HLD-NAC design and evaluation of a fully dilutable lecithin-linker SMEDDS for ibuprofen

Celecoxib Oral Solution and the Benefits of Self-Microemulsifying Drug Delivery Systems (SMEDDS) Technology: A Narrative Review

INTRODUCTION

The oral route of drug delivery is the most widespread and preferred route of administration, but it has several limitations, including variable pharmacokinetics (PK), reduced dissolution and absorption, and gastrointestinal irritation. Further, many compounds have low aqueous solubility, which also limits intestinal absorption.

METHODS

For this narrative review, we conducted a literature search of PubMed until August 2022, focusing on emulsions, microemulsions, nanoemulsions, and self-emulsifying drug delivery systems.

RESULTS

The self-microemulsifying drug delivery system (SMEDDS) overcomes these limitations of hydrophobic compounds to enhance their bioavailability. A SMEDDS formulation is a clear, thermodynamically stable, oil-in-water emulsion of lipid, solubilized drug, and two surfactants, which spontaneously forms droplets < 100 nm in diameter. These components help deliver presolubilized drugs to the gastrointestinal tract, while protecting them from degradation in gastric acid or first-pass hepatic metabolism. SMEDDS formulations have improved oral drug delivery in the treatment of cancer (paclitaxel), viral infections (ritonavir), and migraine headache (ibuprofen and celecoxib oral solution). The American Headache Society recently updated their consensus statement for the acute treatment of migraine and included a selective cyclo-oxygenase-2 selective inhibitor formulated in SMEDDS, celecoxib oral solution. This SMEDDS formulation showed pronounced improvement in bioavailability compared with celecoxib capsules, allowing for a low dose of celecoxib in the oral solution to provide safe and effective acute migraine treatment. Here, we will focus on SMEDDS formulations, what differentiates them from other analogous emulsions as vehicles for poorly soluble drugs, and their clinical application in the acute treatment of migraine.

CONCLUSIONS

Oral drugs reformulated in SMEDDS have shown accelerated times to peak plasma drug concentrations and increased maximum plasma concentrations, compared with capsules, tablets, or suspensions. SMEDDS technology increases both drug absorption and bioavailability of lipophilic drugs, compared with other formulations. Clinically, this allows the use of lower doses with improved PK profiles without compromising efficacy, as shown with celecoxib oral solution for the acute treatment of migraine.

Insights from a Box-Behnken Optimization Study of Microemulsions with Salicylic Acid for Acne Therapy

The present study brings to attention a method to develop salicylic acid-based oil in water (O/W) microemulsions using a tensioactive system based on Tween 80, lecithin, and propylene glycol (PG), enriched with a vegetable oat oil phase and hyaluronic acid. The systems were physically characterized and the Quality by design approach was applied to optimize the attributes of microemulsions using Box-Behnken modeling, combined with response surface methodology. For this purpose, a 33 fractional factorial design was selected. The effect of independent variables namely X1: Tween 80/PG (%), X2: Lecithin (%), X3: Oil phase (%) was analyzed considering their impact upon the internal structure and evaluated parameters chosen as dependent factors: viscosity, mean droplet size, and work of adhesion. A high viscosity, a low droplet size, an adequate wettability-with a reduced mechanical work-and clarity were considered as desirable for the optimal systems. It was found that the optimal microemulsion which complied with the established conditions was based on: Tween 80/PG 40%, lecithin 0.3%, oat oil 2%, salicylic acid 0.5%, hyaluronic acid 1%, and water 56.2%. The response surface methodology was considered an appropriate tool to explain the impact of formulation factors on the physical properties of microemulsions, offering a complex pattern in the assessment of stability and quality attributes for the optimized formulation.