Production of PLGA micro- and nanocomposites by supercritical fluid extraction of emulsions: II. Encapsulation of Ketoprofen

Core-Shell Structured PLGA Particles Having Highly Controllable Ketoprofen Drug Release

The non-steroid anti-inflammatory drug ketoprofen (KP) as a model molecule is encapsulated in different poly(lactide-co-glycolide) (PLGA) nanostructured particles, using Tween20 (TWEEN) and Pluronic F127 (PLUR) as stabilizers to demonstrate the design of a biocompatible colloidal carrier particles with highly controllable drug release feature. Based on TEM images the formation of well-defined core-shell structure is highly favorable using nanoprecipitation method. Stabile polymer-based colloids with ~200-210 nm hydrodynamic diameter can be formed by successful optimization of the KP concentration with the right choice of stabilizer. Encapsulation efficiency (EE%) of 14-18% can be achieved. We clearly confirmed that the molecular weight of the stabilizer thus its structure greatly controls the drug release from the PLGA carrier particles. It can be determined that ~20% and ~70% retention is available with the use of PLUR and TWEEN, respectively. This measurable difference can be explained by the fact that the non-ionic PLUR polymer provides a steric stabilization of the carrier particles in the form of a loose shell, while the adsorption of the non-ionic biocompatible TWEEN surfactant results in a more compact and well-ordered shell around the PLGA particles. In addition, the release property can be further tuned by decreasing the hydrophilicity of PLGA by changing the monomer ratio in the range of ~20-60% (PLUR) and 70-90% (TWEEN).

Enhancement of ketoprofen dissolution rate by the liquisolid technique: optimization and in vitro and in vivo investigations

The objective of the current study is to evaluate the prospective of liquisolid formulation to improve the dissolution rate of ketoprofen and thereby the bioavailability. Different batches of liquisolid were prepared using polyethylene glycol 200 as a solvent, microcrystalline cellulose, and aerosil 200 as carrier and coating material, respectively. Central composite design (3²) was utilized to examine the effects of independent variables (load factor and excipient ratio) on dependent variables (solubility and % in vitro drug release). Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy techniques were employed for characterization of optimized batch (LS-10) of liquisolid formulation. The half-maximal inhibitory concentration (IC₅₀) values for in vitro anti-inflammatory activity for liquisolid formulation exhibited a higher anti-inflammatory effect than ketoprofen and physical mixture. The statistical analysis of in vivo (anti-inflammatory and analgesic) activities data demonstrated that the test (optimized formulation) treatment group resulted in quick pharmacological response in Wistar rats and Albino mice when compared with standard (pure drug) and control treatment groups. The results obtained in the present study illustrated that the liquisolid formulation could be a propitious approach to increase the bioavailability of ketoprofen and could be used in oral therapy.

Ketoprofen-FA Co-crystal: In Vitro and In Vivo Investigation for the Solubility Enhancement of Drug by Design of Expert

The present piece of research work is framed for improving the solubility of ketoprofen by forming co-crystal using fumaric acid as a coformer. Co-crystal of ketoprofen and fumaric acid was prepared by simple solvent-assisted grinding method, containing drug and coformer as independent variables and solubility and % drug release were assumed to be dependent variables. Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, nuclear magnetic resonance and scanning electron microscopy techniques were used to characterize the preparation of optimized batch of co-crystal and further, evaluated for in vitro and in vivo anti-inflammatory and analgesic activities. Based on results of solubility and dissolution rate studies the formulation showed magnified improvement in both the properties on co-crystallization. The values of Gibbs free energy are negative at all levels of carrier demonstrating spontaneity of the drug solubilization process. The IC₅₀ value of optimized batch of co-crystal formulation and the pure drug was observed as 327.33 μg/ml and 556.11 μg/ml, respectively, demonstrating that co-crystal formulation possesses more percentage protection against protein denaturation than the drug ketoprofen. In vivo (anti-inflammatory and analgesic) activities revealed that optimized batch of co-crystal formulation delivered a rapid pharmacological response in Wistar rats and albino mice when compared with standard drug.

Pharmaceutical Applications of Supercritical Fluid Extraction of Emulsions for Micro-/Nanoparticle Formation

Micro-/nanoparticle formulations containing drugs with or without various biocompatible excipients are widely used in the pharmaceutical field to improve the physicochemical and clinical properties of the final drug product. Among the various micro-/nanoparticle production technologies, emulsion-based particle formation is the most widely used because of its unique advantages such as uniform generation of spherical small particles and higher encapsulation efficiency (EE). For this emulsion-based micro-/nanoparticle technology, one of the most important factors is the extraction efficiency associated with the fast removal of the organic solvent. In consideration of this, a technology called supercritical fluid extraction of emulsions (SFEE) that uses the unique mass transfer mechanism and solvent power of a supercritical fluid (SCF) has been proposed to overcome the shortcomings of several conventional technologies such as solvent evaporation, extraction, and spray drying. This review article presents the main aspects of SFEE technology for the preparation of micro-/nanoparticles by focusing on its pharmaceutical applications, which have been organized and classified according to several types of drug delivery systems and active pharmaceutical ingredients. It was definitely confirmed that SFEE can be applied in a variety of drugs from water-soluble to poorly water-soluble. In addition, it has advantages such as low organic solvent residual, high EE, desirable release control, better particle size control, and agglomeration prevention through efficient and fast solvent removal compared to conventional micro-/nanoparticle technologies. Therefore, this review will be a good resource for determining the applicability of SFEE to obtain better pharmaceutical quality when researchers in related fields want to select a suitable manufacturing process for preparing desired micro-/nanoparticle drug delivery systems containing their active material.

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.

PLA/PLGA-Based Drug Delivery Systems Produced with Supercritical CO2-A Green Future for Particle Formulation?

Supercritical carbon dioxide (SC-CO₂) can serve as solvent, anti-solvent and solute, among others, in the field of drug delivery applications, e.g., for the formulation of polymeric nanocarriers in combination with different drug molecules. With its tunable properties above critical pressure and temperature, SC-CO₂ offers control of the particle size, the particle morphology, and their drug loading. Moreover, the SC-CO₂-based techniques overcome the limitations of conventional formulation techniques e.g., post purification steps. One of the widely used polymers for drug delivery systems with excellent mechanical (T_g, crystallinity) and chemical properties (controlled drug release, biodegradability) is poly (lactic acid) (PLA), which is used either as a homopolymer or as a copolymer, such as poly(lactic-co-glycolic) acid (PLGA). Over the last 30 years, extensive research has been conducted to exploit SC-CO₂-based processes for the formulation of PLA carriers. This review provides an overview of these research studies, including a brief description of the SC-CO₂ processes that are widely exploited for the production of PLA and PLGA-based drug-loaded particles. Finally, recent work shows progress in the development of SC-CO₂ techniques for particulate drug delivery systems is discussed in detail. Additionally, future perspectives and limitations of SC-CO₂-based techniques in industrial applications are examined.

Microencapsulation and Nanoencapsulation Using Supercritical Fluid (SCF) Techniques

The unique properties of supercritical fluids, in particular supercritical carbon dioxide (CO₂), provide numerous opportunities for the development of processes for pharmaceutical applications. One of the potential applications for pharmaceuticals includes microencapsulation and nanoencapsulation for drug delivery purposes. Supercritical CO₂ processes allow the design and control of particle size, as well as drug loading by utilizing the tunable properties of supercritical CO₂ at different operating conditions (flow ratio, temperature, pressures, etc.). This review aims to provide a comprehensive overview of the processes and techniques using supercritical fluid processing based on the supercritical properties, the role of supercritical carbon dioxide during the process, and the mechanism of formulation production for each process discussed. The considerations for equipment configurations to achieve the various processes described and the mechanisms behind the representative processes such as RESS (rapid expansion of supercritical solutions), SAS (supercritical antisolvent), SFEE (supercritical fluid extraction of emulsions), PGSS (particles from gas-saturated solutions), drying, and polymer foaming will be explained via schematic representation. More recent developments such as fluidized bed coating using supercritical CO₂ as the fluidizing and drying medium, the supercritical CO₂ spray drying of aqueous solutions, as well as the production of microporous drug releasing devices via foaming, will be highlighted in this review. Development and strategies to control and optimize the particle morphology, drug loading, and yield from the major processes will also be discussed.

Supercritical Fluid Technology: An Emphasis on Drug Delivery and Related Biomedical Applications

During the past few decades, supercritical fluid (SCF) has emerged as an effective alternative for many traditional pharmaceutical manufacturing processes. Operating active pharmaceutical ingredients (APIs) alone or in combination with various biodegradable polymeric carriers in high-pressure conditions provides enhanced features with respect to their physical properties such as bioavailability enhancement, is of relevance to the application of SCF in the pharmaceutical industry. Herein, recent advances in drug delivery systems manufactured using the SCF technology are reviewed. We provide a brief description of the history, principle, and various preparation methods involved in the SCF technology. Next, we aim to give a brief overview, which provides an emphasis and discussion of recent reports using supercritical carbon dioxide (SC-CO2 ) for fabrication of polymeric carriers, for applications in areas related to drug delivery, tissue engineering, bio-imaging, and other biomedical applications. We finally summarize with perspectives.

Au-PLA nanocomposites for photothermally controlled drug delivery

Stimuli-responsive drug delivery systems were obtained by encapsulating near-infrared (NIR) sensitive hollow gold nanoshells (HGNs) together with the molecule to be released into biodegradable poly-lactic acid (PLA) sub-micron particles. The rapid heating of the PLA particles caused by NIR radiation enabled use of the PLA-HGN composites as a photo-triggered drug release system. Rhodamine was used as a test molecule to obtain release profiles under different irradiation conditions. HGNs (32 nm diameter, 4.5 nm shell thickness) were synthesized via galvanic replacement of cobalt nanoparticles, using poly(vinylpyrrolidone) (PVP) as a stabilizer. PLA-HGN sub-micron particles (with mean diameters around 200 nm) encapsulating rhodamine were obtained using the supercritical emulsion extraction (SEE) technique. A good gold dispersion and a loading efficiency around 50% in the polymeric matrix were obtained for different HGN loadings. The release rate could be tuned by controlling the intensity of NIR exposition. Rhodamine release was completed in less than 10 hours when applying intense NIR irradiation for a few minutes, whereas 12 days of release was necessary in its absence. The system also allowed rhodamine release in a pulsed pattern.

CO2-assisted high pressure homogenization: a solvent-free process for polymeric microspheres and drug-polymer composites

The study explores the enabling role of near-critical CO(2) as a reversible plasticizer in the high pressure homogenization of polymer particles, aiming at their comminution as well as at the formation of drug-polymer composites. First, the effect of near-critical CO(2) on the homogenization of aqueous suspensions of poly lactic-co-glycolic acid (PLGA) was investigated. Applying a pressure drop of 900 bar and up to 150 passes across the homogenizer, it was found that particles processed in the presence of CO(2) were generally of microspherical morphology and at all times significantly smaller than those obtained in the absence of a plasticizer. The smallest particles, exhibiting a median x(50) of 1.3 μm, were obtained by adding a small quantity of ethyl acetate, which exerts on PLGA an additional plasticizing effect during the homogenization step. Further, the study concerns the possibility of forming drug-polymer composites through simultaneous high pressure homogenization of the two relevant solids, and particularly the effect of near-critical CO(2) on this process. Therefore, PLGA was homogenized together with crystalline S-ketoprofen (S-KET), a non-steroidal anti-inflammatory drug, at a drug to polymer ratio of 1:10, a pressure drop of 900 bar and up to 150 passes across the homogenizer. When the process was carried out in the presence of CO(2), an impregnation efficiency of 91% has been reached, corresponding to 8.3 wt.% of S-KET in PLGA; moreover, composite particles were of microspherical morphology and significantly smaller than those obtained in the absence of CO(2). The formation of drug-polymer composites through simultaneous homogenization of the two materials is thus greatly enhanced by the presence of CO(2), which increases the efficiency for both homogenization and impregnation.

Supercritical fluid-mediated methods to encapsulate drugs: recent advances and new opportunities

With the advent of the development of novel pharmaceutical products and therapies, there is a need for effective delivery of these products to patients. Dependent on whether they are small-molecular weight drugs or biologics, many new compounds may suffer from poor solubility, poor stability or require frequent administration and therefore require optimized delivery. For example, the utilization of polymorphism and the enhanced solubility in the amorphous state is being exploited to improve the dissolution of small-molecular weight poorly soluble drugs. This can be achieved by the formation of solid dispersions in water-soluble matrices. In addition, encapsulation in biodegradable polymeric materials is one potential route to reduce the frequency of administration through the formation of sustained-release formulations. This is desirable for biologics, for example, which generally require administration once or twice daily. Supercritical fluid processing can achieve both of these outcomes, and this review focuses on the use of supercritical CO2 to encapsulate active pharmaceutical ingredients to enhance solubility or achieve sustained release. Using supercritical CO2-mediated processes provides a clean and potentially solvent-free route to prepare novel drug products and is therefore an attractive alternative to conventional manufacturing technologies.