Controlled release of glaucocalyxin – a self-nanoemulsifying system from osmotic pump tablets with enhanced bioavailability

Self-nanoemulsifying drug delivery systems (SNEDDS) of anti-cancer drugs: a multifaceted nanoplatform for the enhancement of oral bioavailability

OBJECTIVE

A significant problem faced by the health care industry today is that though there are numerous drugs available to tackle diseases like cancer, their intrinsic properties make it difficult to be delivered to patients in a feasible manner. One of the key players that have helped researchers overcome poor solubility and permeability of drugs is Nanotechnology, this article further iterates on the same.

SIGNIFICANCE

Nanotechnology is used as an umbrella term in pharmaceutics and describes under it multiple technologies. Upcoming nanotechnology is a Self Nanoemulsifying System which is considered to be a futuristic delivery system both due to its scientific simplicity and relative ease of patient delivery.

METHODS

Self-Nano Emulsifying Drug Delivery Systems (SNEDDS) are homogenous lipidic concoctions containing the drug solubilized in the oil phase and surfactants. The choice of components depends on the physicochemical properties of the drugs, the solubilization capability of oils and the physiological fate of the drug. The article contains further details of various methodologies that have been adopted by scientists to formulate and optimize such systems in order to make anticancer drugs orally deliverable.

RESULTS

The results that have been generated by scientists across the globe have been summarized in the article and all of the data supports the claim that SNEDDS significantly enhance the solubility and bioavailability of hydrophobic anticancer drugs.

CONCLUSIONS

This article mainly provides the application of SNEDDS in cancer therapy and concludes to provide a step for the oral administration of several BCS class II and IV anticancer drugs.

Self-nanoemulsifying drug delivery system (SNEDDS) mediated improved oral bioavailability of thymoquinone: optimization, characterization, pharmacokinetic, and hepatotoxicity studies

Thymoquinone (TQ) is an antioxidant, anti-inflammatory, and hepatoprotective compound obtained from the black seed oil of Nigella sativa. However, high hydrophobicity, instability at higher pH levels, photosensitivity, and low oral bioavailability hinder its delivery to the target tissues. A self-nanoemulsifying drug delivery system (SNEDDS) was fabricated using the microemulsification technique to address these issues. Its physicochemical properties, thermodynamic stability studies, drug release kinetics, in vivo pharmacokinetics, and hepatoprotective activity were evaluated. The droplet size was in the nano-range (< 90 nm). Zeta potential was measured to be -11.35 mV, signifying the high stability of the oil droplets. In vivo pharmacokinetic evaluation showed a fourfold increase in the bioavailability of TQ-SNEDDS over pure TQ. Furthermore, in a PCM-induced animal model, TQ-SNEDDS demonstrated significant (p < 0.05) hepatoprotective activity compared to pure TQ and silymarin. Reduction in liver biomarker enzymes and histopathological examinations of liver sections further supported the results. In this study, SNEDDS was demonstrated to be an improved oral delivery method for TQ, since it potentiates hepatotoxicity and enhances bioavailability.

Osmotic-controlled release oral tablets: technology and functional insights

In recent years, oral osmotic tablets have sparked a therapeutic paradigm for controlled-release dosage forms due to their intrinsic insensitivity to physiological and physicochemical factors. Despite these benefits, the design of an optimal osmotic technology is precluded by various challenges. These limitations include manufacturing complexity, the lack of understanding of the functional mechanics, and inadequate optimization for the desired bio-performance. This paper systematically reviews the development of an osmotic-driven drug delivery system and the strategy for a zero-order release profile with an emphasis on swellable core technology. We discuss the applicability of the various types of osmotic tablets, their suitability to specific needs, and factors that drive the technology selection. Finally, we review the challenges, opportunities, and future perspectives associated with osmotic tablets.

Self-Nano-Emulsifying Drug-Delivery Systems: From the Development to the Current Applications and Challenges in Oral Drug Delivery

Approximately one third of newly discovered drug molecules show insufficient water solubility and therefore low oral bio-availability. Self-nano-emulsifying drug-delivery systems (SNEDDSs) are one of the emerging strategies developed to tackle the issues associated with their oral delivery. SNEDDSs are composed of an oil phase, surfactant, and cosurfactant or cosolvent. SNEDDSs characteristics, their ability to dissolve a drug, and in vivo considerations are determinant factors in the choice of SNEDDSs excipients. A SNEDDS formulation can be optimized through phase diagram approach or statistical design of experiments. The characterization of SNEDDSs includes multiple orthogonal methods required to fully control SNEDDS manufacture, stability, and biological fate. Encapsulating a drug in SNEDDSs can lead to increased solubilization, stability in the gastro-intestinal tract, and absorption, resulting in enhanced bio-availability. The transformation of liquid SNEDDSs into solid dosage forms has been shown to increase the stability and patient compliance. Supersaturated, mucus-permeating, and targeted SNEDDSs can be developed to increase efficacy and patient compliance. Self-emulsification approach has been successful in oral drug delivery. The present review gives an insight of SNEDDSs for the oral administration of both lipophilic and hydrophilic compounds from the experimental bench to marketed products.

Development of Morin-Loaded Nanoemulsions Containing Various Polymers; Role of Polymers in Formulation Properties and Bioavailability

Emulsions for oral delivery are not suitable for sustained drug absorption because such preparations diffuse rapidly in the gastrointestinal (GI) tract after oral administration. In order to generate sustained drug absorption and increase oral bioavailability, various polymers were added to a morin (MO) nanoemulsion to improve retention in the GI tract and alter the surface properties of oil droplets in the nanoemulsion. The influence of these polymers on the formulation properties was investigated. The area under the blood concentration-time curve (AUC) and the mean residence time (MRT) after oral administration of the nanoemulsions were measured, and the influence of the polymers on bioavailability was investigated. Chitosan (Chi) addition MO nanoemulsion (MO-Chi nanoemulsion) showed the highest AUC and MRT. MO-Chi nanoemulsion increased retention in the GI tract because of the relatively higher viscosity and high affinity between mucin and Chi covering the oil droplets. Furthermore, MO-Chi nanoemulsion could maintain the drug in oil droplets by suppression of drug release through the polymer hydration layer, and sustained drug release achieved continuous drug absorption. Nanoemulsions with sodium carboxymethylcellulose and poly-γ-glutamic acid potassium salt showed the next highest AUC and MRT after MO-Chi nanoemulsion. From these results, it was suggested that by increasing the viscosity of the nanoemulsion, there was high affinity between the added polymer and mucin, and sustained drug release was useful for enhancing the bioavailability of the polymer-containing nanoemulsions.

Self-nanoemulsifying System Optimization for Higher Terconazole Solubilization and Non-Irritant Ocular Administration

Purpose: Eye drops’ formulations of poorly water-soluble drugs, offer the advantage of crossing the lipophilic cornea, but their limited aqueous solubility may lead to low ocular bioavailability limiting their therapeutic uses. Terconazole (TZ) is an antifungal drug with low aqueous solubility, restricting its application in ocular fungal infection. Thus, the aim of the work in this study is to enhance TZ solubilization, permitting better ocular permeation and higher bioavailability. To achieve this goal, different self-nanoemulsifying systems (SNESs) were prepared using different oils, surfactants and co-surfactants.

Methods: Ternary phase diagrams were constructed to identify self nano-emulsification regions for each oil system examined; either Labrafil^® M2125CS or Capryol^™ 90. TZ saturated solubility in the different formulated systems were measured and systems showing highest potential for TZ solubilization were selected. The optimized systems were chosen based on their globule size, polydispersity index, self-emulsification characteristics. Finally, TZ release as well as the irritation effect via Hen’s Egg test-chorioallantoic membrane (HET-CAM test) of the optimized system was observed in vitro.

Results: The optimized system was formulated using 20% w/w Labrafil^® M2125 CS, 50% w/w Tween^® 80 and 30% w/w Transcutol^® HP. Oil globules showed size range of 15.13 nm and self-emulsification time of 12.80 seconds. The system released 100% of the drug within half an hour compared to 2 hours in case of TZ-suspension. Finally, HET-CAM test showed non-irritating response and normal vascularization of the chorioallantoic membrane.

Conclusion: The formulated SNES could be a promising approach to enhance ocular efficacy of TZ.

Double-layered osmotic pump controlled release tablets of actarit: In vitro and in vivo evaluation

The aim of the study was to develop actarit double-layered osmotic pump tablets to overcome the weak points of actarit common tablets, such as short half-life and large plasma concentration fluctuations. Single factor experiment and orthogonal test were applied to optimize the formulation; the pharmacokinetic study was performed in beagle dogs adopting actarit common tablets as reference tablets. The optimal formulation was as follows: drug layer: 150 mg actarit, 240 mg PEO-N80, 50 mg NaCl; push layer: 140 mg PEO-WSR303, 20 mg NaCl; coating solution: 30 g cellulose acetate and 6 g PEG 4000 in 1000 ml 94% acetone solution, 60 mg coating weight gain. The pharmacokinetic study showed that T_max was prolonged by the contrast of commercial common tablets with constant drug release rate, but the bioavailability was equivalent. And a good in vivo–in vitro correlation of the actarit osmotic pump tablets was also established. The designed actarit osmotic pump tablets can be applied for rheumatoid arthritis, proposing a promising replacement for the marked common products.

Formulation optimization and pharmacokinetics evaluation of oral self-microemulsifying drug delivery system for poorly water soluble drug cinacalcet and no food effect

The present research indicated that a new self-microemulsifying drug delivery systems (SMEDDS) were used to reduce the food effect of poorly water-soluble drug cinacalcet and enhance the bioavailability in beagle dogs by oral gavage. Ethyl oleate, OP-10, and PEG-200 was selected as the oil phase, surfactant and co-surfactant of cinacalcet-SMEDDS by the solubility and phase diagram studies. Central Composite Design-Response Surface Methodology was used to determine the ratio of surfactant and co-surfactant, the amount of oil for optimizing the SMEDDS formation. The prepared formulations were further characterized by the droplet size, self-microemulsifying time, zeta potential, polydispersity index (PDI), and robustness to dilution. The in vitro release profile of cinacalcet-SMEDDS was determined in four different release medium and in fasted state and fed state of simulated gastrointestinal fluid. Cinaclcet-SMEDDS were implemented under fed and fasted state in dogs and product REGPARA^® was used as a comparison to the prepared formulation in the pharmacokinetics. The result showed the components of SMEDDS, the amount of oil, the ratio of surfactant, and co-surfactant was optimized using solubility, pseudo-ternary phase diagram studies, and response surface methodology. In vitro drug release studies indicated that the cinacalcet-SMEDDS eliminated the effect of pH variability in release medium and variational gastroenteric environments with improved drug release performance. Pharmacokinetic studies revealed that the profiles of cinacalcet-SMEDDS were similar both in the fasted and fed state compared with commercial product, indicating the formulation significantly promoted the absorption, enhanced bioavailability and had no food effect essentially. It is concluded that poorly water-soluble drug cinacalcet was improved in the solubility and bioavailability by using a successful oral dosage form the SMEDDS, and eliminated food effect as well.

Development, optimization and in vitro evaluation of norcantharidin loadedself-nanoemulsifying drug delivery systems (NCTD-SNEDDS)

This study focused on developing a self-nanoemulsifying drug delivery system (SNEDDS) containing bioactive surfactants under an efficient screening approach for overcoming problems associated with the delivery of norcantharidin (NCTD), a high dose chemotherapy agent having pH dependent solubility. Preliminary screening was implemented to select proper components combination. Besides the solubility of NCTD in the oil phase, emulsifying efficiency, droplet size and size distribution were also employed to select components of the SNEDDS. Moreover, the influence of surfactant and co-surfactant on the interfacial tension and droplets of nanoemulsions were investigated to further understand the mechanism of spontaneous emulsification. Co-surfactant addition promoted the emulsification via reducing the water/oil interfacial tension and viscosity. Ternary phase diagrams were constructed to investigate the phase behavior and designate the optimum systems. The alternative formulations were characterized for cloud point, dilution robustness, droplet size, polydispersity index (PDI) and transmission electron microscopy (TEM). In vitro dissolution study showed that the dissolution rate of optimized formulation (NCTD 10 mg/g, EO 50 wt.%, Cremophor EL 35 wt.%, ethylene glycol 15 wt.%) was slower than drug suspension under the same conditions, confirming that the developed SNEDDS formulation would exhibit sustained release potential.