Lipid-based oral multiparticulate formulations – advantages, technological advances and industrial applications

Solid Lipid Microparticles by Spray Congealing of Water/Oil Emulsion: An Effective/Versatile Loading Strategy for a Highly Soluble Drug

Spray congealing technique was exploited to produce solid lipid microparticles (SLMp) loaded with a highly water-soluble drug (metoclopramide hydrochloride) dissolved in the aqueous phase of a water in oil (W/O) emulsion. The use of an emulsion as starting material for a spray congealing treatment is not so frequent. Moreover, for this application, a W/O emulsion with a drug dissolved in water is a totally novel path. A ternary diagram was built to optimize the emulsion composition, a factorial design was used to identify the factors affecting the properties of the microparticles and a Design of Experiment strategy was applied to define the impact of process conditions and formulation variables on the SLMp properties. SLMp were characterized by particle size distribution, morphology, residual moisture, drug content, release behavior, FT-IR analysis and XRPD. The obtained microparticles presented a spherical shape, particle size distribution between 54-98 µm depending on atomizing pressure used during the production step and 2-5% residual moisture 4 days after the preparation. XRPD analysis revealed that lipid polymorphic transition alfa-beta occurs depending on the presence of water. In vitro drug release tests highlighted that all the formulations had a reduced release rate compared to the drug alone. These results suggest that spray congealing of a W/O emulsion could be proposed as a good strategy to obtain SLMp with a high loading of a hydrophilic drug and able to control its release rate.

Pharmaceutical Product Characterization and Manufacturability of Surfactant-Enriched Oil Marbles with Abiraterone Acetate

The present study investigates the physicochemical properties and stability of a novel lipid-based formulation-surfactant-enriched oil marbles containing abiraterone acetate. While the biopharmaceutical performance of this formulation has been reported recently, this study aims to fill the gap between a promising in vivo performance and industrial applicability. A series of techniques were employed to assess the solid-state characteristics of oil marble cores along with their physicochemical properties upon stability testing. The chemical stability of abiraterone acetate in the formulation was also investigated. The core of the formulation was found to be stable both physically and chemically over 12 months of storage. The in vitro performance of stressed samples was evaluated using a dissolution experiment. The formulation has successfully self-emulsified upon incubation in bio-relevant media, resulting in a fast and complete API release. An important issue connected with the excipient used as a covering material of oil marbles has been identified. The seemingly insignificant water sorption caused agglomeration of the oil marbles and consequently compromised the dissolution rate in some of the stressed samples. Replacing HPMC with lactose as a covering material resulted in more favorable properties upon storage. Overall, it has been shown that oil marbles are an industrially applicable concept of the solidified lipid-based formulation.

Binary isobaric phase diagrams of stearyl alcohol-poloxamer 407 formulations in the molten and solid state

Multiparticulate formulations allow for the design of specialized pharmaceutical dosage forms that cater to the needs of a wide range of patient demographics, such as pediatric and geriatric populations, by affording control over the release rate and facilitating the formulation of fixed-dose combination drugs. Melt spray-congealing (MSC) is a method for preparing multiparticulate dosage forms from a suspension or solid solution of active pharamaceutical ingredients (API) and a molten carrier matrix. Stearyl alcohol and poloxamer 407 mixtures are widely used as carrier matrices in MSC microsphere formulations. In this report, the phase equilibria of stearyl alcohol-poloxamer 407 mixtures were investigated by generating binary phase diagrams of composition, i.e. weight/weight percent of poloxamer 407 in stearyl alcohol, and temperature in the molten form and the solid state. The phase equilibria of the molten state were characterized by ¹H NMR measurements. The miscibility curves of stearyl alcohol-poloxamer 407 molten mixtures revealed that stearyl alcohol and poloxamer 407 are not miscible in all proportions and that miscibility substantially increases with temperature. The phase equilibria of the solid state were characterized by DSC and PXRD experiments. The phase diagrams of the solid state indicate that stearyl alcohol and poloxamer 407 crystallize and melt separately and, thus, do not form a eutectic or a single phase. The phases equilibria of the bulk mixtures were compared to the phases observed in placebo MSC microspheres and it was determined that the microspheres consist of a mixture of thermodynamically stable and metastable stearyl alcohol crystals immediately after manufacture.

Oral delivery of therapeutic peptides and proteins: Technology landscape of lipid-based nanocarriers

The oral administration of therapeutic peptides and proteins is favoured from a patient and commercial point of view. In order to reach the systemic circulation after oral administration, these drugs have to overcome numerous barriers including the enzymatic, sulfhydryl, mucus and epithelial barrier. The development of oral formulations for therapeutic peptides and proteins is therefore necessary. Among the most promising formulation approaches are lipid-based nanocarriers such as oil-in-water nanoemulsions, self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes and micelles. As the lipophilic character of therapeutic peptides and proteins can be tremendously increased such as by the formation of hydrophobic ion pairs (HIP) with hydrophobic counter ions, they can be incorporated in the lipophilic phase of these carriers. Since gastrointestinal (GI) peptidases as well as sulfhydryl compounds such as glutathione and dietary proteins are too hydrophilic to enter the lipophilic phase of these carriers, the incorporated therapeutic peptide or protein is protected towards enzymatic degradation as well as unintended thiol/disulfide exchange reactions. Stability of lipid-based nanocarriers towards lipases can be provided by the use to excipients that are not or just poorly degraded by these enzymes. Nanocarriers with a size <200 nm and a mucoinert surface such as PEG or zwitterionic surfaces exhibit high mucus permeating properties. Having reached the underlying absorption membrane, lipid-based nanocarriers enable paracellular and lymphatic drug uptake, induce endocytosis and transcytosis or simply fuse with the cell membrane releasing their payload into the systemic circulation. Numerous in vivo studies provide evidence for the potential of these delivery systems. Within this review we provide an overview about the different barriers for oral peptide and protein delivery, highlight the progress made on lipid-based nanocarriers in order to overcome them and discuss strengths and weaknesses of these delivery systems in comparison to other technologies.

Quality aspects in the development of pelletized dosage forms

The aim of this work was to identify and collate the major common challenges that arise during pellet development. These challenges focus on aspects right from raw material properties until the final drying process of the pelletization. The challenges associated with the particle size of drug and excipients, physicochemical properties, drug excipient interaction and the effect of type/grade and amount of raw material on the pellet properties are covered in this review. Technological and process related challenges within the commonly used pelletization techniques such as extrusion-spheronization, hot-melt extrusion and layering techniques are also emphasized. The paper likewise gives an insight to the possible ways of addressing the quality of pellets during development.

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.

Solvent-Free Fabrication of Biphasic Lipid-Based Microparticles with Tunable Structure

Lipid-based biphasic microparticles are generally produced by long and complex techniques based on double emulsions. In this study, spray congealing was used as a solvent-free fabrication method with improved processability to transform water-in-oil non-aqueous emulsions into spherical solid lipid-based particles with a biphasic structure (b-MPs). Emulsions were prepared by melt emulsification using different compositions of lipids (Dynasan^®118 and Compritol^®888 ATO), surfactants (Cetylstearyl alcohol and Span^®60) and hydrophilic carriers (PEGs, Gelucire^®48/16 and Poloxamer 188). First, pseudo-ternary phase diagrams were constructed to identify the area corresponding to each emulsion type (coarse emulsion or microemulsion). The hydrophobicity of the lipid mostly affected the interfacial tension, and thus the microstructure of the emulsion. Emulsions were then processed by spray congealing and the obtained b-MPs were characterized in terms of thermal and chemical properties (by DSC and FT-IR), external and internal morphology (by SEM, CLSM and Raman mapping). Solid free-flowing spherical particles (main size range 200–355 µm) with different architectures were successfully produced: microemulsions led to the formation of particles with a homogeneous internal structure, while coarse emulsions generated “multicores-shell” particles consisting of variable size hydrophilic cores evenly distributed within the crystalline lipid phase. Depending on their composition and structure, b-MPs could achieve various release profiles, representing a more versatile system than microparticles based on a single lipid phase. The formulation and technological strategy proposed, provides a feasible and cost-effective way of fabricating b-MPs with tunable internal structure and release behavior.

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.

Bioavailability of a Capsaicin Lipid Multi-particulate Formulation in Rats

Background and Objective

Because of the stomach-burning sensation it induces, capsaicin has been used at relatively low doses as a nutritional supplement, which has limited its bioavailability. The objective of this study was to investigate the serum bioavailability of capsaicin supplementation with or without a lipid multi-particulate (LMP) formulation.

Methods

Thirty-five rats were divided into five groups and administered capsaicin at either 0.2 or 1 mg/kg with or without the LMP formulation. Capsaicin bioavailability was assessed based on the area under the concentation–time curve (AUC), the time to peak concentration (T_max), and the peak serum concentration (C_max).

Results

For each formulation, the capsaicin C_max was reached at 90 min and decreased thereafter. Serum capsaicin concentrations were greater in rats administered the higher dose of capsaicin (1 mg/kg) in the LMP formulation at all measurement times (P  ≤ 0.05). The AUC showed a significant increase, about 20%, when capsaicin was administered in the LMP formulation at the high dose (P  = 0.002). The T_max for oral capsaicin was similar whether or not administration was via the LMP formulation (P  = 0.163). However, the C_max of capsaicin increased in a dose-dependent manner (P  < 0.05). Although the LMP formulation of the high dose of capsaicin resulted in a numerically higher C_max, it was not statistically significantly higher (P  = 0.068).

Conclusions

The present work demonstrated that administration of capsaicin via the LMP formulation significantly impacted the pharmacokinetic parameters and the serum bioavailability of orally administered 1 mg/kg capsaicin in rats. The bioavailability of capsaicin in humans may also be increased by using the LMP formulation.

Challenges in Oral Drug Delivery and Applications of Lipid Nanoparticles as Potent Oral Drug Carriers for Managing Cardiovascular Risk Factors

BACKGROUND

The oral application of drugs is the most popular route through which the systemic effect can be achieved. Nevertheless, oral administration is limited by difficulties related to the physicochemical properties of the drug molecule, including low aqueous solubility, instability, low permeability, and rapid metabolism, all of which result in low and irregular oral bioavailability.

OBJECTIVE

The enhancement of oral bioavailability of drug molecules with such properties could lead to extreme complications in drug preparations. Oral lipid-based nanoparticles seem to possess extensive advantages due to their ability to increase the solubility, simplifying intestinal absorption and decrease or eradicate the effect of food on the absorption of low soluble, lipophilic drugs and therefore improving the oral bioavailability.

METHODS

The present review provides a summary of the general theory of lipid-based nanoparticles, their preparation methods, as well as their oral applications. Moreover, oral drug delivery challenges are discussed.

RESULTS

According to this review, the most frequent types of lipid-based nanoparticle, the solid lipid nanoparticles and nanostructured lipid carriers are potent oral carriers due to their ability to penetrate the oral drug adsorption barriers. Moreover, such lipid nanoparticles can be beneficial drug carriers against cardiovascular risk disorders as diabetes, hypertension, etc. Conclusion: In this review, the most current and promising studies involving Solid Lipid Nanoparticles and Nanostructured Lipid Carriers as oral drug carriers are reported aiming to assist researchers who focus their research on lipid-based nanoparticles.

Twin-Screw Melt Granulation for Oral Solid Pharmaceutical Products

This article highlights the advantages of pharmaceutical continuous melt granulation by twin-screw extrusion. The different melt granulation process options and excipients are described and compared, and a case is made for expanded use of twin-screw melt granulation since it is a flexible and continuous process. Methods for binder selection are profiled with a focus on rheology and physical stability impacts. For twin-screw melt granulation, the mechanism of granulation and process impact on granule properties are described. Pharmaceutical applications of melt granulation ranging from immediate release of soluble and insoluble APIs, taste-masking, and sustained release formulation are reviewed, demonstrating the range of possibilities afforded by twin-screw melt granulation.

Facile L-Glutamine delivery to erythrocytes via DOPC-DPPG mixed liposomes

Sickle cell disease (SCD) is a mortal erythrocyte-based disease which is hard to treat effectively. Development of a treatment method that can prevent deoxygenation of erythrocytes or reduce the oxidative stress of sickle erythrocytes is one of the important issues towards SCD. Among a wide variety of potential drug carriers, liposomes are advantageous and preferable with their easy preparation and biocompatibility. In this study, L-Glutamine (Gln) loaded liposomes were prepared with 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-Dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG). Liposomes were characterized via zeta potential, size measurements, differential scanning calorimetry, Fourier Transform Infra-red Spectroscopy and they were visualized via transmission electron microscopy and scanning electron microscopy. Effect of the encapsulated amount of Gln was investigated by encapsulating Gln at three different concentrations (i.e0.20 mM, 40 mM and 60 mM). Drug encapsulation and release studies were implemented with high pressure liquid chromatography (HPLC). The encapsulation efficiency of Gln was determined to be the higher than the ones reported in the literature: 83.6%, 87.1% and 84.9% for 20 mM, 40 mM and 60 mM Gln, respectively. It was found that after 6 hours, liposomes loaded with 60 mM of Gln had released 45.7% of Gln. Optical microscopy images of the erythrocytes after 3 hours of incubation and haemolysis measurements proved that presence of liposomes did not cause any structural changes on the erythrocyte shape. Overall, it was concluded that L-Gln loaded PC/PG liposomes provide promising results in terms of developing a new drug delivery platform for SCD.

Fate of β-Carotene within Loaded Delivery Systems in Food: State of Knowledge

Nanotechnology has opened new opportunities for delivering bioactive agents. Their physiochemical characteristics, i.e., small size, high surface area, unique composition, biocompatibility and biodegradability, make these nanomaterials an attractive tool for β-carotene delivery. Delivering β-carotene through nanoparticles does not only improve its bioavailability/bioaccumulation in target tissues, but also lessens its sensitivity against environmental factors during processing. Regardless of these benefits, nanocarriers have some limitations, such as variations in sensory quality, modification of the food matrix, increasing costs, as well as limited consumer acceptance and regulatory challenges. This research area has rapidly evolved, with a plethora of innovative nanoengineered materials now being in use, including micelles, nano/microemulsions, liposomes, niosomes, solidlipid nanoparticles, nanostructured lipids and nanostructured carriers. These nanodelivery systems make conventional delivery systems appear archaic and promise better solubilization, protection during processing, improved shelf-life, higher bioavailability as well as controlled and targeted release. This review provides information on the state of knowledge on β-carotene nanodelivery systems adopted for developing functional foods, depicting their classifications, compositions, preparation methods, challenges, release and absorption of β-carotene in the gastrointestinal tract (GIT) and possible risks and future prospects.

Current update on nanoplatforms as therapeutic and diagnostic tools: A review for the materials used as nanotheranostics and imaging modalities

In the last decade, the use of nanotheranostics as emerging diagnostic and therapeutic tools for various diseases, especially cancer, is held great attention. Up to date, several approaches have been employed in order to develop smart nanotheranostics, which combine bioactive targeting on specific tissues as well as diagnostic properties. The nanotheranostics can deliver therapeutic agents by concomitantly monitor the therapy response in real-time. Consequently, the possibility of over- or under-dosing is decreased. Various non-invasive imaging techniques have been used to quantitatively monitor the drug delivery processes. Radiolabeling of nanomaterials is widely used as powerful diagnostic approach on nuclear medicine imaging. In fact, various radiolabeled nanomaterials have been designed and developed for imaging tumors and other lesions due to their efficient characteristics. Inorganic nanoparticles as gold, silver, silica based nanomaterials or organic nanoparticles as polymers, carbon based nanomaterials, liposomes have been reported as multifunctional nanotheranostics. In this review, the imaging modalities according to their use in various diseases are summarized, providing special details for radiolabeling. In further, the most current nanotheranostics categorized via the used nanomaterials are also summed up. To conclude, this review can be beneficial for medical and pharmaceutical society as well as material scientists who work in the field of nanotheranostics since they can use this research as guide for producing newer and more efficient nanotheranostics.

Manufacturing drug co-loaded liposomal formulations targeting breast cancer: Influence of preparative method on liposomes characteristics and in vitro toxicity

Developing more efficient manufacturing methods for nano therapeutic systems is becoming important, not only to better control their physico-chemical characteristics and therapeutic efficacy but also to ensure scale-up is cost-effective. The principle of cross-flow chemistry allows precise control over manufacturing parameters for the fabrication of uniform liposomal formulations, as well as providing reproducible manufacturing scale-up compared to conventional methods. We have herein investigated the use of microfluidics to produce PEGylated DSPC liposomes loaded with doxorubicin and compared their performance against identical formulations prepared by the thin-film method. The isoprenylated coumarin umbelliprenin was selected as a co-therapeutic. Umbelliprenin-loaded and doxorubicin:umbelliprenin co-loaded liposomes were fabricated using the optimised microfluidic set-up. The role of umbelliprenin as lipid bilayer fluidity modulation was characterized, and we investigated its role on liposomes size, size distribution, shape and stability compared to doxorubicin-loaded liposomes. Finally, the toxicity of all liposomal formulations was tested on a panel of human breast cancer cells (MCF-7, MDA-MB 231, BT-474) to identify the most potent formulation by liposomal fabrication method and loaded compound(s). We herein show that the microfluidic system is an alternative method to produce doxorubicin:umbelliprenin co-loaded liposomes, allowing fine control over liposome size (100-250 nm), shape, uniformity and doxorubicin drug loading (>80%). Umbelliprenin was shown to confer fluidity to model lipid biomembranes, which helps to explain the more homogeneous size and shape of co-loaded liposomes compared to liposomes without umbelliprenin. The toxicity of doxorubicin:umbelliprenin co-loaded liposomes was lower than that of free doxorubicin, due to the delayed release of doxorubicin from liposomes. An alternative, rapid and easy manufacturing method for the production of liposomes has been established using microfluidics to effectively produce uniform doxorubicin:umbelliprenin co-loaded liposomal formulations with proven cytotoxicity in human breast cancer cell lines in vitro.

Oral delivery of natural compounds by phospholipid vesicles

The purpose of this report is to summarize and critically analyze emerging trends in phospholipid vesicles for the oral delivery of natural compounds. Liposomes have long been used as delivery systems, thanks to their ability to incorporate diverse bioactives, their biocompatibility and safety. However, the efficacy of oral liposomes is hampered by their low stability under the harsh conditions of the gastrointestinal tract. Different approaches have been utilized with the aim of improving the stability of liposomes and the payload after oral administration. This report provides an overview on the phospholipid vesicles used for oral delivery of natural compounds, exploring the current strategies to improve their performance by modifying the lipid bilayer composition and assembly or the physical state.

Enhancing the oral bioavailability of simvastatin with silica-lipid hybrid particles: The effect of supersaturation and silica geometry

Silica-lipid hybrid (SLH) microparticles are a solidified lipid-based drug delivery system under investigation for their aptitude to enhance the oral bioavailability of poorly water-soluble drugs. The cholesterol-lowering agent, simvastatin (SIM), is poorly water-soluble and undergoes extensive first pass metabolism, resulting in a low oral bioavailability of approximately 5%. Hence, the current pre-clinical studies investigated the application of SLH technology to SIM with a supersaturation approach, aiming to enhance bioavailability and drug loading capacity. Additionally, the effect of silica was explored by evaluating the performance of SLH fabricated with silica of different particle geometries. SLH microparticles with supersaturated SIM loading levels ranging from 100% to 400% above the equilibrium solubility were successfully fabricated using either Aerosil® 300 or Syloid® 244 silica. All SLH formulations existed as white free-flowing powders, consisting of spherical porous microparticles for Aerosil® 300, and aggregated irregular microparticles for Syloid® 244. During in vitro dissolution in pH 7.0 media, the SLH formulations performed up to 4.4-fold greater than pure SIM powder. Furthermore, in vivo oral pharmacokinetics in male Sprague-Dawley rats revealed that the SLH formulations enhanced the oral bioavailability of SIM up to 6.1-fold and 2.9-fold, in comparison to pure SIM powder and a commercially available formulation (Simvastatin Sandoz®), respectively. The greatest in vivo performance enhancement was observed for the SLH formulation manufactured with Syloid® 244 silica with a supersaturation level of 200%. SLH technology demonstrated to be a successful formulation strategy to significantly improve the oral bioavailability of SIM in rodents and therefore, has a strong potential to also improve the oral bioavailability of SIM in humans.

Lipid-Based Nanosystem As Intelligent Carriers for Versatile Drug Delivery Applications

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The contemporary drug discovery research shows that most of the drug candidates are highly potent, but showing poor aqueous solubility leads a variety of challenges for formulation scientists to develop a suitable formulation to improve the systemic bioavailability of such drugs. Lipid-based nanocarriers act as a major and most projecting approach overcoming the limitations which affect several physiochemical properties of drug such as the solubility, partition coefficient and bioavailability or absorption. This also fulfills a variety of product requirements and helps to overcome several limitations as decided by symptoms of the disease, various routes of administration of drug, price concern, increasing strength of product, noxious or harmful effect of drug, and dose efficacy. The lipidic nanosystem formulates aqueous drug in lipid base and is also a commercially feasible approach for the formulation of different dosage forms meant for topical or transdermal, oral, ocular, pulmonary, and parenteral delivery. This review provides a brief on lipid-based drug delivery nanocarrier and the mechanisms by which lipids and lipidic excipients improve the oral absorption of drugs with poor aqueous solubility and also provide a viewpoint on the promising applications of lipidic nanoparticulate systems.

Conditioned food aversion in domestic dogs induced by thiram

BACKGROUND

The conflict between predators and humans for resources such as game species or livestock is an ancient issue, and it is especially sharp in the case of medium-large wild canids. In order to manage this conflict, lethal control methods are often used, which can sometimes be illegal, such as poisoning. As an alternative, conditioned food aversion (CFA) is a non-lethal method to reduce predation in which animals learn to avoid a given food due to the adverse effects caused by the ingestion of an undetectable chemical compound added to this food. The present study aimed to test thiram as a CFA agent in penned dogs as a first approach to use this substance for reducing the predation conflict associated with wild canids.

RESULTS

Thiram, with or without an additional odor cue, produced CFA in penned dogs for more than 2 months. Moreover, thiram seemed to be undetectable and safe after the third ingestion of a 40-60 mg kg^-1 dose. Desirable adverse effects, such as vomits, appeared around 1 h after exposure. These characteristics make thiram optimal for its use in predation reduction through CFA. However, individual variability could prevent CFA acquisition by some animals.

CONCLUSIONS

Thiram has the potential to be used as a CFA agent in wildlife management and conservation to reduce predation by wild canids. Since thiram produced CFA without the problems of detectability and toxicity caused by other substances, it may be an alternative to lethal control methods used to reduce predation on game, livestock and endangered species. © 2019 Society of Chemical Industry.

Selection of new chemicals to be used in conditioned aversion for non-lethal predation control

Globally, native predators and scavengers are threatened through the incidence of illegal poisoning due to increasing human-wildlife conflicts. The use of conditioned taste aversion (CTA) may mitigate such conflicts. CTA is a robust learning paradigm that occurs when animals associate a food with a discomfort induced by a chemical, thereby avoiding that food in subsequent encounters. We reviewed the potential of 167 chemical compounds to be used in CTA, considering effects, margin of safety, accessibility, and detectability. After the review, 15 compounds fulfilled the required characteristics, but only five (thiabendazole, thiram, levamisole, fluconazole and fluralaner) were finally selected to be tested in CTA assays with dogs. Of the tested compounds, thiabendazole, thiram and levamisole caused target food rejection by dogs and reduced the time spent eating during post-conditioning. However, despite being microencapsulated, levamisole appeared to be detectable by dogs, whereas thiram and thiabendazole were not. Fluconazole and fluralaner did not produce any CTA effect. Thiabendazole, thiram and levamisole can therefore induce CTA, and thus are potential candidates as aversive compounds for wildlife management. Thiram is an undetectable, relatively safe and accessible compound that can induce CTA in canids, and opens new possibilities to develop methods of non-lethal predation control.

Bridging the gaps between academic research and industrial product developments of lipid-based formulations

Lipid-based formulations, including self-emulsifying drug delivery systems (SEDDS), are an interesting formulation technology that enables the clinical use of compounds for which a low aqueous solubility may be a limitation. From an academic perspective, the technology is interesting on several levels: what drives solubility, what determines bioperformance, what is the potential for solidification etc. From an industrial perspective, >35 lipid-based formulations are available and there is an unknown number of projects in the pipeline. Hence, while there is scientific interest from both academic and industrial perspectives, the agendas/needs in the two settings are different. From an industrial perspective, risks are associated with uncertainty; hence the more that is known about a technology the better - knowledge that in principle can be generated in both the academia and industry. This focuses on the development of lipid-based formulations and the knowledge gaps that could be investigated -with the hope that all stakeholders in the field of lipid-based formulations, including academia, industry, CRO's, lipid excipient manufacturers etc., would share their insight, so that this technology can be even further developed. Some of the gaps discussed include the selection of compounds suited for lipid-based formulations, which potential modifications that could be investigated, e.g., lipophilic salts, what is a relevant definition of accelerated stability studies, how best to construct an industrial development program of a lipid-based formulation, etc.

Adapting liposomes for oral drug delivery

Liposomes mimic natural cell membranes and have long been investigated as drug carriers due to excellent entrapment capacity, biocompatibility and safety. Despite the success of parenteral liposomes, oral delivery of liposomes is impeded by various barriers such as instability in the gastrointestinal tract, difficulties in crossing biomembranes, and mass production problems. By modulating the compositions of the lipid bilayers and adding polymers or ligands, both the stability and permeability of liposomes can be greatly improved for oral drug delivery. This review provides an overview of the challenges and current approaches toward the oral delivery of liposomes.

Solubilisation behaviour of poorly water-soluble drugs during digestion of solid SMEDDS

Lipid based-formulations can enhance the bioavailability of poorly water-soluble lipophilic drugs through enhanced solubilisation of drugs in the gastrointestinal (GI) tract during digestion. This study investigates the solubilisation behaviour of poorly water-soluble drugs upon digestion of solid self-microemulsifying drug delivery system (S-SMEDDS). The S-SMEDDS were prepared using two different core lipids, Gelucire® 44/14 (GEL) or glyceryl monooleate (GMO), and were loaded with two model drugs, fenofibrate (FEN) and cinnarizine (CINN). S-SMEDDS formulations were characterized using wide-angle X-ray scattering (WAXS) and Raman spectroscopy, and their structural behaviour and drug solubilisation behaviour were monitored using drug-related diffraction peaks during digestion under fasted and fed simulated intestinal conditions using time-resolved small and wide-angle X-ray scattering (SAXS/WAXS). The concentrations of FEN and CINN released into the aqueous phase (AP) during digestion were quantified using high-performance liquid chromatography (HPLC). Both model drugs, FEN and CINN, had greater solubility in the GMO-based S-SMEDDS formulations and were partially solubilised into lipid matrix and uniformly distributed in solid formulations. The extent of digestion was greater for the GEL-based systems (92-94%) than GMO-based systems (65-75%) as was the rate of digestion. GEL-based S-SMEDDS formulations formed a lamellar phase during digestion in the fasted state and formed mixed micelles in the fed state. In contrast, the GMO-based system formed the mixed micelles in both intestinal conditions. The time-resolved SAXS profiles revealed solubilisation of crystalline drugs into the lipolysis products. Synchrotron SAXS results were in correlation with the HPLC measurements, confirming the ability of the SAXS technique to monitor drug behaviour and showing that the digestion of S-SMEDDS can enhance drug solubilisation.

Lipids bearing extruded-spheronized pellets for extended release of poorly soluble antiemetic agent-Meclizine HCl

BACKGROUND

Antiemetic agent Meclizine HCl, widely prescribed in vertigo, is available only in immediate release dosage forms. The approved therapeutic dose and shorter elimination half-life make Meclizine HCl a potential candidate to be formulated in extended release dosage form. This study was aimed to develop extended release Meclizine HCl pellets by extrusion spheronization using natural and synthetic lipids. Influence of lipid type, drug/lipid ratio and combinations of different lipids on drug release and sphericity of pellets were evaluated.

METHODS

Thirty two formulations were prepared with four different lipids, Glyceryl monostearate (Geleol^®), Glyceryl palmitostearate (Precirol^®), Glyceryl behenate (Compritol^®) and Carnauba wax, utilized either alone or in combinations of drug/lipid ratio of 1:0.5-1:3. Dissolution studies were performed at variable pH and release kinetics were analyzed. Fourier transform infrared spectroscopy was conducted and no drug lipid interaction was found.

RESULTS

Sphericity indicated by shape factor (e_R) varied with type and concentration of lipids: Geleol^® (e_R = 0.891-0.997), Precirol^® (e_R = 0.611-0.743), Compritol^® (e_R = 0.665-0.729) and Carnauba wax (e_R = 0.499-0.551). Highly spherical pellets were obtained with Geleol^® (Aspect ratio = 1.005-1.052) whereas irregularly shaped pellets were formed using Carnauba wax (Aspect ratio = 1.153-1.309). Drug release was effectively controlled by three different combinations of lipids: (i) Geleol^® and Compritol^®, (ii) Geleol^® and Carnauba wax and (iii) Geleol^®, Compritol^® and Carnauba wax. Scanning electron microscopy of Compritol^® pellets showed smooth surface with pores, whereas, irregular rough surface with hollow depressions was observed in Carnauba wax pellets. Energy dispersive spectroscopy indicated elemental composition of lipid matrix pellets. Kinetics of (i) Geleol^® and Compritol^® pellets, explained by Korsmeyer-Peppas (R² = 0.978-0.993) indicated non-Fickian diffusion (n = 0.519-0.597). Combinations of (ii) Geleol^® and Carnauba wax and (iii) Geleol^®, Compritol^® and Carnauba wax pellets followed Zero-order (R² = 0.991-0.995). Similarity test was performed using combination of Geleol^® and Compritol^® (i) as a reference.

CONCLUSIONS

Matrices for the extended release of Meclizine HCl from extruded-spheronized pellets were successfully formed by using three lipids (Geleol^®, Compritol^® and Carnauba wax) in different combinations. The encapsulated pellets of Meclizine HCl can be effectively used for treatment of motion sickness, nausea and vertigo for extended period of time.

Surface Modified Multifunctional and Stimuli Responsive Nanoparticles for Drug Targeting: Current Status and Uses

Nanocarriers, due to their unique features, are of increased interest among researchers working with pharmaceutical formulations. Polymeric nanoparticles and nanocapsules, involving non-toxic biodegradable polymers, liposomes, solid lipid nanoparticles, and inorganic-organic nanomaterials, are among the most used carriers for drugs for a broad spectrum of targeted diseases. In fact, oral, injectable, transdermal-dermal and ocular formulations mainly consist of the aforementioned nanomaterials demonstrating promising characteristics such as long circulation, specific targeting, high drug loading capacity, enhanced intracellular penetration, and so on. Over the last decade, huge advances in the development of novel, safer and less toxic nanocarriers with amended properties have been made. In addition, multifunctional nanocarriers combining chemical substances, vitamins and peptides via coupling chemistry, inorganic particles coated by biocompatible materials seem to play a key role considering that functionalization can enhance characteristics such as biocompatibility, targetability, environmental friendliness, and intracellular penetration while also have limited side effects. This review aims to summarize the "state of the art" of drug delivery carriers in nanosize, paying attention to their surface functionalization with ligands and other small or polymeric compounds so as to upgrade active and passive targeting, different release patterns as well as cell targeting and stimuli responsibility. Lastly, future aspects and potential uses of nanoparticulated drug systems are outlined.

Enhancement of the aqueous solubility and permeability of a poorly water soluble drug ritonavir via lyophilized milk-based solid dispersions

In the present study, a lyophilized milk-based solid dispersion (SD) of ritonavir (RTV) was developed with the goal of improving its aqueous solubility. The SD was prepared by lyophilization, and characterized for its physicochemical and functional properties. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photomicroscopy and powder X-ray diffraction (PXRD) were used to confirm the formation and robustness of the SD formulation. The prepared SD formulations were functionally evaluated by saturation solubility, in vitro drug release and ex vivo permeation studies. The optimized SD formulation exhibited a significantly higher (30-fold) aqueous solubility (11.36 ± 0.06 μg/mL), compared to the pure RTV (0.37 ± 0.03 μg/mL). The in vitro dissolution studies revealed a significantly higher (∼10-fold) efficiency of the optimized SD formulation in releasing the RTV, compared to the pure RTV. The ex vivo permeation studies with the everted intestine method showed that prepared SD formulation significantly improved the permeation of RTV (75.6 ± 3.09, % w/w), compared to pure RTV (20.45 ± 1.68, % w/w). Thus, SD formulation utilizing lyophilized milk as a carrier appears to be a promising alternative strategy to improve the aqueous solubility of poorly water soluble drugs.

50years of oral lipid-based formulations: Provenance, progress and future perspectives

Lipid based formulations (LBF) provide well proven opportunities to enhance the oral absorption of drugs and drug candidates that sit close to, or beyond, the boundaries of Lipinski's 'rule-of-five' chemical space. Advantages in permeability, efflux and presystemic metabolism are evident; however, the primary benefit is in increases in dissolution and apparent intestinal solubility for lipophilic, poorly water soluble drugs. This review firstly details the inherent advantages of LBF, their general properties and classification, and provides a brief retrospective assessment of the development of LBF over the past fifty years. More detailed analysis of the ability of LBF to promote intestinal solubilisation, supersaturation and absorption is then provided alongside review of the methods employed to assess formulation performance. Critical review of the ability of simple dispersion and more complex in vitro digestion methods to predict formulation performance subsequently reveals marked differences in the correlative ability of in vitro tests, depending on the properties of the drug involved. Notably, for highly permeable low melting drugs e.g. fenofibrate, LBF appear to provide significant benefit in all cases, and sustained ongoing solubilisation may not be required. In other cases, and particularly for higher melting point drugs such as danazol, where re-dissolution of crystalline precipitate drug is likely to be slow, correlations with ongoing solubilisation and supersaturation are more evident. In spite of their potential benefits, one limitation to broader use of LBF is low drug solubility in the excipients employed to generate formulations. Techniques to increase drug lipophilicity and lipid solubility are therefore explored, and in particular those methods that provide for temporary enhancement including lipophilic ionic liquid and prodrug technologies. The transient nature of these lipophilicity increases enhances lipid solubility and LBF viability, but precludes enduring effects on receptor promiscuity and off target toxicity. Finally, recent efforts to generate solid LBF are briefly described as a means to circumvent the need to encapsulate in soft or hard gelatin capsules, although the latter remain popular with consumers and a proven means of LBF delivery.

Polymer-lipid hybrid systems: merging the benefits of polymeric and lipid-based nanocarriers to improve oral drug delivery

INTRODUCTION

A number of biobarriers limit efficient oral drug absorption; both polymer-based and lipid-based nanocarriers have demonstrated properties and delivery mechanisms to overcome these biobarriers in preclinical settings. Moreover, in order to address the multifaceted oral drug delivery challenges, polymer-lipid hybrid systems are now being designed to merge the beneficial features of both polymeric and lipid-based nanocarriers.

AREAS COVERED

Recent advances in the development of polymer-lipid hybrids with a specific focus on their viability in oral delivery are reviewed. Three classes of polymer-lipid hybrids have been identified, i.e. lipid-core polymer-shell systems, polymer-core lipid-shell systems, and matrix-type polymer-lipid hybrids. We focus on their application to overcome the various biological barriers to oral drug absorption, as exemplified by selected preclinical studies.

EXPERT OPINION

Numerous studies have demonstrated the superiority of polymer-lipid hybrid systems to their non-hybrid counterparts in providing improved drug encapsulation, modulated drug release, and improved cellular uptake. These features have encouraged their applications in the delivery of chemotherapeutics, proteins, peptides, and vaccines. With further research expected to optimize the manufacturing and scaling up processes and in-depth pre-clinical pharmacological and toxicological assessments, these multifaceted drug delivery systems will have significant clinical impact on the oral delivery of pharmaceuticals and biopharmaceuticals.

Revealing facts behind spray dried solid dispersion technology used for solubility enhancement

Poor solubility and bioavailability of an existing or newly synthesized drug always pose challenge in the development of efficient pharmaceutical formulation. Numerous technologies can be used to improve the solubility and among them amorphous solid dispersion based spray drying technology can be successfully useful for development of product from lab scale to commercial scale with a wide range of powder characteristics. Current review deals with the importance of spray drying technology in drug delivery, basically for solubility and bioavailability enhancement. Role of additives, selection of polymer, effect of process and formulation parameters, scale up optimization, and IVIVC have been covered to gain the interest of readers about the technology. Design of experiment (DoE) to optimize the spray drying process has been covered in the review. A lot more research work is required to evaluate spray drying as a technology for screening the right polymer for solid dispersion, especially to overcome the issue related to drug re-crystallization and to achieve a stable product both in vitro and in vivo. Based on the recent FDA recommendation, the need of the hour is also to adopt Quality by Design approach in the manufacturing process to carefully optimize the spray drying technology for its smooth transfer from lab scale to commercial scale.

Solvent-free melting techniques for the preparation of lipid-based solid oral formulations

Lipid excipients are applied for numerous purposes such as taste masking, controlled release, improvement of swallowability and moisture protection. Several melting techniques have evolved in the last decades. Common examples are melt coating, melt granulation and melt extrusion. The required equipment ranges from ordinary glass beakers for lab scale up to large machines such as fluid bed coaters, spray dryers or extruders. This allows for upscaling to pilot or production scale. Solvent free melt processing provides a cost-effective, time-saving and eco-friendly method for the food and pharmaceutical industries. This review intends to give a critical overview of the published literature on experiences, formulations and challenges and to show possibilities for future developments in this promising field. Moreover, it should serve as a guide for selecting the best excipients and manufacturing techniques for the development of a product with specific properties using solvent free melt processing.

A perspective overview on lipospheres as lipid carrier systems

Both hydrophilic and lipophilic therapeutics can be delivered successfully into deep and peripheral tissues such as cerebrospinal fluid and central nervous system by encapsulating them with crystalline lipids as lipospheres. The advent of lipospheres was meant to deliver both therapeutic moieties with enhanced efficacy and added stability to reach out intended tissue areas. Although extensive information is available on physicochemical, analytical and biopharmaceutical aspects of lipospheres, there was no specific order pertaining to critical composition and rationale of component selection available for academic and pilot scale processing of lipospheres. With the interest of compiling key points in a typical formulation of lipid lipospheres, this article was intrigued to discuss melt method, co-solvent, microemulsion, super critical fluid, spray drying and spray congealing techniques that were employed to scale up lipospheres. The selection criteria for both the drugs and lipids in liposphere formulations were demonstrated here. The quality assessment with variables like loading capacity and entrapment efficiency was explained. A note on preliminary screening factors to determine the liposphere formation such as liposphere dimensions with morphological scenario was detailed in this article. This article also includes the stability and storage issues with reference to photolysis. The marked differential in enhancing solubility and permeability characteristics of Class II and IV drug candidates by liposphere delivery systems with an evident of in vivo outcomes were emphasized.

Insights on novel particulate self-assembled drug delivery beads based on partial inclusion complexes between triglycerides and cyclodextrins

Most of the newly designed drug molecules are lipophilic in nature and often encounter erratic absorption and low bioavailability after oral administration. Finding ways to enhance the absorption and bioavailability of these lipophilic drugs is one of the major challenges that face pharmaceutical industry nowadays. In view of that, the purpose of this review is to shed some light on a novel particulate self-assembling system named "beads" than can act as a safe carrier for delivering lipophilic drugs. The beads are prepared simply by mixing oils with cyclodextrin (CD) aqueous solution in mild conditions. A unique interaction between oil components and CD molecules occurs to form in situ surface-active complexes which are prerequisites for beads formation. This review mainly focuses on the fundamentals of beads preparation through reviewing present, yet scarce, literature. The key methods used for beads characterization are discussed in details. Also, the potential mechanisms by which beads increase the bioavailability of lipophilic drugs are illustrated. Finally, the related research areas that needs to be addressed in future for optimizing this promising delivery system are briefly outlined.

Liposomes coated with thiolated chitosan enhance oral peptide delivery to rats

The aim of the present study was the in vivo evaluation of thiomer-coated liposomes for an oral application of peptides. For this purpose, salmon calcitonin was chosen as a model drug and encapsulated within liposomes. Subsequently, the drug loaded liposomes were coated with either chitosan-thioglycolic acid (CS-TGA) or an S-protected version of the same polymer (CS-TGA-MNA), leading to an increase in the particle size of about 500 nm and an increase in the zeta potential from approximately -40 mV to a maximum value of about +44 mV, depending on the polymer. Coated liposomes were demonstrated to effectively penetrate the intestinal mucus layer where they came in close contact with the underlying epithelium. To investigate the permeation enhancing properties of the coated liposomes ex vivo, we monitored the transport of fluoresceinisothiocyanate-labeled salmon calcitonin (FITC-sCT) through rat small intestine. Liposomes coated with CS-TGA-MNA showed the highest effect, leading to a 3.8-fold increase in the uptake of FITC-sCT versus the buffer control. In vivo evaluation of the different formulations was carried out by the oral application of 40 μg of sCT per rat, either encapsulated within uncoated liposomes, CS-TGA-coated liposomes or CS-TGA-MNA-coated liposomes, or given as a solution serving as negative control. The blood calcium level was monitored over a time period of 24h. The highest reduction in the blood calcium level, to a minimum of 65% of the initial value after 6h, was achieved for CS-TGA-MNA-coated liposomes. Comparing the areas above curves (AAC) of the blood calcium levels, CS-TGA-MNA-coated liposomes led to an 8.2-fold increase compared to the free sCT solution if applied orally in the same concentration. According to these results, liposomes coated with S-protected thiomers have demonstrated to be highly valuable carriers for enhancing the oral bioavailability of salmon calcitonin.

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.

Evaluation of in vivo behavior of controlled and pulsatile release pastilles using pharmacokinetic and γ-scintigraphic techniques

OBJECTIVE

To evaluate the in vivo behavior of controlled and pulsatile release pastilles for chronic treatment of asthma and chronic obstructive pulmonary disease (COPD) and for the chronotherapeutic management of nocturnal asthma, respectively.

RESEARCH DESIGN & METHODS

The prepared immediate release and controlled release pastilles were subjected to in vivo pharmacokinetic studies in rats. Whereas, pulsatile release formulation was subjected to γ-scintigraphic study in rats to study the gastrointestinal transit of the formulations and its results were correlated with the previous pharmacokinetic data.

RESULTS

The in vivo pharmacokinetic study of controlled release pastille formulation showed significant decrease in C(max) with increase in t(max), which indicates that the effect of dosage form would last for longer duration. Thus, the prepared formulation can be useful for the chronic treatment of asthma and COPD. The γ-scintigraphic study and pharmacokinetic data indicated that the pastilles coated with the enteric coat and the additional floating coat were effective in significantly delaying the in vivo drug release (by 4-5 h) required for the chronotherapeutic treatment of nocturnal asthma.

CONCLUSION

This study opens a new alternative to the conventional tablet or capsule dosage form for the development of both immediate and modified release drug delivery systems.

An overview of the analytical characterization of nanostructured drug delivery systems: towards green and sustainable pharmaceuticals: a review

The analytical characterization of drug delivery systems prepared by means of green manufacturing technologies using CO(2) as a processing fluid is here reviewed. The assessment of the performance of nanopharmaceuticals designed for controlled drug release may result in a complex analytical issue and multidisciplinary studies focused on the evaluation of physicochemical, morphological and textural properties of the products may be required. The determination of the drug content as well as the detection of impurities and solvent residues are often carried out by chromatography. Assays on solid state samples relying on X-ray, vibrational and nuclear magnetic resonance spectroscopies are of great interests to study the composition and structure of pharmaceutical forms. The morphology and size of particles are commonly checked by microscopy and complementary chemical information can be extracted in combination with spectroscopic accessories. Regarding the thermal behavior, calorimetric and thermogravimetric techniques are applied to assess the thermal transitions and stability of the samples. The evaluation of drug release profiles from the nanopharmaceuticals can be based on various experimental set-ups depending on the administration route to be considered. Kinetic curves showing the evolution of the drug concentration as a function of time in various physiological conditions (e.g., gastric, plasmatic or topical) are recorded commonly by UV-vis spectroscopy and/or chromatography. Representative examples are commented in detail to illustrate the characterization strategies.