Preparation of redispersible dry emulsions by spray drying

Enhanced Pharmacokinetics and Anti-inflammatory Activity of Curcumin Using Dry Emulsion as Drug Delivery Vehicle

BACKGROUND AND OBJECTIVE

Many naturally available dietary molecules such as curcumin have not seen the market due to poor solubility, bioavailability, and photodegradability. Successful development of a lipid-based dry emulsion may overcome these issues and help in reaching the markets for natural dietary molecules such as curcumin. The current study aims to develop a dry emulsion formulation of curcumin using natural oil and evaluate its dissolution, photostability, pharmacokinetics, and anti-inflammatory activity.

METHODS

Dry emulsions were prepared using emu oil and corn oil as the lipid phase, Caproyl 90 and Cremophor RH 40 as surfactants, and dextrin as a hydrophilic carrier.

RESULTS

Microscopic studies showed the formation of spherical porous particles, and solid-state characterization using differential scanning calorimetry and powder X-ray diffraction showed the conversion of curcumin to an amorphous form. About 80% drug release was observed from formulation, whereas pure drug showed only 50% drug release in 30 min. In vivo pharmacokinetic studies showed fivefold improvement in the maximum concentration of curcumin in plasma (C_max) and sevenfold improvement in the area under the concentration-time curve of curcumin from emu oil formulation compared with pure curcumin. Significant differences were observed in the anti-inflammatory activity of curcumin dry emulsion and plain curcumin. Emu-oil-based formulations showed synergistic anti-inflammatory activity over corn-oil-based formulations with improved photostability.

CONCLUSION

The present study suggests that the dry emulsion may enhance the bioavailability with synergistic anti-inflammatory activity and photostability of curcumin when given orally.

Dispersion Mechanism of Styrene-Butadiene Rubber Powder Modified by Itaconic Acid and Its Toughening Effect on Oil Well Cement

Styrene-butadiene rubber (SBR) has been extensively applied to enhance the toughness of hardened cement. The instability of existing liquid latex leads to difficulties in storage and transportation, and even performance regression. Thus, the well-dispersed carboxylated butylbenzene (SISBR) latex powders were fabricated through the seed emulsion polymerization of liquid polybutadiene (LPB), styrene (St), itaconic acid (IA), and sodium p-styrenesulfonate (SSS) to overcome the difficulties. The dispersion performance of latex powders with various IA amounts was quantitatively evaluated using particle size distribution, zeta potential, and ultraviolet-visible spectrophotometry. Results showed that the carboxylic ionic (COO-) from IA enhanced the dispersing abilities of SISBR latex powders, which ensured the uniform distribution in water. Based on this, the influence of latex powder on cement was assessed mainly by fluidity, isothermal heat flow calorimetry, X-ray diffraction (XRD), and triaxial mechanical testing. Results showed the fluidity and dispersion performance of cement were improved with more IA in latex, while the hydration of cement was retarded due to excessive adsorption of carboxyl (-COOH) groups in IA. Triaxial mechanical testing showed that cement with SISBR-3 (latex containing 3% IA) exhibited the minimal elastic modulus of 3.16 GPa, which was lower than that of plain cement (8.34 GPa).

Processing of Lipid Nanodispersions into Solid Powders by Spray Drying

Spray drying is a promising technology for drying lipid nanodispersions. These formulations can serve as carrier systems for poorly water-soluble active pharmaceutical ingredients (APIs) that are loaded into the lipid matrix to improve their bioavailability. Once the API-loaded nanocarriers have been further processed into solid dosage forms, they could be administered orally, which is usually preferred by patients. Various solid lipids as well as oils were used in this study to prepare lipid nanodispersions, and it was shown that their nanoparticulate properties could be maintained when lactose in combination with SDS was used as matrix material in the spray-drying process. In addition, for lipid nanoemulsions loaded with fenofibrate, a good redispersibility with particle sizes below 300 nm at a lipid content of 26.8 wt.% in the powders was observed. More detailed investigations on the influence of the drying temperature yielded good results when the inlet temperature of the drying air was set at 110 °C or above, enabling the lactose to form an amorphous matrix around the embedded lipid particles. A tristearin suspension was developed as a probe to measure the temperature exposure of the lipid particles during the drying process. The results with this approach indicate that the actual temperature the particles were exposed to during the drying process could be higher than the outlet temperature.

Fundamental Aspects of Lipid-Based Excipients in Lipid-Based Product Development

Poor aqueous solubility of drugs is still a foremost challenge in pharmaceutical product development. The use of lipids in designing formulations provides an opportunity to enhance the aqueous solubility and consequently bioavailability of drugs. Pre-dissolution of drugs in lipids, surfactants, or mixtures of lipid excipients and surfactants eliminate the dissolution/dissolving step, which is likely to be the rate-limiting factor for oral absorption of poorly water-soluble drugs. In this review, we exhaustively summarize the lipids excipients in relation to their classification, absorption mechanisms, and lipid-based product development. Methodologies utilized for the preparation of solid and semi-solid lipid formulations, applications, phase behaviour, and regulatory perspective of lipid excipients are discussed.

Influence of Polymer Modifiers on Selected Properties and Microstructure of Cement Waterproofing Mortars

This paper presents the results of research on the influence of polymer modifiers: styrene-acrylic copolymer, vinyl acetate/ethylene (EVA), vinyl acetate/acrylic copolymer (VAAc), and VA/VeoVa/acrylic terpolymer on the water permeability and adhesion of cement-containing waterproofing mortars in concrete. The content of the polymers in the composition of the mortars was 15, 20 and 26% (m/m) in relation to the weight of the dry ingredients. Using microscopic methods, an attempt was made to analyse the relationship between the microstructure of the mortars and the properties of these polymers. The EVA and the vinyl acetate/acrylic copolymer, which were used in the form of dry powders, had the most favourable effect on water permeability and adhesion to the concrete substrate. They may prove to be useful for the production of one-component cement-containing waterproofing mortars. On the other hand, the VA/VeoVa/acrylic terpolymer modifier had the least favourable effect on the tested properties. For mortars with this modifier, the desired water-permeability parameters were not achieved. Depending on the amount of polymer modifier, the mortars were characterized by differences in watertightness, as established on the basis of changes in porosity and differences in the adhesion of the cement-polymer paste to the surface of aggregate grains. It was determined that the type of polymer and its dispergation properties influence the water permeability of mortars, as well as their adhesion to concrete substrates.

Formulation of re-dispersible dry o/w emulsions using cellulose nanocrystals decorated with metal/metal oxide nanoparticles

This study describes for the first time the preparation of re-dispersible surfactant-free dry eicosane oil emulsion using cellulose nanocrystals (CNCs) using the freeze-drying technique. Surface properties of CNCs constitute a critical point for the stability of o/w emulsions and thus can affect both the droplet size and dispersion properties of the emulsion. Therefore, surface modification of CNCs was performed to understand its effect on the size of the obtained re-dispersible dry o/w eicosane emulsion. Decoration of the CNC surface with metal and metal oxide nanoparticles was conducted through the available alcoholic groups of glycosidic units of CNC, which played a dual role in reducing and stabilizing nanoparticles. Of these nanoparticles, silver (AgNPs), gold (AuNPs), copper oxide (CuO-NPs), and iron oxide (Fe₃O₄-NPs) nanoparticles were prepared via a facile route using alkali activated CNCs. Thorough characterizations pertaining to the as-prepared nanoparticles and their re-dispersible dry eicosane o/w emulsions were investigated using UV-vis spectroscopy, TEM, XRD, particle size, zeta potential, and STEM. Results confirmed the ability of CNCs to stabilize and/or reduce the formed nanoparticles with different sizes and shapes. These nanoparticles showed different shapes and surface charges accompanied by individual morphologies, reflecting on the stability of the re-dispersed dry eicosane emulsions with droplet sizes varying from 1.25 to 0.5 μm.

Schematic diagram for the detailed preparation of dry eicosane o/w emulsions.

Impact of Pleurotus ostreatus β-Glucans on Oxidative Stability of Active Compounds Encapsulated in Powders during Storage and In Vitro Digestion

Polyunsaturated fatty acids and α-tocopherol were encapsulated in powders by spray drying using maltodextrins DE 12 as wall material and different emulsifiers (Tween®20, acacia gum or β-glucans-rich extracts from Pleurotus ostreatus). The aim was to study the effects of the surfactants on: (a) the oil droplet size distribution and α-tocopherol stability during in vitro digestion, and (b) the oxidative stability during 15 days of accelerated storage. Acacia gum sample had the most stable particle size distribution up to the gastric phase, but showed a significant α-tocopherol degradation prior to the intestinal stage. On the contrary, β-glucan-samples displayed a bimodal distribution in the oral and gastric phases but retained α-tocopherol up to the beginning of the intestinal stage. At the end of intestinal stage, no α-tocopherol was found in the samples. The storage study showed that β-glucans improved the oxidative stability of the powders, which displayed 82% α-tocopherol retention after 5 days under accelerated conditions (60 °C), corresponding to 310 days at 20 °C, while acacia gum and Tween® 20 did not delay α-tocopherol degradation. Results highlight the potential antioxidant activity of β-glucans used as emulsifying agents during in vitro digestion and accelerated aging conditions.

Formulation and Characterization of Novel Dry Suspension and Dry Emulsion of 20(S)-Protopanaxadiol

To improve the absorption of poorly water-soluble 20(S)-protopanaxadiol (20(S)-PPD), novel 20(S)-PPD-loaded redispersible dry suspension and dry emulsion were developed in this study. 20(S)-PPD dry suspension (PPD-DS) was prepared by enabling drug fully dispersed with suspending agent Avicel CL611 and solubilizer Poloxamer 188. 20(S)-PPD dry emulsion (PPD-DE) was prepared by employing oleic acid as oil phase, Cremophor RH-40 as surfactant, and n-butyl alcohol as co-surfactant. Both PPD-DS and PPD-DE were evaluated for their physicochemical characterization after being dispersed in distilled water. The in vivo pharmacokinetics was evaluated by UPLC-MS/MS. The droplet size of PPD-DS and PPD-DE was in the scope of 1446-1653 nm and 652.8-784.5 nm. The sedimentation volume ratios of PPD-DS and PPD-DE were both at value of 1. The zeta potential of PPD-DS and PPD-DE were from - 53.7 to - 70.4 mV and - 27.5 to - 34.5 mV, respectively, which indicated stable systems. PPD-DS and PPD-DE both achieved dramatically enhanced aqueous solubility and higher perfusion of 20(S)-PPD in rats' intestine. Although statistically, no oral bioavailability enhancements of 20(S)-PPD were achieved in PPD-DE and PPD-DS, there were some improvements in the pharmacokinetic behaviors. Especially, PPD-DS could be a promising drug delivery carrier for 20(S)-PPD with the advantages of long-term stability, dosing flexibility, and the convenience of administering to infants and to those who have difficulty swallowing tablets or capsules.

Eco-Friendly Tadalafil Surfactant-Free Dry Emulsion Tablets (SFDETs) Stabilized by In Situ Self-Assembled Aggregates of Natural Oil and Native Cyclodextrins

The main principles of green chemistry and engineering were extended to pharmaceutical formulations to prepare eco-friendly surfactant-free dry emulsion tablets (SFDETs) devoid of solvents or synthetic surfactants. Surfactant-free emulsions were stabilized by in situ cyclodextrins/sweet almond oil inclusion complexes and assessed for creaming stability. Formulation variables' effects on the emulsion droplet size and tadalafil solubility were studied using 2² × 3 factorial design. The emulsions exhibited nanometric and micrometric droplet sizes. The optimized nanoemulsion was loaded with tadalafil, morphologically evaluated, and utilized for preparing lyophilized SFDETs using different gelatin/Pearlitol® ratios. The tablets were characterized and the selected formulation was subjected to storage for 6 months. The emulsions prepared using β-cyclodextrin or higher concentrations of α-cyclodextrin showed little or no phase separation. Statistical analysis revealed significant influence of cyclodextrin type and amount on droplet size, while cyclodextrin type and oil volume exhibited significant effect on drug solubility. Morphological examination revealed non-aggregated spherical emulsion droplets. The prepared tablets showed satisfactory mechanical strength, short disintegration times, and enhanced drug dissolution. The selected tablet formulation (gelatin/Pearlitol®, 4:2 w/w) showed acceptable stability at 25°C/60% relative humidity. An overall conclusion claims that the absence of surfactants is expected to minimize the proposed tablets' in vivo toxicity and environmental concerns.

The Effect of Pharmaceutical Excipients for Applying to Spray-Dried Omega-3 Powder

Omega-3 fatty acid plays a role in protecting cells in the human body, maintaining the structure of the cell, and helping smooth metabolism. Also, it inhibits the formation of blood clotting and is effective in enhancing the formation of bone. However, the instability due to fatty acid oxidation and a fishy smell are the reasons it is avoided by people. In this study, we tried to obtain the omega-3 powder through spray-drying method using a variety of binders and surfactants for improving the limit of omega-3 fatty acid. First of all, an olive oil was used instead of omega-3 for optimization of the preparation of spray-dried omega-3 powder. Through the screening of binders and surfactants, γ-cyclodextrin and hydrogenated lecithin were chosen as a binder and a surfactant, respectively. Omega-3-loaded spray-dried powder was obtained, eventually. The morphology of omega-3-loaded spray-dried powder was spherical of 310 nm and the DHA amount was 98%. This study suggested that the transformation of omega-3 fatty acid into solid state by spray-drying using a binder and a surfactant was successively performed.

Core-Shell Morphology of Redispersible Powders in Polymer-Cement Waterproof Mortars

Redispersible powders based on soft core-hard shell polymer particles can be used as additives in polymer-cement mortars. The role of this morphology on the spray-drying production of these powders and on the crack-bridging properties of the corresponding cement-based membranes is investigated. Different polymer latexes at high solid content with varied core-shell ratio, shell thickness and chemical composition (hardness) were prepared from styrene and 2-ethylhexyl acrylate monomers via semi-batch emulsion polymerization. The latexes were characterized in terms of size, composition, and glass transition temperature (T g ), and spray-dried to obtain redispersible polymer powders (RPPs) using poly (vinyl alcohol) and limestone powder as anti-caking agents. The polymer powders were mixed with a mortar mixture and redispersed in water to produce cement-based membranes, which were tested for crack-bridging properties at different temperatures. The results showed that it was not possible to spray-dry a dispersion of homogeneous polymer particles with T g of -25 ∘ C, unless these particles are protected by much harder (high T g ) shell. In particular, it was observed that a thicker shell improved the spray-ability, but lowered the crack-bridging properties of the produced membrane. A trade-off between these two was revealed to be the key for the optimal design of the polymer nanoparticles, as proven by the systematic study of the core-shell morphology reported in this work. The best compromise was shown to consist of particles larger than 300 nm, shell thickness of about 5 nm, and core-shell ratio of 97%, with styrene content in the shell not larger than 80% to avoid excessive hydrophobicity.

Reconstitutable spray dried ultra-fine dispersion as a robust platform for effective oral delivery of an antihyperlipidemic drug

The current article highlights the application of spray drying technique to produce an ultra-fine powder encapsulating the antihyperlipidemic drug, atorvastatin calcium (ATV). First, ATV was dissolved in an emulsion formulation, and different carriers (pectin, alginate, chitosan HCl and hydroxypropylmethyl cellulose) in two concentrations (1.5 and 3%) were added. Then, these carrier-containing formulations were subjected to spray drying, whereby ultra-fine ATV-loaded spray dried emulsions were produced (ATV-SDE). The optimum formulation; ATV-SDE7 containing 3% w/w pectin was selected showing an obviously enhanced dissolution profile compared to the other used polymers which could be attributed to its lower ability to swell in acidic medium, resulting in faster drug diffusion into release medium. Thus, ATV-SDE7 was subjected to further characterization including; DSC, XRPD, SEM and flowability properties. In-vivo studies were conducted using high-fat induced hyperlipidemic rats. The optimum formulation depicted normal lipid profile showing significant reduction in the measured parameters at the end of daily oral treatment, compared to ATV marketed tablets and control hyperlipidemic rats confirmed by normal liver sections upon histopathological examination. The superior lipid-lowering activity of ATV-SDE7 was not only due to the enhanced dissolution of ATV but also due to the presence of pectin which is capable of lowering both cholesterol and triglyceride serum levels. Hence, the present study suggests that the formulation strategy employing ultrafine redispersible spray dried emulsion with pectin as a carrier holds a promising approach for the development of a novel dosage form of enhanced antihyperlipidemic effect for ATV.

Microencapsulation of fish oil using supercritical antisolvent process

In order to improve the encapsulation process, a newly supercritical antisolvent process was developed to encapsulate fish oil using hydroxypropyl methyl cellulose as a polymer. Three factors, namely, temperature, pressure, and feed emulsion rate were optimized using response surface methodology. The suitability of the model for predicting the optimum response value was evaluated at the conditions of temperature at 60°C, pressure at 150 bar, and feed rate at 1.36 mL/min. At the optimum conditions, particle size of 58.35 μm was obtained. The surface morphology of the micronized fish oil was also evaluated using field emission scanning electron microscopy where it showed that particles formed spherical structures with no internal voids. Moreover, in vitro release of oil showed that there are significant differences of release percentage of oil between the formulations and the results proved that there was a significant decrease in the in vitro release of oil from the powder when the polymer concentration was high.

Physicochemical analysis in the evaluation of reconstituted dry emulsion tablets

The aim of this study was to characterize the formation of emulsions by droplet size analysis and turbidimetry during reconstitution from a solid dosage form, namely from dry emulsion systems, which carry an oil phase for poorly soluble active ingredients. For the dry emulsion systems tablets were prepared either from oil-in-water systems using a freeze-drying process or through direct compression containing the same oil and excipients. The ratios of oil to emulgents and oil to xanthan gum were equal in both methods. In the preparation methods applied, mannitol, erythritol and lactose were used as excipients and mannitol was found to be the most effective excipient based on droplet size reconstitution, turbidimetry and physical properties. Quality control involved testing the physical properties of tablets and characterizing the reconstituted emulsions.

Development of a solidified self-microemulsifying drug delivery system (S-SMEDDS) for atorvastatin calcium with improved dissolution and bioavailability

To improve the dissolution and oral bioavailability (BA) of atorvastatin calcium (ATV), we previously introduced an optimized self-microemulsifying drug delivery system (SMEDDS) using Capmul(®) MCM (oil), Tween(®) 20 (surfactant), and tetraglycol (cosurfactant). In this study, various solid carriers were employed to develop a solidified SMEDDS (S-SMEDDS): mannitol (M) and lactose (L) as water-soluble carriers, and Sylysia(®) 350 (S) and Aerosil(®) 200 (A) as water-insoluble carriers. Maximum solidifying capacities (SCmax) of water-insoluble carriers were significantly greater than those of water-soluble carriers were. The resultant powders were free flowing with an angle of repose <40° and Carr's index 5-20%, regardless of the solid carrier types. S-SMEDDS with mannitol (S(M)-SMEDDS) or lactose (S(L)-SMEDDS) had a smaller droplet size and greater dissolution than S-SMEDDS with Sylysia(®) 350 (S(S)-SMEDDS) or Aerosil(®) 200 (S(A)-SMEDDS). Following oral administration of various formulations to rats at a dose equivalent to 25mg/kg of ATV, plasma drug levels were measured by LC-MS/MS. The relative BAs (RBAs) of SMEDDS, S(M)-SMEDDS, and S(S)-SMEDDS were 345%, 216%, and 160%, respectively, compared to that of ATV suspension. Additionally, at a reduced dose of ATV equivalent to 5mg/kg, the RBAs of S(M)-SMEDDS and S(S)-SMEDDS compared to that of SMEDDS were 101% and 65%, respectively. These results suggest that S(M)-SEMDDS offers great potential for the development of solid dosage forms with improved oral absorption of drugs with poor water solubility.

Optimization, physicochemical characterization and in vivo assessment of spray dried emulsion: A step toward bioavailability augmentation and gastric toxicity minimization

The limited solubility of BCS class II drugs diminishes their dissolution and thus reduces their bioavailability. Our aim in this study was to develop and optimize a spray dried emulsion containing indomethacin as a model for Class II drugs, Labrasol®/Transuctol® mixture as the oily phase, and maltodextrin as a solid carrier. The optimization was carried out using a 2(3) full factorial design based on two independent variables, the percentage of carrier and concentration of Poloxamer® 188. The effect of the studied parameters on the spray dried yield, loading efficiency and in vitro release were thoroughly investigated. Furthermore, physicochemical characterization of the optimized formulation was performed. In vivo bioavailability, ulcerogenic capability and histopathological features were assessed. The results obtained pointed out that poloxamer 188 concentration in the formulation was the predominant factor affecting the dissolution release, whereas the drug loading was driven by the carrier concentration added. Moreover, the yield demonstrated a drawback by increasing both independent variables studied. The optimized formulation presented a complete release within two minutes thus suggesting an immediate release pattern as well, the formulation revealed to be uniform spherical particles with an average size of 7.5μm entrapping the drug in its molecular state as demonstrated by the DSC and FTIR studies. The in vivo evaluation, demonstrated a 10-fold enhancement in bioavailability of the optimized formulation, with absence of ulcerogenic side effect compared to the marketed product. The results provided an evidence for the significance of spray dried emulsion as a leading strategy for improving the solubility and enhancing the bioavailability of class II drugs.

Novel Nanostructured Solid Materials for Modulating Oral Drug Delivery from Solid-State Lipid-Based Drug Delivery Systems

Lipid-based drug delivery systems (LBDDS) have gained significant attention in recent times, owing to their ability to overcome the challenges limiting the oral delivery of poorly water-soluble drugs. Despite the successful commercialization of several LBDDS products over the years, a large discrepancy exists between the number of poorly water-soluble drugs displaying suboptimal in vivo performances and the application of LBDDS to mitigate their various delivery challenges. Conventional LBDDS, including lipid solutions and suspensions, emulsions, and self-emulsifying formulations, suffer from various drawbacks limiting their widespread use and commercialization. Accordingly, solid-state LBDDS, fabricated by adsorbing LBDDS onto a chemically inert solid carrier material, have attracted substantial interest as a viable means of stabilizing LBDDS whilst eliminating some of the various limitations. This review describes the impact of solid carrier choice on LBDDS performance and highlights the importance of appropriate solid carrier material selection when designing hybrid solid-state LBDDS. Specifically, emphasis is placed on discussing the ability of the specific solid carrier to modulate drug release, control lipase action and lipid digestion, and enhance biopharmaceutical performance above the original liquid-state LBDDS. To encourage the interested reader to consider their solid carrier choice on a higher level, various novel materials with the potential for future use as solid carriers for LBDDS are described. This review is highly significant in guiding future research directions in the solid-state LBDDS field and fostering the translation of these delivery systems to the pharmaceutical marketplace.

Self-microemulsifying drug delivery system (SMEDDS)--challenges and road ahead

Self-microemulsifying drug delivery system (SMEDDS) has emerged as a vital strategy to formulate poor water soluble compounds for bioavailability enhancement. However, certain limitations are associated with SMEDDS formulations which include in vivo drug precipitation, formulation handling issues, limited lymphatic uptake, lack of predictive in vitro tests and oxidation of unsaturated fatty acids. These limitations restrict their potential usage. Inclusion of polymers or precipitation inhibitors within lipid based formulations helps to maintain drug supersaturation after dispersion. This, thereby, improves the bioavailability and reduces the variability on exposure. Also, formulating solid SMEDDS helps to overcome liquid handling and stability problems. Usage of medium chain triglycerides (MCT) and suitable antioxidants to minimize oxidation of unsaturated fatty acids are few of the steps to overcome the limitations associated with SMEDDS. The review discussed here, in detail, the limitations of SMEDDS and suitable measures that can be taken to overcome them.

Lipid-based formulations for oral administration of poorly water-soluble drugs

Lipid-based drug delivery systems have shown great potentials in oral delivery of poorly water-soluble drugs, primarily for lipophilic drugs, with several successfully marketed products. Pre-dissolving drugs in lipids, surfactants, or mixtures of lipids and surfactants omits the dissolving/dissolution step, which is a potential rate limiting factor for oral absorption of poorly water-soluble drugs. Lipids not only vary in structures and physiochemical properties, but also in their digestibility and absorption pathway; therefore selection of lipid excipients and dosage form has a pronounced effect on the biopharmaceutical aspects of drug absorption and distribution both in vitro and in vivo. The aim of this review is to provide an overview of the different lipid-based dosage forms from a biopharmaceutical point of view and to describe effects of lipid dosage forms and lipid excipients on drug solubility, absorption and distribution.

Spray-dried oil-in-water emulsion to improve the intestinal absorption and oral bioavailability of ZLR-8, a nitric oxide-releasing derivative of diclofenac

Objectives

Spray-dried emulsion (SDE) was prepared and characterized to improve the intestinal absorption and oral bioavailability of ZLR-8, a nitric oxide-releasing derivative of diclofenac, currently under preclinical development.

Methods

The intestinal absorption of ZLR-8 was characterized by single pass intestinal perfusion technique to obtain its absorption and permeability parameters. SDE of ZLR-8 was prepared and characterized by particle size measurements and in-vitro release study. Accurate and precise RP-HPLC methods for the detection of ZLR-8 and its metabolite diclofenac were constructed to perform the bioavailability study.

Key findings

It was demonstrated that ZLR-8 was absorbed in the whole intestine, of which the duodenum segment exhibited the largest absorption ability. ZLR-8 can be classified into BCS Class 2. SDE significantly enhanced the intestinal absorption rate of ZLR-8 in duodenum and jejunum but had indistinctive effect on permeability. All concentrations of ZLR-8 in rat plasma was lower than the limit of detection. A bicompartment model gave the best fit to the plasma diclofenac concentration–time curves. Calculated on AUC0–12h, the mean relative bioavailability of SDE was 105.4-fold that of ZLR-8 suspension.

Conclusions

SDE significantly improved the intestinal absorption of ZLR-8 and resulted in a dramatic improvement in its bioavailability.

Physicochemical and pharmacokinetic characterization of a spray-dried malotilate emulsion

Malotilate (MT) is a hepatoprotective drug administered orally. However, MT was found to be a poorly water-soluble drug with low oral bioavailability. In the present investigation, a novel spray-dried emulsion (SDE) loaded with MT was prepared, and its physicochemical properties were characterized by rheological evaluation, particle size measurement, in vitro release, and surface morphology. The pharmacokinetic study of SDE, in comparison to MT suspension with the pure MT powder homogeneously dispersed in 0.5% CMC-Na solution, was also performed in rats after a single oral dose. It was found that SDE exhibited a 2.9-fold higher peak plasma concentration (C(max)) and 2.3-fold higher area under the curve (AUC) than MT suspension.

Electrospraying, spray drying and related techniques for production and formulation of drug nanoparticles

IMPORTANCE OF THE FIELD

Spray drying and electrospraying are two widely used liquid atomization-based techniques for production and formulation of drug nanoparticles. The importance of spray drying in particular has increased lately in the production of nanostructured microparticles. The value of the particles is that they maintain the properties of individual nanoparticles but they are micrometer sized.

AREAS COVERED IN THIS REVIEW

In this review the most important liquid atomization techniques, spray drying and electrospraying, are presented in detail, and a short introduction is presented for other methods, including the aerosol flow reactor method and spray congealing.

WHAT THE READER WILL GAIN

A description of the possible tailoring processes depending on the technique and process parameters. Different product properties can be achieved; for example, nanosuspensions or dry powder formulations may be produced.

TAKE HOME MESSAGE

The most important advantage of these techniques as compared with many other particle formation techniques is that the production of dried powders is possible without any extra drying step.