Bioavailability assessment of vitamin A self-nanoemulsified drug delivery systems in rats: a comparative study

Pharmacokinetics of vitamin dosage forms: A complete overview

Vitamins are crucial for sustaining life because they play an essential role in numerous physiological processes. Vitamin deficiencies can lead to a wide range of severe health issues. In this context, there is a need to administer vitamin supplements through appropriate routes, such as the oral route, to ensure effective treatment. Therefore, understanding the pharmacokinetics of vitamins provides critical insights into absorption, distribution, and metabolism, all of which are essential for achieving the desired pharmacological response. In this review paper, we present information on vitamin deficiencies and emphasize the significance of understanding vitamin pharmacokinetics for improved clinical research. The pharmacokinetics of several vitamins face various challenges, and thus, this work briefly outlines the current issues and their potential solutions. We also discuss the feasibility of enhanced nanocarrier-based pharmaceutical formulations for delivering vitamins. Recent studies have shown a preference for nanoformulations, which can address major limitations such as stability, solubility, absorption, and toxicity. Ultimately, the pharmacokinetics of pharmaceutical dosage forms containing vitamins can impede the treatment of diseases and disorders related to vitamin deficiency.

Design and Optimization of Rivaroxaban-Cyclodextrin-Polymer Triple Complex Formulation with Improved Solubility

Purpose

This study aimed to ensure the convenience of administration and reproducibility of efficacy, regardless of the meal, by improving the solubility of rivaroxaban (RIV).

Methods

RIV is a non-vitamin K antagonist oral anticoagulants that exhibits a coagulation effect by directly inhibiting coagulation factor Xa. However, RIV has a very low solubility; therefore, it must be administered with a meal at high doses. We used a drug- hydroxypropyl-beta-cyclodextrin (CD)-water-soluble polymer triple complex (R-C-P complex) to solubilize RIV. Using Minitab, we evaluated the effect of each factor on RIV solubility and developed an optimal R-C-P complex formulation. The amount of CD, amount of polymer, and polymer type were set as the independent variables X₁, X₂, and X₃, respectively. RIV solubility (Y₁) and dissolution rate for 45 min in pH 4.5 medium (Y₂) and pH 1.2 medium (Y₃) were set as response variables.

Results

The most efficient RIV solubilization effect was obtained from the composition using CD and HPMC 2208, and physicochemical properties and dissolution parameters were analyzed. RIV in the R-C-P complex was present in an amorphous form and showed high solubility. Unlike commercial products, it showed a 100% dissolution rate. The R-C-P complex formulation secured high RIV solubility and 100% release regardless of pH.

Conclusion

The results imply that high-dose RIV can be administered regardless of the meal, reducing the risk of changing the drug effect due to the patient's administration mistake.

Physiologically Based Pharmacokinetic Models Predicting Renal and Hepatic Concentrations of Industrial Chemicals after Virtual Oral Doses in Rats

Recently developed high-throughput in vitro assays in combination with computational models could provide alternatives to animal testing. The purpose of the present study was to model the plasma, hepatic, and renal pharmacokinetics of approximately 150 structurally varied types of drugs, food components, and industrial chemicals after virtual external oral dosing in rats and to determine the relationship between the simulated internal concentrations in tissue/plasma and their lowest-observed-effect levels. The model parameters were based on rat plasma data from the literature and empirically determined pharmacokinetics measured after oral administrations to rats carried out to evaluate hepatotoxic or nephrotic potentials. To ensure that the analyzed substances exhibited a broad diversity of chemical structures, their structure-based location in the chemical space underwent projection onto a two-dimensional plane, as reported previously, using generative topographic mapping. A high-throughput in silico one-compartment model and a physiologically based pharmacokinetic (PBPK) model consisting of chemical receptor (gut), metabolizing (liver), central (main), and excreting (kidney) compartments were developed in parallel. For 159 disparate chemicals, the maximum plasma concentrations and the areas under the concentration-time curves obtained by one-compartment models and modified simple PBPK models were closely correlated. However, there were differences between the PBPK modeled and empirically obtained hepatic/renal concentrations and plasma maximal concentrations/areas under the concentration-time curves of the 159 chemicals. For a few compounds, the lowest-observed-effect levels were available for hepatotoxicity and nephrotoxicity in the Hazard Evaluation Support System Integrated Platform in Japan. The areas under the renal or hepatic concentration-time curves estimated using PBPK modeling were inversely associated with these lowest-observed-effect levels. Using PBPK forward dosimetry could provide the plasma/tissue concentrations of drugs and chemicals after oral dosing, thereby facilitating estimates of nephrotoxic or hepatotoxic potential as a part of the risk assessment.

Probucol Self-Emulsified Drug Delivery System: Stability Testing and Bioavailability Assessment in Human Volunteers

BACKGROUND

Self-Emulsifying Drug Delivery System (SEDDS), if taken orally, is expected to self-emulsify in GIT and improve the absorption and bioavailability. Probucol (PB) is a highly lipophilic compound with very low and variable bioavailability.

OBJECTIVE

The objectives of this study were to examine the stability and conduct bioavailability of the prepared Probucol Self-Emulsified Drug Delivery System (PBSEDDS) in human volunteers.

METHODS

The methods included preparation of different PBSEDDS using soybean oil (solvent), Labrafil M1944CS (surfactant) and Capmul MCM-C8 (co-surfactant). The formulations were characterized in vitro for spontaneity of emulsification, droplet size, turbidity and dissolution in water after packing in HPMC capsules. The optimized formulations were evaluated for stability at different storage temperatures and human bioavailability compared with the drug dissolved in soybean oil (reference).

RESULTS

The results showed that formulations (F1-F4) were stable if stored at 20 °C. The mean (n=3) pharmacokinetic parameters for stable formulations were: The Cmax, 1070.76, 883.16, 2876.43, 3513.46 and 1047.37 ng/ml; the Tmax, 7.93, 7.33, 3.96, 3.67 and 4.67 hr.; the AUC (0-t), 41043.41, 37763.23, 75006.26, 46731.36 and 26966.43 ng.hr/ml for F1, F2, F3, F4 and reference, respectively. The percentage relative bioavailability was in this order: F3> F4> F1> F2>.

CONCLUSION

In conclusion, the PBSEDDS formulations were stable at room temperature. F4 showed the highest Cmax and the shortest Tmax. All the formulations showed significant enhancement of bioavailability compared with the reference. The results illustrated the potential use of SEDDS for the delivery of probucol hydrophobic compound.

Nanoparticulate-based drug delivery systems for small molecule anti-diabetic drugs: An emerging paradigm for effective therapy

Emergence of nanoparticulate drug delivery systems in diabetes has facilitated improved delivery of small molecule drugs which could dramatically improve the quality of life for diabetics. Conventional dosage forms of the anti-diabetic drugs exhibit variable/less bioavailability and short half-life, demanding frequent dosing and causing increased side-effects resulting in ineffectiveness of therapy and non-compliance with the patients. Considering the chronic nature of diabetes, nanotechnology-based approaches are more promising in terms of providing site-specific delivery of drugs with higher bioavailability and reduced dosage regimen. Nanomedicines act at the cellular and molecular levels to enhance the uptake of the drug into the cells or block the efflux mechanisms thus retaining the drug inside the cell for a longer duration of time. Many studies have hinted at the possibility of administering peptide drugs like glucagon like peptides orally by encapsulation into nanoparticles. Nanoparticles also allow further modifications including their encapsulation into microparticles, polyethylene glycol (PEG)-PEGylation- or functionalization with ligands for active targeting. Nevertheless, such remarkable benefits are fraught with their long-term safety concerns, regulatory hurdles, limitations of scale-up and ineffective patent protection which have hindered their commercialization. This review summarizes the latest advances in the area of nanoformulations as applied to the delivery of anti-diabetics. STATEMENT OF SIGNIFICANCE: The present work describes the latest advancements in the area of nanoformulations for anti-diabetic therapy along with highlighting the advantages that these nanoformulations offer at molecular level for diabetes. Although several potent orally active anti-hyperglycemic agents are available, the current challenges in efficient management of diabetes include optimization of the present therapies to ensure an optimum and stable level of glucose, and also to reduce the occurrence of long term complications associated with diabetes. Nanoformulations because of their high surface area to volume ratio provide improved efficacy, targeting their delivery to the desired site of action tends to minimize adverse effects and administration of peptide drugs by oral route is also possible by encapsulating them in nanoparticles. As we reflect on the success and failures of latest research on nanoformulations for the treatment of diabetes, it is important not to dwell on lack of FDA approvals but rather define future directions that guarantee more effective anti-diabetic treatment. In proposed review we have explored the latest advancement in anti-diabetic nanotechnology based formulations.

Self-microemulsifying drug delivery system (SMEDDS)--challenges and road ahead

Self-microemulsifying drug delivery system (SMEDDS) has emerged as a vital strategy to formulate poor water soluble compounds for bioavailability enhancement. However, certain limitations are associated with SMEDDS formulations which include in vivo drug precipitation, formulation handling issues, limited lymphatic uptake, lack of predictive in vitro tests and oxidation of unsaturated fatty acids. These limitations restrict their potential usage. Inclusion of polymers or precipitation inhibitors within lipid based formulations helps to maintain drug supersaturation after dispersion. This, thereby, improves the bioavailability and reduces the variability on exposure. Also, formulating solid SMEDDS helps to overcome liquid handling and stability problems. Usage of medium chain triglycerides (MCT) and suitable antioxidants to minimize oxidation of unsaturated fatty acids are few of the steps to overcome the limitations associated with SMEDDS. The review discussed here, in detail, the limitations of SMEDDS and suitable measures that can be taken to overcome them.

Improved oral bioavailability of BCS class 2 compounds by self nano-emulsifying drug delivery systems (SNEDDS): the underlying mechanisms for amiodarone and talinolol

PURPOSE

Superior bioavailability of BCS Class 2 compounds incorporated into SNEDDS was previously reported. This study aims to elucidate the underlying mechanisms accountable for this phenomenon.

METHODS

SNEDDS of amiodarone (AM) and talinolol were developed. Pharmacokinetic parameters were assessed in vivo. Effect on intestinal permeability, P-gp efflux and toxicity was evaluated in vitro (Caco-2) and ex vivo (Ussing). Solubilization was assessed in vitro (Dynamic Lipolysis Model). Effect on intraenterocyte metabolism was evaluated using CYP3A4 microsomes.

RESULTS

Oral administration of AM-SNEDDS and talinolol-SNEDDS resulted in higher and less variable AUC and Cmax. In vitro, higher talinolol-SNEDDS Papp indicated Pgp inhibition. Lipolysis of AM-SNEDDS resulted in higher AM concentration in the fraction available for absorption. Incubation of AM-SNEDDS with CYP3A4 indicated CYP inhibition. SNEDDS didn't alter mannitol Papp and TEER. SNEDDS effect was transient.

CONCLUSIONS

Multiple mechanisms are accountable for improved bioavailability and reduced variability of Class-2 compounds by SNEDDS: increased solubilization, reduced intraenterocyte metabolism and reduced P-gp efflux. SNEDDS effect is reversible and doesn't cause intestinal tissue or cell damage. These comprehensive findings can be used for intelligent selection of drugs for which oral bioavailability will improve upon incorporation into SNEDDS, based on recognition of the drug's absorption barriers and the ability of SNEDDS to overcome them.

Encapsulation of antioxidants in gastrointestinal-resistant nanoparticulate carriers

Reactive oxygen species (ROS) are known to cause several human pathologies. For this reason, antioxidants have gained utmost importance because of their potential as prophylactic and therapeutic agents in many diseases. Examples of their application include their use in diabetic patients, as aging drugs, in cancer diseases, Parkinson's, Alzheimer's, autoimmune disorders, and also in inflammation. Antioxidants have limited absorption profiles, therefore low bioavailability and low concentrations at the target site. Efforts have been done towards loading antioxidant molecules in advanced nanoparticulate carriers, e.g., liposomes, polymeric nanoparticles, solid lipid nanoparticles, self-emulsifying drug delivery system. Examples of -successful achievements include the encapsulation of drugs and other active ingredients, e.g., coenzyme Q10, vitamin E and vitamin A, resveratrol and polyphenols, curcumin, lycopene, silymarin, and superoxide dismutase. This review focuses on the comprehensive analysis of using nanoparticulate carriers for loading these molecules for oral administration.

Potentials and challenges in self-nanoemulsifying drug delivery systems

INTRODUCTION

A significant number of new chemical entities (almost 40%), that are outcome of contemporary drug discovery programs, have a potential therapeutic promise for patient, as they are highly potent but poorly water soluble resulting in reduced oral bioavailability. Self-nanoemulsifying drug delivery systems (SNEDDS) have emerged as a vital strategy to formulate these poorly soluble compounds for bioavailability enhancement.

AREAS COVERED

The review gives an insight about potential of SNEDDS with regards to oral drug delivery. The effect of various key constituents on formulation of SNEDDS and their applications in oral drug delivery is also discussed. Various aspects of formulation, characterization and biopharmaceutical aspects of SNEDDS are also been explored. The choice and selection of excipients for development of SNEDDS is also discussed.

EXPERT OPINION

The ability of SNEDDS to present the drug in single unit dosage form either as soft or hard gelatin capsule with enhanced solubility maintaining the uniformity of dose is unique. With the ease of large-scale production, high drug-loading capacity, improvement in release behavior of poorly water-soluble drugs and improvement of oral bioavailability, SNEDDS have emerged as preferable system for the formulation of drug compounds with bioavailability problems due to poor aqueous solubility.

Enhancement of bioavailability of cefpodoxime proxetil using different polymeric microparticles

Poorly water-soluble drugs such as cefpodoxime proxetil (400 μg/ml) offer a challenging problem in drug formulation as poor solubility is generally associated with poor dissolution characteristics and thus poor oral bioavailability. According to these characteristics, preparation of cefpodoxime proxetil microparticle has been achieved using high-speed homogenization. Polymers (methylcellulose, sodium alginate, and chitosan) were precipitated on the surface of cefpodoxime proxetil using sodium citrate and calcium chloride as salting-out agents. The pure drug and the prepared microparticles with different concentrations of polymer (0.05-1.0%) were characterized in terms of solubility, drug content, particle size, thermal behavior (differential scanning calorimeter), surface morphology (scanning electron microscopy), in vitro drug release, and stability studies. The in vivo performance was assessed by pharmacokinetic study. The dissolution studies demonstrate a marked increase in the dissolution rate in comparison with pure drug. The considerable improvement in the dissolution rate of cefpodoxime proxetil from optimized microparticle was attributed to the wetting effect of polymers, altered surface morphology, and micronization of drug particles. The optimized microparticles exhibited excellent stability on storage at accelerated condition. The in vivo studies revealed that the optimized formulations provided improved pharmacokinetic parameter in rats as compared with pure drug. The particle size of drug was drastically reduced during formulation process of microparticles.