Preparation and Characterization of the Sulfobutylether-β-Cyclodextrin Inclusion Complex of Amiodarone Hydrochloride with Enhanced Oral Bioavailability in Fasted State

The Influence of the Polymer Type on the Quality of Newly Developed Oral Immediate-Release Tablets Containing Amiodarone Solid Dispersions Obtained by Hot-Melt Extrusion

The present study aims to demonstrate the influence of the polymer-carrier type and proportion on the quality performance of newly developed oral immediate-release tablets containing amiodarone solid dispersions obtained by hot-melt extrusion. Twelve solid dispersions including amiodarone and different polymers (PEG 1500, PEG 4000; PEG 8000, Soluplus^®, and Kolliphor^® 188) were developed and prepared by hot-melt extrusion using a horizontal extruder realized by the authors in their own laboratory. Only eleven of the dispersions presented suitable physical characteristics and they were used as active ingredients in eleven tablet formulations that contain the same amounts of the same excipients, varying only in solid dispersion type. The solid dispersions’ properties were established by optical microscopy with reflected light, volumetric controls and particle size evaluation. In order to prove that the complex powders have appropriate physical characteristics for the direct compression process, they were subjected to different analyses regarding their flowability and compressibility behavior. Additionally, the Fourier transform infrared spectroscopy and X-ray diffraction analysis were performed on the obtained solid dispersions. After confirming the proper physical attributes for all blends, they were processed into the form of tablets by direct compression technology. The manufactured tablets were evaluated for pharmacotechnical (dimensions–diameter and thickness, mass uniformity, hardness and friability) and in vitro biopharmaceutical (disintegration time and drug release) performances. Furthermore, the influence of the polymer matrix on their quality was determined. The high differences in flow and compression performances of the solid dispersions prove the relevant influence of the polymer type and their concentration-dependent plasticizing properties. The increase in flowability and compressibility characteristics of the solid dispersions could be noticed after combining them with direct compression excipients owning superior mechanical qualities. The influence of the polymer type is best detected in the disintegration test, where the obtained values are quite different between the studied formulations. The use of PEG 1500 alone or combined in various proportions with Soluplus^® leads to rapid disintegration. In contrast, the mixture of PEG 4000 and Poloxamer 188 in equal proportions determined the increase in disintegration time to 120 s. The use of Poloxamer 188 alone and a 3:1 combination of PEG 4000 and Soluplus^® also generates a prolonged disintegration time for the tablets.

Fast-Fed Variability: Insights into Drug Delivery, Molecular Manifestations, and Regulatory Aspects

Among various drug administration routes, oral drug delivery is preferred and is considered patient-friendly; hence, most of the marketed drugs are available as conventional tablets or capsules. In such cases, the administration of drugs with or without food has tremendous importance on the bioavailability of the drugs. The presence of food may increase (positive effect) or decrease (negative effect) the bioavailability of the drug. Such a positive or negative effect is undesirable since it makes dosage estimation difficult in several diseases. This may lead to an increased propensity for adverse effects of drugs when a positive food effect is perceived. However, a negative food effect may lead to therapeutic insufficiency for patients suffering from life-threatening disorders. This review emphasizes the causes of food effects, formulation strategies to overcome the fast-fed variability, and the regulatory aspects of drugs with food effects, which may open new avenues for researchers to design products that may help to eliminate fast-fed variability.

Antinociceptive effects of bupivacaine and its sulfobutylether-β-cyclodextrin inclusion complex in orofacial pain

Bupivacaine hydrochloride (BVC) represents an option to produce long-lasting analgesia, and complexation in cyclodextrins has shown improvements in biopharmaceutical properties. This study aimed to characterize and test the cytotoxicity and antinociceptive effects of BVC complexed in sulfobutylether-β-cyclodextrin (SBEβCD). The kinetics and stoichiometry of complexation and BVC-SBEβCD association constant were evaluated by phase solubility study and Job's plot. Evidence of the BVC-SBEβCD complex formation was obtained from scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The cytotoxicity was evaluated in keratinocyte (HaCaT) and neuroblastoma (SH-SY5Y). Antinociceptive effects were registered via orofacial pain models: the formalin test, carrageenan-induced hyperalgesia, and postoperative pain (intraoral incision). The complex formation occurred at a 1:1 BVC-SBEβCD molar ratio, with a low association constant (13.2 M^-1). SEM, DSC, and FTIR results demonstrated the host-guest interaction. The IC_50% values determined in SH-SY5Y were 216 µM and 149 µM for BVC and BVC-SBEβCD, respectively (p < 0.05). There was no difference in HaCaT IC_50%. In orofacial pain model, BVC-SBEβCD significantly prolonged antinociceptive effect, in about 2 h, compared to plain BVC. SBEβCD can be used as a drug delivery system for bupivacaine, whereas the complex showed long-lasting analgesic effects.

Bio-enabling strategies to mitigate the pharmaceutical food effect: a mini review

The concomitant administration of oral drugs with food can result in significant changes in bioavailability, leading to variable pharmacokinetics and considerable clinical implications, such as over- or under-dosing. Consequently, there is increasing demand for bio-enabling formulation strategies to reduce variability in exposure between the fasted and fed state and/or mitigate the pharmaceutical food effect. The current review critically evaluates technologies that have been implemented to overcome the positive food effects of pharmaceutical drugs, including, lipid-based formulations, nanosized drug preparations, cyclodextrins, amorphisation and solid dispersions, prodrugs and salts. Additionally, improved insight into preclinical models for predicting the food effect is provided. Despite the wealth of research, this review demonstrates that application of optimal formulation strategies to mitigate the positive food effects and the evaluation in preclinical models is not a universal approach, and improved standardisation of models to predict the food effects would be desirable. Ultimately, the successful reformulation of specific drugs to eliminate the food effect provides a panoply of advantages for patients with regard to clinical efficacy and compliance.

Crucial Role of PLGA Nanoparticles in Mitigating the Amiodarone-Induced Pulmonary Toxicity

BACKGROUND

Amiodarone (AMD) is a widely used anti-arrhythmic drug, but its administration could be associated with varying degrees of pulmonary toxicity. In attempting to circumvent this issue, AMD-loaded polymeric nanoparticles (AMD-loaded NPs) had been designed.

MATERIALS AND METHODS

AMD was loaded in NPs by the nanoprecipitation method using two stabilizers: bovine serum albumin and Kolliphor® P 188. The physicochemical properties of the AMD-loaded NPs were determined. Among the prepared NPs, two ones were selected for further investigation of spectral and thermal analysis as well as morphological properties. Additionally, in vitro release patterns were studied and kinetically analyzed at different pH values. In vitro cytotoxicity of an optimized formula (NP4) was quantified using A549 and Hep-2 cell lines. In vivo assessment of the pulmonary toxicity on Sprague Dawley rats via histopathological and immunohistochemical evaluations was applied.

RESULTS

The developed NPs achieved a size not more than 190 nm with an encapsulation efficiency of more than 88%. Satisfactory values of loading capacity and yield were also attained. The spectral and thermal analysis demonstrated homogeneous entrapment of AMD inside the polymeric matrix of NPs. Morphology revealed uniform, core-shell structured, and sphere-shaped particles with a smooth surface. Furthermore, the AMD-loaded NPs exhibited a pH-dependent and diffusion-controlled release over a significant period without an initial burst effect. NP4 demonstrated a superior cytoprotective efficiency by diminishing cell death and significantly increasing the IC50 by more than threefold above the pure AMD. Also, NP4 ameliorated AMD-induced pulmonary damage in rats. Significant downregulation of inflammatory mediators and free radicle production were noticed in the NP4-treated rats.

CONCLUSION

The AMD-loaded NPs could ameliorate the pulmonary injury induced by the pure drug moieties. Cytoprotective, anti-fibrotic, anti-inflammatory, and antioxidant properties were presented by the optimized NPs (NP4). Future studies may be built on these findings for diminishing AMD-induced off-target toxicities.

Factors and dosage formulations affecting the solubility and bioavailability of P-glycoprotein substrate drugs

Introduction: Expression of P-glycoprotein (P-gp) increases toward the distal small intestine, implying that the duodenum is the preferential absorption site for P-gp substrate drugs. Oral bioavailability of poorly soluble P-gp substrate drugs is low and varied but increases with high-fat meals that supply lipoidal components and bile in the duodenum.Areas covered: Absorption properties of P-gp substrate drugs along with factors and oral dosage formulations affecting their solubility and bioavailability were reviewed with PubMed literature searches. An overview is provided from the viewpoint of the 'spring-and-parachute approach' that generates supersaturation of poorly soluble P-gp substrate drugs.Expert opinion: The oral bioavailability of P-gp substrate drugs is difficult to predict because of their low solubility, preferential absorption sites, and overlapping substrate specificities with CYP3A4, along with the scattered intestinal P-gp expression/function. To attain high and steady oral bioavailability of poorly soluble P-gp substrate drugs, physicochemical modification of drugs to improve solubility, or oral dosage formulations that generate long-lasting supersaturation in the duodenum, is preferred. In particular, supersaturable lipid-based drug delivery systems that can increase passive diffusion and/or lymphatic absorption are effective and applicable to many poorly soluble P-gp substrate drugs.

The Development and Optimization of Hot-Melt Extruded Amorphous Solid Dispersions Containing Rivaroxaban in Combination with Polymers

Rivaroxaban (RXB), a novel oral anticoagulant that directly inhibits factor Xa, is a poorly soluble drug belonging to Biopharmaceutics Classification System (BCS) class II. In this study, a hot-melt extruded amorphous solid dispersion (HME-ASD) containing RXB is prepared by changing the drug:polymer ratio (Polyvinylpyrrolidione-vinyl acetate 64, 1:1–1:4) and barrel temperature (200–240 °C), fixed at 20% of Cremophor^® RH 40 and 15 rpm of the screw speed, using the hot-melt extruding technique. This study evaluates the solubility, dissolution behavior, and bioavailability for application to oral drug delivery and optimizes the formulation of rivaroxaban amorphous solid dispersion (RXB-ASD). Based on a central composite design, optimized RXB-ASD (PVP VA 64 ratio 1:4.1, barrel temperature 216.1 °C, Cremophor^® RH 40 20%, screw speed 15 rpm) showed satisfactory results for dependent variables. An in vitro drug dissolution study exhibited relatively high dissolution in four media and achieved around an 80% cumulative drug release in 120 min. Optimized RXB-ASD was stable under the accelerated condition for three months without a change in crystallinity and the dissolution rate. A pharmacokinetic study of RXB-ASD in rats showed that the absorption was markedly increased in terms of rate and amount, i.e., the systemic exposure values, compared to raw RXB powder. These results showed the application of quality by design (QbD) in the formulation development of hot-melt extruded RXB-ASD, which can be used as an oral drug delivery system by increasing the dissolution rate and bioavailability.

Chitosan caged liposomes for improving oral bioavailability of rivaroxaban: in vitro and in vivo evaluation

In this study, chitosan (CS) caged classic liposomes (CLs) and flexible liposomes (FLs) were developed to enhance the oral bioavailability of rivaroxaban (RVX) in the fasted condition. The prepared formulations were subjected to physicochemical characterization included: FTIR, DSC, zeta potential, particle size, polydispersity index, entrapment efficiency, in vitro dissolution, and transmission electron microscope imaging. The selected formulation (RVX-TFL2) composed of PL S100/Tween 80 (85/15% w/w) and coated with CS solution in the strength of (0.2% w/v) had a particle size of 105.67 nm, a zeta potential of +5.67 mV and EE of 96.07%. Compared to RXV suspension, the pharmacokinetic parameters (C _max, AUC_0-24, and AUC_0-∞) of RVX-TFL2 showed no statistically significant difference (P > 0.05) in the fasted and fed test animals. Besides, RVX bioavailability with RVX-TFL2 was improved by 59.66% and 26.97% in the fed and fasted states, respectively, compared to RVX suspension in the fed state. The result highlighted the efficacy of the prepared liquid formulation comprising CS coated liposomes in improving the oral bioavailability of RVX regardless of the fed state. Moreover, the studied liquid formulation could be utilized in developing a liquid dosage form that might be useful as a pediatric formulation of RVX.

Effect of excipients on oral absorption process according to the different gastrointestinal segments

INTRODUCTION

Excipients are necessary to develop oral dosage forms of any Active Pharmaceutical Ingredient (API). Traditionally, excipients have been considered inactive and inert substances, but, over the years, numerous studies have contradicted this belief. This review focuses on the effect of excipients on the physiological variables affecting oral absorption along the different segments of the gastrointestinal tract. The effect of excipients on the segmental absorption variables are illustrated with examples to help understand the complexity of predicting their in vivo effects.

AREAS COVERED

The effects of excipients on disintegration, solubility and dissolution, transit time, and absorption are analyzed in the context of the different gastrointestinal segments and the physiological factors affecting release and membrane permeation. The experimental techniques used to study excipient effects and their human predictive ability are reviewed.

EXPERT OPINION

The observed effects of excipient in oral absorption process have been characterized in the past, mainly in vitro (i.e. in dissolution studies, in vitro cell culture methods or in situ animal studies). Unfortunately, a clear link with their effects in vivo, i.e. their impact on Cmax or AUC, which need a mechanistic approach is still missing. The information compiled in this review leads to the conclusion that the effect of excipients in API oral absorption and bioavailability is undeniable and shows the need of implementing standardized and reproducible preclinical tools coupled with mechanistic and predictive physiological-based models to improve the current empirical retrospective approach.

Synthesis and biological evaluation of novel shikonin-benzo[b]furan derivatives as tubulin polymerization inhibitors targeting the colchicine binding site

A novel series of shikonin-benzo[b]furan derivatives were designed and synthesized as tubulin polymerization inhibitors, and their biological activities were evaluated. Most compounds revealed the comparable anti-proliferation activities against the cancer cell lines to that of shikonin and simultaneously low cytotoxicity to non-cancer cells. Among them, compound 6c displayed powerful anti-cancer activity with the IC₅₀ value of 0.18 μM against HT29 cells, which was significantly better than that of the reference drugs shikonin and CA-4. What's more, 6c could inhibit tubulin polymerization and compete with [³H] colchicine in binding to tubulin. Further biological studies depicted that 6c can induce cell apoptosis and cell mitochondria depolarize, regulate the expression of apoptosis related proteins in HT29 cells. Besides, 6c actuated the HT29 cell cycle arrest at G2/M phase, and influenced the expression of the cell-cycle related protein. Moreover, 6c displayed potent inhibition on cell migration and tube formation that contributes to the antiangiogenesis. These results prompt us to consider 6c as a potential tubulin polymerization inhibitor and is worthy for further study.

Study on the Role of the Inclusion Complexes with 2-Hydroxypropyl-β-cyclodextrin for Oral Administration of Amiodarone

The aim of this study was to improve the solubility of amiodarone hydrochloride (AMD) and the drug release using its inclusion complexes with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The inclusion complexes were prepared by coprecipitation and freeze-drying. The solubility enhancement of AMD/HP-β-CD inclusion complexes by 4–22 times was evaluated by the phase solubility method. The inclusion complexes were studied both in solution and in solid state by spectroscopic methods, dynamic light scattering (DLS) and zeta potential analysis, SEM, and DSC. The formulations of AMD/HP-β-CD inclusion complexes both as powdered form and as matrix tablets showed superior pharmacokinetic performance in improving loading and release properties in respect of those of the insoluble AMD drug. In vitro kinetic study reveals a complex mechanism of release occurring in three steps: the first one being attributed to a burst effect and the other two to different bonding existing in inclusion complexes. An in vivo test on matrix tablets containing Kollidon® and chitosan also reveals a multiple (at least two) peaks release diagram because of both structures of the inclusion complexes and also of different sites of absorption in biological media (digestive tract).

Preparation, Characterization, and Properties of Inclusion Complexes of Balofloxacin with Cyclodextrins

The study mainly aimed to improve the aqueous solubility of Balofloxacin (BLFX) by preparing the inclusion complexes (ICs) of BLFX with cyclodextrins (CDs). In this study, ICs in solid state were obtained by using beta-CD (β-CD), 2-hydroxypropyl-β-CD (HP-β-CD), 2, 6-dimethyl-β-CD (DM-β-CD) through a freeze-drying technique. The formation of ICs was confirmed through Fourier-transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, nuclear magnetic resonance, and scanning electron microscopy. Results demonstrated that the water solubility and dissolution rates of three ICs were distinctly improved than that of parent BLFX. Bacteriostatic experiment manifested that the antibacterial effect of BLFX was not inhibited after encapsulation in CDs. The damage of BLFX to kidney and liver cells was reduced. Consequently, successful preparation of the ICs of BLFX with CDs provided possibility for devising new dosage form of BLFX, which held great promise for further applications in clinical fields.

Design and Evaluation of Hydrophilic Matrix System for pH-Independent Sustained Release of Weakly Acidic Poorly Soluble Drug

The aim of this research was to design and evaluate a hydrophilic matrix system for sustained release of glipizide, a weakly acidic poor soluble drug. A combination of inclusion complexation and microenvironmental pH modification techniques was utilized to improve the dissolution and pH-independent release of glipizide. Hydroxypropyl-β-cyclodextrin (HP-β-CD) was used as the complexation agent while sodium citrate and magnesium oxide (MgO) were used as model pH modifiers. The hydrophilic matrix tablets were prepared by powder direct compression and evaluated by in vitro dissolution study respectively in pH 6.8 and pH 1.2 dissolution media. The formulations containing MgO exhibited increased cumulative drug release from less than 40% in the reference formulation to 90% within 24 h in acidic media (pH 1.2). The release profile in acidic media was similar to the alkaline media (pH 6.8) with a similarity factor (f₂) of 55.0, suggesting the weakening of the effect of pH on the dissolution efficiency of glipizide. The release profile fitted well into the Higuchi model and the dominant mechanism of drug release was Fickian diffusion while case II transport/polymer relaxation occurred. In conclusion, combining inclusion complexation agents and pH modifiers had improved the dissolution of glipizide as well as achieved the pH-independent release profile.

Food for thought: formulating away the food effect - a PEARRL review

OBJECTIVES

Co-ingestion of oral dosage forms with meals can cause substantial changes in bioavailability relative to the fasted state. Food-mediated effects on bioavailability can have significant consequences in drug development, regulatory and clinical settings. To date, the primary focus of research has focused on the ability to mechanistically understand the causes and predict the occurrence of these effects.

KEY FINDINGS

The current review describes the mechanisms underpinning the occurrence of food effects, sheds new insights on the relative frequency for newly licensed medicines and describes the various methods by which they can be overcome. Analysis of oral medicines licensed by either the EMA or FDA since 2010 revealed that over 40% display significant food effects. Due to altered bioavailability, these medicines are often required to be dosed, rather restrictively, in either the fed or the fasted state, which can hinder clinical usefulness.

SUMMARY

There are clinical and commercial advantages to predicting the presence of food effects early in the drug development process, in order to mitigate this risk of variable food effect bioavailability. Formulation approaches aimed at reducing variable food-dependent bioavailability, through the use of bio-enabling formulations, are an essential tool in addressing this challenge and the latest state of the art in this field are summarised here.

Preparation and Optimization of Rivaroxaban by Self-Nanoemulsifying Drug Delivery System (SNEDDS) for Enhanced Oral Bioavailability and No Food Effect

In this paper, a novel self-nanoemulsifying drug delivery system (SNEDDS) was used to improve the oral bioavailability in fasted state and diminish the food effect for rivaroxaban. Oil, surfactant, and co-surfactant were selected by saturated solubility study. IPM, Tween80, and 1,2-propanediol were finally selected as oil, surfactant, and co-surfactant, respectively. The pseudo-ternary-phase diagram was utilized to optimize the preliminary composition of SNEDDS formulation. The optimized rivaroxaban-SNEDDS formulation was selected by central composite design (CCD) of response surface methodology. Optimized SNEDDS formulation was evaluated for drug content, self-emulsifying time, droplet size, zeta potential, polydispersity index, Fourier transform-infrared (FTIR) spectroscopy, and transmission electron microscope (TEM). The drug dissolution profile compared to the commercial formulation Xarelto® (20 mg rivaroxaban) was determined in four different media (pH 1.2HCl, pH 4.5NaAc-HAc, pH 6.8PBS, and water). The result indicated that the SNEDDS formulation had successfully increased the drug solubility in four different media. A HPLC-MS method that indicated a high sensitivity, strong attribute, and high accuracy characteristic was built to measure the drug concentration in plasma. The fast/fed in vivo pharmacokinetics studies of SNEDDS formulation and Xarelto® were carried out in adult beagle dog, rivaroxaban with no food effect was achieved in SNEDDS formulation compared with Xarelto® in fed state. The result suggested that SNEDDS formulation in this study is useful to increase the oral bioavailability and diminish the food effect in fasted state.

Dual Activity of Hydroxypropyl-β-Cyclodextrin and Water-Soluble Carriers on the Solubility of Carvedilol

Carvedilol (CAR) is a non-selective α and β blocker categorized as class II drug with low water solubility. Several recent studies have investigated ways to overcome this problem. The aim of the present study was to combine two of these methods: the inclusion complex using hydroxypropyl-β-cyclodextrin (HPβCD) with solid dispersion using two carriers: Poloxamer 188 (PLX) and Polyvinylpyrrolidone K-30 (PVP) to enhance the solubility, bioavailability, and the stability of CAR. Kneading method was used to prepare CAR-HPβCD inclusion complex (KD). The action of different carriers separately and in combination on Carvedilol solubility was investigated in three series. CAR-carrier and KD-carrier solid dispersions were prepared by solvent evaporation method. In vitro dissolution test was conducted in three different media: double-distilled water (DDW), simulative gastric fluid (SGF), and PBS pH 6.8 (PBS). The interactions between CAR, HPβCD, and different carriers were explored by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (XRD), and differential scanning colorimetry (DSC). The results showed higher solubility of CAR in KD-PVP solid dispersions up to 70, 25, and 22 fold compared to pure CAR in DDW, SGF, and PBS, respectively. DSC and XRD analyses indicated an improved degree of transformation of CAR in KD-PVP solid dispersion from crystalline to amorphous state. This study provides a new successful combination of two polymers with the dual action of HPβCD and PLX/PVP on water solubility and bioavailability of CAR.