AI & experimental-based discovery and preclinical IND-enabling studies of selective BMX inhibitors for development of cancer therapeutics

The current work aims to design and provide a preliminary IND-enabling study of selective BMX inhibitors for cancer therapeutics development. BMX is an emerging target, more notably in oncological and immunological diseases. In this work, we have employed a predictive AI-based platform to design the selective inhibitors considering the novelty, IP prior protection, and drug-likeness properties. Furthermore, selected top candidates from the initial iteration of the design were synthesized and chemically characterized utilizing 1H NMR and LC-MS. Employing a panel of biochemical (enzymatic) and cancer cell lines, the selected molecules were tested against these assays. In addition, we used artificial intelligence to predict and evaluate several critical IND-focused physicochemical and pharmacokinetics values of the selected molecules. A secondary objective of the current work was also to validate the sole role of BMX in animal models known to be mediated by BMX. More than 50 molecules were designed in the present study employing five novel discovered scaffolds. Two molecules were nominated for further IND-focused studies. Compound II showed promising in-vitro activity against BMX in both enzymatic assays compared to other kinases and in cancer cell lines with known BMX overexpression. Interestingly, compound II showed very favorable physicochemical and pharmacokinetics properties as predicted by the used platforms. The animal study further confirmed the sole role of BMX in the disease model. The current work provides promising data on a selective BMX inhibitor as a potential lead for therapeutics development, and the asset is currently in the optimization stage. Notably, the current study shows a framework for a combined approach employing both AI and experimentation that can be used by academic labs in their research programs to more streamline programs into IND-focused to be bridged easily for further clinical development with industrial partners.

Compounding Education in US PharmD Curricula

OBJECTIVE

To determine the extent of compounding education (CE) offered in United States (US) doctor of pharmacy curricula.

METHODS

A 24-item survey instrument addressing various aspects of CE was developed and validated. An email containing the link to the survey instrument was shared with instructors of compounding at 122 of 141 accredited schools and colleges of pharmacy in the US.

RESULTS

Of these, 112 schools and colleges responded, rendering a survey response rate of 91.8%. Survey results indicate that CE is offered to a similar extent either as a required standalone course or as integrated instruction as part of a standard course. Whereas 70.8% of programs reported mostly hands-on training in CE in their curricula, there were about 11% programs that mostly offered didactic instruction in CE. Dispersed systems and semisolid formulations are the most prepared in nonsterile compounding, while proper hand washing, garbing, and gloving are the most taught techniques in sterile compounding. Compounding education is delivered principally by pharmaceutics faculty (62.3%) compared to practice faculty (32.1%).

CONCLUSION

The survey determined the extent to which CE is addressed across different schools and colleges of pharmacy in the US. Although some institutions lack minimal nonsterile or sterile compounding facilities, they may improve by modeling the established programs in the country. Leadership at pharmacy institutions may need to allocate funds for CE, and support faculty who instruct in compounding.

Sustained release of curcumin self-emulsifying drug delivery system (SEDDS) from solvent-cast Soluplus® films

The objective of the present study was to investigate the feasibility of formulating and loading Curcumin SEDDS (Self-Emulsified Drug Delivery Systems) into films made from Soluplus^® as the film-forming polymer. Films with up to 30% of Curcumin SEDDS were prepared by the solvent casting technique and analyzed for their mechanical and dissolution properties. A nine-run, two-factor, three-level factorial design was utilized to investigate the effect of SEDDS load (10, 20, and 30% w/w) and film thickness (10, 25, and 40 mils) on the tensile strength, elongation, and adhesiveness of the films. The dissolution profile of the films was also investigated by a USP Type 1 method. SEDDS loading was found to plasticize Soluplus^® and to yield transparent films of good mechanical properties. Increasing SEDDS load, however, was found to reduce the tensile strength of the films, while increasing their adhesiveness and elongation. On the other hand, while an increase in film thickness was found to increase the tensile strength of the films, it reduced the elongation capacity of the films. Loading SEDDS into Soluplus^® films was also found to sustain their release over 6 h, where a significant delay in release was found at lower SEDDS loads. This study demonstrated that Soluplus^® can be used not only to formulate SEDDS into polymeric films but also to sustain their release over an extended time.

Preparation and characterization of aqueous vitamin E/Soluplus® dispersions for film coating applications

OBJECTIVE

The goals of this study were to (1) delineate a technique to prepare stable aqueous vitamin E/Soluplus® dispersions; (2) characterize films cast from the aqueous dispersions; and (3) demonstrate the utility of the aqueous dispersions in fluid bed coating applications. This study demonstrated the feasibility of using vitamin E in the preparation of amphiphilic film withs potential use in delayed-release coating applications.

METHODS

Low viscosity aqueous vitamin E/Soluplus® dispersions were prepared by first spray drying ethanolic vitamin E/Soluplus® solutions followed by high-shear homogenization of the solid dispersions in water. Concentrated (10%) aqueous dispersions containing 0%, 10%, 20%, and 30% of vitamin E in the binary blend with Soluplus® were then cast into films and characterized for contact angle and mechanical strength by texture analysis.

RESULTS

All films were hydrophilic and homogenous, which confirmed the utility of vitamin E as a plasticizer for the Soluplus® polymer. The 0% and 10% films were brittle whereas the 30% were tacky. The 20% dispersion was subsequently used to coat acetaminophen granules by a fluidized bed process to a dry weight gain of 10-30%. When tested by a dissolution study, a delay in acetaminophen release was observed as a function of weight gain.

CONCLUSION

The results from this study demonstrated that it is feasible to produce stable vitamin E/Soluplus® aqueous dispersions to be used as solvent-free functional film coating materials.

Modulation of the sublingual microenvironment and pH-dependent transport pathways to enhance atropine sulfate permeability for the treatment of organophosphates poisoning

Atropine sulfate (AS) auto-injectors are the only approved antidote for out-of-hospital emergency treatment of organophosphates (OP) toxicity. However, they are only available for military use and require the administration of multiple auto-injectors. Therefore, an alternative, patient-friendly and more affordable fast-disintegrating sublingual tablets (FDSTs) of AS were previously developed. In this article, the effect of modifying the microenvironment's pH and/or using penetration enhancers on AS sublingual transport pathways were evaluated in an attempt to further enhance AS sublingual permeability. Ten different AS FDST formulations with or without the incorporation of alkalizer and various penetration enhancers were manufactured and characterized. AS permeability was investigated through excised porcine sublingual membrane using Franz cells. Results showed that the incorporation of either a transcellular enhancer or alkalizer achieved a significantly higher AS permeability enhancement (twofold). Combining sodium bicarbonate (Na Bicarb) 2% as alkalizer with sodium dodecyl sulfate (SDS) 1% as a transcellular enhancer resulted in the greatest synergistic enhancement in AS sublingual permeability (up to twelvefold). In conclusion, the modified AS FDST developed in this work has the potential to improve the pharmacokinetic parameters of AS following sublingual administration for the first-aid treatment of OP toxicity in future animal bioequivalency studies.

Abstract 1232: Using mesoporous silica nanoparticles (MSNs) for delivering the mesoionic compound MIH 2.4Bl in treating breast cancer

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in women worldwide, accounting for approximately 24% of all new cancer cases and is the leading cause of cancer death in over 100 countries. Thus, breast cancer is one of the most critical public health problems in the world facing women. There is a growing interest in studying the biological activity of mesoionic compounds, which possesses a 5-membered heterocyclic aromatic ring associated with a sextet of electrons. Mesoionic compounds have shown promising potential as anti-cancer agents due to their unique structure and reaction properties. We reported the synthesis of a new 1,3-thiazolium-5-thiolate derivative of a mesoionic compound (MIH 2.4Bl) and the characterization of its selective cytotoxicity on a panel of breast cancer cells lines. The results of our studies suggest a possible induction of apoptotic death through mitochondrial dysfunction by the treatment with MIH 2.4Bl. Based on our previous findings, MIH 2.4Bl is a promising candidate for treating breast cancer. However, a major challenge facing cancer therapy is the selective destruction of malignant cells while sparing normal cells to preserve tissue integrity. The development and use of drug delivery systems is a recognized approach to improve the efficacy of chemotherapy agents. Nonetheless, drug delivery systems have been unexplored in the context of mesoionic compounds. Drug delivery based on nanotechnology has flourished as a platform applicable to cancer therapy. Among various types of nanoparticles, mesoporous silica nanoparticles (MSNs) are more attractive nanomaterials for a broad range of functionality including gene/drug delivery, cancer therapy and bioimaging due to their broad surface area, less toxicity, low density, excellent biocompatibility, higher drug loading capacity, and impressive mechanical and thermal stability. In this preliminary work, we present an improved delivery strategy of a newly developed formulation of MIH 2.4BI compound with MSNs as the delivery agent. Also, physico-chemical characterization of the nanoparticles and cytotoxicity analyses using a panel of breast cancer cell lines were performed. These studies support the potential therapeutic use of MIH 2.4Bl in treating breast cancer.

Citation Format: Dipti Debnath, Sami Nazzal, Suchismita Acharya, Helivaldo Diógenes da Silva Souza, Petrônio Filgueiras de Athayde Filho, Rafal Fudala, J Michael Mathis. Using mesoporous silica nanoparticles (MSNs) for delivering the mesoionic compound MIH 2.4Bl in treating breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1232.

A full factorial experimental design to study the effect of flavoring agents on the mechanical properties of curcumin chewing gum tablets with high solids content

Objective: Developing chewing gum tablets (CGTs) with high drug loads is a challenge due to the loss of mastication properties. We postulated that poor mastication properties of such gums could be improved by adjusting the concentration of liquid flavors to serve as plasticizers and consequently increase the flexibility of the elastomer in the gum base. To test this hypothesis, the objective of this work was to evaluate the effects of flavor type and concentration, and storage conditions on the textural properties of CGTs loaded with 20% curcumin (CUR) by weight.Methods: CGTs were made by directly compressing Health in Gum^® base with CUR. The resultant CGTs were characterized by single and two bites textural tests to measure their yield strength, post-bite failure rate, and compressibility.Results: Flavor concentration (X₂) had a significant impact on the masticatory properties of the chewing gums, which could be ascribed to the plasticizing effect of peppermint oil. Addition of liquid flavors and storage at low temperature (X₄) produced CGTs with the desirable properties of low yield strength (Y₁) and post-bite structural failure rate (Y₂), and high compressibility (Y₃). The effect of flavors however was negated at high temperatures, especially when flavored gums were stored for extended time at 50 °C. Flavor type (X₁) on the other hand had no effect on the masticatory properties of the chewing gums.Conclusions: This study concluded that it is feasible to formulate CGTs with high solids content without negatively impacting their mechanical properties by controlling the concentration of liquid flavors.

Development and validation of a HPLC-UV method for the simultaneous detection and quantification of paclitaxel and sulforaphane in lipid based self-microemulsifying formulation

Paclitaxel (PTX) and sulforaphane (SFN) are known anticancer molecules. Their activity was found to be potentiated when tested concurrently. Only recently, however, a novel SFN enabled PTX self-microemulsifying formulation (SMEDDS) was developed for their simultaneous delivery. This necessitated the development of an analytical method for the simultaneous detection and quantitation of PTX and SFN. In this study, a simple and sensitive isocratic high performance liquid chromatography-ultraviolet (HPLC-UV) analytical method was developed and validated per International Conference on Harmonization guidelines to satisfy this objective. Its application was demonstrated when quantifying the amount of PTX and SFN released from the SMEDDS in various dissolution media. The separation of the analytes was performed with the aid of a reversed phase C18 column at ambient temperature using a 60:40 mixture of acetonitrile and KH2PO4 buffer (pH 5.0) as the mobile phase. PTX and SFN peaks were detected at 202 nm with high resolution without interference from excipients. This method showed linearity within 2.5-100 μg/mL range with r2 > 0.999. The limit of detection and lower limit of quantitation were 0.1638 and 0.4964 μg/mL for PTX and 0.4419 and 1.3389 μg/mL for SFN, respectively. A total of 98-101% of the injected samples was recovered with RSD of 0.06-0.68% indicating the suitability of the method for the simultaneous detection and quantitation of the molecules in dissolution media.

Development and evaluation of paclitaxel nanoemulsion for cancer therapy

Tocosol™ is a tocopherol-based paclitaxel (PTX) nanoemulsion consisting of α-tocopherol (α-T) isomer of vitamin E as a solubilizer and vitamin E TPGS as the primary emulsifier. Despite its positive attributes in early clinical studies, it failed the pivotal phase III clinical trials. The long-term goal of this work was to reformulate Tocosol™. In this study, Tocosol™ formulation was optimized by replacing the α-T isomer with the more pharmacological active isomer γ-tocotrienol (γ-T₃), and the surfactant vitamin E TPGS was replaced with in-house designed PEGylated γ-T₃ surfactant. The reformulated paclitaxel γ-T₃/PEGylated γ-T₃ -based nanoemulsion was significantly more active against pancreatic tumor cell lines than α-T/Vitamin E TPGS based formulation (IC₅₀ = 0.5 μM and 1.1 μM, respectively). Furthermore, the reformulated product showed an average size of 220 ± 6 nm with surface charge equal to -42 ± 2 mV. The optimized product was physically and chemically stable over 6 months per ICH storage condition guidelines.

Ceramide-Rubusoside Nanomicelles, a Potential Therapeutic Approach to Target Cancers Carrying p53 Missense Mutations

Ceramide (Cer) is an active cellular sphingolipid that can induce apoptosis or proliferation-arrest of cancer cells. Nanoparticle-based delivery offers an effective approach for overcoming bioavailability and biopharmaceutics issues attributable to the pronounced hydrophobicity of Cer. Missense mutations of the protein p53, which have been detected in approximately 42% of cancer cases, not only lose the tumor suppression activity of wild-type p53, but also gain oncogenic functions promoting tumor progression and drug resistance. Our previous works showed that cellular Cer can eradicate cancer cells that carry a p53 deletion-mutation by modulating alternative pre-mRNA splicing, restoring wild-type p53 protein expression. Here, we report that new ceramide-rubusoside (Cer-RUB) nanomicelles considerably enhance Cer in vivo bioavailability and restore p53-dependent tumor suppression in cancer cells carrying a p53 missense mutation. Natural RUB encapsulated short-chain C₆-Cer so as to form Cer-RUB nanomicelles (∼32 nm in diameter) that substantially enhanced Cer solubility and its levels in tissues and tumors of mice dosed intraperitoneally. Intriguingly, Cer-RUB nanomicelle treatments restored p53-dependent tumor suppression and sensitivity to cisplatin in OVCAR-3 ovarian cancer cells and xenograft tumors carrying p53 R248Q mutation. Moreover, Cer-RUB nanomicelles showed no signs of significant nonspecific toxicity to noncancerous cells or normal tissues, including bone marrow. Furthermore, Cer-RUB nanomicelles restored p53 phosphorylated protein and downstream function to wild-type levels in p53 R172H^/+ transgenic mice. Altogether, this study, for the first time, indicates that natural Cer-RUB nanomicelles offer a feasible approach for efficaciously and safely targeting cancers carrying p53 missense mutations.

Gold nanoparticles and angiogenesis: molecular mechanisms and biomedical applications

Angiogenesis is the formation of new blood vessels from pre-existing vessels. It is a highly regulated process as determined by the interplay between pro-angiogenic and anti-angiogenic factors. Under certain conditions the balance between angiogenesis stimulators and inhibitors is altered, which results in a shift from physiological to pathological angiogenesis. Therefore, the goal of therapeutic targeting of angiogenic process is to normalize vasculature in target tissues by enhancing angiogenesis in disease conditions of reduced vascularity and blood flow, such as tissue ischemia, or alternatively to inhibit excessive and abnormal angiogenesis in disorders like cancer. Gold nanoparticles (AuNPs) are special particles that are generated by nanotechnology and composed of an inorganic core containing gold which is encircled by an organic monolayer. The ability of AuNPs to alter vasculature has captured recent attention in medical literature as potential therapeutic agents for the management of pathologic angiogenesis. This review provides an overview of the effects of AuNPs on angiogenesis and the molecular mechanisms and biomedical applications associated with their effects. In addition, the main synthesis methods, physical properties, uptake mechanisms, and toxicity of AuNPs are briefly summarized.

Novel olive oil phenolic (-)-oleocanthal (+)-xylitol-based solid dispersion formulations with potent oral anti-breast cancer activities

Epidemiological studies have compellingly documented the ability of the Mediterranean diet rich in extra-virgin olive oil to reduce the incidence of certain malignancies, and cardiovascular diseases, and slow the Alzheimer's disease progression. S-(-)-Oleocanthal (OC) was identified as the most bioactive olive oil phenolic with documented anti-inflammatory, anticancer, and anti-Alzheimer's activities. OC consumption causes irritating sensation at the oropharynx via activation of TRPA1. Accordingly, a taste-masked formulation of OC is needed for its future use as a nutraceutical while maintaining its bioactivity and unique chemistry. Therefore, the goal of this study was to prepare a taste-masked OC solid formulation with improved dissolution and pharmacodynamic profiles, by using (+)-xylitol as an inert carrier. Xylitol was hypothesized to serve as an ideal vehicle for the preparation of OC solid dispersions due to its low melting point and sweetness. The optimized OC-(+)-xylitol solid dispersion was physically and chemically characterized and showed effective taste masking and enhanced dissolution properties. Furthermore, OC-(+)-xylitol solid dispersion maintained potent in vivo anti-breast cancer activity. It effectively suppressed the human triple negative breast cancer development, growth, and recurrence after primary tumor surgical excision in nude mice orthotopic xenograft models. Collectively, these results suggest the OC-(+)-xylitol solid dispersion formulation as a potential nutraceutical for effective control and prevention of human triple negative breast cancer.

Prognostic relevance of topoisomerase II α and minichromosome maintenance protein 6 expression in colorectal cancer

BACKGROUND

Despite rising incidence rates of colorectal malignancies, only a few prognostic tools have been implemented in proven clinical routine. Cell division and proliferation play a significant role in malignancies. In terms of colorectal cancer, the impact of proliferation associated proteins is controversially debated. The aim of our study was to examine the expression of topoisomerase II α and minichromosome maintenance protein 6 and to correlate these findings with the clinical data.

METHODS

Tissue samples of 619 patients in total were stained using the antibodies Ki-S4 and Ki-MCM6 targeting topoisomerase II α as well as minichromosome maintenance protein 6. The median rate of proliferation was correlated with clinical and follow up data.

RESULTS

The expression rate of minichromosome maintenance protein 6 is significantly higher than the proportion of topoisomerase II α in tumour cells (p < 0.001). A high expression of both proteins coincides with a beneficial outcome for the patient, indicating a favourable prognostic marker (p < 0.001 and p = 0.008).

CONCLUSIONS

We have demonstrated that high expression rates of proliferative markers is linked to a beneficial patient outcome. According to the general opinion, a high expression rate correlates with a poor patient outcome. In this study, we were able to refute this assertion.

Novel liquid-liquid extraction and self-emulsion methods for simplified isolation of extra-virgin olive oil phenolics with emphasis on (-)-oleocanthal and its oral anti-breast cancer activity

Epidemiological and clinical studies compellingly documented the ability of Mediterranean diet rich in extra-virgin olive oil (EVOO) to reduce breast and colon cancers incidence, cardiovascular diseases, and aging cognitive functions decline. (-)-Oleocanthal (OC) and other EVOO phenolics gain progressive research attention due to their documented biological effects against cancer, inflammations, and Alzheimer’s disease. There is no simple, reliable, and cost-effective isolation protocol for EVOO phenolics, which hinder their therapeutic applications. This study develops novel methods to isolate OC and other EVOO phenolics. This includes the use of ultra-freezing to eliminate most EVOO fats and the successful water capacity to efficiently extract OC and EVOO phenolics as self-emulsified nano-emulsion. Subsequent resin entrapment and size exclusion chromatography afforded individual EVOO phenolics in high purity. OC in vitro and in vivo oral anti-breast cancer (BC) activities validated its lead candidacy. Effective isolation of EVOO phenolics provided in this study will facilitate future preclinical and clinical investigations and stimulate the therapeutic development of these important bioactive natural products.

STEMI mimicker in a 26-year-old man

We herein describe a case of acute myocarditis which may mimic myocardial infarction, since affected patients experience ‘typical’ chest pain, the ECG changes are identical to those observed in acute coronary syndromes, and serum markers are increased. This case emphasises the importance of performing appropriate cardiac MRI to help in the differential and definitive diagnosis as well as the extent of myocardial involvement. ST elevation myocardial infarction is rare in young adults and when it is encountered, it should raise the differential diagnosis of its mimickers.

The physiochemical, mechanical, and adhesive properties of solvent-cast vitamin E/Soluplus® films

Soluplus® is an amphiphilic graft copolymer used in hot melt extrusion applications and electrospinning. Very little information is available on the use of Soluplus® as a film former and in the development of film-based formulations. The overall aim of this work was to study the mechanical and adhesive properties of Soluplus® films prepared by the solvent casting technique. More specifically, we discovered that vitamin E can serve as a plasticizer for the Soluplus® polymer and to significantly modulate its mechanical and adhesive properties. Vitamin E (0-75% w/w) and Soluplus® were dissolved in ethanol and cast on liners to produce transparent films. Cast films were tested for their physiochemical properties by IR, XRD, and MDSC, and for their adhesive and mechanical properties by texture analysis. Vitamin E was found to be miscible with Soluplus® and to reduce the crystallinity of the films. Vitamin E also decreased the films' tensile strength and Young's modulus while significantly increasing their percent elongation. The most notable effect was the observed increase in the adhesiveness (tackiness) and hydrophobicity of the films, which was evidenced by a significant increase in their water contact angle and a decrease in their swelling capacity and disintegration. These observations indicated that vitamin E/Soluplus® blends might be used for the preparation of highly pliable films, especially when made with 30-50% vitamin E, and in the development of a new type of pressure sensitive adhesive films when prepared with ≥65% vitamin E load.

Mechanical Characterization and Dissolution of Chewing Gum Tablets (CGTs) Containing Co-compressed Health in Gum® and Curcumin/Cyclodextrin Inclusion Complex

Curcumin chewing gums could be therapeutically beneficial if used by the head and neck cancer patients. High curcumin loading in chewing gums however is needed to achieve desired therapeutic effect. Preparing gums with high drug load is nonetheless challenging because of the negative impact of solids on their masticatory properties. The use of liquid flavors was found to partially solve this problem. The objectives of this study were to (1) determine the maximum amount of curcumin that can be loaded into co-compressed chewing gums made from Health in Gum® as the base and flavored with 1.5% peppermint oil, (2) determine if addition of sweeteners can improve the yield strength and compressibility of the gums when examined by a texture analyzer, (3) examine the effect of temperature over a storage period of one month on the physical stability of the chewing gums, and (4) study the impact of substituting curcumin with its inclusion complex with SBE-β-CD on drug release. It was found that when flavored, Health in Gum® could load up to 25% curcumin by weight without compromising its masticatory properties. When tested for drug release, SBE-β-CD was found to significantly increase the amount of curcumin dissolved within 30 min. Despite poor drug release from gums loaded with insoluble curcumin, the fragmentation of the gums during mastication by the Erweka tester is nonetheless expected to produce a suspension for absorption in the lower GIT. This study demonstrated how modulating gum composition and storage conditions can impact the mechanical properties of chewing gums with high solids content.

Medicated Chewing Gums (MCGs): Composition, Production, and Mechanical Testing

Medicated chewing gums (MCGs) represent a unique platform for drug delivery. They have been defined as solid single-dose preparations, which may contain more than one active pharmaceutical ingredient (API) with base consisting primarily of gum that has to be chewed for a certain period of time. They mainly contain a tasteless masticatory gum base as the core with other minor nonmasticatory ingredients, such as flavors and sweeteners. Despite their advantages in drug delivery, MCGs remain a niche product due to the complexity of their formulation, lack of acceptable testing methods, and intricacy of their manufacturing. Few studies have been reported on their use, and most of the information on their composition and production could be found in patent search. The aim of this review is to provide an overview of gum composition, manufacturing process, and characterization. Due to the scarcity of studies concerning the evaluation of the mechanical properties of MCGs, greater emphasis was placed on the available performance tests and procedures for the estimation of their mechanical and textural properties. While very few tests have been recommended by the official pharmacopeias, several tests have been suggested for assessing the mechanical properties of MCGs in vitro. Properties, such as chewiness, elasticity, and firmness, of chewing gums during mastication are imperative quality attributes that have been found to strongly correlate with gum composition and mouth feel.

The rheological and textural characterization of Soluplus®/Vitamin E composites

Soluplus® is a graft amphiphilic copolymer that is frequently used as an excipient in solid dosage forms as a dissolution and a solubility enhancer. We discovered that Soluplus® can be dissolved in vitamin E. The result is a tacky and highly adhesive material. Our research objective was to evaluate the rheological, adhesive, and textural properties of the Soluplus®/Vitamin E composites. In this study, Soluplus® was dissolved under heat in vitamin E at increasing concentrations from 0 to 40% (by weight). The flow behavior of the Soluplus®/Vitamin E composites was determined by applying shear stress using an advanced AR2000 rheometer. Under the linear viscoelastic region (LVR), the rheological properties of the blends such as dynamic viscosity (η'), storage modulus (G'), loss modulus (G″), and the phase angle tangent (tan δ) were measured. Hardness, adhesiveness, and cohesiveness of the blends were also measured with a TA.XT plus texture analyzer. Rheological analysis showed that the viscosity of the Soluplus®/Vitamin E composites increased with an increase in Soluplus® concentration but decreased as the temperature increased from 20 to 90 °C. The adhesiveness of the blends also significantly increased with an increase in Soluplus® concentration. The results from this study indicated that Soluplus®/Vitamin E composites have the potential to be exploited in applications where the use of highly adhesive material is desirable.

Development and in-vitro characterization of nanoemulsions loaded with paclitaxel/γ-tocotrienol lipid conjugates

Vitamin E TPGS is a tocopherol (α-T) based nonionic surfactant that was used in the formulation of the Tocosol™ paclitaxel nanoemulsion, which was withdrawn from phase III clinical trials. Unlike tocopherols, however, the tocotrienol (T₃) isomers of vitamin E were found to have innate anticancer activity and were shown to potentiate the antitumor activity of paclitaxel. The primary objective of the present study was therefore to develop a paclitaxel nanoemulsions by substituting α-T oil core of Tocosol™ with γ-T₃ in, and vitamin E TPGS with PEGylated γ-T₃ as the shell, and test the nanoemulsions against Bx-PC-3 and PANC-1 pancreatic tumor cells. A secondary objective was to test the activity of paclitaxel when directly conjugated with the γ-T₃ isomer of vitamin E. The synthesis of the conjugates was confirmed by NMR and mass spectroscopy. Developed nanoemulsions were loaded with free or lipid conjugated paclitaxel. Nanoemulsions droplets were <300 nm with fastest release observed with formulations loaded with free paclitaxel when γ-T₃ was used as the core. Substituting α-T with γ-T₃ was also found to potentiate the anticancer activity of the nanoemulsions. Although marginal increase in activity was observed when nanoemulsions were loaded with free paclitaxel, a significant increase in activity was observed when lipid conjugates were used. The results from this study suggest that the developed paclitaxel nanoemulsions with either γ-T₃, PEGylated γ-T₃, or paclitaxel lipid conjugates may represent a more promising option for paclitaxel delivery in cancer chemotherapy.

Development of postcompressional textural tests to evaluate the mechanical properties of medicated chewing gum tablets with high drug loadings

Medicated chewing gum tablets (CGTs) represent a unique platform for drug delivery. Loading directly compressible gums with high concentrations of powdered medication, however, results in compacts with hybrid properties between a chewable gum and a brittle tablet. The aim of the present study was to develop textural tests that can identify the point at which CGTs begin to behave like a solid tablet upon drug incorporation. Curcumin (CUR) CGTs made with Health in gum were prepared with increasing CUR load from 0 to 100% and were characterized for their mechanical properties by a single-bite (knife) and a two-bite tests. From each test several parameters were extracted and correlated with drug loading. In the single-bite test, the change in the resistance of the compacts to plastic deformation was found to give a definitive guide on whether they behave as gums or tablets. A more in depth analysis of the impact of CUR loading on the chewability of the CGTs was provided by the two-bite test where CUR loading was found to have a nonlinear impact on the mechanical properties of compacts. An upper limit of 10% was found to yield compacts with gum-like properties, which were abolished at higher CUR loads. The textural test procedure outlined in this study are expected to assist those involved in the formulation of medicated gums for pharmaceutical applications in making an informed decision on the impact of drug loading on gum behavior before proceeding with clinical testing.

PRACTICAL APPLICATIONS

There is a growing interest in utilizing medicated chewing gums for drug delivery, especially those made using directly compressible gum bases, such as Health in gum. Directly compressing a gum base with high amounts of solid drug powder, however, poses a challenge as it may result in compressed compacts with hybrid properties between a chewing gum and a hard tablet. Currently, official Pharmacopeias do not specify a testing procedure for the estimation of the mechanical and textural properties of chewing gum tablets. To fill in the knowledge gap, we demonstrated in the present study how complementing a single-bite (knife) test with a modified two-bite test could be used to discriminate between chewing gums and hard tablets that were prepared by directly compressing Health in gum base with increasing concentration of curcumin powder in the blend. By utilizing these two tests, it was possible to identify clear demarcations between conventional tablets and chewing gums. In this study, we found that a 10% load by weight is the upper limit for curcumin loading in a binary blend with Health in gum to maintain the mastication properties of the compacts, which become brittle tablets at 30% load.

Extraction of Vitamin E Isomers from Palm Oil: Methodology, Characterization, and in Vitro Anti-Tumor Activity

Vitamin E refers to a family of eight tocopherols (T) and tocotrienol (T3) isomers. Due to the unique pharmacological and anticancer activity of the individual isomers, there is a need to extract and separate the individual T3 isomers from T/T3 rich fractions of palm oil. The objective of the present study was to present a detailed protocol for the extraction of gram quantities of vitamin E isomers from a T3 rich fraction (Tocotrol™) that was obtained from palm oil, by column chromatography using a binary hexane:EtOAc (1-12%) phase system. The chemical integrity and identity of the extracted isomers was confirmed by TLC, HPLC, ¹H-NMR, and Raman analysis. To evaluate their anticancer activity, vitamin E isomers were first entrapped into nanoemulsions and then tested against a panel of breast and pancreatic cancer cell lines. Nanoemulsions were prepared by the solvent evaporation technique. They had an average droplet size between 156-200 nm. In confirmation to what has been reported in the literature, γ-T3 and δ-T3 isomers were found to be significantly more active against tumor cells than the α-T and α-T3 isomers. The current study has demonstrated the feasibility of extracting the individual vitamin E isomers at high yields from natural sources while maintaining their chemical integrity and pharmacological activity.

Synthesis, physiochemical characterization, and in vitro antitumor activity of the amide and pH cleavable hydrazone conjugates of γ-tocotrienol isomer of vitamin E with methoxy-poly(ethylene) glycol

The anticancer activity of water soluble methoxy polyethylene glycol (mPEG) derivatives of tocotrienol (T3) isomers of vitamin E was previously found to be reduced when compared to the parent free isomers. This could be due to the ester bond formation between the mPEG and the 6-OH group on the chroman moiety of the T3 isomer. To further investigate, the objectives of the current study were to (1) synthesize and characterize stable amide and cleavable hydrazone conjugates between mPEG and carbon-5 on the chroman moiety of T3, and (2) examine the cytotoxicity of the newly synthesized mPEG conjugates against breast (MCF-7 and MDA-MB-231) and pancreatic (BxPC-3 and PANC-1) cancer cells. Conjugates were synthesized by direct conjugation of succinyl chloride derivatives of mPEG to the α-tocopherol and γ-tocotrienol isomers of vitamin E, and were characterized by ¹H NMR, FT-IR, and mass spectrometry. The micelles of the amide and hydrazone self-assembled conjugates were characterized for size, zeta, CMC, and stability at different pH media. The hydrolysis of the hydrazone conjugate was pH dependent with highest release at acidic (pH 5.5) conditions, whereas the amide conjugate was stable in all tested media. The amide conjugate nonetheless showed greater cytotoxicity than the hydrazone conjugate, which suggested that maintaining solubility and the presence of free 6-OH group are important for γ-T3 to exert anticancer activity in vitro. The results from the current study demonstrated the importance of considering the nature of the chemical bond between T3 and mPEG when designing functional ingredients for use in drug delivery.

Gemcitabine-vitamin E conjugates: Synthesis, characterization, entrapment into nanoemulsions, and in-vitro deamination and antitumor activity

Gemcitabine is the first line therapy for pancreatic cancer. It is, however, extensively metabolized to the inactive form by deamination enzymatic reaction. Conjugation of gemcitabine with fatty acids on its 4-amino group was found to protect it from deamination deactivation reaction. The objective of the present study was to test the in-vitro anticancer activity of gemcitabine conjugated to the γ-tocotrienol isomer of vitamin E against pancreatic tumor cells. This objective was based on reported studies in which it was demonstrated that free tocotrienol isomers of vitamin E can potentiate the anticancer activity of gemcitabine. To accomplish this objective, a full synthesis scheme for gemcitabine conjugation to fatty acids (stearic and linoleic) and the tocopherol and tocotrienol isomers of vitamin E (α-T and γ-T3) was presented. The conjugates were characterized by ¹H NMR and mass spectrometry analysis and tested for their susceptibility to deamination. Also discussed is the impact of entrapping the conjugates into nanoemulsions on the physiochemical properties of the delivery system and the in vitro anticancer activity of gemcitabine against Bx-PC-3 and PNAC-1 pancreatic cancer cells. In-vitro enzymatic deamination study showed that the γ-T3 conjugate of gemcitabine was least affected by deamination deactivation reaction when compared with the free and conjugated gemcitabine in solution. Furthermore, in-vitro cytotoxicity study demonstrated that entrapment of gemcitabine-lipid conjugates into nanoemulsions significantly enhanced their anticancer activity when compared to the free drug. It was concluded that conjugation to the γ-T3 isomer is a viable option for gemcitabine delivery and is worthy of further investigation.

Development and qualification of an LC-MS/MS method for investigating the biological implications of micelle entrapped paclitaxel in cell culture and rats

Paclitaxel is a front-line antineoplastic drug used in chemotherapeutic modalities for treatment of various types of malignancies. However, its efficacy is limited by dose-related toxicities. In this study, we have explored two important biological aspects of entrapping paclitaxel in PEG₂₀₀₀ -DSPE micelles. First, we evaluated the impact of this micellar delivery system on P-glycoprotein (P-gp)-paclitaxel interaction, and we investigated differences in plasma pharmacokinetics of free and micelle-entrapped paclitaxel. For quantification of paclitaxel, an LC-MS/MS method was developed. Paclitaxel was extracted from samples using a simple one-step protein precipitation. Chromatographic conditions included a C₁₈ column with a mobile phase consisting of 0.1% formic acid in acetonitrile-water (60:40, v/v) pumped at 1 mL/min. The lower limit of quantitation in both plasma and cell lysate was 1.0 ng/mL. The quantitative linear range was 1-1000 ng/mL. In addition, P-gp efflux studies on free and micellar paclitaxel showed the proficiency of PEG₂₀₀₀ -DSPE micelles in evading P-gp-mediated efflux, thus increasing paclitaxel uptake. Furthermore, the micellar paclitaxel levels were maintained in the body for longer time as compared with taxol, which is desirable for increasing the efficacy of paclitaxel in cancer treatment.

Curcumin complexation with cyclodextrins by the autoclave process: Method development and characterization of complex formation

One approach to enhance curcumin (CUR) aqueous solubility is to use cyclodextrins (CDs) to form inclusion complexes where CUR is encapsulated as a guest molecule within the internal cavity of the water-soluble CD. Several methods have been reported for the complexation of CUR with CDs. Limited information, however, is available on the use of the autoclave process (AU) in complex formation. The aims of this work were therefore to (1) investigate and evaluate the AU cycle as a complex formation method to enhance CUR solubility; (2) compare the efficacy of the AU process with the freeze-drying (FD) and evaporation (EV) processes in complex formation; and (3) confirm CUR stability by characterizing CUR:CD complexes by NMR, Raman spectroscopy, DSC, and XRD. Significant differences were found in the saturation solubility of CUR from its complexes with CD when prepared by the three complexation methods. The AU yielded a complex with expected chemical and physical fingerprints for a CUR:CD inclusion complex that maintained the chemical integrity and stability of CUR and provided the highest solubility of CUR in water. Physical and chemical characterizations of the AU complexes confirmed the encapsulated of CUR inside the CD cavity and the transformation of the crystalline CUR:CD inclusion complex to an amorphous form. It was concluded that the autoclave process with its short processing time could be used as an alternate and efficient methods for drug:CD complexation.

Synthesis, characterization, and in-vitro antitumor activity of the polyethylene glycol (350 and 1000) succinate derivatives of the tocopherol and tocotrienol isomers of Vitamin E

Vitamin E refers to a group of saturated tocopherol (T) isomers and the biologically more active unsaturated tocotrienol (T₃) isomers. PEGylated α-tocopherol, commercially known as Vitamin E TPGS, has been used as an emulsifier and therapeutic agent for children with vitamin E deficiency. Limited information, however, is available about the PEG conjugates of the tocotrienol isomers of vitamin E. The current work was therefore undertaken to synthesize and characterize the water soluble polyethylene glycol (PEG 350 and 1000) derivatives of T and T₃. Yield and the identity of the synthesized products were confirmed by ¹H NMR, mass spectroscopy, HPLC, and thermal analysis. The self-assembly of the PEGylated vitamin E isomers in water at critical micelle concentrations (CMC) was further confirmed by size, zeta, and Cryo-TEM image analysis. While stable at pH 7.4, PEG conjugates were found to rapidly hydrolyze at pH 1.2. Our data showed that PEGylated T₃ isomers were significantly more active as inhibitors for P-glycoprotein than PEGylated T. The in vitro cytotoxicity of the conjugates was also tested against a large panel of normal and tumorigenic cells. Of the conjugates, γ-T₃PGS 1000 and δ-T₃PGS 1000 were found to have the least toxicity against non-tumorigenic breast and pancreatic cell lines, which may be advantageous for its use as functional excipients in drug delivery. The results from the current work have demonstrated the feasibility of synthesizing PEGylated conjugates of vitamin E isomers and highlighted the potential use of these conjugates in drug delivery as functional and safer excipients especially for γ-T₃PGS 1000 and δ-T₃PGS 1000 conjugate.

pH-Dependent Solubility and Dissolution Behavior of Carvedilol--Case Example of a Weakly Basic BCS Class II Drug

The objective of this study was to investigate the pH-dependent solubility and dissolution of weakly basic Biopharmaceutical Classification Systems (BCS) class II drugs, characterized by low solubility and high permeability, using carvedilol, a weak base with a pK a value of 7.8, as a model drug. A series of solubility and in vitro dissolution studies was carried out using media that simulate the gastric and intestinal fluids and cover the physiological pH range of the GI from 1.2 to 7.8. The effect of ionic strength, buffer capacity, and buffer species of the dissolution media on the solubility and dissolution behavior of carvedilol was also investigated. The study revealed that carvedilol exhibited a typical weak base pH-dependent solubility profile with a high solubility at low pH (545.1-2591.4 μg/mL within the pH range 1.2-5.0) and low solubility at high pH (5.8-51.9 μg/mL within the pH range 6.5-7.8). The dissolution behavior of carvedilol was consistent with the solubility results, where carvedilol release was complete (95.8-98.2% released within 60 min) in media simulating the gastric fluid (pH 1.2-5.0) and relatively low (15.9-86.2% released within 240 min) in media simulating the intestinal fluid (pH 6.5-7.8). It was found that the buffer species of the dissolution media may influence the solubility and consequently the percentage of carvedilol released by forming carvedilol salts of varying solubilities. Carvedilol solubility and dissolution decreased with increasing ionic strength, while lowering the buffer capacity resulted in a decrease in carvedilol solubility and dissolution rate.

PEGylated γ-tocotrienol isomer of vitamin E: Synthesis, characterization, in vitro cytotoxicity, and oral bioavailability

Vitamin E refers to a family of eight isomers divided into two subgroups, tocopherols and the therapeutically active tocotrienols (T3). The PEGylated α-tocopherol isomer of vitamin E (vitamin E TPGS) has been extensively investigated for its solubilizing capacity as a nonionic surfactant in various drug delivery systems. Limited information, however, is available about the PEG conjugates of the tocotrienol isomers of vitamin E. In this study two PEGylated γ-T3 variants with mPEG molecular weights of 350 (γ-T3PGS 350) and 1000 (γ-T3PGS 1000) were synthesized by a two-step reaction procedure and characterized by (1)H NMR, HPLC, and mass spectroscopy. The physical properties of their self-assemblies in water were characterized by zeta, CMC, and size analysis. Similar physical properties were found between the PEGylated T3 and vitamin E TPGS. PEGylated T3 were also found to retain the in vitro cytotoxic activity of the free T3 against the MCF-7 and the triple-negative MDA-MB-231 breast cancer cells. PEGylated γ-T3 also increased the oral bioavailability of γ-T3 by threefolds when compared to the bioavailability of γ-T3 formulated into a self-emulsified drug delivery system. No significant differences in biological activity were found between the PEG 350 and 100 conjugates. Results from this study suggest that PEGylation of γ-T3 represents a viable platform for the oral and parenteral delivery of γ-T3 for potential use in the prevention of breast cancer.

Marine natural products-inspired phenylmethylene hydantoins with potent in vitro and in vivo antitumor activities via suppression of Brk and FAK signaling

Breast and prostate cancers are among the most common cancers worldwide with devastating statistics for the metastatic, chemotherapy- and radiotherapy-resistant phenotypes. Novel therapies interfering with new and/or multiple pathways involved in the pathology of cancer are urgently needed. Preliminary results showed that the marine natural product Z-4-hydroxyphenylmethylene hydantoin (PMH, ) and its 4-ethylthio-analog (SEth, ) promoted tight junction formation and showed anti-invasive and anti-migratory activities in vitro against metastatic prostate cancer cells and inhibited tumor growth and micrometastases in distant organs in orthotopic and transgenic mice models. This study focuses on the design and synthesis of second-generation PMHs with enhanced antitumor activities. A series of substituted benzaldehydes was selected based on earlier SAR studies and reacted with hydantoin to yield 11 new compounds . Compounds were evaluated for their antiproliferative, antimigratory and anti-invasive properties in vitro against the human mammary and prostate cancer cell lines MDA-MB-231 and PC-3, respectively. A Western blot analysis of the most active analog showed its ability to suppress the expression of the total levels of c-Met and FAK, with subsequent reduction of their phosphorylated (activated) levels in MDA-MB-231 cells. In addition, also inhibited Brk, paxillin and Rac1 phosphorylation. was formulated using hydroxypropyl β-cyclodextrin (HPCD) to improve its solubility and was further evaluated in a nude mice xenograft model using MDA-MB-231/GFP cells. PMH reduced breast tumor growth and suppressed Ki-67, CD31, p-Brk and p-FAK expression in tumor samples. Thus, is a potential lead for the control of invasive breast malignancies.

Enhanced solubility and oral bioavailability of γ-tocotrienol using a self-emulsifying drug delivery system (SEDDS)

The aim of this study was to evaluate the in vitro and in vivo performance of γ-tocotrienol (γ-T3) incorporated in a self-emulsifying drug delivery system (SEDDS) and to compare its enhanced performance to a commercially available product, namely Tocovid Suprabio™ (hereafter Tocovid), containing tocotrienols. The solubilization of γ-T3 was tested in a dynamic in vitro lipolysis model followed by in vitro cellular uptake study for the lipolysis products. In addition, in vitro uptake studies using Caco2 cells were conducted at different concentrations of γ-T3 prepared as SEDDS, Tocovid, or mixed micelles. γ-T3 incorporated in SEDDS or Tocovid was orally administered to rats at different doses and absolute oral bioavailability from both formulations were determined. The dynamic in vitro lipolysis experiment showed about two fold increase in the solubilization of γ-T3 prepared as SEDDS compared to Tocovid, which correlated with higher cellular uptake in the subsequent uptake studies. In vitro cellular uptake and in vivo oral bioavailability studies have shown a twofold increase in the cellular uptake and oral bioavailability of γ-T3 incorporated in SEDDS compared to Tocovid as a result of improvement in its solubility and passive uptake as confirmed by in vitro studies. In conclusion, incorporation of γ-T3 in SEDDS formulation enhanced γ-T3 solubilization and passive permeability, thus its cellular uptake and oral bioavailability when compared to Tocovid.

Oxazine derivatives of γ- and δ-tocotrienol display enhanced anticancer activity in vivo

BACKGROUND

Oxazine derivatives of tocotrienols display enhanced anticancer activity. Studies were conducted to further characterize these effects in vivo.

MATERIALS AND METHODS

Tetrazolium assay was used to determine the inhibitory effects of oxazine derivatives of γ-tocotrienol and δ-tocotrienol in vitro. These compounds were further formulated as lipid nanoemulsions and intralesional administration was used to examine their anticancer activity in vivo.

RESULTS

Tocotrienol oxazine derivatives significantly inhibited +SA mammary tumor growth in syngeneic mice as compared to their respective parent compound, and these effects were associated with a reduction in cell proliferation and survival (phosphorylated protein kinase B (AKT) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), and cyclooxygenase-2 (COX2) and cell-cycle progression (cyclin D1, cyclin-dependent kinase 2 (CDK2), CDK4 and CDK6) markers, and increase in cell-cycle arrest proteins (p21 and p27).

CONCLUSION

Tocotrienol oxazine derivatives may provide benefit as therapeutic agents against breast cancer.

Entrapment into nanoemulsions potentiates the anticancer activity of tocotrienols against the highly malignant (+SA) mouse mammary epithelial cells

The highly malignant +SA mouse mammary epithelial cells were used as the model cell line over the years to establish the anticancer activity of tocotrienols. Tocotrienols, however, have poor oral bioavailability and were therefore entrapped into parenteral nanoemulsions for parenteral administration. The objective of this work was to test whether the activity of tocotrienols in lipid nanoemulsions against the +SA cells was retained. A secondary objective was to test whether stabilizing the nanoemulsions with poloxamer or sodium oleate would affect their activity. Nanoemulsions were found to be significantly more potent than tocotrienol/albumin conjugate. The IC50 values of the poloxamer and sodium oleate nanoemulsions were 3 and 6 microM, respectively, whereas the IC50 value of the conjugate was 10 microM. The antiproliferative activity of the nanoemulsions was also found to inversely correlate with particle size. No activity was observed with nanoemulsions loaded with alpha-tocopherol or vehicle, which confirmed the cytotoxic activity of tocotrienols and the potential use of nanoemulsions in cancer therapy.

Effect of lipid viscosity and high-pressure homogenization on the physical stability of "Vitamin E" enriched emulsion

Recently there has been a growing interest in vitamin E for its potential use in cancer therapy. The objective of this work was therefore to formulate a physically stable parenteral lipid emulsion to deliver higher doses of vitamin E than commonly used in commercial products. Specifically, the objectives were to study the effects of homogenization pressure, number of homogenizing cycles, viscosity of the oil phase, and oil content on the physical stability of emulsions fortified with high doses of vitamin E (up to 20% by weight). This was done by the use of a 27-run, 4-factor, 3-level Box-Behnken statistical design. Viscosity, homogenization pressure, and number of cycles were found to have a significant effect on particle size, which ranged from 213 to 633 nm, and on the percentage of vitamin E remaining emulsified after storage, which ranged from 17 to 100%. Increasing oil content from 10 to 20% had insignificant effect on the responses. Based on the results it was concluded that stable vitamin E rich emulsions could be prepared by repeated homogenization at higher pressures and by lowering the viscosity of the oil phase, which could be adjusted by blending the viscous vitamin E with medium-chain triglycerides (MCT).

Effect of PEG surface conformation on anticancer activity and blood circulation of nanoemulsions loaded with tocotrienol-rich fraction of palm oil

Tocotrienol-rich fraction of palm oil, which contains the isomers of vitamin E, was shown to possess potent anticancer activity against mammary adenocarcinoma cell lines. Its clinical use, however, is limited by poor oral bioavailability and short half-life. Previously, we developed tocotrienol-rich lipid nanoemulsions for intravenous administration. The objective of this study was to investigate the effect of surface grafted polyethylene glycol (PEG) on the properties of the nanoemulsions. PEGylation was achieved by the addition of equimolar PEG groups using poloxamer or 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)2000] (PEG2000-DSPE). The effect of PEG surface topography on the antiproliferative activity of nanoemulsions against mammary adenocarcinoma cells, their susceptibility to protein adsorption, and its effect on blood hemolysis and circulation time was investigated. Nanoemulsions PEGylated with poloxamer or PEG2000-DSPE were stable under physical stress. Poloxamer nanoemulsion, however, displayed higher uptake and potency against MCF-7 tumor cells in 2D and 3D culture and increased hemolytic effect and susceptibility to IgG adsorption, which was reflected in its rapid clearance and short circulation half-life (1.7 h). Conversely, PEGylation with PEG2000-DSPE led to a 7-fold increase in mean residence time (12.3 h) after IV injection in rats. Reduced activity in vitro and improved circulation time suggested strong shielding of plasma proteins from the droplets. Differences between the nanoemulsions were attributed to polymer imbibitions and the differences in PEG conformation and density on the surface of the droplets.

Nonlinear absorption kinetics of self-emulsifying drug delivery systems (SEDDS) containing tocotrienols as lipophilic molecules: in vivo and in vitro studies

Self-emulsifying drug delivery systems (SEDDS) have been broadly used to promote the oral absorption of poorly water-soluble drugs. The purpose of the current study was to evaluate the in vivo oral bioavailability of vitamin E isoforms, δ-tocotrienol (δ-T3) and γ-tocotrienol (γ-T3) administered as SEDDS, as compared to commercially available UNIQUE E® Tocotrienols capsules. Results from studies in rats showed that low dose treatment with δ-T3 (90%) and γ-T3 (10%) formulated SEDDS showed bioavailability of 31.5% and 332%, respectively. However, bioavailability showed a progressive decrease with increased treatment dose that displayed nonlinear absorption kinetics. Additional in vitro studies examining cellular uptake studies in Caco 2 cells revealed that the SEDDS formulation increased passive permeability of δ-T3 and γ-T3 by threefold as compared to the commercial capsule formulation. These studies also showed that free surfactants decreased δ-T3 and γ-T3 absorption. Specifically, combined treatment cremophor EL or labrasol with tocotrienols caused a 60-85% reduction in the cellular uptake of δ-T3 and γ-T3 and these effects appear to result from surfactant-induced inhibition of the δ-T3 and γ-T3 transport protein Niemann-Pick C1-like 1 (NPC1L1). In summary, results showed that SEDDS formulation significantly increases the absorption and bioavailability δ-T3 and γ-T3. However, this effect is self-limiting because treatment with increasing doses of SEDDS appears to be associated with a corresponding increase in free surfactants levels that directly and negatively impact tocotrienol transport protein function and results in nonlinear absorption kinetics and a progressive decrease in δ-T3 and γ-T3 absorption and bioavailability.

Preparation and characterization of cosmeceutical liposomes loaded with avobenzone and arbutin

The objective of this study was to develop and characterize a liposome delivery system coencapsulating two cosmeceutical ingredients, avobenzone (AVO) and arbutin (AR). Two different liposome preparation methods, that is, thin film hydration and reverse-phase evaporation, were evaluated. To obtain the optimal formulation, various ratios of lipid to AVO or AR were tested. The effects of liposome formulation and preparation method on particle size, entrapment efficiency (EE), and skin permeation rate were studied. The mean particle size of the liposome formulations obtained by the thin film hydration method was smaller than that obtained by the reverse-phase evaporation method. The EE of AR and AVO in liposomes prepared by the thin film method, however, was lower than that prepared by the reverse-phase evaporation method. No differences in membrane permeation were observed between the two preparation methods. A large portion of AR permeated through the membrane into the receptor chamber. On the other hand, AVO remained in the donor chamber or accumulated in the membrane. The results of this study revealed that liposomes are a promising delivery system for coencapsulated AR and AVO. Liposomes may aid in retaining the sunscreen (AVO) at the surface of the skin for sun protection meanwhile facilitating the penetration of the whitening agent (AR) into the deeper layers of the skin for whitening effect.