techniques utilizing nanocarrier systems such as liposomes, polymeric and solid lipid nanoparticles, polymeric micelles, submicron lipid emulsions, and nanogels. We will chiefly highlight the composition of these systems and their applications in designing oral therapeutic delivery systems successful in masking the taste of bitter molecules.

Development and In Vitro Evaluation of Controlled Release Viagra® Containing Poloxamer-188 Using Gastroplus™ PBPK Modeling Software for In Vivo Predictions and Pharmacokinetic Assessments

Sildenafil is the active substance in Viagra^® tablets, which is approved by the FDA to treat sexual dysfunction in men. Poor solubility and short half-life, however, can limit the span of its effectiveness. Therefore, this study focused on an oral controlled release matrix system with the aim to improve solubility, control the drug release, and sustain the duration of drug activity. The controlled release matrices were prepared with poloxamer-188, hydroxypropyl methylcellulose, and magnesium stearate. Various formulations of different ratios were developed, evaluated in vitro, and assessed in silico. Poloxamer-188 appeared to have a remarkable influence on the release profile of sildenafil citrate. In general, the rate of drug release decreased as the amount of polymer was gradually increased in the matrix system, achieving a maximum release period over 12 h. The in silico assessment by using the GastroPlus™ PBPK modeling software predicted a significant variation in C_max, t_max, t_1/2, and AUC_0-t among the formulations. In conclusion, the combination of polymers in matrix systems can have substantial impact on controlling and modifying the drug release pattern.

Niclosamide-Clay Intercalate Coated with Nonionic Polymer for Enhanced Bioavailability toward COVID-19 Treatment

Niclosamide (NIC), a conventional anthelmintic agent, is emerging as a repurposed drug for COVID-19 treatment. However, the clinical efficacy is very limited due to its low oral bioavailability resulting from its poor aqueous solubility. In the present study, a new hybrid drug delivery system made of NIC, montmorillonite (MMT), and Tween 60 is proposed to overcome this obstacle. At first, NIC molecules were immobilized into the interlayer space of cationic clay, MMT, to form NIC–MMT hybrids, which could enhance the solubility of NIC, and then the polymer surfactant, Tween 60, was further coated on the external surface of NIC–MMT to improve the release rate and the solubility of NIC and eventually the bioavailability under gastrointestinal condition when orally administered. Finally, we have performed an in vivo pharmacokinetic study to compare the oral bioavailability of NIC for the Tween 60-coated NIC–MMT hybrid with Yomesan^®, which is a commercially available NIC. Exceptionally, the Tween 60-coated NIC–MMT hybrid showed higher systemic exposure of NIC than Yomesan^®. Therefore, the present NIC–MMT–Tween 60 hybrid can be a potent NIC drug formulation with enhanced solubility and bioavailability in vivo for treating Covid-19.

Highly Controlled Diffusion Drug Release from Ureasil-Poly(ethylene oxide)-Na+-Montmorillonite Hybrid Hydrogel Nanocomposites

In this work, we report the effects of incorporation of variable amounts (1-20 wt %) of sodium montmorillonite (MMT) into a siloxane-poly(ethylene oxide) hybrid hydrogel prepared by the sol-gel route. The aim was to control the nanostructural features of the nanocomposite, improve the release profile of the sodium diclofenac (SDCF) drug, and optimize the swelling behavior of the hydrophilic matrix. The nanoscopic characteristics of the siloxane-cross-linked poly(ethylene oxide) network, the semicrystallinity of the hybrid, and the intercalated or exfoliated structure of the clay were investigated by X-ray diffraction, small-angle X-ray scattering, and differential scanning calorimetry. The correlation between the nanoscopic features of nanocomposites containing different amounts of MMT and the swelling behavior revealed the key role of exfoliated silicate in controlling the water uptake by means of a flow barrier effect. The release of the drug from the nanocomposite displayed a stepped pattern kinetically controlled by the diffusion of SDCF molecules through the mass transport barrier created by the exfoliated silicate. The sustained SDCF release provided by the hybrid hydrogel nanocomposite could be useful for the prolonged treatment of painful conditions, such as arthritis, sprains and strains, gout, migraine, and pain after surgical procedures.

Review of Clay-Drug Hybrid Materials for Biomedical Applications: Administration Routes

Focus here is placed on the pharmaceutical and biomedical applications of novel clay-drug hybrid materials categorized by methods of administration. Clay minerals have been used for many years as pharmaceutical and medicinal ingredients for therapeutic purposes. A number of studies have attempted to explore clay-drug hybrid materials for biomedical applications with desired functions, such as sustained release, increased solubility, enhanced adsorption, mucoadhesion, biocompatibility, targeting, etc. The present review attempts not only to summarize the state-of-the-art of clay-drug hybrid materials and their advantages, depending on the methods of administration, but also to deal with challenges and future perspectives of clay mineral-based hybrids for biomedical applications.

pH- and ion-sensitive polymers for drug delivery

INTRODUCTION

Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body.

AREAS COVERED

Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations.

EXPERT OPINION

Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients.