The influence of viscosity of hydrogels on the spreading and migration of cells in 3D bioprinted skin cancer models.

Various in vitro three-dimensional (3D) tissue culture models of human and diseased skin exist. Nevertheless, there is still room for the development and improvement of 3D bioprinted skin cancer models. The need for reproducible bioprinting methods, cell samples, biomaterial inks, and bioinks is becoming increasingly important. The influence of the viscosity of hydrogels on the spreading and migration of most types of cancer cells is well studied. There are however limited studies on the influence of viscosity on the spreading and migration of cells in 3D bioprinted skin cancer models. In this review, we will outline the importance of studying the various types of skin cancers by using 3D cell culture models. We will provide an overview of the advantages and disadvantages of the various 3D bioprinting technologies. We will emphasize how the viscosity of hydrogels relates to the spreading and migration of cancer cells. Lastly, we will give an overview of the specific studies on cell migration and spreading in 3D bioprinted skin cancer models.

Immunogenic profile of a plant-produced nonavalent African horse sickness viral protein 2 (VP2) vaccine in IFNAR-/- mice.

A safe, highly immunogenic multivalent vaccine to protect against all nine serotypes of African horse sickness virus (AHSV), will revolutionise the AHS vaccine industry in endemic countries and beyond. Plant-produced AHS virus-like particles (VLPs) and soluble viral protein 2 (VP2) vaccine candidates were developed that have the potential to protect against all nine serotypes but can equally well be formulated as mono- and bi-valent formulations for localised outbreaks of specific serotypes. In the first interferon α/ß receptor knock-out (IFNAR-/-) mice trial conducted, a nine-serotype (nonavalent) vaccine administered as two pentavalent (5 µg per serotype) vaccines (VLP/VP2 combination or exclusively VP2), were directly compared to the commercially available AHS live attenuated vaccine. In a follow up trial, mice were vaccinated with an adjuvanted nine-serotype multivalent VP2 vaccine in a prime boost strategy and resulted in the desired neutralising antibody titres of 1:320, previously demonstrated to confer protective immunity in IFNAR-/- mice. In addition, the plant-produced VP2 vaccine performed favourably when compared to the commercial vaccine. Here we provide compelling data for a nonavalent VP2-based vaccine candidate, with the VP2 from each serotype being antigenically distinguishable based on LC-MS/MS and ELISA data. This is the first preclinical trial demonstrating the ability of an adjuvanted nonavalent cocktail of soluble, plant-expressed AHS VP2 proteins administered in a prime-boost strategy eliciting high antibody titres against all 9 AHSV serotypes. Furthermore, elevated T helper cells 2 (Th2) and Th1, indicative of humoral and cell-mediated memory T cell immune responses, respectively, were detected in mouse serum collected 14 days after the multivalent prime-boost vaccination. Both Th2 and Th1 may play a role to confer protective immunity. These preclinical immunogenicity studies paved the way to test the safety and protective efficacy of the plant-produced nonavalent VP2 vaccine candidate in the target animals, horses.

Flow cytometry as an analytical method of drug-induced apoptosis in 3D bioprinted melanoma cells.

Three-dimensional (3D) cell culture systems have gained increasing interest in drug discovery and tissue engineering due to its inherent advantages in providing more physiologically relevant information and more predictive data forin vivotests. Along with the development of more physiologically relevant 3D cell culture models, researchers bear the responsibility to validate new cell assay techniques capable of measuring and evaluating constructs that are physically larger and more complex compared to two-dimensional cell cultures. It is important to note that assays based on monolayer cultures may be insufficient for the use in 3D cell cultures models. In this study we firstly fabricated a 3D bioprinted hydrogel melanoma scaffold. This was used to validate a flow cytometry-based analytical method as a tool for 3D bioprinted structures to assess drug-induced apoptosis. The results indicated high robustness, reproducibility and sensitivity of the flow cytometric method established on the 3D cell-laden A375 melanoma hydrogel scaffolds. Over and above this, it was possible to determine the effect of etoposide on A375 melanoma cells using Annexin V and propidium iodide apoptosis assay.

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.

Investigating In Vitro and Ex Vivo Properties of Artemether/Lumefantrine Double-Fixed Dose Combination Lipid Matrix Tablets Prepared by Hot Fusion.

Highly lipophilic antimalarial drugs, artemether and lumefantrine, whilst an effective fixed-dose combination treatment to lower the malarial disease burden, are therapeutically hindered by low aqueous solubility and varied bioavailability. This work investigates the plausibility of directly compressed lipid matrix tablets, their role as lipid-based formulations and their future standing as drug delivery systems. Lipid matrix tablets were manufactured from solid lipid dispersions in various lipid:drug ratios employing hot fusion-the melt mixing of highly lipophilic drugs with polymer(s). Sequential biorelevant dissolution media, multiple mathematical models and ex vivo analysis utilizing porcine tissue samples were employed to assess drug release kinetics and more accurately predict in vitro performance. Directly compressed stearic acid tablets in a 0.5:1 lipid:drug ratio were deemed optimal within investigated parameters. Biorelevant media was of immense value for artemether release analysis, with formulation SA0.5C1 (Stearic Acid:double fixed dose in a 0.5:1 ratio (i.e., Stearic acid 70 mg + Lumefantrine 120 mg + Artemether 20 mg); CombiLac® as filler (q.s.); and 1% w/w magnesium stearate) yielding a higher percentage of artemether release (97.21%) than the commercially available product, Coartem® (86.12%). However, dissolution media lacked the specificity to detect lumefantrine. Nonetheless, stearic acid lipid:drug ratios governed drug release mechanisms. This work demonstrates the successful utilization of lipids as pharmaceutical excipients, particularly in the formulation of lipid matrix tablets to augment the dissolution of highly lipophilic drugs, and could thus potentially improve current malarial treatment regimens.

Development and characterization of nano-emulsions and nano-emulgels for transdermal delivery of statins.

BACKGROUND: Oral administration of statins for the treatment of familial hypercholesterolemia results in poor therapeutic outcomes and patient compliance. An alternative administration route is proposed to circumvent the current limitations. This research is aimed at developing nano-emulsions and nano-emulgels as the ultimate potential delivery systems of statins for administration via the transdermal route. METHODS: Oil-in-water (o/w) nano-formulations (nano-emulsions and nano-emulgels) containing 2% (w/w) of the selected statin and 8% apricot kernel oil as oil phase were formulated. The nano-formulations were characterized using transmission electron microscopy (TEM), pH, viscosity, droplet size and zeta-potential. RESULTS: Nano-emulsions' and nano-emulgels' droplet size ranged between 114.23-169.83 nm and 149.83-267.53 nm, respectively. The addition of Carbopol® Ultrez 20 increased the nano-emulsions' viscosity (3.59-8.38 cP) resulting in the formation of nano-emulgels (viscosity: 1911.00-46,090.00 cP). The entrapment efficiency (90.77-99.55%) confirmed the incorporation of the statins. Membrane release studies indicated that statins were released at higher flux values in nano-emulsions compared to their respective nano-emulgels. Ex vivo (skin diffusion) studies indicated higher median values in the nano-emulgels compared to their nano-emulsion counterparts. CONCLUSIONS: The results indicate the benefits of nano-emulsions and nano-emulgels as potential alternative delivery systems for the transdermal delivery of statins.

Anti-Melanoma Activities of Artemisone and Prenylated Amino-Artemisinins in Combination With Known Anticancer Drugs.

The most frequently occurring cancers are those of the skin, with melanoma being the leading cause of death due to skin cancer. Breakthroughs in chemotherapy have been achieved in certain cases, though only marginal advances have been made in treatment of metastatic melanoma. Strategies aimed at inducing redox dysregulation by use of reactive oxygen species (ROS) inducers present a promising approach to cancer chemotherapy. Here we use a rational combination of an oxidant drug combined with a redox or pro-oxidant drug to optimize the cytotoxic effect. Thus we demonstrate for the first time enhanced activity of the amino-artemisinin artemisone and novel prenylated piperazine derivatives derived from dihydroartemisinin as the oxidant component, and elesclomol-Cu(II) as the redox component, against human malignant melanoma cells A375 in vitro. The combinations caused a dose dependent decrease in cell numbers and increase in apoptosis. The results indicate that oxidant-redox drug combinations have considerable potential and warrant further investigation.

Characterization of solid lipid dispersions prepared by hot fusion containing a double-fixed dose combination of artemether and lumefantrine.

OBJECTIVE: The World Health Organization has called for the development of novel drug delivery systems to combat malaria - the fourth most prevalent cause of death globally. The plausibility of utilizing hot fusion to prepare solid lipid dispersions containing the prescribed first-line, double-fixed dose combination (artemether and lumefantrine), proposed for inclusion in directly compressed lipid matrix tablets, was investigated. Significance: Currently, no anti-malarial product is commercially available that employs lipid technology in a solid oral dosage form that contains this double-fixed dose combination. Through developing lipid matrix tablets, the stability, solubility and subsequent bioavailability of these drugs could be significantly enhanced in the presence of lipids or oils. METHODS: Hot fusion encompasses encompassed melt mixing of a selected lipid base and the dispersion of the active ingredient(s) therein below their glass transition temperatures. Solid-state characterization, particle size analysis and pharmacotechnical properties were evaluated, with particular focus given to powder flowability. RESULTS: Stearic acid in a 0.5:1 lipid:drug ratio demonstrated the best powder flow properties of the investigated solid lipid dispersion for inclusion into prospective lipid-matrix tablets duly based on an increase in overall particle size, a more spherical particle shape and improved powder flow properties compared to the individual active ingredients. CONCLUSION: Good powder flow is critical for powders destined for inclusion into tablets - especially when employing direct compression as method of manufacture - in this case, lipid matrix tablets, which have demonstrated huge promise as a prospective dosage form for future use in malarial treatment.

In-vitro cytotoxicity of various Siphonochilus aethiopicus (Schweinf.) B.L. Burtt extracts in combination with selected tableting excipients.

OBJECTIVES: To investigate the cytotoxic potential of S. aethiopicus extracts in combination with chitosan and Pharmacel® 101, on two cell lines. METHODS: Extracts were chemically characterised utilising UPLC-Q-TOF/MS, followed by determination of cell viability and membrane integrity. KEY FINDINGS: Ethanol (EtOH) and diethyl ether (DiEt) extracts contained significant quantities of all chosen biomarker molecules; however, only two were scarcely quantifiable in aqueous extracts. Aqueous extracts did not induce any cytotoxic effects, whereas EtOH and DiEt extracts caused concentration-dependent decreases in cell viability and membrane integrity loss in both cell lines. Ensuing exposure to EtOH extracts at 50, 100 and 150 µg/ml, HepG2 cells were considered 15.5%, 12.5% and 32.8% apoptotic, whereas DiEt extracts caused 4.5%, 13.5% and 33.9% apoptotic cells. Exposure to EtOH and DiEt extracts at 50 µg/ml ensued in 20.2% and 21.3% apoptosis in Caco-2 cells; 100 µg/ml induced apoptosis in 19.9% and 10.3% of Caco-2 cells; whereas exposure to 150 µg/ml EtOH extracts caused 12.6% apoptosis compared to 11.7% induced by the DiEt extract. CONCLUSIONS: None of the excipients caused any significantly altered cellular effects, indicating little chance for physicochemical interactions. Aqueous extracts did not possess any cytotoxic properties. However, it is clear that organic extracts caused apoptotic and necrotic cell death.

Antimicrobial Peptides: the Achilles' Heel of Antibiotic Resistance?

Antibiotic resistance is an imminent threat to the effective treatment of bacterial infections, and alternative antibiotic strategies are urgently required. The golden epoch of antibiotics is coming to an end, and the development of new therapeutic agents to combat bacterial infections should be prioritized. This article will review the potential of antimicrobial peptides (AMPs) to combat the threat of antimicrobial resistance. The modern-day antimicrobial resistance dilemma is briefly discussed followed by a review of the potential of AMPs to be used alone or in combination with current antibiotics in order to enhance antibacterial properties of antibiotics while also potentially combatting resistance. This article reiterates that many AMPs exhibit direct microbial killing activity and also play an integral role in the innate immune system. These properties make AMPs attractive alternative antimicrobial agents. Furthermore, AMPs are promising candidates to be used as adjuvants in combination with current antibiotics in order to combat antibiotic resistance. Combinations of AMPs and antibiotics are less likely to develop resistance or transmit cross-resistance. The further identification and therapeutic development of AMPs and antibiotic-AMP combinations are strongly recommended.

Topical Delivery of Withania somnifera Crude Extracts in Niosomes and Solid Lipid Nanoparticles.

BACKGROUND: Withania somnifera is a medicinal plant native to India and is known to have anticancer properties. It has been investigated for its anti-melanoma properties, and since melanoma presents on the skin, it is prudent to probe the use of W. somnifera in topical formulations. To enhance topical drug delivery and to allow for controlled release, the use of niosomes and solid lipid nanoparticles (SLNs) as delivery vesicles were explored. OBJECTIVE: The objective of this study is to determine the stability and topical delivery of W. somnifera crude extracts encapsulated in niosomes and SLNs. MATERIALS AND METHODS: Water, ethanol, and 50% ethanol crude extracts of W. somnifera were prepared using 24 h soxhlet extraction which were each encapsulated in niosomes and SLNs. Franz cell diffusion studies were conducted with the encapsulated extracts to determine the release and skin penetration of the phytomolecules, withaferin A, and withanolide A. RESULTS: The niosome and SLN formulations had average sizes ranging from 165.9 ± 9.4 to 304.6 ± 52.4 nm with the 50% ethanol extract formulations having the largest size. A small particle size seemed to have correlated with a low encapsulation efficiency (EE) of withaferin A, but a high EE of withanolide A. There was a significant difference (P < 0.05) between the amount of withaferin A and withanolide A that were released from each of the formulations, but only the SLN formulations managed to deliver withaferin A to the stratum corneum-epidermis and epidermis-dermis layers of the skin. CONCLUSION: SLNs and niosomes were able to encapsulate crude extracts of W. somnifera and release the marker compounds, withaferin A, and withanolide A, for delivery to certain layers in the skin. SUMMARY: Withania somnifera crude extracts were prepared using ethanol, water, and 50% ethanol as solvents. These three extracts were then incorporated into niosomes and solid lipid nanoparticles (SLNs) for use in skin diffusion studies, thus resulting in six formulations (ethanol niosome, water niosome, 50% ethanol niosome, ethanol SLN, water SLN, and 50% ethanol SLN). The diffusion of two marker compounds (withaferin A and withanolide A) from the formulations into the skin was then determined. Abbreviations used: API: Active pharmaceutical ingredient, ANOVA: Analysis of variance, ED: Epidermis-dermis, HPLC: High-performance liquid chromatography, HLB: Hydrophilic-lipophilic balance, NMR: Nuclear magnetic resonance spectroscopy, PDI: Polydispersity index, SLN: Solid lipid nanoparticle, SD: Standard deviation, SCE: Stratum corneum-epidermis, TEM: Transmission electron microscopy.

Exposure to high levels of fumarate and succinate leads to apoptotic cytotoxicity and altered global DNA methylation profiles in vitro.

In the Krebs cycle, succinate is oxidized to fumarate by succinate dehydrogenase (SDH), followed by the conversion of fumarate to malate by fumarate hydratase (FH). In cells with defective SDH and FH, the Krebs cycle is congested, respiration impaired and fumarate and succinate accumulates. Several studies have indicated that the accumulation of these substrates are associated with cytotoxicity and oncogenesis. High levels of succinate and fumarate induce hypoxia inducible factor (HIF1A) hydroxylases, leading to the activation of oncogenic HIF pathways. However, the role of HIF as primary inducer of oncogenic change has been questioned, as other non-enzymatic mechanisms have been shown to interfere with cellular metabolism, cell signalling as well as disrupting protein function. Owing to the essential roles that SDH and FH play in cellular energy metabolism, and their associated tumor suppressor capacity, it is vital to understand the biochemical effects resulting from the accumulation of their associated metabolites. Therefore, in this study, we investigated the effect of high concentrations of succinate and fumarate exposure on cell viability, genome integrity and global DNA methylation using a human hepatocellular carcinoma (HepG2) cell culture model. It was found that relatively high concentrations of succinate and fumarate cause a loss of cell viability, which seems to be orchestrated through an apoptotic pathway. Cells exposed to high levels of succinate also presented with elevated caspase 3 and/or caspase 7 levels. In addition, elevated levels of fumarate lead to extensive DNA fragmentation, which may contribute pathophysiologically by inducing chromosomal instability, while succinate demonstrated lower genotoxicity. Furthermore, both succinate and fumarate altered the global DNA methylation patterns via significant DNA hypermethylation. Since numerous studies have reported correlations between aberrant DNA methylation and oncogenesis, hypermethylation may contribute to the oncogenesis observed in cells exposed to high concentrations of these metabolites.

Evaluation of the cytotoxic properties, gene expression profiles and secondary signalling responses of cultured cells exposed to fumonisin B1, deoxynivalenol and zearalenone mycotoxins.

Mycotoxins are toxic secondary metabolites produced by a range of fungi and are common contaminants of agricultural crops. These toxins are chemically diverse and structurally stable, enabling them to enter the food chain which can lead to numerous adverse health effects in animals and humans. Although mycotoxin exposure is associated with the development of several cancers, it has proved challenging to show a direct connection between exposure and oncogenic change. This study investigates the in vitro cytotoxicity, molecular mechanisms and secondary signalling responses associated with the exposure to three major mycotoxins, fumonisin B1 (FB1), deoxynivalenol (Don) and zearalenone (Zea). The cytotoxicity of FB1, Don and Zea were investigated in cultured HepG2 and Caco-2 cells using cell viability assays as well as flow cytometry. FB1 proved to be less cytotoxic than its counterparts, while Don and Zea demonstrated high cytotoxicity through an apoptotic mechanism. Expression profiles of 84 genes involved in mediating communication between tumour cells and the cellular mediators of inflammation as well as the innate immune system were also studied. The expression profiles associated with the different mycotoxins were further explored for functional networks, biological functions, canonical pathways, toxicological association as well as to predict network associations between the differentially expressed genes. RT-qPCR revealed the significant differential expression of 46 genes, including the expression of several genes strongly associated with cancer and aberrant inflammatory signalling, after mycotoxin exposure. Aberrant inflammatory signalling seems to be a credible contributing factor that initiates the malignant change observed in cells exposed to mycotoxins.

An Enquiry Concerning the Characteristics of Cell-Free DNA Released by Cultured Cancer Cells.

Non-invasive screening that utilizes cell-free DNA (cfDNA) offers remarkable potential as a method for the early detection of genetic disorders and a wide variety of cancers. Unfortunately, one of the most prominent elements delaying the translation of cfDNA analyses to clinical practice is the lack of knowledge regarding its origin and composition. The elucidation of the origin of cfDNA is complicated by the apparently arbitrary variability of quantitative and qualitative characteristics of cfDNA in the blood of healthy as well as diseased individuals. These factors may contribute to false positive/negative results when applied to clinical pathology. Although many have acknowledged that this is a major problem, few have addressed it. We believe that many of the current difficulties encountered in in vivo cfDNA studies can be partially circumvented by in vitro models. The results obtained in this study indicate that the release of cfDNA from 143B cells is not a consequence of apoptosis, necrosis or a product of DNA replication, but primarily the result of actively released DNA, perhaps in association with a protein complex. Moreover, this study demonstrates the potential of in vitro cell culture models to obtain useful information about the phenomenon of cfDNA.

In vivo efficacy and bioavailability of lumefantrine: Evaluating the application of Pheroid technology.

The oral absorption of compounds with low aqueous solubility, such as lumefantrine, is typically limited by the dissolution rate in the gastro-intestinal tract, resulting in erratic absorption and highly variable bioavailability. In previous studies we reported on the ability of Pheroid vesicles to improve the bioavailability of poorly soluble drugs. In the present study a Pro-Pheroid formulation, a modification of the previous formulation, was applied to improve the solubility of lumefantrine after oral administration and compared to lumefantrine in DMSO:water (1:9 v/v) solution (reference solution). A bioavailability study of lumefantrine was conducted in a mouse model in fed and fasted states. When using the reference solution, the bioavailability of the lumefantrine heavily depended on food intake, resulting in a 2.7 times higher bioavailability in the fed state when compared to the fasted state. It also showed large between-subject variability. When formulated using Pro-Pheroid, the bioavailability of lumefantrine was 3.5 times higher as compared to lumefantrine in the reference solution and fasting state. Pro-Pheroid also dramatically reduced the effects of food intake and the between-subject variability for bioavailability observed with the reference. In vivo antimalarial efficacy was also evaluated with lumefantrine formulated using Pro-Pheroid technology compared to the reference solution. The results indicated that lumefantrine in Pro-Pheroid formulation exhibited improved antimalarial activity in vitro by 46.8%, when compared to the reference. The results of the Peters' 4-day suppressive test indicated no significant difference in the efficacy or mean survival time of the mice in the Pro-Pheroid formulation and reference test groups when compared to the positive control, chloroquine. These findings suggest that using the Pro-Pheroid formulation improves the bioavailability of lumefantrine, eliminates the food effect associated with lumefantrine as well as significantly reduces the between subject variability in bioavailability when compared to the reference solution.

The Potential Use of Natural and Structural Analogues of Antimicrobial Peptides in the Fight against Neglected Tropical Diseases.

Recently, research into the development of new antimicrobial agents has been driven by the increase in resistance to traditional antibiotics and Emerging Infectious Diseases. Antimicrobial peptides (AMPs) are promising candidates as alternatives to current antibiotics in the treatment and prevention of microbial infections. AMPs are produced by all known living species, displaying direct antimicrobial killing activity and playing an important role in innate immunity. To date, more than 2000 AMPs have been discovered and many of these exhibit broad-spectrum antibacterial, antiviral and anti-parasitic activity. Neglected tropical diseases (NTDs) are caused by a variety of pathogens and are particularly wide-spread in low-income and developing regions of the world. Alternative, cost effective treatments are desperately needed to effectively battle these medically diverse diseases. AMPs have been shown to be effective against a variety of NTDs, including African trypanosomes, leishmaniosis and Chagas disease, trachoma and leprosy. In this review, the potential of selected AMPs to successfully treat a variety of NTD infections will be critically evaluated.

Review of natural compounds for potential skin cancer treatment.

Most anti-cancer drugs are derived from natural resources such as marine, microbial and botanical sources. Cutaneous malignant melanoma is the most aggressive form of skin cancer, with a high mortality rate. Various treatments for malignant melanoma are available, but due to the development of multi-drug resistance, current or emerging chemotherapies have a relatively low success rates. This emphasizes the importance of discovering new compounds that are both safe and effective against melanoma. In vitro testing of melanoma cell lines and murine melanoma models offers the opportunity for identifying mechanisms of action of plant derived compounds and extracts. Common anti-melanoma effects of natural compounds include potentiating apoptosis, inhibiting cell proliferation and inhibiting metastasis. There are different mechanisms and pathways responsible for anti-melanoma actions of medicinal compounds such as promotion of caspase activity, inhibition of angiogenesis and inhibition of the effects of tumor promoting proteins such as PI3-K, Bcl-2, STAT3 and MMPs. This review thus aims at providing an overview of anti-cancer compounds, derived from natural sources, that are currently used in cancer chemotherapies, or that have been reported to show anti-melanoma, or anti-skin cancer activities. Phytochemicals that are discussed in this review include flavonoids, carotenoids, terpenoids, vitamins, sulforaphane, some polyphenols and crude plant extracts.

Applications of lipid based formulation technologies in the delivery of biotechnology-based therapeutics.

In the last decades several new biotechnologically-based therapeutics have been developed due to progress in genetic engineering. A growing challenge facing pharmaceutical scientists is formulating these compounds into oral dosage forms with adequate bioavailability. An increasingly popular approach to formulate biotechnology-based therapeutics is the use of lipid based formulation technologies. This review highlights the importance of lipid based drug delivery systems in the formulation of oral biotechnology based therapeutics including peptides, proteins, DNA, siRNA and vaccines. The different production procedures used to achieve high encapsulation efficiencies of the bioactives are discussed, as well as the factors influencing the choice of excipient. Lipid based colloidal drug delivery systems including liposomes and solid lipid nanoparticles are reviewed with a focus on recent advances and updates. We further describe microemulsions and self-emulsifying drug delivery systems and recent findings on bioactive delivery. We conclude the review with a few examples on novel lipid based formulation technologies.

In vitro evaluation of the cytotoxic and apoptogenic properties of aloe whole leaf and gel materials.

Aloe gel and whole-leaf materials have shown biological effects with potential therapeutic applications, and recently, their drug-absorption enhancement properties have been discovered. It is important to establish a safety profile for these materials before they can be used in pharmaceutical products. The aim of the study was to investigate the in vitro cytotoxicity of Aloe vera, Aloe marlothii, Aloe speciosa and Aloe ferox against human hepatocellular (HepG2), human neuroblastoma cells (SH-SY5Y) and human adenocarcinoma epithelial cells (HeLa). Flow cytometry was used to measure cell viability, apoptosis and reactive oxygen species (ROS). The aloe gel materials investigated only decreased cell viability at concentrations of >10 mg/mL and exhibited half-maximal cytotoxic concentration (CC(50)) values above 1000 mg/mL, except for A. vera gel in HepG2 cells (CC(50) = 269.3 mg/mL). A. speciosa whole-leaf material showed a significant decrease in viability of Hela cells, whereas the other whole-leaf materials did not show a similar effect. The aloe gel materials in general showed low levels of apoptosis, whereas A. vera and A. speciosa whole-leaf materials caused a dose-dependent increase of apoptosis in HeLa cells. None of the aloe materials investigated exhibited a significant increase in ROS. It can be concluded that the selected aloe materials caused only limited reduction in cell viability with limited in vitro cytotoxicity effects. Further, neither significant apoptosis effects were observed nor induction of ROS.

Formulation and evaluation of Pheroid vesicles containing mefloquine for the treatment of malaria.

OBJECTIVES: Mefloquine (MQ) is an antimalarial drug with high efficacy, often used in the treatment and chemoprophylaxis of malaria. However, it has low solubility in water, a long elimination half-life (4 days), and is neurotoxic, which leads to unwanted side effects. METHODS: We investigated a lipid-based drug delivery system, Pheroid vesicles, in combination with MQ (Pheroid MQ), to promote future clinical use. MQ was incorporated into Pheroid vesicles and the formulations characterized. The formulations were evaluated in terms of in-vitro efficacy and toxicity. In-vivo bioavailability studies were conducted in C57 BL6 mice. KEY FINDINGS: The vesicles incorporated MQ with ~63% entrapment efficiency. The IC50 values of MQ after 48-h incubation in chloroquine-resistant (RSA11) and chloroquine sensitive (3D7) strains, were reduced by ~50% and ~30% respectively. In-vivo bioavailability study revealed no change in the pharmacokinetic parameters of MQ, and the incorporation of the drug in Pheroid vesicles reduced the in-vitro haemolytic activity by ~75%. Furthermore, the cytotoxicity against human neuroblastoma cells (SH-SY5Y) of the free drug was reduced by ~64% with Pheroid MQ. CONCLUSIONS: Pheroid vesicles may therefore decrease the toxicity of MQ and thereby improve its therapeutic index, a strategy that may provide an effective alternative for malaria chemoprophylaxis and treatment.