Characterization and in vitro release of inhalation quercetin solid lipid microparticles: Effect of lipid

This study purposes to develop solid lipid microparticles (SLM) inhalation delivery system for respiratory diseases with Quercetin as the active agent. Quercetin has various functions, such as for antioxidant, anti-inflammatory, immunomodulator, and antivirus. SLM is formed from a mixture of lipids and surfactants, namely, Glyceryl Behenate as solid lipid, Poloxamer 188 as the surfactant, and production of SLM using the melt o/w emulsification technique and was dried using freeze dryer. The effect of lipid concentration was studied in this research. Quercetin SLM was characterized by moisture content, Fourier transform infrared, particle size, yield, drug loading, and encapsulation efficiency. The SLM particles produced were spherical in shape and had a smooth surface with sizes of F1, F2, and F3 were 1.79 μm, 1.88 μm, and 1.91 μm, respectively. According to the target particle size of inhalation, Quercetin SLM had good flowability according to Carr's Index (F1 = 12.73% ± 0.38, F2 = 14.28% ± 0.65, F3 = 14.65% ± 0.62), in which the highest drug loading and EE of F3 were 10.94% and 88.48%, respectively. In vitro release study showed that in 630 min about 31%-33% Quercetin released indicated sustained release following Higuchi kinetics and quercetin release rate was not affected by the amount of lipid. To sum up, quercetin SLM demonstrates its potential as an inhalation delivery system and it is recommended to study its stability.

Oral Bioavailability Enhancement of Raloxifene with Nanostructured Lipid Carriers

Raloxifene hydrochloride (RLX) shows poor bioavailability (<2%), high inter-patient variability and extensive gut metabolism (>90%). The objective of this study was to develop nanostructured lipid carriers (NLCs) for RLX to enhance its bioavailability. The NLC formulations were produced with glyceryl tribehenate and oleic acid. The particle characteristics, entrapment efficiency (EE), differential scanning calorimetry (DSC), in vitro drug release, oral bioavailability (in rats) and stability studies were performed. The optimized nanoparticles were 120 ± 3 nm in size with positive zeta potential (14.4 ± 0.5 mV); % EE was over 90% with the drug loading of 5%. The RLX exists in an amorphous form in the lipid matrix. The optimized RLX-NLC formulation showed sustained release in vitro. The RLX-NLC significantly (p < 0.05) enhanced oral bioavailability 3.19-fold as compared to RLX-free suspension in female Wistar rats. The RLX-NLC can potentially enhance the oral bioavailability of RLX. It can also improve the storage stability.

Preparation of Sustained Release Tablet with Minimized Usage of Glyceryl Behenate Using Post-Heating Method

The purpose of this study was to prepare sustained release (SR) matrix tablets using a direct compression incorporated with a post-heating process. Allopurinol was selected due to the water-soluble property and Compritol 888 ATO® (also known as glyceryl behenate) was used as an SR matrix-forming agent. The API, SR material, microcrystalline cellulose, and magnesium stearate (lubricant) were mixed and prepared into a tablet by a direct compression method. The compressed tablets were stored in a dry oven at four temperatures (60, 70, 80, and 90°C) and for three time periods (15, 30, 45 min). The DSC and PXRD data indicated that the crystallinity of the API was not altered by the post-heating method. However, SEM images demonstrated that Compritol 888 ATO® was melted by the post-heating method, and that the melted Compritol 888 ATO® could form a strong matrix. This strong matrix led to the significant sustained release behavior of hydrophilic APIs. As little as 3 mg of Compritol 888 ATO® (0.65% of total tablet weight), when heated at 80°C for 15 min, showed sustained release over 10 h. The post-heating method exerted a significant influence on lipid-based matrix tablets and allowed a reduction in the amount of material required for a water-soluble drug. This will also provide a valuable insight into lipid-based SR tablets and will allow their application to higher quality products and easier processing procedures.

Comparative Study of Glyceryl Behenate or Polyoxyethylene 40 Stearate-Based Lipid Carriers for Trans-Resveratrol Delivery: Development, Characterization and Evaluation of the In Vitro Tyrosinase Inhibition

Trans-resveratrol (RSV) is a natural compound with several properties, such as the ability to inhibit the tyrosinase enzyme, with potential application as a skin-lightning agent and for the treatment of skin disorders associated with hyperpigmentation and melanogenesis. However, the drug faces several drawbacks which altogether limit its therapeutic application. Thus, drug loading into nanocarriers emerge as an alternative to circumvent these problems. Herein, nanostructured lipid carriers (NLCs) have been employed for RSV encapsulation, with comparison of two different lipids, glyceryl behenate (more hydrophobic), and polyoxyethylene 40 (PEG 40) stearate. PEG 40 stearate-containing NLCs presented smaller particle size and polydispersity compared with glyceryl behenate, attributed to better emulsification and nanoparticle formation, resulting in higher RSV encapsulation efficiency. Drug was loaded in both carriers as a molecular dispersion. Furthermore, the formulations had very low RSV release, which occurred due to the crystallinity degree of lipid matrix, in accordance with the DSC data. Moreover, RSV cytotoxicity against L-929 cells was not increased when loaded into nanocarriers. Interestingly, RSV-loaded formulation prepared with PEG-40 stearate resulted on greater tyrosinase inhibition than RSV solution and formulation containing glyceryl behenate, equivalent to 1.31 and 1.83 times higher, respectively, demonstrating that the incorporation of RSV into NLC allowed an enhanced tyrosinase inhibitory activity. Overall, the results obtained herein evidence potential for future in vivo evaluation of RSV-loaded NLCs.

Compritol 888 ATO: a multifunctional lipid excipient in drug delivery systems and nanopharmaceuticals

INTRODUCTION

Compritol® 888 ATO is a lipid excipient that is generally used in cosmetic industry as a surfactant, emulsifying agent and viscosity-inducing agent in emulsions or creams. Based on its chemical composition, Compritol 888 ATO is a blend of different esters of behenic acid with glycerol.

AREAS COVERED

Recently, there has been great interest in the multiple roles that Compritol 888 ATO plays in various pharmaceutical delivery systems. Accordingly, this review aimed at summarizing the current and potential applications of Compritol 888 ATO in various drug delivery areas.

EXPERT OPINION

Different researches have highlighted the feasibility of using Compritol 888 ATO as a lubricant or coating agent for oral solid dosage formulations. It has also been explored as a matrix-forming agent for controlling drug release. At present, the most common pharmaceutical application of Compritol 888 ATO is in lipid-based colloidal drug delivery system such as solid lipid microparticles, solid lipid nanoparticles and nanostructured lipid carriers. Although, Compritol 888 ATO has acceptable regulatory and safety profiles and although the number of articles that emphasize on its applicability as an innovative excipient in pharmaceutical technology is continuously increasing, it is not widely used in the pharmaceutical market products and its use is limited to its sustain release ability in extended release tablets.

Preparation and characterization of solid lipid nanoparticles containing cyclosporine by the emulsification-diffusion method

Solid lipid nanoparticles (SLNs) have been used for carrying different therapeutic agents because they improve absorption and bioavailability. The aim of the study was to prepare lipidic nanoparticles containing cyclosporine (CyA) by the emulsification-diffusion method and to study their physicochemical stability. Glyceryl behenate (Compritol(®) ATO 888) and lauroyl macrogolglycerides (Gelucire(®) 44/14) were used as carrier materials. Nanoparticles with good stability were obtained with Gelucire(®), while it was difficult to obtain stable systems with Compritol(®). Systems with Gelucire(®) were characterized by particle size, Z-potential, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), entrapment efficiency and in vitro release. Particle size and Z-potential were evaluated for at least three months. With a high CyA content (≥60 mg) in Gelucire(®) SLNs, variations in size were greater and particle size also increased over time in all batches; this effect may have been caused by a probable expulsion of the drug due to the lipid's partial rearrangement. While the Z-potential decreased 10 mV after three months, this effect may be explained by the superficial properties of the drug that make the molecules to be preferably oriented at the solid-liquid interface, causing a change in the net charge of the particle. SEM confirmed size and shape of the nanoparticles. DSC studies evidenced that CyA affects the lipid structure by a mechanism still unknown. The entrapment efficiency was higher than 92%, and CyA release from SLNs was relatively fast (99.60% in 45 min).