The modulation of drug-loading stability within lipid membranes via medium chain triglycerides incorporation

Medium-Chain Triacylglycerols (MCTs) and Their Fractions in Drug Delivery Systems : A Systematic Review

Medium-chain triacylglycerol (MCT) is a type of triacylglycerol that has six or seven to twelve carbon chains. It consists of three molecules of fatty acids attached to one molecule of glycerol. Drug delivery system (DDS) is defined as a formulation to distribute drugs into the human body. The unique properties of MCTs have garnered interest in using them as excipients in DDS. Even though there are many significant effects attributed to the use of MCTs, especially in modulating the rate of drug delivery in various DDS, they are all limited and intermittent. This warrants a detailed summary of the previous studies on the use of MCTs in various DDS. Therefore, this review focuses on presenting a systematic review of previous studies on the use of MCTs in the last six years and explores the types and effects of MCTs on DDS that employ various types of delivery routes. A systematic search through PubMed, Science Direct and Scopus was performed. Keywords like "medium-chain triglycerides", "medium-chain fatty acids", "medium-chain triglycerides and their fractions", "medium-chain fatty acids and their fractions", "MCTs", "MCFA", "in drug delivery", "in drug delivery system" and their combinations were used. The synonyms of the words were also used to extend the search. A total of 17 articles that met the inclusion criteria were identified. Findings from this review have identified the several MCTs and their fractions used in DDS that employed the oral/enteral, topical, transdermal, parenteral, and pulmonary routes of drug delivery. The review also highlights that the usage of MCTs in DDS results in a better transportation of drugs into the human body.

Design of Novel Tricaprylin-Incorporated Multi-Layered Liposomal System for Skin Delivery of Ascorbic Acid with Improved Chemical Stability

L-ascorbic acid (Vit C) possesses a variety of dermatological functions in maintaining skin health and anti-aging properties. However, its topical application is challenging owing to its liability to light, oxygen, or heat. Therefore, in this study, a novel liposomal system, including a lipophilic neutral oil named a lipo-oil-some (LOS), was designed to improve the chemical stability and aid the skin absorption of Vit C. The vesicular systems were prepared using the ethanol injection method, employing phosphatidylcholine, cholesterol, dipalmitoyl-sn-glycerol-3-phosphoglycerol, and tricaprylin as neutral oil. The optimized LOS was characterized as follows: shape, multi-layered sphere; size, 981 nm; zeta potential, -58 mV; and Vit C encapsulation efficiency, 35%. The encapsulation of the labile compound into the novel system markedly enhanced photostability, providing over 10% higher Vit C remaining compared to Vit C solution or Vit C-loaded conventional liposome under a light intensity of 20,000 lx. On the other hand, the ex vivo skin permeation and accumulation of Vit C with the LOS system were comparable to those of smaller conventional liposomes (198 nm) in a Franz diffusion cell model mounted with porcine skin. Based on these findings, we concluded that the novel liposomal system could be utilized for skin delivery of Vit C with enhanced chemical stability.

Liposomes for oral delivery of protein and peptide-based therapeutics: challenges, formulation strategies, and advances

Throughout the past decade, there has been a rapid growth in the development of protein/peptide-based therapeutics. These therapeutics have found widespread applications in the treatment of cancer, infectious diseases, and other metabolic disorders owing to their several desirable attributes, such as reduced toxicity, diverse biological activities, high specificity, and potency. Most protein/peptide-based drugs are still administered parenterally, and there is an unprecedented demand in the pharmaceutical industry to develop oral delivery routes to increase patient acceptability and convenience. Recent advancements in nanomedicine discoveries have led to the development of several nano and micro-particle-based oral delivery platforms for protein/peptide-based therapeutics and among these, liposomes have emerged as a prominent candidate. Liposomes are spherical vesicles composed of one or more phospholipid bilayers enclosing a core aqueous phase. Their unique amphiphilic nature enables encapsulation of a diverse range of bioactives/drugs including both hydrophobic and hydrophilic compounds for delivery. Against this backdrop, this review provides an overview of the current approaches and challenges associated with the routes and methods of oral administration of protein/peptide-based therapeutics by using liposomes as a potential vehicle. First, the conventional and innovative liposome formation approaches have been discussed along with their applications. Next, the challenges associated with current approaches for oral delivery of protein and peptide-derived therapeutics have been thoroughly addressed. Lastly, we have critically reviewed the potential of liposomes utilization as vehicles for oral delivery of proteins emphasizing the current status and future directions in this area.

Optimization, and in vitro and in vivo evaluation of etomidate intravenous lipid emulsion

The aim of this investigation was to develop an etomidate intravenous lipid emulsion (ETM-ILE) and evaluate its properties in vitro and in vivo. Etomidate (ETM) is a hydrophobic drug, and organic solvents must be added to an etomidate injectable solution (ETM-SOL) to aid dissolution, that causes various adverse reactions on injection. Lipid emulsions are a novel drug formulation that can improve drug loading and reduce adverse reactions. ETM-ILE was prepared using high-pressure homogenization. Univariate experiments were performed to select key conditions and variables. The proportion of oil, egg lecithin, and poloxamer 188 (F68) served as variables for the optimization of the ETM-ILE formulation by central composite design response surface methodology. The optimized formulation had the following characteristics: particle size, 168.0 ± 0.3 nm; polydispersity index, 0.108 ± 0.028; zeta potential, −36.4 ± 0.2 mV; drug loading, 2.00 ± 0.01 mg/mL; encapsulation efficiency, 97.65% ± 0.16%; osmotic pressure, 292 ± 2 mOsmol/kg and pH value, 7.63 ± 0.07. Transmission electron microscopy images showed that the particles were spherical or spheroidal, with a diameter of approximately 200 nm. The stability study suggested that ETM-ILE could store at 4 ± 2 °C or 25 ± 2 °C for 12 months. Safety tests showed that ETM-ILE did not cause hemolysis or serious vascular irritation. The results of the pharmacokinetic study found that ETM-ILE was bioequivalent to ETM-SOL. However, a higher concentration of ETM was attained in the liver, spleen, and lungs after administration of ETM-ILE than after administration of ETM-SOL. This study found that ETM-ILE had great potential for clinical applications.