Standardization of an ex vivo method for determination of intestinal permeability of drugs using everted rat intestine apparatus

Development and Characterization of Pentaerythritol-EudragitRS100 Co-processed Excipients as Solid Dispersion Carriers for Enhanced Aqueous Solubility, In Vitro Dissolution, and Ex Vivo Permeation of Atorvastatin

Atorvastatin (ATV), a lipid-lowering agent, has low oral bioavailability due to its poor water solubility, permeability, and low dissolution rate. Therefore, pentaerythritol-EudragitRS100 co-processed excipients (PECE) were synthesized, and their feasibility as solid dispersion carriers (ATV-PECE-SD) for improving the solubility, permeability, and dissolution rate of ATV was explored. Solid dispersions were assessed in terms of particle size and zeta potential, and solubility, in vitro dissolution, and ex vivo permeation studies were studied. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) were used as characterization tools. ATV-PECE-SD3 (1:4) formulations exhibited a small particle size with high stability. Physicochemical evaluation evidenced the formation of solid dispersion due to the involvement of weak electrostatic interaction between the polar functional groups of ATV and PECE carriers. ATV-PECE-SD3 (1:4) significantly enhanced the water solubility by ∼43-fold compared to pure ATV. In vitro dissolution studies showed that optimized formulation enhanced the dissolution rate of ATV compared to pure ATV. Ex vivo permeation results revealed that ATV-PECE-SD3 (1:4) enhanced the permeation rate of ATV compared to pure ATV. The optimized formulations significantly improved the dissolution rate of ATV in the fed state due to the food effect and micelle formation mechanism compared to the fasted state. The study concludes that co-processed excipients could be used as promising solid dispersion carriers to enhance the aqueous solubility, permeability, and dissolution rate of ATV.

The passive diffusion improvement of Vitamin B12 intestinal absorption by Gelucire that fit for commercialized production

Vitamin B₁₂ (VB₁₂) is a vital micronutrient to maintain the normal state of the hematopoietic system. It must be obtained from the diet since the human body cannot synthesize it. Moreover, the absorption of VB₁₂ needs to be mediated by intrinsic factor on the gastrointestinal (GI) track. The abnormalities in the stomach or lack of such intrinsic factors may result in poor oral absorption of VB₁₂. However, the very advanced formulation strategies were generally very costly and still in the development stage. Thus, the objectives of the present study were to increase the VB₁₂ intestinal absorption by conventional excipients of Gelucire 44/14 (G44/14) or Labrasol, which could be potentially formulated as a cost effect balanced product. The in vitro Caco-2 cell model was applied for the absorption study. A novel VB₁₂ solid dispersion was subsequently prepared and further characterized by Differential scanning calorimetry, Fourier transform infrared spectroscopy, and Scanning electron microscopy, respectively. The membrane permeability of the VB₁₂ solid dispersion was finally evaluated using ex vivo rat everted gut sac method. The results suggested that G44/14 could significantly enhance the intestinal absorption of VB₁₂ via P-glycoprotein inhibition in vitro (P < 0.01). The membrane permeability of VB₁₂could be significantly (P < 0.01) improved by G44/14-VB₁₂ solid dispersion at a proportion of carrier: drug ratio of 20:1.The liquidfied solid dispersion was finally directly filled in the hard gelatin capsules. In conclusion, the cheap and simplified process of VB₁₂ complex prepared by G44/14 could potentially increase VB₁₂ intestinal absorption, which may be liable to commercial manufacturing.

Recent Options and Techniques to Assess Improved Bioavailability: In Vitro and Ex Vivo Methods

Bioavailability assessment in the development phase of a drug product is vital to reveal the disadvantageous properties of the substance and the possible technological interventions. However, in vivo pharmacokinetic studies provide strong evidence for drug approval applications. Human and animal studies must be designed on the basis of preliminary biorelevant experiments in vitro and ex vivo. In this article, the authors have reviewed the recent methods and techniques from the last decade that are in use for assessing the bioavailability of drug molecules and the effects of technological modifications and drug delivery systems. Four main administration routes were selected: oral, transdermal, ocular, and nasal or inhalation. Three levels of methodologies were screened for each category: in vitro techniques with artificial membranes; cell culture, including monocultures and co-cultures; and finally, experiments where tissue or organ samples were used. Reproducibility, predictability, and level of acceptance by the regulatory organizations are summarized for the readers.

Enhanced Intestinal Permeability of Cefixime by Self-Emulsifying Drug Delivery System: In-Vitro and Ex-Vivo Characterization

BACKGROUND

Cefixime (CFX) belongs to a group of third-generation cephalosporin antibiotics with low water solubility and low intestinal permeability, which ultimately leads to significantly low bioavailability.

AIM

This study aimed to increase solubility, improve drug release, and intestinal permeability of CFX by loading into SEDDS.

METHODS

Suitable excipients were selected based on drug solubility, percent transmittance, and emulsification efficiency. Pseudo-ternary phase diagram was fabricated for the identification of effective self-emulsification region. The best probably optimized formulations were further assessed for encumbered drug contents, emulsification time, cloud point measurement, robustness to dilution, mean droplet size, zeta potential, polydispersity index (PDI), and thermodynamic and chemical stability. Moreover, in vitro drug release studies and ex vivo permeation studies were carried out and apparent drug permeability P_app of different formulations was compared with the marketed brands of CFX.

RESULTS

Amongst the four tested SEDDS formulations, F-2 formulation exhibited the highest drug loading of 96.32%, emulsification time of 40.37 ± 3 s, mean droplet size of 19.01 ± 1.12 nm, and demonstrated improved long-term thermodynamic and chemical stability when stored at 4 °C. Release studies revealed a drug release of 97.32 ± 4.82% within 60 min in simulated gastric fluid. Similarly, 97.12 ± 5.02% release of CFX was observed in simulated intestinal fluid within 120 min; however, 85.13 ± 3.23% release of CFX was observed from the marketed product. Ex vivo permeation studies displayed a 2.7-fold increase apparent permeability compared to the marketed product in 5 h.

CONCLUSION

Owing to the significantly improved drug solubility, in vitro release and better antibacterial activity, it can be assumed that CFX-loaded SEDDS might lead to an increased bioavailability and antibacterial activity, possibly leading to improved therapeutic effectiveness.

Experimental and computational models to investigate intestinal drug permeability and metabolism

Oral administration is the preferred route for drug administration that leads to better therapy compliance. The intestine plays a key role in the absorption and metabolism of oral drugs, therefore, new intestinal models are being continuously proposed, which contribute to the study of intestinal physiology, drug screening, drug side effects, and drug-drug interactions.Advances in pharmaceutical processes have produced more drug formulations, causing challenges for intestinal models. To adapt to the rapid evolution of pharmaceuticals, more intestinal models have been created. However, because of the complexity of the intestine, few models can take all aspects of the intestine into account, and some functions must be sacrificed to investigate other areas. Therefore, investigators need to choose appropriate models according to the experimental stage and other requirements to obtain the desired results.To help researchers achieve this goal, this review summarised the advantages and disadvantages of current commonly used intestinal models and discusses possible future directions, providing a better understanding of intestinal models.

Preparation and characterisation of self-emulsifying drug delivery system (SEDDS) for enhancing oral bioavailability of metformin hydrochloride using hydrophobic ion pairing complexation

AIM

The aim of this study was preparation of a self-emulsifying drug delivery system (SEEDS) containing metformin hydrochloride.

METHODS

Hydrophobic ion paired complexes were prepared by electrostatic interaction between metformin and sodium lauryl sulphate (SLS). The nanodroplets were optimised using two-level full factorial methodology and their morphology were examined. In vitro release of metformin from SEDDS was evaluated in simulated gastric and intestinal fluids. Finally, the ex-vivo efficacy of the optimised formulation in enhancing the intestinal permeability of metformin was evaluated using non-everted intestinal sac.

RESULTS

The data revealed that in weight ratio 1:4(metformin: SLS), the highest recovery was achieved. The physico-chemical properties of the optimised nano-droplets including size, polydispersity index (PdI), zeta potential, and loading efficiency (%) were 192.33 ± 9.9 nm, 0.275 ± 0.051; -1.52 mV, and 93.75 ± 0.77% (w/w), respectively.

CONCLUSIONS

The data obtained from the intestinal transport study demonstrated that SEDDS can significantly enhance the oral permeability of the compound.

Cationic biopolymer decorated Asiatic Acid and Centella asiatica extract incorporated liposomes for treating early-stage Alzheimer's disease: An In-vitro and In-vivo investigation

Background: Asiatic acid (AA) is a naturally occurring triterpenoid derivative of Centella asiatica (CA) with neuroprotective effect. The study aimed to design an ideal oral drug delivery system to treat Alzheimer's disease (AD) and develop chitosan-embedded liposomes comprising an extract of CA (CLCAE) and compare them with the chitosan-coated liposomes of asiatic acid (CLAA) for oral delivery to treat the initial phases of AD.  Methods: The solvent evaporation technique was used to develop CLCAE and CLAA, optimised with the experiment's design, and was further evaluated. Results: Nuclear magnetic resonance (NMR) studies confirmed coating with chitosan. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) indicated the successful formation of CLCAE and CLAA. Differential scanning colorimetry (DSC) confirmed the drug-phospholipid complex. Furthermore, the rate of  in vitro release of CLCAE and CLAA was found to be 69.43±0.3 % and 85.3±0.3 %, respectively, in 24 h.  Ex vivo permeation of CLCAE and CLAA was found to be 48±0.3 % and 78±0.3 %, respectively. In the Alcl3-induced AD model in rats, disease progression was confirmed by Y-maze, the preliminary histopathology evaluation showed significantly higher efficacy of the prepared liposomes (CLCAE and CLAA) compared to the Centella asiatica extract (CAE) and they were found to have equivalent efficacy to the standard drug (rivastigmine tartrate). The considerable increase in pharmacodynamic parameters in terms of neuronal count in the CLAA group indicated the protective role against Alcl3 toxicity and was also confirmed by assessing acetylcholine (Ach) levels. The pharmacokinetic study, such as C _max, T _max, and area under curve (AUC) parameters, proved an increase in AA bioavailability in the form of CLAA compared to the pure AA and CLCAE forms. Conclusion: The preclinical study suggested that CLAA was found to have better stability and an ideal oral drug delivery system to treat AD.

Current trends and perspectives on bioaccessibility and bioavailability of food bioactive peptides: in vitro and ex vivo studies

The bioaccessibility and bioavailability of food-derived bioactive compounds are important issues when assessing their in vivo physiological health-promoting effects. Food components such as proteins and peptides are exposed to different proteases and peptidases during gastrointestinal digestion and absorption. Different in vitro approaches have therefore been developed to evaluate the bioaccessibility and stability of bioactive peptides. The static simulated gastrointestinal digestion model (SGD) was widely reported to assess the bioaccessibility of bioactive peptides. On the other hand, although the dynamic SGD model may better simulate human digestion, it has rarely been explored in bioaccessibility studies of food bioactive peptides due to its high cost and lack of standardization. For bioavailability studies, the Caco-2 cell monolayer model has been used extensively for the assessment of food bioactive peptides. In fact, very few reports using alternative methods for determining transepithelial transport of bioactive peptides have been employed. In this sense, ex vivo tissue-based models such as the Ussing chamber and the everted sac gut have been used. Current evidence supports the fact that using SGD with cell-based models for evaluating the bioaccessibility, absorption, and bioavailability of food-derived bioactive peptides, is the most commonly used approach. Nevertheless, SGD with ex vivo tissue-based models such as the everted sac, remains to be further explored because it seems to be the model that better mimics the physiological process - it is also fast and inexpensive, and several compounds may be tested simultaneously. In the present review, we discuss information available on the different in vitro approaches for the determination of bioaccessibility and bioavailability of food-derived bioactive peptides with special emphasis on ex vivo tissue-based models such as the everted sac and the Ussing chamber models. © 2022 Society of Chemical Industry.

Vilazodone-phospholipid mixed micelles for enhancing oral bioavailability and reducing pharmacokinetic variability between fed and fasted states

Despite the effectiveness and high tolerability of vilazodone (VLZ) as an antidepressant, its use is still limited due to its poor solubility and food dependent absorption. This study aims to load VLZ-phospholipid complex into self-assembled micelles forming VLZ-PL mixed micelles (VLZ-PL-MM), that can enhance VLZ solubility, improve its bioavailability and reduce the pharmacokinetic variability between the fed and fasting conditions. The effect of the surfactant type and concentration was assessed using four different non-ionic surfactants (Brij 58, Tween 80, Labrasol and Pluronic F127) in four different weight ratios between the drug-complex and surfactant (1:0.5, 1:1, 1:2 and 1:3 w/w). Two VLZ-PL-MM formulae prepared using Brij 58 and Labrasol in 1:3 w/w ratio were selected as optimised ones since they have the highest encapsulation efficiency (100.83 and 93.87%, respectively), a particle size below 250 nm (206.73 and 221.33 nm, respectively) and negative zeta potential values (-29.63, -17.20 mV, respectively). Lyophilisation of these formulations using 3% sucrose was successful with no statistical changes in particle size and zeta potential upon rehydration. Both formulations elicited faster and higher in-vitro drug release profiles compared to the pure drug and the marketed tablet. In addition, both selected formulae improved ex-vivo permeation across rabbit intestinal membrane compared to the pure drug and the marketed tablet, with marked superiority of the one prepared using Brij 58. The results of the in vivo study in male albino rabbits revealed similar AUC_0-24 values after the oral administration of the best achieved VLZ-PL-MM system under fed and fasting conditions (769.89 and 741.55 ng.h mL^-1, respectively). On the other hand, the marketed product showed significantly lower values of the AUC_0-24 relative to the VLZ-PL-MM system and there was a marked enhancement of absorption of drug from the marketed product in presence of food (244.24 and 174.96 ng.h mL^-1 under fed and fasting conditions, respectively. In addition, VLZ concentrations in the brain after 24 hours obtained from the selected VLZ-PL-MM were significantly higher than those obtained from marketed tablet under fed and fasting conditions. Thus, the phospholipid mixed micelle formulation enhances the oral bioavailability of the poorly soluble drug and reduces the pharmacokinetic variability between fasting and fed conditions.

Nanocarrier Drug Delivery Systems: Characterization, Limitations, Future Perspectives and Implementation of Artificial Intelligence

There has been an increasing demand for the development of nanocarriers targeting multiple diseases with a broad range of properties. Due to their tiny size, giant surface area and feasible targetability, nanocarriers have optimized efficacy, decreased side effects and improved stability over conventional drug dosage forms. There are diverse types of nanocarriers that have been synthesized for drug delivery, including dendrimers, liposomes, solid lipid nanoparticles, polymersomes, polymer-drug conjugates, polymeric nanoparticles, peptide nanoparticles, micelles, nanoemulsions, nanospheres, nanocapsules, nanoshells, carbon nanotubes and gold nanoparticles, etc. Several characterization techniques have been proposed and used over the past few decades to control and predict the behavior of nanocarriers both in vitro and in vivo. In this review, we describe some fundamental in vitro, ex vivo, in situ and in vivo characterization methods for most nanocarriers, emphasizing their advantages and limitations, as well as the safety, regulatory and manufacturing aspects that hinder the transfer of nanocarriers from the laboratory to the clinic. Moreover, integration of artificial intelligence with nanotechnology, as well as the advantages and problems of artificial intelligence in the development and optimization of nanocarriers, are also discussed, along with future perspectives.

Recent advance of <i>in vitro</i> models in natural phytochemicals absorption and metabolism

Natural phytochemicals absorption and metabolic process are mainly in the human gut. Simulating the absorption and metabolism of natural phytochemicals in vitro to predict the rate and degree of absorption of natural phytochemicals provides convenience for many researchers. However, in this process, many physiological factors <i>in vitro</i> are affected, such as stomach and intestinal juice composition, pH, intestinal transmission rate and so on. In recent years, the research methods have gradually improved to make these models more suitable for the natural phytochemicals absorption process, <i>in vitro</i> simulation models have become an essential means to study natural phytochemicals absorption. Therefore, this paper introduces the advantages and disadvantages of commonly used <i>in vitro</i> simulation models of natural phytochemicals absorption and metabolism, as well as briefly introduces the working principle of each model. To provide a theoretical basis for simulating natural phytochemicals absorption <i>in vitro</i> and development and utilization of natural phytochemicals.

Pharmacokinetic Study of Withanosides and Withanolides from Withania somnifera Using Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS)

Withania somnifera is a traditional Indian herb described under the 'Rasayana' class in Ayurveda, which gained immense popularity as a dietary supplement in the USA, Europe, Asia, and the Indian domestic market. Despite enormous research on the pharmacological effect of withanosides and withanolides, bioanalytical method development and pharmacokinetics remained challenging and unexplored for these constituents due to isomeric and isobaric characteristics. In current research work, molecular descriptors, pharmacokinetic, and toxicity prediction (ADMET) of these constituents were performed using Molinspiration and admetSAR tools. A rapid, selective, and reproducible bioanalytical method was developed and validated for seven withanosides and withanolides as per USFDA/EMA guidelines, further applied to determine pharmacokinetic parameters of Withania somnifera root extract (WSE) constituents in male Sprague Dawley rats at a dose of 500 mg/kg. Additionally, an ex vivo permeability study was carried out to explore the absorption pattern of withanosides and withanolides from the intestinal lumen. In silico, ADMET revealed oral bioavailability of withanosides and withanolides following Lipinski's rules of five with significant absorption from the gastrointestinal tract and the ability to cross the blood-brain barrier. Upon oral administration of WSE, Cmax was found to be 13.833 ± 3.727, 124.415 ± 64.932, 57.536 ± 7.523, and 7.283 ± 3.341 ng/mL for withanoside IV, withaferin A, 12-Deoxy-withastramonolide, and withanolide A, respectively, with Tmax of 0.750 ± 0.000, 0.250 ± 0.000, 0.291 ± 0.102, and 0.333 ± 0.129 h. Moreover, at a given dose, withanoside V, withanolide B, and withanone were detected in plasma; however, the concentration of these constituents was found below LLOQ. Thus, these four major withanoside and withanolides were quantified in plasma supported by ex vivo permeation data exhibiting a time-dependent absorption of withanosides and withanolides across the intestinal barrier. These composite findings provide insights to design a clinical trial of WSE as a potent nutraceutical.

Lipid nanocarrier of selegiline augmented anti-Parkinson's effect via P-gp modulation using quercetin

In the present study, SEL was loaded in a lipid nanocarrier (LNC) formulation with a P-gp pump inhibitor i.e., Quercetin (QUR) for improving the bioavailability of the SEL in the brain via the oral route. SEL-QUR LNC was formulated using modified emulsiosonication method and optimized using central composite rotatable design (CCRD) design. The results showed that optimized SEL-QUR LNC formulation was spherical with globule size, polydispersity index, entrapment efficiency and zeta potential within the range of 92.46-95.34 nm, 0.239-0.248, 88.94-91.26%, and -6.21 to -7.75 mV respectively. A 4-fold and 6-fold increase was observed in the permeation of SEL from SEL-QUR LNC across the gut sac in comparison with SEL-QUR and SEL suspensions respectively. CLSM images showed 2-fold deeper permeation of SEL across intestinal membrane demonstrating excellent in vivo prospect of the formulation. The behavioural studies including forced swimming, muscle coordination, locomotor activity, akinesia, and catalepsy were performed in the haloperidol-induced PD rats that demonstrated increased efficacy of the formulation in contrast to the SEL-QUR and SEL suspensions. These studies concluded that developed LNC formulation loaded SEL with P-gp inhibitor had the potential in improving bioavailability of SEL in the brain via oral route.

An overview of in vitro, ex vivo and in vivo models for studying the transport of drugs across intestinal barriers

Oral administration is the most commonly used route for drug delivery owing to its cost-effectiveness, ease of administration, and high patient compliance. However, the absorption of orally delivered compounds is a complex process that greatly depends on the interplay between the characteristics of the drug/formulation and the gastrointestinal tract. In this contribution, we review the different preclinical models (in vitro, ex vivo and in vivo) from their development to application for studying the transport of drugs across intestinal barriers. This review also discusses the advantages and disadvantages of each model. Furthermore, the authors have reviewed the selection and validation of these models and how the limitations of the models can be addressed in future investigations. The correlation and predictability of the intestinal transport data from the preclinical models and human data are also explored. With the increasing popularity and prevalence of orally delivered drugs/formulations, sophisticated preclinical models with higher predictive capacity for absorption of oral formulations used in clinical studies will be needed.

Pharmaceutical Formulations with P-Glycoprotein Inhibitory Effect as Promising Approaches for Enhancing Oral Drug Absorption and Bioavailability

P-glycoprotein (P-gp) is crucial in the active transport of various substrates with diverse structures out of cells, resulting in poor intestinal permeation and limited bioavailability following oral administration. P-gp inhibitors, including small molecule drugs, natural constituents, and pharmaceutically inert excipients, have been exploited to overcome P-gp efflux and enhance the oral absorption and bioavailability of many P-gp substrates. The co-administration of small molecule P-gp inhibitors with P-gp substrates can result in drug–drug interactions and increased side effects due to the pharmacological activity of these molecules. On the other hand, pharmaceutically inert excipients, including polymers, surfactants, and lipid-based excipients, are safe, pharmaceutically acceptable, and are not absorbed from the gut. Notably, they can be incorporated in pharmaceutical formulations to enhance drug solubility, absorption, and bioavailability due to the formulation itself and the P-gp inhibitory effects of the excipients. Different formulations with inherent P-gp inhibitory activity have been developed. These include micelles, emulsions, liposomes, solid lipid nanoparticles, polymeric nanoparticles, microspheres, dendrimers, and solid dispersions. They can bypass P-gp by different mechanisms related to their properties. In this review, we briefly introduce P-gp and P-gp inhibitors, and we extensively summarize the current development of oral drug delivery systems that can bypass and inhibit P-gp to improve the oral absorption and bioavailability of P-gp substrates. Since many drugs are limited by P-gp-mediated efflux, this review is helpful for designing suitable formulations of P-gp substrates to enhance their oral absorption and bioavailability.

Effect and molecular mechanism research of Astragalus membranaceus on inhibiting intestinal absorption of six alkaloids of Aconitum carmichaelii in spleen deficiency rats

Objective

To investigate the effect and the mechanism of Astragalus membranaceus (Huangqi in Chinese, HQ) extract on the intestinal absorption of six alkaloids of Aconitum carmichaelii (Fuzi in Chinese, FZ) in rats with spleen deficiency and provide novel insights into the application of HQ on modulating intestinal barrier.

Methods

Four-week-old male Sprague-Dawley rats were fed with Xiaochengqi Decoction to induce the spleen deficiency model for 40 d. Single-pass intestinal perfusion model were used to study the effects of HQ extract on the absorption of alkaloids. Protein expression and mRNA levels of MRP2 and BCRP and tight junction proteins (TJ, including Claudin-1, Occludin and ZO-1) were measured using Western blot and real-time PCR, respectively. The location and expression of TJ protein was also investigated by the immunofluorescence method.

Results

Compared with the normal group, the protein expression of MRP2, BCRP and TJ proteins in the model group were significantly down-regulated. After oral administration of HQ, the alkaloid absorption in intestinal villi was inhibited, MRP2, BCRP and TJ proteins were up-regulated, the green fluorescence staining of Claudin-1, Occludin, and ZO-1 was enhanced, and a thick layer of mucus was deposited on the surface of the epithelium of the intestinal cavity.

Conclusion

HQ as an intestinal barrier modulator improves the physiological changes of the intestinal environment of spleen deficiency to reduce the absorption of toxic components, leading to a decrease in the absorption of drug-like molecules.

Traditional Chinese herbal medicine Astragalus Radix and its effects on intestinal absorption of aconite alkaloids in rats

Objective

Methods

Results

Conclusion

Egg White Protein Carrier-Assisted Development of Solid Dispersion for Improved Aqueous Solubility and Permeability of Poorly Water Soluble Hydrochlorothiazide

Hydrochlorothiazide (HTZ) is a first-line drug used in the treatment of hypertension suffered from low oral bioavailability due to poor aqueous solubility and permeability. Hence, lyophilized egg white protein-based solid dispersion (HTZ-EWP SD) was developed to explore its feasibility as a solid dispersion carrier for enhanced aqueous solubility and permeability of HTZ. The HTZ-EWP SD was prepared using the kneading method. HTZ-EWP SD was characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FT-IR), powder X-ray diffractometer (PXRD), solubility, in vitro dissolution, and ex vivo permeation studies. The physico-chemical evaluation suggested the formation of the solid dispersion. Optimized HTZ-EWP SD4 drastically enhanced (~32-fold) aqueous solubility (~16.12 ± 0.08 mg/mL) over to pure HTZ (~ 0.51 ± 0.03 mg/mL). The dissolution study in phosphate buffer media (pH 6.8) revealed that HTZ-EWP SD4 significantly enhanced the release rate of HTZ (~ 87 %) over to HTZ (~ 25 %). The permeation rate of HTZ from optimized HTZ-EWP SD4 was enhanced significantly (~ 84 %) compared to pure HTZ (~ 24 %). Optimized HTZ-EWP-SD4 enhanced the rate of HTZ dissolution (~ 86 %) in FeSSIF (fed state simulated intestinal fluid), compared to a low dissolution rate (~ 72 %) in FaSSIF (fasted state simulated intestinal fluid) state after 2-h study. Obtained results conclude that lyophilized egg white protein can be utilized as an alternative solid dispersion carrier for enhancing the solubility and permeability of HTZ.

Determining the glycaemic responses of foods: conventional and emerging approaches

A low-glycaemic diet is crucial for those with diabetes and cardiovascular diseases. Information on the glycaemic index (GI) of different ingredients can help in designing novel food products for such target groups. This is because of the intricate dependency of material source, composition, food structure and processing conditions, among other factors, on the glycaemic responses. Different approaches have been used to predict the GI of foods, and certain discrepancies exist because of factors such as inter-individual variation among human subjects. Besides other aspects, it is important to understand the mechanism of food digestion because an approach to predict GI must essentially mimic the complex processes in the human gastrointestinal tract. The focus of this work is to review the advances in various approaches for predicting the glycaemic responses to foods. This has been carried out by detailing conventional approaches, their merits and limitations, and the need to focus on emerging approaches. Given that no single approach can be generalised to all applications, the review emphasises the scope of deriving insights for improvements in methodologies. Reviewing the conventional and emerging approaches for the determination of GI in foods, this detailed work is intended to serve as a state-of-the-art resource for nutritionists who work on developing low-GI foods.

Protective Effect of Lacticaseibacillus casei CRL 431 Postbiotics on Mitochondrial Function and Oxidative Status in Rats with Aflatoxin B1-Induced Oxidative Stress

Studies have shown that the intracellular content of probiotic (postbiotics) has antioxidant properties, which can improve the antioxidant status in vivo. However, its absorption and mechanisms underlying the protective effects are still unknown. The antioxidant capacity of Lacticaseibacillus casei CRL431 (IC-431) postbiotics was determined after an in vitro simulated digestive process. Permeability of antioxidant constituents of IC-431 was determined by an ex vivo everted duodenum assay. Aflatoxin B₁-induced oxidative stress rat models were established and treated with IC-431; biomarkers of hepatic mitochondrial function and H₂O₂ levels, oxidative stress, and oxidative stress index (OSi) were examined. The antioxidant capacity of IC-431 (477 ± 45.25 μmol Trolox Equivalent/L) was reduced by exposure to the simulated digestive process. No difference (p > 0.05) was found among digested and the permeate fraction of IC-431. A protective effect was observed by significantly lower OSi and higher liver glutathione peroxidase and catalase activities. Lower H₂O₂ production, a higher degree of mitochondrial uncoupling, and lower mitochondrial respiration coefficient were also observed (p < 0.05). These results suggest that IC-431 antioxidant components permeate intestinal barriers to enter the bloodstream and regulate antioxidant status during AFB₁-induced oxidative stress by reducing hepatic mitochondrial dysfunction, thus enhancing antioxidant enzyme response.

Use of combined nanocarrier system based on chitosan nanoparticles and phospholipids complex for improved delivery of ferulic acid

A novel nanocarrier system of phospholipids complex loaded chitosan nanoparticles (FAPLC CNPs) was developed to improve the oral bioavailability and antioxidant potential of FA. FAPLC CNPs were optimized using a Box-Behnken Design (BBD). FAPLC CNPs were characterized using differential scanning calorimetry, Fourier transforms infrared spectroscopy, powder x-ray diffractometry, proton nuclear magnetic resonance, solubility, in vitro dissolution, ex vivo permeation, and in vivo antioxidant activity in carbon tetrachloride (CCl₄)-induced albino rat model. The characterization studies indicated a formation of the complex as well as FAPLC CNPs. The FAPLC CNPs exhibited a lower particle size ~123.27 nm, PDI value ~0.31, and positive zeta potential ~32 mV respectively. Functional characterization studies revealed a significant improvement in the aqueous solubility, dissolution, and permeation rate of FAPLC and FAPLC CNPs compared to FA and FA CNPs. The FAPLC CNPs showed significant enhancement of in vivo antioxidant activity of FA by restoring the elevated marker enzymes in the CCl₄-intoxicated rat model compared to FA CNPs. Moreover, the pharmacokinetic analysis demonstrated a significant enhancement of oral bioavailability of FA from FAPLC CNPs compared to FA CNPs. These findings show that FAPLC CNPs could be used as an effective nanocarrier for improving the oral delivery of FA.

Integration of in silico, in vitro and ex vivo pharmacology to decode the anti-diabetic action of Ficus benghalensis L. bark

BACKGROUND

Traditionally, Ficus benghalensis L. is used to treat metabolic disorders and is also recorded in the Ayurvedic pharmacopeia of India. The present study aimed to evaluate the anti-diabetic property of hydroalcoholic extract/fraction(s) of F. benghalensis L. bark via in silico, in vitro, and ex vivo approach.

METHODS

Enzyme inhibitory activity, glucose uptake in rat hemidiaphragm, and glucose permeability, and adsorption assays were performed using in vitro and ex vivo methods as applicable. Further, the PASS was used to identify the probable lead enzyme inhibitors. The presence of predicted enzyme inhibitors was confirmed via the LC-MS. Similarly, the docking of ligands with respective targets was performed using autodock4.0.

RESULTS

Flavonoids rich fraction possessed the highest α-amylase, and α-glucosidase inhibitory activity followed by maximum efficacy for glucose uptake in rat hemidiaphragm. Similarly, the hydroalcoholic extract showed the highest efficacy to inhibit glucose diffusion. Likewise, 3,4-dihydroxybenzoic acid was predicted for the highest pharmacological activity for α-amylase, ursolic acid for PTP1B, and apigenin for α-glucosidase inhibition respectively. The LC-MS analysis also identified the presence of the above hit molecules in the hydroalcoholic extract.

CONCLUSION

The analogs of 3,4-dihydroxybenzoic acid, apigenin, and ursolic acid could be the choice of lead hits as the α-amylase, α-glucosidase, and PTP1B inhibitors respectively. Additionally, the majority of secondary metabolites from the hydroalcoholic extract of F. benghalensis may be involved in enhancing the glucose uptake to support the process of glycogenesis.

Nanostructured lipid carrier potentiated oral delivery of raloxifene for breast cancer treatment

Nanotherapeutics in cancer treatment are dominating global science and research, and have been recognized as the pioneering medical care regimen. Raloxifene (RLN) has been used for its anti-proliferative action on mammary tissue, however, it suffers from poor oral bioavailability. This investigation gives an account of the design and development of RLN-loaded nanostructured lipid carriers (RLN-NLCs) using a simple and scalable ultrasonication method for improved oral efficacy and limited offsite toxicity using Compritol^® 888 ATO as a solid lipid and Transcutol^® HP as a liquid lipid. In addition, the optimized RLN-NLCs were in the nanometric range (121 nm) with high % entrapment efficiency (%EE) (81%) for RLN, and were further freeze-dried in the presence of mannitol to enhance the stability of RLN-NLCs in the dry state for long-term use. Morphological observation under a transmission electron microscope and scanning electron microscope revealed the spherical smooth surface nanometric size of RLN-NLCs. Powder x-ray diffraction confirmed the encapsulation of RLN into the RLN-NLC's matrix with reduced crystallinity of the drug. The in vitro release study showed a burst release for an initial 4 h, and sustained release for up to 24 h. Furthermore, the RLN-NLCs showed higher cytotoxicity towards MCF-7 cells in vitro in comparison to RLN suspension, and an ex vivo intestinal permeation study demonstrated improved intestinal permeability of RLN-NLCs. Moreover, the in vivo pharmacokinetic study in female Wistar rats showed a 4.79-fold increment in oral bioavailability of RLN from RLN-NLCs compared to RLN suspension. Taken together, our results pave the way for a new nanotherapeutic approach towards breast cancer treatment.

A dynamic and integrated in vitro/ex vivo gastrointestinal model for the evaluation of the probability and severity of infection in humans by Salmonella spp. vehiculated in different matrices

The lack of proper gastrointestinal models assessing the inter-strain virulence variability of foodborne pathogens and the effect of the vehicle (food matrix) affects the risk estimation. This research aimed to propose a dynamic and integrated in vitro/ex vivo gastrointestinal model to evaluate the probability and severity of infection of foodborne pathogens at different matrices. An everted gut sac was used to determine the adhesion and invasion of Salmonella enterica and tissue damage. S. Typhimurium ATCC 14028 was used as a representative bacterium, and two matrices (water and cheese) were used as vehicles. No differences (p > 0.05) in the probability of infection (P_inf) were found for intra-experimental repeatability. However, the P_inf of cheese-vehiculated S. Typhimurium was different compared to water- vehiculated S. Typhimurium, 7.2-fold higher. The histological analysis revealed Salmonella-induced tissue damage, compared with the control (p < 0.05). In silico proposed interactions between two major Salmonella outer membrane proteins (OmpA and Rck) and digested peptides from cheese casein showed high binding affinity and stability, suggesting a potential protective function from the food matrix. The results showed that the everted gut sac model is suitable to evaluate the inter-strain virulence variability, considering both physiological conditions and the effect of the food matrix.

Phospholipid complex-loaded self-assembled phytosomal soft nanoparticles: evidence of enhanced solubility, dissolution rate, ex vivo permeability, oral bioavailability, and antioxidant potential of mangiferin

In this study, self-assembled phytosomal soft nanoparticles encapsulated with phospholipid complex (MPLC SNPs) using a combination of solvent evaporation and nanoprecipitation method were developed to enhance the biopharmaceutical and antioxidant potential of MGN. The mangiferin-Phospholipon® 90H complex (MPLC) was produced by the solvent evaporation method and optimized using central composite design (CCD). The optimized MPLC was converted into MPLC SNPs using the nanoprecipitation method. The physicochemical and functional characterization of MPLC and MPLC SNPs was carried out by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffractometer (PXRD), proton nuclear magnetic resonance (¹H-NMR), solubility, in vitro dissolution, oral bioavailability, and in vivo antioxidant studies. A CCD formed stable MPLC with the optimal values of 1:1.76, 50.55 °C, and 2.02 h, respectively. Characterization studies supported the formation of a complex. MPLC and MPLC SNPs both enhanced the aqueous solubility (~ 32-fold and ~ 39-fold), dissolution rate around ~ 98% via biphasic release pattern, and permeation rate of ~ 97%, respectively, compared with MGN and MGN SNPs. Liver function tests and in vivo antioxidant studies exhibited that MPLC SNPs significantly preserved the CCl₄-intoxicated liver marker and antioxidant marker enzymes, compared with MGN SNPs. The oral bioavailability of MPLC SNPs was increased appreciably up to ~ 10-fold by increasing the main pharmacokinetic parameters such as C_max, T_max, and AUC. Thus, MPLC SNPs could be engaged as a nanovesicle delivery system for improving the biopharmaceutical and antioxidant potential of MGN. Graphical abstract.

Hydrophobic ion pair loaded self-emulsifying drug delivery system (SEDDS): A novel oral drug delivery approach of cromolyn sodium for management of bronchial asthma

The aim of the present study is to develop a self-emulsifying drug delivery system (SEDDS) for the hydrophobic ion pair (HIP) complex of cromolyn sodium (CS), in order to enhance its intestinal absorption and biological activity. Two ion pairing agents (IPAs) were investigated: hexadecyl pyridininum chloride (HPC) and myristyl trimethyl ammonium bromide (MTAB). The optimum binding efficiency for complexation between investigated IPAs and CS was observed at a molar ratio of 1.5:1, where CS binding efficiency was found to be 76.10 ± 2.12 and 91.37 ± 1.73% for MTAB and HPC, respectively. The two prepared complexes exhibited a significant increase in partition coefficient indicating increased lipophilicity. The optimized CS-HIP complex was incorporated into SEDDS formulations. SEDDS formulations F2 (40% oleic acid, 40% Brij^TM98, 20% propylene glycol) and F3 (25% oleic acid, 50% Brij^TM98, 25% propylene glycol) exhibited nanometric droplet diameters with monodisperse distribution and nearly neutral zeta potential values. Ex vivo intestinal permeation study, using the non-everted gut sac technique, revealed a significantly higher cumulative amount of permeated drug, after 2 h, for F2 and F3 (53.836 and 77.617 µg/cm², respectively) compared to 8.649 µg/cm² for plain CS solution. The in vivo evaluation of plain CS solution compared to F2 and F3 was conducted in an ovalbumin sensitization-induced bronchial asthma rat model. Lung function parameters (tidal volume and peak expiratory flow), biochemical parameters (interleukin-5, immunoglobulin-E, myeloperoxidase and airway remodelling parameters) were assessed in addition to histopathological examination. The results indicated the superiority of F3 followed by F2 compared to plain CS solution for prophylaxis of bronchial asthma in rats.

First-Pass Metabolism of Polyphenols from Selected Berries: A High-Throughput Bioanalytical Approach

Small berries are rich in polyphenols whose first-pass metabolism may alter their ultimate physiological effects. The antioxidant capacity and polyphenol profile of three freeze-dried berries (blackberry, raspberry, Red Globe grape) were measured and their apparent permeability (Papp) and first-pass biotransformation were tracked with an ex vivo bioanalytical system [everted gut sac (rat) + three detection methods: spectrophotometry, HPLC-ESI-QTOF-MS, differential pulse voltammetry (DPV)]. Total polyphenol (ratio 0.07-0.14-1.0) and molecular diversity (anthocyanins>flavan-3-ols), antioxidant capacity (DPPH, FRAP), anodic current maxima and Papp (efflux> uptake) were in the following order: blackberry > raspberry > Red Globe grape. Epicatechin, pelargonidin & cyanin (all), callistephin (raspberry/blackberry), catechin (grape), cyanidin glycosides (blackberry) and their derived metabolites [quinic acid, epicatechin, cyanidin/malvidin glucosides, and chlorogenic/caffeic acids] were fruit-specific and concentration-dependent. Time-trend DPV kinetic data revealed concurrent epithelial permeability & biotransformation processes. Regular permeability and high-biotransformation of berry polyphenols suggest fruit-specific health effects apparently at the intestinal level.

Encapsulated Curcumin Enhances Intestinal Absorption and Improves Hepatic Damage in Alcoholic Liver Disease-Induced Rats

Encapsulated curcumin (ENCC) was prepared from a commercial curcuminoids complex and was evaluated for its intestinal permeability and hepatoprotective effects. Intestinal permeability was evaluated using a Caco-2 intestinal cell monolayer system and the non-everted gut sac method. The hepatoprotective effect was evaluated in experimental rats administered alcohol for 4 weeks. The intestinal permeability results suggested that encapsulation is a useful method for enhancing adsorption of curcumin via the intestinal epithelium. ENCC administration resulted in the significant reduction of various serum indicators. Notably, most of the indicators elevated by ethanol decreased below normal levels when rats were administered a high dose of ENCC. Oral administration of ENCC also augmented the activity of glutathione peroxidase in the liver, and both normal curcumin and ENCC significantly alleviated high levels of malondialdehyde. Our results demonstrate a significant hepatoprotective effect of ENCC in vivo owing to its ability to improve bioavailability of curcumin.

Curcumin as a permeability enhancer enhanced the antihyperlipidemic activity of dietary green tea extract

Background

Green tea has polyphenols like flavonoids and catechins; mainly epigallocatechin-3-gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and epicatechin (EC), out of which EGCG is of higher abundance. EGCG has shown preventive role in hypercholesterolemia. However, due to low oral bioavailability, a need arises to improve its membrane permeability and transporter-mediated intestinal efflux. Therefore, an attempt was made to enhance permeability and bioavailability of EGCG using curcumin to treat hyperlipidemia. Further, it was formulated in herbal tea bags to achieve patient compliance.

Methods

EGCG extracted from green tea leaves was confirmed by High Performance Thin Layer Chromatography. Green tea extract (GTE), curcumin and their mixtures were subjected to Fourier Transform Infra-Red spectroscopy and Differential Scanning Calorimetry for compatibility studies. Powder formulation was prepared comprising GTE, curcumin, sucralose and cardamom.

Results

Ex-vivo study was performed on everted goat intestine, analyzed by HPLC and demonstrated highest permeation of GTE:curcumin (220:50) (53.15%) than GTE (20.57%). Antihyperlipidemic activity was performed in rats for 15 days. Blood sample analysis of rats of test groups (formulation and GTE solution) fed on high fat diet showed (mg/dl):cholesterol 80 and 90, triglycerides 73.25 and 85.5, HDL 50.75 and 46, LDL 43.9 and 46, VLDL 14.65 and 17.1 respectively with significant lipid regulating effect.

Conclusion

Curcumin enhanced permeability of EGCG. Therefore, P-glycoprotein pump inside intestine can be potential mechanism to enhance permeability of EGCG. Thus, EGCG-curcumin herbal tea bag is promising nutraceutical to treat hyperlipidemia in day-to-day life achieving patient compliance.

Ex-vivo intestinal absorption study of boswellic acid, cyclodextrin complexes and poloxamer solid dispersions using everted gut sac technique

Acetyl- Keto-β-boswellic acid (AKBA) is a pentacyclic triterpenic acid found in gum resin of Boswellia serrata. Even though it is shown to have anti-inflammatory activity, its bioavailability gets limited due to its poor aqueous solubility and permeability. The present study, hence, deals in enhancement of the intestinal absorption of AKBA from total boswellic acid fraction (TA fraction) using cyclodextrin (CD) and poloxamer solid dispersion (PXM SDs) formulations. Absorption studies were performed using the everted gut sac model prepared from rat jejunum. The glucose uptake assay was performed to show viability of gut sac tissue. The apparent permeability (P_app) value of AKBA from TA fraction was 1.08 ± 0.17 × 10^-6 which was found to be increased by 10-14 fold with CD complex and SD formulations. The intestinal absorption studies showed highest absorption of AKBA from HP-β-CD complex and PXM 407 SD as compared to that from TA fraction. From this study, it can be concluded that HP-β-CD and PXM 407 effectively enhanced intestinal absorption through improved solubility, highlighting their role as efficient drug delivery agents and bioavailability enhancers.

Synthesis of 5-hydroxy-2-methyl-naphthalene-1,4-dione cocrystals with pyridine-3-carboxamide using electrospray technology: physicochemical characterization and in vitro non-everted rat intestinal absorption study

Plumbagin with nicotinamide cocrystals synthesised by electrospray technology demonstrated two-, three- and nine-fold enhancements in solubility, dissolution and permeability coefficient.

Physicochemical QSAR Analysis of Passive Permeability Across Caco-2 Monolayers

Caco-2 cell line is frequently used as a simplified in vitro model of intestinal absorption. In this study, a database of 1366 Caco-2 permeability coefficients (P_e) for 768 diverse drugs and drug-like compounds was compiled from public sources. The collected data represent permeation rates measured at varying experimental conditions (pH from 4.0 to 8.0, and stirring rates from 0 to >1000 rpm) that presumably account for passive diffusion across mucosal epithelium. These data were subjected to multistep nonlinear regression analysis using a minimal set of physicochemical descriptors (octanol-water log D, pKa, hydrogen bonding potential, and molecular size). The model was constructed in a mechanistic manner incorporating the following components: (i) a hydrodynamic equation of size- and charge-specific along with nonspecific diffusion across the paracellular pathway; (ii) transcellular diffusion represented by thermodynamic membrane/water partitioning ratio; (iii) stirring-dependent limit of maximum achievable permeability due to the presence of unstirred water layer. The obtained model demonstrates good accuracy of log P_e predictions with a residual mean square error <0.5 log units for all training and validation sets. Given its robust performance and straightforward interpretation in terms of simple physicochemical properties, the proposed model may serve as a valuable tool to guide drug discovery efforts toward readily absorbable compounds.

Spheroid Size Does not Impact Metabolism of the β-blocker Propranolol in 3D Intestinal Fish Model

Compared to two-dimensional (2D) cell culture, cellular aggregates or spheroids (3D) offer a more appropriate alternative in vitro system where individual cell-cell communication and micro-environment more closely represent the in vivo organ; yet we understand little of the physiological conditions at this scale. The relationship between spheroid size and oxygen microenvironment, an important factor influencing the metabolic capacity of cells, was first established using the fish intestine derived RTgutGC cell line. Subsequently, pharmaceutical metabolism (Propranolol), as determined by high performance liquid chromatography, in this intestinal model was examined as a function of spheroid size. Co-efficient of variation between spheroid size was below 12% using the gyratory platform method, with the least variation observed in the highest cell seeding density. The viable, high oxygen micro-environment of the outer rim of the spheroid, as determined by electron paramagnetic resonance (EPR) oximetry, decreased over time, and the hypoxic zone increased as a function of spheroid size. Despite a trend of higher metabolism in smaller spheroids, the formation of micro-environments (quiescent, hypoxic or anoxic) did not significantly affect metabolism or function of an environmentally relevant pharmaceutical in this spheroid model.

Improvement of Oral Bioavailability of Lopinavir Without Co-administration of Ritonavir Using Microspheres of Thiolated Xyloglucan

Lopinavir is a BCS Class IV drug exhibiting poor bioavailability due to P-gp efflux and limited permeation. The aim of this research was to formulate and characterize microspheres of lopinavir using thiolated xyloglucan (TH-MPs) as carrier to improve its oral bioavailability without co-administration of ritonavir. Thiomeric microspheres were prepared by ionotropic gelation between alginic acid and calcium ions. Interaction studies were performed using Fourier transform infrared spectroscopy (FT-IR). The thiomeric microspheres were characterized for its entrapment efficiency, T₈₀, surface morphology, and mucoadhesion employing in vitro wash off test. The microspheres were optimized by 3² factorial design. The optimized thiomeric microsphere formulation revealed 93.12% entrapment efficiency, time for 80% drug release (T₈₀) of 358.1 min, and 88% mucoadhesion after 1 h. The permeation of lopinavir from microspheres was enhanced 3.15 times as determined by ex vivo study using everted chick intestine and increased relative bioavailability over 3.22-fold over combination of lopinavir and ritonavir as determined by in vivo study in rat model.

Application of the rainbow trout derived intestinal cell line (RTgutGC) for ecotoxicological studies: molecular and cellular responses following exposure to copper

There is an acknowledged need for in vitro fish intestinal model to help understand dietary exposure to chemicals in the aquatic environment. The presence and use of such models is however largely restrictive due to technical difficulties in the culturing of enterocytes in general and the availability of appropriate established cell lines in particular. In this study, the rainbow trout (Oncorhynchus mykiss) intestinal derived cell line (RTgutGC) was used as a surrogate for the "gut sac" method. To facilitate comparison, RTgutGC cells were grown as monolayers (double-seeded) on permeable Transwell supports leading to a two-compartment intestinal model consisting of polarised epithelium. This two-compartment model divides the system into an upper apical (lumen) and a lower basolateral (portal blood) compartment. In our studies, these cells stained weakly for mucosubstances, expressed the tight junction protein ZO-1 in addition to E-cadherin and revealed the presence of polarised epithelium in addition to microvilli protrusions. The cells also revealed a comparable transepithelial electrical resistance (TEER) to the in vivo situation. Importantly, the cell line tolerated apical saline (1:1 ratio) thus mimicking the intact organ to allow assessment of uptake of compounds across the intestine. Following an exposure over 72 h, our study demonstrated that the RTgutGC cell line under sub-lethal concentrations of copper sulphate (Cu) and modified saline solutions demonstrated uptake of the metal with saturation levels comparable to short term ex situ gut sac preparations. Gene expression analysis revealed no significant influence of pH or time on mRNA expression levels of key stress related genes (i.e. CYP3A, GST, mtA, Pgp and SOD) in the Transwell model. However, significant positive correlations were found between all genes investigated suggesting a co-operative relationship amongst the genes studied. When the outlined characteristics of the cell line are combined with the division of compartments, the RTgutGC double seeded model represents a potential animal replacement model for ecotoxicological studies. Overall, this model could be used to study the effects and predict aquatic gastrointestinal permeability of metals and other environmentally relevant contaminants in a cost effective and high throughput manner.

Chitosan-coated diacerein nanosuspensions as a platform for enhancing bioavailability and lowering side effects: preparation, characterization, and ex vivo/in vivo evaluation

Nanodrug delivery systems have been widely reviewed for their use in several drug formulations to improve bioavailability, sustain effect, and decrease side effects of many candidate drugs. The objective of this study was to evaluate the potential of chitosan (CS)-coated nanosuspensions to enhance bioavailability and reduce the diarrheal side effect of diacerein (DCN) after oral administration. DCN nanosuspensions (DNS) were prepared by sonoprecipitation technique using different stabilizers at three different concentrations. The selected DNS with optimum particle size (PS), polydispersity index (PDI), and Zeta potential (ZP) was coated with three different concentrations of CS-coated DNS (CS-DNS) and screened. In vitro dissolution was performed for the selected lyophilized formulae and compared with DCN powder in addition to the assessment of drug crystallinity via scanning electron microscopy, X-ray powder diffraction, and differential scanning calorimetry. Ex vivo drug permeability using noneverted rat intestine, intraluminal content, and mucoadhesion evaluation was studied for nominated formulae in comparison to DCN suspension. Moreover, in vivo study, pharmacokinetic parameters, and evaluation of diarrheal potential were conducted after oral administration of selected formulae. Polyvinyl pyrrolidone (PVP)-stabilized DNS showed a significant increase (P≤0.05) in PS and PDI as the stabilizer concentration increased. PVP-stabilized DNS with the lowest CS concentration was protected from aggregation by lyophilization with mannitol. A remarked enhancement in dissolution parameters was observed in the nanocrystals’ formulae. Morphological examination and X-ray diffraction confirmed drug crystallinity. The intermediate permeation parameters of CS-DNS-F10, lowest rhein-to-DCN ratio in intraluminal content along with the highest percentage of mucoadhesive, could serve as a sustaining profile of coated formula. CS-DNS-F10 showed a significantly higher C_max of 0.74±0.15 µg/mL at a delayed T_max of 3.60±0.55 hours with a relative bioavailability of 172.1% compared to DCN suspension. CS-coated nanosuspensions could serve as promising revenue to enhance bioavailability and reduce the diarrheal side effect of DCN after oral administration.

Freeze Dried Quetiapine-Nicotinamide Binary Solid Dispersions: A New Strategy for Improving Physicochemical Properties and Ex Vivo Diffusion

Improving the physicochemical properties and oral bioavailability of quetiapine fumarate (QF) enabling enhanced antipsychotic attributes are the main aims of this research. The freeze dried solid dispersion strategy was adopted using nicotinamide (NIC) as highly soluble coformer. The prepared dispersions were characterized using scanning electron microscopy (SEM) differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Static disc intrinsic dissolution rate and ex vivo diffusion through intestinal tissues were conducted and compared to pure quetiapine fumarate. The results demonstrated a highly soluble coamorphous system formed between quetiapine fumarate and nicotinamide at 1 : 3 molar ratio through H-bonding interactions. The results showed >14-fold increase in solubility of QF from the prepared dispersions. Increased intrinsic dissolution rate (from 0.28 to 0.603 mg cm⁻² min⁻¹) and faster flux rate through duodenum (from 0.027 to 0.041 mg cm⁻² h⁻¹) and jejunum (0.027 to 0.036 mg cm⁻² h⁻¹) were obtained. The prepared coamorphous dispersion proved to be effective in improving the drug solubility and dissolution rate and ex vivo diffusion. Therefore, binary coamorphous dispersions could be a promising solution to modify the physicochemical properties, raise oral bioavailability, and change the biopharmaceutics classification (BCS) of some active pharmaceutical ingredients.

The role of phospholipid as a solubility- and permeability-enhancing excipient for the improved delivery of the bioactive phytoconstituents of Bacopa monnieri

In an attempt to improve the solubility and permeability of Standardized Bacopa Extract (SBE), a complexation approach based on phospholipid was employed. A solvent evaporation method was used to prepare the SBE-phospholipid complex (Bacopa Naturosome, BN). The formulation and process variables were optimized using a central-composite design. The formation of BN was confirmed by photomicroscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Powder X-ray Diffraction (PXRD). The saturation solubility, the in-vitro dissolution, and the ex-vivo permeability studies were used for the functional evaluation of the prepared complex. BN exhibited a significantly higher aqueous solubility compared to the pure SBE (20-fold), or the physical mixture of SBE and the phospholipid (13-fold). Similarly, the in-vitro dissolution revealed a significantly higher efficiency of the prepared complex (BN) in releasing the SBE (>97%) in comparison to the pure SCE (~42%), or the physical mixture (~47%). The ex-vivo permeation studies showed that the prepared BN significantly improved the permeation of SBE (>90%), compared to the pure SBE (~21%), or the physical mixture (~24%). Drug-phospholipid complexation may thus be a promising strategy for solubility enhancement of bioactive phytoconstituents.