Effect of microfluidization parameters on the physical properties of PEG-PLGA nanoparticles prepared using high pressure microfluidization

PLGA-based nanomedicines manufacturing: Technologies overview and challenges in industrial scale-up

Nanomedicines based on poly(lactic-co-glycolic acid) (PLGA) carriers offer tremendous opportunities for biomedical research. Although several PLGA-based systems have already been approved by both the Food and Drug Administration (FDA) and the European Medicine Agency (EMA), and are widely used in the clinics for the treatment or diagnosis of diseases, no PLGA nanomedicine formulation is currently available on the global market. One of the most impeding barriers is the development of a manufacturing technique that allows for the transfer of nanomedicine production from the laboratory to an industrial scale with proper characterization and quality control methods. This review provides a comprehensive overview of the technologies currently available for the manufacturing and analysis of polymeric nanomedicines based on PLGA nanoparticles, the scale-up challenges that hinder their industrial applicability, and the issues associated with their successful translation into clinical practice.

Scalable Manufacturing Processes for Solid Lipid Nanoparticles

BACKGROUND

Solid lipid nanoparticles offer a range of advantages as delivery systems but they are limited by effective manufacturing processes.

OBJECTIVE

In this study, we outline a high-throughput and scalable manufacturing process for solid lipid nanoparticles.

METHODS

The solid lipid nanoparticles were formulated from a combination of tristearin and 1,2-Distearoyl-phosphatidylethanolamine-methyl-polyethyleneglycol conjugate-2000 and manufactured using the M-110P Microfluidizer processor (Microfluidics Inc, Westwood, Massachusetts, US).

RESULTS

The manufacturing process was optimized in terms of the number of process cycles (1 to 5) and operating pressure (20,000 to 30,000 psi). The solid lipid nanoparticles were purified using tangential flow filtration and they were characterized in terms of their size, PDI, Z-potential and protein loading. At-line particle size monitoring was also incorporated within the process. Our results demonstrate that solid lipid nanoparticles can be effectively manufactured using this process at pressures of 20,000 psi with as little as 2 process passes, with purification and removal of non-entrapped protein achieved after 12 diafiltration cycles. Furthermore, the size could be effectively monitored at-line to allow rapid process control monitoring and product validation.

CONCLUSION

Using this method, protein-loaded solid lipid nanoparticles containing a low (1%) and high (16%) Pegylation were manufactured, purified and monitored for particle size using an at-line system demonstrating a scalable process for the manufacture of these nanoparticles.

Microfluidization trends in the development of nanodelivery systems and applications in chronic disease treatments

Plant bioactive compounds are known for their extensive health benefits and therefore have been used for generations in traditional and modern medicine to improve the health of humans. Processing and storage instabilities of the plant bioactive compounds, however, limit their bioavailability and bioaccessibility and thus lead researchers in search of novel encapsulation systems with enhanced stability, bioavailability, and bioaccessibility of encapsulated plant bioactive compounds. Recently many varieties of encapsulation methods have been used; among them, microfluidization has emerged as a novel method used for the development of delivery systems including solid lipid nanocarriers, nanoemulsions, liposomes, and so on with enhanced stability and bioavailability of encapsulated plant bioactive compounds. Therefore, the nanodelivery systems developed using microfluidization techniques have received much attention from the medical industry for their ability to facilitate controlled delivery with enhanced health benefits in the treatment of various chronic diseases. Many researchers have focused on plant bioactive compound-based delivery systems using microfluidization to enhance the bioavailability and bioaccessibility of encapsulated bioactive compounds in the treatment of various chronic diseases. This review focuses on various nanodelivery systems developed using microfluidization techniques and applications in various chronic disease treatments.

A comparative assessment of continuous production techniques to generate sub-micron size PLGA particles

The clinical and commercial development of polymeric sub-micron size formulations based on poly(lactic-co-glycolic acid) (PLGA) particles is hampered by the challenges related to their good manufacturing practice (GMP)-compliant, scale-up production without affecting the formulation specifications. Continuous process technologies enable large-scale production without changing the process or formulation parameters by increasing the operation time. Here, we explore three well-established process technologies regarding continuity for the large-scale production of sub-micron size PLGA particles developed at the lab scale using a batch method. We demonstrate optimization of critical process and formulation parameters for high-shear mixing, high-pressure homogenization and microfluidics technologies to obtain PLGA particles with a mean diameter of 150-250 nm and a small polydispersity index (PDI, ≤0.2). The most influential parameters on the particle size distribution are discussed for each technique with a critical evaluation of their suitability for GMP production. Although each technique can provide particles in the desired size range, high-shear mixing is found to be particularly promising due to the availability of GMP-ready equipment and large throughput of production. Overall, our results will be of great guidance for establishing continuous process technologies for the GMP-compliant, large-scale production of sub-micron size PLGA particles, facilitating their commercial and clinical development.

Taste-masked tacrolimus-phospholipid nanodispersions: dissolution enhancement, taste masking and reduced gastric complications

Through the integration of orthogonal central composite design and desirability function, this work aimed to explore the potential of quality by design in understanding the formulation of phospholipid-stabilized tacrolimus nanodispersions by microfluidization. The influence of homogenization pressure, microfluidization time and phospholipid concentration (X1-X3) on nanodispersion performance was studied. Nanodispersions were characterized by differential scanning calorimetric (DSC), X-ray diffractometer (XRD) and Fourier transform infrared (FTIR) analysis. Moreover, masking the unpalatable taste of tacrolimus and reducing the gastric complications were also evaluated. FTIR analysis indicated its interaction with phospholipid. DSC and XRD analysis revealed the amorphous transformation of tacrolimus within nanodispersions. The dissolution was enhanced by 35 folds and 15 folds after 0.5 and 2 h, respectively. Maximum tacrolimus content, yield, polydispersity index, percentages dissolved after 0.5 and 2 h of 99.3%, 100%, 0.864, 39.7% and 95.3%, respectively, with particle size of 160 nm were obtained at X1, X2 and X3 values of 20 000 psi, 6 min and 30%, respectively. The Euclidean distance values demonstrated masking the unpalatable taste and taste perversion to stimuli of tacrolimus in its optimized nanodispersion. Moreover, the ulcerative indices following raw tacrolimus and its optimized nanodispersion oral administration were 6.73 and 2.45, respectively, to indicate that nanodispersion was significantly less irritating to the gastric mucosa.

Topical drug delivery to retinal pigment epithelium with microfluidizer produced small liposomes

Drug delivery from topically instilled eye drops to the posterior segment of the eye has long been one of the greatest challenges of ocular drug development. We developed methods of liposome preparation utilizing a microfluidizer to achieve adjustable nanoparticle size (even less than 80 nm) and high loading capacity of plasmid DNA. The microfluidizing process parameters were shown to affect the size of the liposomes. Higher operating pressures and passage for at least 10 times through the microfluidizer produced small liposomes with narrow size distribution. The liposomes were physically stable for several months at +4°C. In vivo distribution of the optimized liposome formulations in the rat eyes was investigated with confocal microscopy of the histological specimens. Transferrin was used as a targeting ligand directed to retinal pigment epithelium. Size dependent distribution of liposomes to different posterior segment tissues was seen. Liposomes with the diameter less than 80 nm permeated to the retinal pigment epithelium whereas liposomes with the diameter of 100 nm or more were distributed to the choroidal endothelium. Active targeting was shown to be necessary for liposome retention to the target tissue. In conclusion, these microfluidizer produced small liposomes in eye drops are an attractive option for drug delivery to the posterior segment tissues of the eye.