Formulation and Characterization of Solid Dispersions of Etoricoxib Using Natural Polymers

Fabrication of gastro-floating sustained-release etoricoxib and famotidine tablets: design, optimization, in-vitro, and in-vivo evaluation

In this study, a new gastro-floating sustained-release tablet (GFT) with a combination of Etoricoxib (ET) and Famotidine (FM) was successfully developed. GFTs were prepared by using a combination of hydrophilic swellable natural/semi-synthetic polymers as a controlled-release layer. Through a 24 full factorial statistical experimental design, the effects of formulation factors on the release of GFTs were conducted. The ideal floating tablet (FT) comprised konjac-gum (150 mg), guar-gum (26.57 mg), xanthan-gum (54.17 mg), and HPMC-K15-M (69.25 mg). The ideal FT exhibited a high swelling index (SI) (297.7%) and rapid FLT (around 50 s) in 0.1 N HCl as well as controlled release of ET (22.43% in 1 h and 77.47% in 8 h) and FM (24.89% in 1 h and 93.82% in 8 h) with the absence of any drug-excipient interactions. The AUC0∼72 (ng h/mL) of ET and FM in the GFTs were approximately double-fold of the market, respectively. The relative bioavailability was (207.48 ± 12.02% and 208.51 ± 13.11%) compared with commercial tablets. The X-ray imaging showed a promising buoyancy ability for approximately 8 h. These findings revealed the successful preparation of the sustained-release floating tablet with improved dual drug delivery.

Quantification of Etoricoxib in Low Plasma Volume by UPLC-PDA and Application to Preclinical Pharmacokinetic Study

An ultra-performance liquid chromatography with photodiode array (UPLC-PDA) UV detection method was developed here for the first time for simple, rapid, selective and sensitive quantification of the commonly prescribed selective cyclooxygenase-2 (COX-2) inhibitor etoricoxib in low plasma volumes (50 μL). The method includes protein precipitation followed by liquid-liquid extraction, evaporation and reconstitution. A gradient mobile phase of 75:25 going to 55:45 (v/v) water:acetonitrile (1 mL/min flow rate) was applied. Total run time was 8 min, representing a significant improvement relative to previous reports. Excellent linearity (r2 = 1) was obtained over a wide (0.1-12 µg/mL) etoricoxib concentration range. Short retention times for etoricoxib (4.9 min) and the internal standard trazodone (6.4 min), as well as high stability, recovery, accuracy, precision and reproducibility, and low etoricoxib LOD (20 ng/mL) and LOQ (100 ng/mL), were achieved. Finally, the method was successfully applied to a pharmacokinetic study (single 20 mg/kg orally administered etoricoxib mini-capsule) in rats. In conclusion, the advantages demonstrated in this work make this analytical method both time- and cost-efficient for drug monitoring in pre-clinical/clinical settings.

Taste Masking of Steroids for Oral Formulations

Objectives

Oral steroids are commonly prescribed to children. Steroids have a strong bitter taste that limits their oral acceptance in children. The objective of this study was to formulate a pediatric-friendly and palatable oral dosage form of steroids.

Materials and Methods

Solid dispersions of dexamethasone were prepared using polyethylene glycol, pectin, and Eudragit as carrier polymers, and chocolate as a flavoring agent. Taste masking efficiency was evaluated by healthy volunteers to select the best formula. The selected formula was pressed into chewable tablets with varying amounts of sweeteners. Chewable tablets were evaluated for palatability, hardness, and chewing index. The typical application of the taste masking approach was confirmed using prednisolone.

Results

Eudragit-based solid dispersions were effective in dexamethasone taste masking. Using 40% mannitol resulted in palatable tablets with acceptable hardness and chewing difficulty. The effectiveness of the taste masking approach was successfully used to prepare prednisolone chewable tablets. However, an increase in the carrier: drug ratio and a change in the flavor to pineapple were necessary to achieve maximum palatability of prednisolone chewable tablets.

Conclusion

Eudragit solid dispersion is an effective method for the taste masking highly bitter steroids. The solid dispersion was successfully pressed into a palatable, easy-to-chew, and pediatric-friendly chewable tablet dosage form. The carrier: drug ratio and the choice of flavoring agent are crucial factors in improving tablet palatability.

Merging konjac glucomannan with other copolymeric hydrogels as a cutting-edge liquid raft system for dual delivery of etoricoxib and famotidine

This study aimed to formulate and evaluate a floating raft system for the co-delivery of etoricoxib (ETO) and famotidine (FAM) using a combination of glucomannan with natural/semi-synthetic polysaccharides. Formulation variables affect gelation lag time (GLT), floating lag time (FLT), and release percentage of drugs after 1-8 h, Stability, and viscosity parameters were evaluated. In vivo X-ray studies, followed by the pharmacokinetic study, were performed on human volunteers. Formulations exhibited pseudoplastic behavior for ease of swallowing. The optimum raft system (ORS) comprised 1% Na alginate, 0.1% Low Methoxyl (LM) pectin, 0.8% Konjac glucomannan (KGL), 1% Precirol, and 1% CaCO₃. ORS exhibited rapid GLT and FLT (around 42 and 8 sec respectively) in 0.1 N HCl as well as controlled release of ETO (15% in 1 h and 82% in 8 h) and FAM (29% in 1 h and 85% in 8 h). Formulation stability with the absence of any drug-excipient interactions was observed. The X-ray imaging showed a promising buoyancy ability for approximately 8 h. Compared with marketed products, ORS showed superior relative bioavailability for both drugs. These findings revealed the successful preparation of a promising raft system with improved dual drug delivery.

A Comparative Study on Cyclodextrin Derivatives in Improving Oral Bioavailability of Etoricoxib as a Model Drug: Formulation and Evaluation of Solid Dispersion-Based Fast-Dissolving Tablets

Etoricoxib, as a model drug, has a poor solubility and dissolution rate. Cyclodextrin derivatives can be used to solve such a problem. A comparative study was run on three cyclodextrin derivatives, namely β-CD, HP β-CD, and SBE β-CD, to solve the drug problem through the formulation of solid dispersions and their preparation into fast-dissolving tablets. Preparations utilized different (1:1, 1:2, and 1:4) drug:carrier ratios. Nine fast-dissolving tablets (containing 1:4 drug: carrier) were formulated using Prosolv ODT® and/or F-melt® type C as super-disintegrants. Optimized formulation was chosen based on a 32 factorial design. The responses chosen were the outcomes of the in vitro evaluation tests. The optimized formulation that had the highest desirability (0.86) was found to be SD-HP3, which was prepared from etoricoxib: HP β-CD at a 1:4 ratio using equal amounts of Prosolv ODT® and F-melt® type C. An in vivo evaluation of SD-HP3 on a rabbit model revealed its superiority over the marketed product Arcoxia®. SD-HP3 showed a significantly lower Tmax (13.3 min) and a significantly higher Cmax (9122.156 μg/mL), as well as a significantly higher AUC, than Arcoxia®. Thus, the solubility, dissolution, and bioavailability of etoricoxib were significantly enhanced.

Pharmacotechnical Evaluation by SeDeM Expert System to Develop Orodispersible Tablets

Sediment delivery model (SeDeM) system is innovative tool to correlate micromeritic properties of powders with compressibility. It involves computation of indices which facilitate direct compressibility of solids and enable corrective measures through particle engineering. Study had multiple objectives, viz, (i) to enhance solubility of BCS class II, nevirapine using solid dispersions; (ii) SeDeM analyses of excipients and solid dispersions to analyze direct compressibility; and (iii) prepare orodispersible tablets (ODT). Solid dispersions were prepared by solvent evaporation. Superdisintegrants and solid dispersions were analyzed for primary indices of dimension, compressibility, flowability, stability, and disgregability derived from micromeritic properties. Radar diagrams were constructed to provide visual clues to deficient properties for direct compressibility. ODTs were prepared using excipients which passed criteria for direct compressibility and evaluated for tablet properties. Solid dispersions with Eudragit S100 revealed 6 to 10 fold increase in solubility in various dissolution media including biorelevant media in comparison with plain drug. Solubility was found to be pH dependent. SeDeM analyses facilitated identification of superdisintegrants and excipients with unfavorable compressibility. Radar diagrams provided a clear pictorial evidence of lacunae in powder properties. Based on SeDeM results, tablets were formulated by direct compression using crosspovidone, croscarmellose sodium, and mannitol. All batches showed 40% release in first minute in simulated salivary fluid.

Designing Natural Polymer-Based Capsules and Spheres for Biomedical Applications-A Review

Natural polymers, such as polysaccharides and polypeptides, are potential candidates to serve as carriers of biomedical cargo. Natural polymer-based carriers, having a core-shell structural configuration, offer ample scope for introducing multifunctional capabilities and enable the simultaneous encapsulation of cargo materials of different physical and chemical properties for their targeted delivery and sustained and stimuli-responsive release. On the other hand, carriers with a porous matrix structure offer larger surface area and lower density, in order to serve as potential platforms for cell culture and tissue regeneration. This review explores the designing of micro- and nano-metric core-shell capsules and porous spheres, based on various functions. Synthesis approaches, mechanisms of formation, general- and function-specific characteristics, challenges, and future perspectives are discussed. Recent advances in protein-based carriers with a porous matrix structure and different core-shell configurations are also presented in detail.

Using X-ray Diffraction Techniques for Biomimetic Drug Development, Formulation, and Polymorphic Characterization

Drug development is a decades-long, multibillion dollar investment that often limits itself. To decrease the time to drug approval, efforts are focused on drug targets and drug formulation for optimal biocompatibility and efficacy. X-ray structural characterization approaches have catalyzed the drug discovery and design process. Single crystal X-ray diffraction (SCXRD) reveals important structural details and molecular interactions for the manifestation of a disease or for therapeutic effect. Powder X-ray diffraction (PXRD) has provided a method to determine the different phases, purity, and stability of biological drug compounds that possess crystallinity. Recently, synchrotron sources have enabled wider access to the study of noncrystalline or amorphous solids. One valuable technique employed to determine atomic arrangements and local atom ordering of amorphous materials is the pair distribution function (PDF). PDF has been used in the study of amorphous solid dispersions (ASDs). ASDs are made up of an active pharmaceutical ingredient (API) within a drug dispersed at the molecular level in an amorphous polymeric carrier. This information is vital for appropriate formulation of a drug for stability, administration, and efficacy purposes. Natural or biomimetic products are often used as the API or the formulation agent. This review profiles the deep insights that X-ray structural techniques and associated analytical methods can offer in the development of a drug.

Lamotrigine Nanoparticle Laden Polymer Composite Oral Dissolving Films for Improving Therapeutic Potential of the Hydrophobic Antiepileptic Molecule

Lamotrigine is used for neurological disorders and antiepileptic therapy at frequent dosing due to its poor solubility. The present work aims to study the influence of combining the Lamotrigine nanoparticles and polymer composite oral dissolving film to improve the solubility and dissolution kinetics of the drug. The Lamotrigine-Eudragit E100 nanoparticles were synthesized through solvent evaporation followed by precipitation process, which were laden in oral dissolving films through solvent casting technique. The optimized nanoparticles were assessed for particle size, colloidal stability, drug entrapment efficiency, in vitro release profile, physicochemical characteristics, and cytotoxicity. The optimized polymeric nanoparticles of Lamotrigine: Eudragit E100 (1:0.5) exhibited monodispersed particles with 103 nm average size, +7.96 mV zeta potential, and 82.96% ± 1.2% entrapment efficiency. The composite oral matrix films blended with polyvinyl alcohol and polyvinyl pyrrolidone (0.5:0.5 ratio) incorporated with the polymeric nanoparticles demonstrated >64% drug release within 2 h. The nanoparticles and its composite films exhibited 9- and 11-fold higher drug release than pure drug, respectively. The analytical characterization studies proved the formation of nanoparticles with mild drug-polymer interactions and optimum stability, which resulted in enhanced solubility and dissolution of drug. The nanoparticles displayed lesser cytotoxicity to the normal (Vero) cells at concentration of 10-50 μg/mL compared to pure drug. The optimized polymeric nanoparticle loaded oral films could be suitable for in vivo administration of Lamotrigine at low doses to improve bioavailability and therapeutic efficiency with reduced side effects.