Development of Solid SEDDS, IV: Effect of Adsorbed Lipid and Surfactant on Tableting Properties and Surface Structures of Different Silicates

Focused ion beam-scanning electron microscopy provides novel insights of drug delivery phenomena

Scanning electron microscopy (SEM) has long been a standard tool for morphological analyses, providing sub micrometer resolution of pharmaceutical formulations. However, analysis of internal morphologies of such formulations can often be biased due to the introduction of artifacts that originate from sample preparation. A recent advancement in SEM, is the focused ion beam scanning electron microscopy (FIB-SEM). This technique uses a focused ion beam (FIB) to remove material with nanometer precision, to provide virtually sample-independent access to sub-surface structures. The FIB can be combined with SEM imaging capabilities within the same instrumentation. As a powerful analytical tool, electron microscopy and FIB-milling are performed sequentially to produce high-resolution 3D models of structural peculiarities of diverse drug delivery systems or their behavior in a biological environment, i.e. intracellular or -tissue distribution. This review paper briefly describes the technical background of the method, outlines a wide array of potential uses within the drug delivery field, and focuses on intracellular transport where high-resolution images are an essential tool for mechanistical insights.

The effect of polymeric binder type and concentration on flow and dissolution properties of SMEDDS loaded mesoporous silica-based granules

Self-microemulsifying drug delivery systems (SMEDDS) are lipid-based formulations, designed to improve the solubility of poorly-water soluble drugs. Mesoporous silica is frequently used for SMEDDS solidification by various techniques. One of them is wet granulation, which enables achieving both high SMEDDS load and good flow properties. This study investigated the effect of six polymeric binders' addition to granulation dispersion (GD) (povidone K30, povidone K90, copovidone, Pharmacoat® 603, Pharmacoat® 615 and Methocel™ K100 Premium LV) on characteristics of produced SMEDDS granules, prepared by wet granulation. By incorporation of polymer in GD, it was possible to produce mesoporous silica-based free-flowing granules, with preserved self-microemulsifying properties, responsible for improved in vitro release of carvedilol. The incorporation of higher molecular weight binders resulted in slower in vitro release, while high binder concentration was related to faster drug release. The highest release rate was achieved with povidone K30 at 7.45 % binder concentration, as corresponding granules exhibited complete drug release already in 5 min. Granulation method (manual vs. high-shear) influenced the release rate of carvedilol as it was released slower from SMEDDS granules prepared using the granulator. Finally, SMEDDS tablet formulation was optimized to achieve maximum granule content and adequate tablet hardness. Increased granule content found to negatively influence tablet hardness, as maximum granule content of 25 % was needed to obtain appropriate hardness. Such tablets exhibited short disintegration time, so this final prototype can be considered as orodispersible tablet.

Functionalized calcium carbonate (FCC) as a novel carrier to solidify supersaturated self-nanoemulsifying drug delivery systems (super-SNEDDS)

Functionalized calcium carbonate (FCC), a novel pharmaceutical excipient, has shown promising properties in the field of oral drug delivery. The current study aimed at evaluating the feasibility of FCC as a carrier for the solidification of self-nanoemulsifying drug delivery systems (SNEDDS) containing the poorly water-soluble model drug carvedilol (CRV). Conventional, subsaturated SNEDDS (80 %-SNEDDSliquid) and supersaturated SNEDDS (200 %-SNEDDSliquid) were loaded onto FCC via physical adsorption at three ratios; 2.5:1, 3.0:1 and 3.5:1 (w/w) of FCC:SNEDDSliquid, respectively, generating free-flowing powders (SNEDDSFCC) with drug loading ranging from 0.8 % to 2.6 % (w/w) CRV. The emulsification of SNEDDSFCC in a USP II dissolution setup (in purified water) was characterized using dynamic light scattering, resulting in similar droplet sizes and PDIs as observed for their liquid counterparts. The morphology and physical state of the obtained SNEDDSFCC were characterized using scanning electron microscopy and differential scanning calorimetry. The physical stability and drug release upon dispersion were assessed as a function of storage time. The 200 %-SNEDDSliquid were physically stable for 6 days, however, solidification using FCC stabilized the supersaturated concentrations of CRV for a test period of up to 10 weeks (solidification ratios 3.0:1 and 3.5:1 (FCC:SNEDDSliquid)). SNEDDSFCC achieved an improved rate and extent of drug release upon dispersion compared to the crystalline CRV in tap water (pH 7.5), however, to a lesser extent than their liquid counterparts. After 8 weeks of storage (25 °C at dry conditions), FCC was still able to rapidly release the SNEDDSliquid and demonstrated the same rate and extent of drug release as freshly prepared samples. The solidification of 200 %-SNEDDSliquid in presence of FCC greatly improved the drug loading and showed an enhanced drug release profile compared to the conventional systems. In conclusion, FCC showed potential as a carrier for solidification of SNEDDS and for the development of novel supersaturated solid SNEDDS for the oral delivery of poorly water-soluble drugs.

Formulation and processing of solid self-emulsifying drug delivery systems (HME S-SEDDS): A single-step manufacturing process via hot-melt extrusion technology through response surface methodology

The objective of the current study is the formulation development and manufacturing of solid self-emulsifying drug delivery systems (HME S-SEDDS) via a single-step continuous hot-melt extrusion (HME) process. For this study, poorly soluble fenofibrate was selected as a model drug. From the results of pre-formulation studies, Compritol® HD5 ATO, Gelucire® 48/16, and Capmul® GMO-50 were selected as oil, surfactant and co-surfactant respectively for manufacturing of HME S-SEDDS. Neusilin® US2 was selected as a solid carrier. The design of experiments (response surface methodology) was employed to prepare formulations via a continuous HME process. The formulations were evaluated for emulsifying properties, crystallinity, stability, flow properties and drug release characteristics. The prepared HME S-SEDDS showed excellent flow properties, and the resultant emulsions were stable. The globule size of the optimized formulation was 269.6 nm. The DSC and XRD studies revealed the amorphous nature of the formulation and FTIR studies showed no significant interaction between fenofibrate and excipients. The drug release studies showed significant (p < 0.05) improvement in solubility compared to the pure drug (DE15 = 45.04 for the optimized formulation), as >90% of drug release was observed within 15 min. The stability studies for the optimized formulation were conducted for 3 months at 40 °C/75% RH.

Improvement of dissolution profile of eplerenone with solidified self-emulsifying drug delivery systems (S-SEDDS)

BACKGROUND

Eplerenone is a member of antihypertensives used individually or in combination with other medicines. Eplerenone exhibits poor solubility and is considered a class II drug.

OBJECTIVE

Increasing the solubility of eplerenone by using both liquid and solid self-emulsifying drug delivery system as an alternative to its marketed tablet product.

METHODS

Solubility studies of eplerenone were done with different oils, surfactants, and co-surfactants to determine which one has the highest solubility for eplerenone and determine the preference in the formulations of liquid self-emulsifying drug delivery system. The solidification process was carried out with the adsorption to solid carrier method. Optimal ratios of components were specified with pseudo-ternary phase diagram technique. Self-emulsifying drug delivery system formulations were characterized in terms of chemical interaction, droplet size/distribution, crystallization behaviors, and rheological evaluation. In vitro drug release studies were conducted and compared to pure drug and marketed product.

RESULTS

The solubility screening results showed high solubility of EPL in triacetin (11.99 mg/mL) as oil, Kolliphor®EL (≈ 2.65 mg/mL), and Tween^®80 (≈ 1.91 mg/mL) as surfactant and polyethylene glycol 200 (PEG200) (≈ 8.50 mg/mL), dimethyl sulfoxide (≈ 7.57 mg/mL), Transcutol^®P (≈ 6.03 mg/mL) as co-surfactant, respectively. Rheology studies revealed that liquid self-emulsifying drug delivery formulations exhibited non-Newtonian pseudoplastic flow.

CONCLUSION

Solid self-emulsifying drug delivery systems prepared with Aerosil and Neusilin have shown tremendous improvement in terms of eplerenone dissolution by releasing the entire dose with boosted effect within 5 and 30 minutes respectively compared to the marketed product and pure eplerenone (p < 0.05).

Application of Machine-Learning Algorithms for Better Understanding the Properties of Liquisolid Systems Prepared with Three Mesoporous Silica Based Carriers

The processing of liquisolid systems (LSS), which are considered a promising approach to improving the oral bioavailability of poorly soluble drugs, has proven challenging due to the relatively high amount of liquid phase incorporated within them. The objective of this study was to apply machine-learning tools to better understand the effects of formulation factors and/or tableting process parameters on the flowability and compaction properties of LSS with silica-based mesoporous excipients as carriers. In addition, the results of the flowability testing and dynamic compaction analysis of liquisolid admixtures were used to build data sets and develop predictive multivariate models. In the regression analysis, six different algorithms were used to model the relationship between tensile strength (TS), the target variable, and eight other input variables. The AdaBoost algorithm provided the best-fit model for predicting TS (coefficient of determination = 0.94), with ejection stress (ES), compaction pressure, and carrier type being the parameters that influenced its performance the most. The same algorithm was best for classification (precision = 0.90), depending on the type of carrier used, with detachment stress, ES, and TS as variables affecting the performance of the model. Furthermore, the formulations with Neusilin® US2 were able to maintain good flowability and satisfactory values of TS despite having a higher liquid load compared to the other two carriers.

Curcumin-Loaded Oil-Free Self-Assembled Micelles Inhibit the Influenza A Virus Activity and the Solidification of Curcumin-Loaded Micelles for Pharmaceutical Applications

Curcumin, a well-known natural lipophilic phenolic compound, plays a vital role in inhibiting the influenza infection. Currently, many kinds of formulations for the enhancement of a water dispersion of curcumin have been developed; however, the anti-influenza abilities of formulated curcumin have been much less investigated. In this study, the optimized self-assembled micelles of RH 40/Tween 80 loaded with curcumin (Cur-M) in an oil-free-based system were spherical with a hydrodynamic size at 13.55 nm ± 0.208 and polydispersity at 0.144 characterized by atomic force microscopy and dynamic light scattering, respectively. Additionally, Cur-M significantly increased the bioactivity/stability of curcumin and effectively inhibited the influenza A virus infection and its replication after viral entry, indicating the alteration of the inhibition mechanisms of curcumin against virus infection via RH 40/Tween 80 micelle formulation. Furthermore, a solid formulation (Cur-SM) of Cur-M was successfully developed by a one-pot physical adsorption method using a small amount of adsorbent and ~50% of curcumin/Cur-M that could be burst released from Cur-SM in 1 h, facilitating the fast-releasing applications. Ultimately, all of the results show that Cur-SM acts as a good nano-formulation of curcumin with improved solubility/dispersity in aqueous solutions and demonstrate new anti-influenza mechanisms of curcumin for pharmaceutical development.

High-Shear Wet Granulation of SMEDDS Based on Mesoporous Carriers for Improved Carvedilol Solubility

Mesoporous carriers are a convenient choice for the solidification of self-microemulsifying drug delivery systems (SMEDDS) designed to improve the solubility of poorly water-soluble drugs. They are known for high liquid load capacity and the ability to maintain characteristics of dry, free-flowing powders. Therefore, five different mesoporous carriers were used for the preparation of carvedilol-loaded SMEDDS granules by wet granulation methods—in paten (manually) and using a high-shear (HS) granulator. Granules with the highest SMEDDS content (63% and 66% of total granules mass, respectively) and suitable flow properties were obtained by Syloid^® 244FP and Neusilin^® US2. SMEDDS loaded granules produced by HS granulation showed superior flow characteristics compared to those obtained manually. All SMEDDS granules exhibited fast in vitro release, with 93% of carvedilol releasing from Syloid^® 244FP-based granules in 5 min. Upon compaction into self-microemulsifying tablets, suitable tablet hardness and very fast disintegration time were achieved, thus producing orodispersible tablets. The compaction slightly slowed down the carvedilol release rate; nevertheless, upon 1 h (at pH 1.2) or 4 h (at pH 6.8) of in vitro dissolution testing, the amount of released drug was comparable with granules, confirming the suitability of orodispersible tablets for the production of the SMEDDS loaded single unit oral dosage form.

Gastroretentive Sustained-Release Tablets Combined with a Solid Self-Micro-Emulsifying Drug Delivery System Adsorbed onto Fujicalin®

Gastroretentive drug delivery systems (GRDDS) get retained in the stomach for a long time, thus facilitating the absorption of drugs in the upper gastrointestinal tract. However, drugs that are difficult to dissolve or unstable in an acidic environment are not suitable for GRDDS. The current study designs GRDDS combined with a self-micro-emulsifying drug delivery system (SMEDDS) for drugs with solubility or stability problems in the stomach. The model drug fenofibrate was formulated into the optimized liquid SMEDDS composed of 50 w/w% Capryol^® PGMC, 40 w/w% Kolliphor^® RH40, and 10 w/w% Transcutol^® HP and solidified through adsorption on several porous adsorbents. In a dissolution medium at pH 1.2, the powdered SMEDDS using Fujicalin^® dissolved quickly and achieved higher drug dissolution than other adsorbents. Based on these results, a gastroretentive bilayer tablet consisting of a drug release layer and a swelling layer was designed. The drug release layer was formulated with the powdered SMEDDS and hydroxypropyl methylcellulose (HPMC) as a release modifier. HPMC was also added to the swelling layer as a water-swellable polymer. The dissolution rate depended on the viscosity of the HPMC in the drug release layer. The time for 90% drug release was extended from 3.7 to 12.0 h by increasing the viscosity grade of HPMC from 0.1 to 100 K. Moreover, the tablet swelled and maintained a size comparable to a human pylorus diameter or more for at least 24 h. This GRDDS could apply to a broader range of drug candidates.

Comparative Study of Powder Carriers Physical and Structural Properties

High specific surface area (SSA), porous structure, and suitable technological characteristics (flow, compressibility) predetermine powder carriers to be used in pharmaceutical technology, especially in the formulation of liquisolid systems (LSS) and solid self-emulsifying delivery systems (s-SEDDS). Besides widely used microcrystalline cellulose, other promising materials include magnesium aluminometasilicates, mesoporous silicates, and silica aerogels. Clay minerals with laminar or fibrous internal structures also provide suitable properties for liquid drug incorporation. This work aimed at a comparison of 14 carriers’ main properties. Cellulose derivatives, silica, silicates, and clay minerals were evaluated for flow properties, shear cell experiments, SSA, hygroscopicity, pH, particle size, and SEM. The most promising materials were magnesium aluminometasilicates, specifically Neusilin^® US2, due to its proper flow, large SSA, etc. Innovative materials such as FujiSil^® or Syloid^® XDP 3050 were for their properties evaluated as suitable. The obtained data can help choose a suitable carrier for formulations where the liquid phase is incorporated into the solid dosage form. All measurements were conducted by the same methodology and under the same conditions, allowing a seamless comparison of property evaluation between carriers, for which available company or scientific sources do not qualify due to different measurements, conditions, instrumentation, etc.

Development of self-microemulsifying tablets containing dutasteride for enhanced dissolution and pharmacokinetic profile

This study aimed to develop self-microemulsifying tablets containing the hydrophobic drug dutasteride for easy administration and high in vivo absorption. The candidate lipids and surfactants were formulated into a self-microemulsifying drug delivery system (SMEDDS), and their mean droplet size upon dilution was evaluated. The SMEDDS containing Capmul® MCM, Captex® 355, and Cremophor® EL showed improved dissolution in the gastric medium when compared to the dissolution of the conventional product (Avodart®) and the raw drug. Among the various porous silicon microparticles for solidifying SMEDDS, Neusilin® US2 showed favorable properties in terms of maximum adsorption capacity, powder flow, and compaction. However, the amount of drug released from the solidified SMEDDS after the adsorption process was lower than that of liquid SMEDDS, indicating incomplete desorption. After observing the effect of the solid-to-liquid ratio and pre-filling the pores with blank SMEDDS, complete desorption was obtained when the pores were first adsorbed with polyvinylpyrrolidone. The self-microemulsifying tablets exhibited improved bioavailability (29.9% and 15.2%) compared to the conventional soft gelatin product. Therefore, the proposed system could successfully solubilize the hydrophobic drug while maintaining rapid and complete desorption from the solid carrier, resulting in enhanced in vivo performance.

Technology of Processing Plant Extracts Using an Aluminometasilicate Porous Carrier into a Solid Dosage Form

A method of preparing tablets called liquisolid technique is currently emerging. In these formulations, an important role is played by porous carriers, which are the basic building blocks of liquisolid systems (LSSs). The most common are microcrystalline cellulose (MCC), magnesium aluminometasilicates, silica aerogels, mesoporous silicates, clays, etc. In this study, magnesium aluminometasilicate is used to prepare modified LSS formulations with plant extracts as model drugs dissolved in water (W) or ethanol (E). The modification involves drying tablets in a microwave (MW) and hot air dryer (HA) for a specified period. Powder blends and tablets were evaluated for physical properties, and their antioxidant activity (AA) was measured in a modified dissolution by ferric reducing antioxidant power assay (FRAP). PLS and ANOVA were used to compare tablets properties depending on the composition and technology. The experiment is based on a previous one, in which the plant extracts were processed into tablets using a similar method. Therefore, extending the study to include more plants and the robust statistical evaluation and comparison of the products was a procedure to justify the suitability of the presented method for a wide range of liquid plant extracts. As a result, we obtained tablets with excellent physical properties, including a short disintegration and dissolution, which is problematic in tableted extracts.

Solidification of Self-Emulsifying Drug Delivery Systems as a Novel Approach to the Management of Uncomplicated Malaria

Malaria affects millions of people annually, especially in third-world countries. The mainstay of treatment is oral anti-malarial drugs and vaccination. An increase in resistant strains of malaria parasites to most of the current anti-malarial drugs adds to the global burden. Moreover, existing and new anti-malarial drugs are hampered by significantly poor aqueous solubility and low permeability, resulting in low oral bioavailability and patient noncompliance. Lipid formulations are commonly used to increase solubility and efficacy and decrease toxicity. The present review discusses the findings from studies focusing on specialised oral lipophilic drug delivery systems, including self-emulsifying drug delivery systems (SEDDSs). SEDDSs facilitate the spontaneous formation of liquid emulsions that effectively solubilise the incorporated drugs into the gastrointestinal tract and thereby improve the absorption of poorly-soluble anti-malaria drugs. However, traditional SEDDSs are normally in liquid dosage forms, which are delivered orally to the site of absorption, and are hampered by poor stability. This paper discusses novel solidification techniques that can easily and economically be up-scaled due to already existing industrial equipment that could be utilised. This method could, furthermore, improve product stability and patient compliance. The possible impact that solid oral SEDDSs can play in the fight against malaria is highlighted.

Formulation and In Vivo Evaluation of a Solid Self-Emulsifying Drug Delivery System Using Oily Liquid Tocotrienols as Model Active Substance

Self-emulsifying drug delivery systems (SEDDS) can improve the oral bioavailability of poorly water-soluble drugs. Solid self-emulsifying drug delivery systems (s-SEDDS) offer several advantages including improved drug stability, ease of administration, and production. Most compounds employed in developing s-SEDDS are solid in nature, with a high amount of surfactants added. The aim of this study was to develop an s-SEDDS using a tocotrienol-rich fraction (TRF) as the model liquid active substance via a simple adsorption method. The solid formulation was developed using magnesium aluminosilicate as the carrier with 70% TRF and 30% surfactants (poloxamer and Labrasol^®). The formulation showed good self-emulsification efficiency with stable emulsion formed, excellent powder flowability, and small emulsion droplet size of 210–277 nm. The s-SEDDS with combined surfactants (poloxamer and Labrasol^®) showed a faster absorption rate compared to preparations with only a single surfactant and enhanced oral bioavailability (3.4–3.8 times higher) compared to the non-self-emulsifying oily preparation when administered at a fasted state in rats. In conclusion, an s-SEDDS containing a high amount of TRF was successfully developed. It may serve as a useful alternative to a liquid product with enhanced oral bioavailability and the added advantage of being a solid dosage form.

Solid self emulsifying drug delivery system: Superior mode for oral delivery of hydrophobic cargos

A significant proportion of recently approved drug molecules possess poor aqueous solubility which further restrains their desired bioavailability. Poor aqueous solubility of these drugs poses significant hurdles in development of novel drug delivery systems and achieving target response. Self-emulsifying drug delivery systems (SEDDS) emerged as an insightful approach for delivering highly hydrophobic entities to enhance their bioavailability. Conventional SEDDS were developed in a liquid form which owned numerous shortcomings like low stability and drug loading efficiency, fewer choices of dosage forms and irreversible precipitation of drug or excipients. To address these curbs solid-SEDDS (S-SEDDS) was introduced as an efficient strategy that combined advantages of solid dosage forms such as increased stability, portability and patient compliance along with substantial improvement in the bioavailability. S-SEDDS are isotropic mixtures of oil, surfactant, solvent and co-solvents generated by solidification of liquid or semisolid self-emulsifying ingredients onto powders. The present review highlights components of S-SEDDS, their peculiarities to be considered while designing solid dosage forms and various methods of fabrication. Lastly, key challenges faced during development, applications and future directions for the research in this area are thoroughly summarized.

Evaluation of solid carvedilol-loaded SMEDDS produced by the spray drying method and a study of related substances

In this study, various formulations of solidified carvedilol-loaded SMEDDS with high SMEDDS loading (up to 67% w/w) were produced with the spray drying process using various porous silica-based carriers. The process yield was improved with higher atomization gas flow rate during the spray drying process and with prolonged mixing time of dispersion of liquid SMEDDS and solid porous carriers prior to the spray drying process. Depending on the choice of the carrier and the SMEDDS:carrier ratio in solid SMEDDS, different drug loading, self-microemulsifying properties, drug release rates, and released drug fractions were obtained. The products exhibited fast drug release due to preserved self-microemulsifying properties and the absence of crystalline carvedilol, which was confirmed with XRD and Raman mapping. A decrease in drug content during the stability study was observed and investigated. This was at least partially attributed to the chemical degradation of the drug. Key degradation products determined by the LC-MS method were amides formed by in situ reaction of carvedilol with fatty acids present in the oily phase of SMEDDS.

A One-Step Twin-Screw Melt Granulation with Gelucire 48/16 and Surface Adsorbent to Improve the Solubility of Poorly Soluble Drugs: Effect of Formulation Variables on Dissolution and Stability

Fenofibrate is an effective lipid-lowering drug; however, its poor solubility and high log p (5.2) result in insufficient absorption from the gastrointestinal tract, leading to poor bioavailability. In this study, a one-step continuous twin-screw melt granulation process was investigated to improve the solubility and dissolution of fenofibrate using Gelucire® 48/16 and Neusilin® US2 as the solubilizer and surface adsorbent, respectively. The formulations (granules) were prepared at different ratios of fenofibrate, Gelucire® 48/16, and Neusilin® US2 based on phase-solubility studies and characterized using dissolution, differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy analyses and studies on flow properties. In the phase-solubility studies, a linear relation was observed between Gelucire® 48/16 concentration and the amount of fenofibrate dissolved. In contrast, the dissolution rate of the prepared formulations was independent of the fenofibrate: Gelucire® 48/16 ratio and dependent on the Neusilin® US2 levels in the formulation. Increasing Neusilin® US2 levels decreased the rate of dissolution of the granules but improved the stability of the tablets under storage at accelerated stability conditions. Interestingly, higher Gelucire® 48/16 levels in the granules resulted in tablets with a hard matrix, which slowed disintegration and dissolution. All formulations exhibited improved dissolution compared to pure fenofibrate.

Stress-Dependent Particle Interactions of Magnesium Aluminometasilicates as Their Performance Factor in Powder Flow and Compaction Applications

In the pharmaceutical industry, silicates are commonly used excipients with different application possibilities. They are especially utilized as glidants in low concentrations, but they can be used in high concentrations as porous carriers and coating materials in oral solid drug delivery systems. The desirable formulations of such systems must exhibit good powder flow but also good compactibility, which brings opposing requirements on inter-particle interactions. Since magnesium aluminometasilicates (MAS) are known for their interesting flow behavior reported as "negative cohesivity" yet they can be used as binders for tablet compression, the objective of this experimental study was to investigate their particle interactions within a broad range of mechanical stress from several kPa to hundreds of MPa. Magnesium aluminometasilicate (Neusilin^® US2 and Neusilin^® S2)-microcrystalline cellulose (Avicel^® PH102) physical powder mixtures with varying silicate concentrations were prepared and examined during their exposure to different pressures using powder rheology and compaction analysis. The results revealed that MAS particles retain their repulsive character and small contact surface area under normal conditions. If threshold pressure is applied, the destruction of MAS particles and formation of new surfaces leading to particle interactions are observed. The ability of MAS particles to form interactions intensifies with increasing pressure and their amount in a mixture. This "function switching" makes MAS suitable for use as multifunctional excipients since they can act as a glidant or a binder depending on the applied pressure.

Formulation and in vitro evaluation of self-nanoemulsifying liquisolid tablets of furosemide

Self-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.

Overdose and Alcohol Sensitive Immediate Release System (OASIS) for Deterring Accidental Overdose or Abuse of Drugs

Death from an accidental or intentional overdose of sleeping tablets has increased exponentially in the USA. Furthermore, the simultaneous consumption of sleeping tablets with alcoholic beverages not only intensifies the effect of sleeping tablets but also leads to blackouts, sleepwalking, and death in many cases. In this article, we proposed a unique and innovative technology to prevent multi-tablet and alcohol-associated abuse of sleeping tablet. Agonist- and antagonist-loaded polymeric filaments of appropriate Eudragit® polymers were prepared using hot melt extrusion. Metoprolol tartrate and hydrochlorothiazide were used as model drugs in place of zolpidem tartrate (agonist-BCS class I) and flumazenil (antagonist-BCS class IV), respectively. Crushed filaments were converted into a tablet with a novel rapidly soluble co-processed alkalizing agent. Dissolution studies of single tablet and multiple tablets (5) in fasted state simulated gastric fluid (FaSSGF) confirmed that the release of the agonist was significantly (p < 0.0001) reduced in multi-tablet dissolution. Furthermore, the release of antagonist was significantly higher when tablet was exposed to FaSSGF+20% ethanol and various alcoholic beverages. Thus, appropriate use of Eudragit® polymer's chemistry could help design a tablet to prevent the release of agonist in case of overdose and simultaneous release of antagonist when consumed with alcohol.

Development of a Solid Formulation Containing a Microemulsion of a Novel Artemisia Extract with Nematocidal Activity for Oral Administration

Background: Intestinal nematode infections are usually treated with benzimidazole drugs, but the emergence of resistance to these drugs has led to an increasing demand of new anthelmintic strategies. A new microemulsion formulation (ME) consisting of an Artemisia absinthium extract with proven nematocidal efficacy was previously developed. The aim of our study is to implement a D-optimal mixture design methodology to increase the amount of a silica material (loaded with this ME) in a tablet formulation, considering its tensile strength and disintegration time. Methods: 16 experiments or combinations of the 6 tablet components (loaded silica, microcrystalline cellulose, polyvinylpyrrolidone, croscarmellose, Syloid^® 244 FP and magnesium stearate) were assessed. Tensile strength and disintegration time models were developed, and an optimization process was carried out. Results: Tensile strength was improved by increasing the polyvinylpyrrolidone content, while croscarmellose decreased the disintegration time. The optimized powder mixture contains 49.7% w/w of the loaded silica material. A compression force of 12 kN was applied to the powder mixture to form tablets with a tensile strength of 2.0 MPa and a disintegration time of 3.8 min. Conclusions: Our results show that D-optimal mixture designs provide a promising approach to formulate liquid-loaded silica materials.

Solidification of SMEDDS by fluid bed granulation and manufacturing of fast drug release tablets

Solidification of self-microemulsifying drug delivery systems (SMEDDS) is a rising experimental field with important potential for pharmaceutical industry, however fluid-bed granulation with SMEDDS is yet an unexplored solidification technique. The aim of the study was to solidify carvedilol-loaded SMEDDS utilizing fluid bed granulation process and to investigate how the formulation variables (type of solid carrier, optimization of granulation dispersion) and fluid-bed granulation process variables can be optimized in order to achieve suitable agglomeration process, high drug loading and appropriate product characteristics. Obtained granulates exhibited complete drug release, comparable to liquid SMEDDS and superior to crystalline carvedilol, nevertheless compromise between large SMEDDS loading and appropriate flow properties of the granules has to be made. Representative granulates with highest drug loading were further compressed into tablets. It was shown that the optimal excipient selection of compression mixture and compression force can lead to fast carvedilol release even from the tablets. Selfmicroemulsifying properties were not impaired neither after the solidification process and nor after the compression of solid SMEDDS into tablets. This suggests that fluid-bed granulation with SMEDDS offers a perspective alternative for solidification of the SMEDDS, enabling preservation of self-microemulsifying properties, acceptable drug loading and complete drug release.

SELECTION OF FLAVOUR ADDITIVES AND METHOD OF THEIR INTRODUCTION IN THE COMPOSITION OF COMPRESSED MEDICATED CHEWING GUMS

An important characteristic of oral medicines, which include medicated chewing gums, is their pleasant taste. This can be achieved by adding taste coregents to their composition. The aim: to choose rational flavour additives and justify the method of their introduction to the compressed medicated chewing gums that are being developed. Materials and methods: mint (Natural Mint Flavor SD, Kerry Inc., Malaysia), apple (Nat Apple FlavorWonf, Kerry Inc., Malaysia) and banana (Banana FLV, Kerry Inc., Malaysia) have been used as powdered flavour additives. As flavourings – oil solutions: Peppermint Natural WonfFlavor, Kerry Inc., Malaysia), Apple (Nat Apple FlavorWonf, Kerry Inc., Malaysia), Strawberry (Strawberry FlavorWonf, Kerry Inc., Malaysia), Melon (Chemical-Food Aromatic PlantLLC, Russian Federation) and Lemon (Chemical-Food Aromatic Plant LLC, Russian Federation). Aerosil brand 380 (Evonik Resource Efficiency GmbH, Germany), Syloid® 244FP (Grace Discovery Sciences, USA) and Neusilin® ULP 2 (Fuji Chemical Industry Co. Ltd, Japan) have been taken as carriers. The choice of flavour additives and flavourings was made using organoleptic methods of coregents evaluation according to A. I. Tentsova and I. A.Yegorov. The technological and physicochemical properties of the samples were studied according to conventional methods of the State Pharmacopoeia of Ukraine. Results and discussion. In determining the taste of medicated chewing gums samples with different coregents, the combination of powder additive and liquid flavouring "Apple" has got the highest mark. In order to substantiate the rational method of liquid flavouring introduction in the composition of the compressed chewing gums, it is proposed to introduce the adsorbents Aerosil 380, Syloid® 244FP and Neusilin® ULP 2, which also play the role of moisture regulators and glidants. Microscopic analysis of adsorbents mixtures with flavouring, as well as physicochemical and technological investigations of the mass for pressing have revealed that the best adsorbing, moisture-regulating and flow properties has Syloid® 244FP. Conclusions. As a coregent in medicated chewing gums was selected a combination of powdered (2.0 %) and liquid (0.6 %) flavours “Apple”. The method of introducing the oil flavouring into the composition of the compressed gums has been chosen – by spraying on the adsorbent with subsequent mixing. Based on the studies, Syloid®244FP at a concentration of 1.0 % was chosen as the rational carrier.

Development and Permeability Testing of Self-Emulsifying Atorvastatin Calcium Pellets and Tablets of Compressed Pellets

Self-emulsifying pellets (SEPs) of Atorvastatin Calcium (AtrCa) were developed and processed into tablets (SETs). Self-emulsifying drug delivery system (SEDDS) composed of oleic acid, Tween 20, Span 80 and N-Methyl-2-pyrolidone gave great solubility improvement and was used as oil in water emulsion for the preparation of SEPs. Due to the high 60% w/w SEDDS content required to achieve a therapeutic dose in the final tablet form, sonication was necessary to improve fluidity and stability. Colloidal silicon dioxide (CSD) and microcrystalline cellulose (MCC) were the solids in the pellet formulation employed at a ratio 7:3, which enabled production of pellets with high SEDDS content and acceptable friability as well. Emulsions were characterized physico-chemically, SEPs for physical properties and reconstitution, and tablets of compressed pellets for mechanical strength, disintegration into pellets and drug release. SEPs compressed with 30% MCC at 60 MPa gave tablets of adequate strength that disintegrated rapidly into pellets within 1 min. Emulsion reconstitution took longer than drug release due to adsorption of SEDDS on CSD, implying dissolution at the pellet surface in parallel to that from the dispersed droplets. Compared to the commercial tablet, drug release from the self-emulsifying forms was faster at pH 1.2 where the drug solubility is poor, but slower at pH 6.8 where the solubility is higher. Permeability and cytotoxicity were also studied using Caco-2 cells. The results showed that drug transport from the apical to basolateral compartment of the test well was 1.27 times greater for SEPs than commercial tablets, but 0.86 times lower in the opposite direction. Statistical analysis confirmed the significance of these results. Toxicity was slightly reduced. Therefore, the increased permeability in conjunction with the protection of the drug being dissolved in the SEDDS droplets, may reduce the overall effect of presystemic metabolism and enhance bioavailability.

Erlotinib-Valproic Acid Liquisolid Formulation: Evaluating Oral Bioavailability and Cytotoxicity in Erlotinib-Resistant Non-small Cell Lung Cancer Cells

Lung cancer patients develop acquired resistance to tyrosine kinase inhibitors including erlotinib (ERL) after few months of primary treatment. Evidently, new chemotherapy strategies to delay or overcome the resistance are urgently needed to improve the clinical outcome in non-small cell lung cancer (NSCLC) patients. In this paper, we have investigated the cytotoxic interaction of ERL and valproic acid (VA) in ERL-resistant NSCLC cells and developed a liquisolid formulation of ERL-VA for improving oral bioavailability of ERL. ERL is weakly basic, biopharmaceutical classification system (BCS) class II drug with extremely poor aqueous solubility while VA is a branched chain fatty acid. Ionic interaction between ERL and VA (1:2 M ratio) resulted in significant enhancement in saturation solubility of ERL at different pH range. Liquisolid formulation of ERL-VA (EVLF) developed using PEG 400 and mesoporous calcium silicate was characterized for solid state and in vitro dissolution in biorelevant dissolution medium (FaSSIF and FeSSIF). Cytotoxicity of ERL was enhanced by 2-5 folds on co-incubation with VA in HCC827/ERL cell line. Flow cytometry analysis using AnnexinV-FITC assay demonstrated that VA and ERL alone have poor apoptotic effect on HCC827/ERL cells while combination showed around 69% apoptotic cells. Western blot analysis confirmed the role of survivin in overcoming resistance. In vivo pharmacokinetic studies of EVLF in rats demonstrated a 199% relative bioavailability compared to ERL suspension. Thus, EVLF could be a promising alternative to current ERL formulations in the treatment of NSCLC.

Solidification to improve the biopharmaceutical performance of SEDDS: Opportunities and challenges

Self-emulsifying drug delivery systems (SEDDS) offer potential for overcoming the inherent slow dissolution and poor oral absorption of hydrophobic drugs by retaining them in a solubilised state during gastrointestinal transit. However, the promising biopharmaceutical benefits of liquid lipid formulations has not translated into widespread commercial success, due to their susceptibility to long term storage and in vivo precipitation issues. One strategy that has emerged to overcome such limitations, is to combine the solubilisation and dissolution enhancing properties of lipids with the stabilising effects of solid carrier materials. The development of intelligent hybrid drug formulations has presented new opportunities to harness the potential of emulsified lipids in optimising oral bioavailability for lipophilic therapeutics. Specific emphasis of this review is placed on the impact of solidification approaches and excipients on the biopharmaceutical performance of self-emulsifying lipids, with findings highlighting the key design considerations that should be implemented when developing hybrid lipid-based formulations.

Enhancement of Aqueous Solubility and Dissolution of Celecoxib through Phosphatidylcholine-Based Dispersion Systems Solidified with Adsorbent Carriers

This study aimed to design phosphatidylcholine (PC)-based solid dispersion (SD) systems for enhancing the apparent aqueous solubility and dissolution of celecoxib (CLC), a selective cyclooxygenase-2 inhibitor with a highly hydrophobic property. Although PC-based dispersion formulations considerably increased solubilities of CLC, the lipidic texture of PC was not appropriate as a solid dosage form for oral administration of CLC. To mask the lipidic texture of PC-based matrices, Neusilin^® US2, an adsorbent material with a porous structure and large surface area widely used in the pharmaceutical industry, was employed and thereby fully powderized PC-based dispersion formulations could be fabricated. However, PC matrices containing CLC strongly adsorbed to the pores of Neusilin^® US2 was not able to be rapidly released. To address this problem, different hydrophilic materials were examined to promote the release of the CLC-dispersed PC matrices from Neusilin^® US2. Among tested hydrophilic materials, croscarmellose sodium was the most suitable to facilitate fast drug dissolution from Neusilin^® US2 particles, showing significantly enhanced apparent aqueous solubility and dissolution behavior of CLC. Through differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy (FT-IR) analysis, a considerably reduced crystallinity of CLC dispersed in the PC-based dispersion formulations was demonstrated. The PC-based SD formulations developed in this study would be useful for improving the oral bioavailability of poorly soluble drugs such as CLC.

Nanoemulsifying drug delivery system to improve the bioavailability of piroxicam

OBJECTIVE

The aim of this study is to develop and characterize self-nanoemulsifying drug delivery system (SNEDDS) of piroxicam in liquid and solid forms to improve its dissolution, absorption and therapeutic efficacy.

MATERIALS AND METHODS

The generation of liquid SNEDDS (L-SNEDDS) was composed of soybean or coconut oil/Tween 80/Transcutol HP (12/80/8%w/w) and it was selected as the optimized formulation based on the solubility study and pseudo-ternary phase diagram. Optimized L-SNEDDS and liquid supersaturatable SNEDDS (L-sSNEDDS) preparations were then adsorbed onto adsorbents and formulated as directly compressed tablets.

RESULTS AND DISCUSSION

The improved drug dissolution rate in the solid supersaturatable preparation (S-sSNEDDS) may be due to the formation of a nanoemulsion and the presence of drug in an amorphous state with hydrogen bond interaction between the drug and SNEDDS components. In vivo pharmacokinetic studies on eight healthy human volunteers showed a significant improvement in the oral bioavailability of piroxicam from S-sSNEDDS (F12) compared with both the pure drug (PP) and its commercial product (Feldene^®) (commercial dosage form (CD)). The relative bioavailability of S-sSNEDDS (F12) relative to PP or CD was about 151.01 and 98.96%, respectively.

CONCLUSION

The obtained results ratify that S-sSNEDDS is a promising drug delivery system to enhance the oral bioavailability of piroxicam.

Isolation and Physical Property Optimization of an Amorphous Drug Substance Utilizing a High Surface Area Magnesium Aluminometasilicate (Neusilin(®) US2)

Control and optimization of the physical properties of a drug substance (DS) are critical to the development of robust drug product manufacturing processes and performance. A lack of isolatable, for example, crystalline, DS solid forms can present challenges to achieving this control. In this study, an isolation scheme for an amorphous DS was developed and integrated into the synthetic route producing DS with optimized properties. An inert absorbent excipient (Neusilin® US2) was used to isolate the DS via a novel antisolvent scheme as the final step of the route. Isolation was executed at kilogram scale utilizing conventional equipment. The resulting 50 wt% DS:Neusilin complex had improved physical stability and exceptional micromeritic and tableting properties. Improved dissolution was observed and attributed to enhanced dispersion and increased surface area. Characterization data suggest a high degree of penetration of the DS into the Neusilin, with DS occupying 70% of mesopore and 12% of macropore volume. This approach has application in the isolation and particle engineering of difficult to isolate DS without additional unit operation, such as spray drying, and has the potential for a high degree of optimization and control of physical properties over the course of DS development.

The effect of superdisintegrants on the properties and dissolution profiles of liquisolid tablets containing rosuvastatin

CONTEXT

The preparation of liquisolid systems (LSS) represents a promising method for enhancing a dissolution rate and bioavailability of poorly soluble drugs. The release of the drug from LSS tablets is affected by many factors, including the disintegration time.

OBJECTIVE

The evaluation of differences among LSS containing varying amounts and types of commercially used superdisintegrants (Kollidon® CL-F, Vivasol® and Explotab®).

MATERIALS AND METHODS

LSS were prepared by spraying rosuvastatin solution onto Neusilin® US2 and further processing into tablets. Varying amounts of superdisintegrants were used and the differences among LSS were evaluated. The multiple scatter plot method was used to visualize the relationships within the obtained data.

RESULTS AND DISCUSSION

All disintegrants do not showed negative effect on the flow properties of powder blends. The type and concentration of superdisintegrant had an impact on the disintegration time and dissolution profiles of tablets. Tablets with Explotab® showed the longest disintegration time and the smallest amount of released drug. Fastest disintegration and dissolution rate were observed in tablets containing Kollidon® CL-F (≥2.5% w/w). Also tablets with Vivasol® (2.5-4.0% w/w) showed fast disintegration and complete drug release.

CONCLUSION

Kollidon® CL-F and Vivasol® in concentration ≥2.5% are suitable superdisintegrants for LSS with enhanced release of drug.

Modern evaluation of liquisolid systems with varying amounts of liquid phase prepared using two different methods

Liquisolid systems are an innovative dosage form used for enhancing dissolution rate and improving in vivo bioavailability of poorly soluble drugs. These formulations require specific evaluation methods for their quality assurance (e.g., evaluation of angle of slide, contact angle, or water absorption ratio). The presented study is focused on the preparation, modern in vitro testing, and evaluation of differences of liquisolid systems containing varying amounts of a drug in liquid state (polyethylene glycol 400 solution of rosuvastatin) in relation to an aluminometasilicate carrier (Neusilin US2). Liquisolid powders used for the formulation of final tablets were prepared using two different methods: simple blending and spraying of drug solution onto a carrier in fluid bed equipment. The obtained results imply that the amount of liquid phase in relation to carrier material had an effect on the hardness, friability, and disintegration of tablets, as well as their height. The use of spraying technique enhanced flow properties of the prepared mixtures, increased hardness values, decreased friability, and improved homogeneity of the final dosage form.