Experimental evaluation of icodextrin delivery as pressurized aerosol (PIPAC): Antiadhesive and cytotoxic effects.

BACKGROUND: Icodextrin (IDX) is an antiadhesive polymer that can be used as a carrier solution for intraperitoneal (IP) delivery of chemotherapeutic drugs. METHODS: We investigated the suitability of IDX solution as a carrier of Cisplatin and Doxorubicin for delivery as pressurized intraperitoneal aerosol chemotherapy (PIPAC). We examined the sprayability of IDX, the aerosol characteristics, the stability of the molecule after aerosolization, the effects of IDX on the adhesion of MKN45 human gastric cancer cells, the synergistic effect of aerosolized IDX with Cisplatin and Doxorubicin, and the chemical stability of IDX, Cisplatin, and Doxorubicin in combination. RESULTS: Delivery of IDX as PIPAC is feasible with no particular restrictions. The median droplet size of 35.7 µm did not change at increasing concentrations. IDX withstood the shear forces applied by the nebulizer and remained stable after aerosolization (ANOVA, p = 0.97). IDX did not impair the cytotoxic effects of Cisplatin and Doxorubicin (ns). IDX had a significant antiadhesive impact alone (p < 0.03) and in combination with Cisplatin and Doxorubicin (p < 0.02). IDX as a carrier for Cisplatin and Doxorubicin remained stable at 4 °C for three months and did not cause degradation of those two substances. CONCLUSION: The proposed combination takes advantage of the antiadhesive properties of IDX, the cytotoxic effect of Cisplatin and Doxorubicin, and an advanced drug delivery system.

Enhanced intraperitoneal delivery of charged, aerosolized curcumin nanoparticles by electrostatic precipitation.

Aims: To investigate the potential of curcumin-loaded polylactic-co-glycolic acid nanoparticles (CUR-PLGA-NPs), alone and with electrostatic precipitation, for improving tissue uptake during pressurized intraperitoneal aerosol chemotherapy (PIPAC). Methods: Positively and negatively charged CUR-PLGA-NPs were delivered as PIPAC into inverted bovine urinary bladders ex vivo. The experiment was repeated with the additional use of electrostatic precipitation pressurized intraperitoneal aerosol chemotherapy (electrostatic PIPAC). Results: Positively charged CUR-PLGA-NPs increased depth of tissue penetration by 81.5% and tissue concentration by 80%. Electrostatic precipitation further improved the uptake of positively charged CUR-PLGA-NPs by 41.8%. Conclusion: The combination of positive charge and electrostatic precipitation have significant potential to improve tissue uptake of nanoparticles during intraperitoneal chemotherapy.

Nanostructured Lipid Carriers (NLCs) for Drug Delivery: Role of Liquid Lipid (Oil).

In recent years, SLNs and NLCs are among the popular drug delivery systems studied for the delivery of lipophilic drugs. Both systems have demonstrated several beneficial properties as an ideal drug-carrier, optimal drug-loading, and good long-term stability. NLCs are getting popular due to their stability advantages and the possibility to load various oil components either as an active or as a matrix. This review screens types of oils used till date in combination with solid lipids to form NLCs. These oils are broadly classified into two categories: Natural oils and Essential oils. NLCs offer range of advantages in drug delivery due to the formation of an imperfect matrix owing to the presence of oil. The type and percentage of oil used, determine optimal drug loading and stability. Literature shows that a variety of oils is/are used in NLCs mainly as the matrix, which is from natural origin, triglycerides class. On the other hand, essential oils not only serve as a matrix but also as an active moiety. In short, oil is the key ingredient in the formation of NLCs, hence it needs to be selected wisely as per the performance criteria expected. The aim of this article is to discuss shortly the role of liquid lipids and highlight the use of variety of oils in NLCs preparation.

Nanoformulation of Leonotis leonurus to improve its bioavailability as a potential antidiabetic drug.

Nanostructured lipid carriers (NLCs) of Leonotis leonurus were successfully produced using high-pressure homogenisation (HPH) on a LAB 40 homogeniser. The particle size was determined for the formulation as well as short-term stability study. The formulation was exposed to Chang liver cells for a glucose uptake study and to INS-1 cells for a chronic insulin release study under normoglycaemic and hyperglycaemic conditions. The particle size of the extract NLC was 220 nm with a PdI of 0.08 after homogenisation at 800 bar. The formulation was stable at the tested temperatures. The extract NLC formulation at 1 µg/ml improved glucose uptake, relative to the control liver cells. Insulin release in INS-1 cells was also elevated under hyperglycaemic conditions when exposed to the NLCs, in comparison with the control untreated cells and the non-formulated extract. The plant extract encapsulated in NLC improved the uptake of glucose and enhanced the insulin sensitivity in vitro, compared to the extract.

Polyethylene glycol (PEG): a versatile polymer for pharmaceutical applications.

INTRODUCTION: Polyethylene glycol (PEG) is a polymer of choice in drug delivery systems. This USFDA-approved polymer is popular due to its tunable properties and well-established safety profile: prime requisites considered during the selection of any excipient in formulation development. AREAS COVERED: The unique properties and applications of PEG have been discussed at length in the existing literature. However, a proper guidance on selection of PEG grade to cater to one's purpose is lacking. This article provides preliminary guidelines to formulators on selection of appropriate PEG grade, typically based on its physico-chemical properties and role-based functional application in pharmaceuticals. It should be noted that the aim article is not to deep dive in each application area. EXPERT OPINION: Guidance on PEG application and grade of choice is lacking in the available literature. The authors have discussed and provided guidance to formulators on the appropriate PEG grade selection for particular application based on the available in vitro and in vivo literature data. In this review a State-of-the-art use of PEG in therapeutic applications, its clinical status and commercial use is also summarized. Nevertheless, toxicities related to different PEG grades and related impurities are discussed in this review.

Therapeutic interventions in sepsis: current and anticipated pharmacological agents.

Sepsis is a clinical syndrome characterized by a multisystem response to a pathogenic assault due to underlying infection that involves a combination of interconnected biochemical, cellular and organ-organ interactive networks. After the withdrawal of recombinant human-activated protein C (rAPC), researchers and physicians have continued to search for new therapeutic approaches and targets against sepsis, effective in both hypo- and hyperinflammatory states. Currently, statins are being evaluated as a viable option in clinical trials. Many agents that have shown favourable results in experimental sepsis are not clinically effective or have not been clinically evaluated. Apart from developing new therapeutic molecules, there is great scope for for developing a variety of drug delivery strategies, such as nanoparticulate carriers and phospholipid-based systems. These nanoparticulate carriers neutralize intracorporeal LPS as well as deliver therapeutic agents to targeted tissues and subcellular locations. Here, we review and critically discuss the present status and new experimental and clinical approaches for therapeutic intervention in sepsis.

Trehalose is not a universal solution for solid lipid nanoparticles freeze-drying.

OBJECTIVE: To prepare stable and easy to handle formulation of solid lipid nanoparticles (SLNs) by freeze-drying with or without cryoprotectants, as appropriate. MATERIALS AND METHODS: SLNs were freeze-dried without cryoprotectants or with cryoprotectants in quantities selected by freeze-thaw test (sucrose, glucose) or literature search (trehalose, maltose). Appearance, re-dispersability and size distribution of re-dispersed samples were evaluated. RESULTS: SLN could be freeze-dried using 10% sucrose, trehalose or maltose. Trehalose was effective in protecting one of presented formulations that was already very stable on its own; its efficiency in protecting other two formulations was limited. DISCUSSION: Our results are in line with various reports of successful freeze-drying of SLN, but considering the stability of original dispersions, no improvement was achieved. CONCLUSION: We confirmed that trehalose is among the most suitable cryoprotectant for SLN, however it did not improve shelf-life of the most stable formulation.

Effect of four different size reduction methods on the particle size, solubility enhancement and physical stability of nicergoline nanocrystals.

Nicergoline, a poorly soluble active pharmaceutical ingredient, possesses vaso-active properties which causes peripheral and central vasodilatation. In this study, nanocrystals of nicergoline were prepared in an aqueous solution of polysorbate 80 (nanosuspension) by using four different laboratory scale size reduction techniques: high pressure homogenization (HPH), bead milling (BM) and combination techniques (high pressure homogenization followed by bead milling HPH + BM, and bead milling followed by high pressure homogenization BM + HPH). Nanocrystals were investigated regarding to their mean particles size, zeta potential and particle dissolution. A short term physical stability study on nanocrystals stored at three different temperatures (4, 20 and 40 °C) was performed to evaluate the tendency to change in particle size, aggregation and zeta potential. The size reduction technique and the process parameters like milling time, number of homogenization cycles and pressure greatly affected the size of nanocrystals. Among the techniques used, the combination techniques showed superior and consistent particle size reduction compared to the other two methods, HPH + BM and BM + HPH giving nanocrystals of a mean particle size of 260 and 353 nm, respectively. The particle dissolution was increased for any nanocrystals samples, but it was particularly increased by HPH and combination techniques. Independently to the production method, nicergoline nanocrystals showed slight increase in particle size over the time, but remained below 500 nm at 20 °C and refrigeration conditions.

Long-term stability of quercetin nanocrystals prepared by different methods.

OBJECTIVES: This study aimed to examine the long-term physical stability of quercetin nanocrystals produced by three methods. METHODS: Quercetin nanocrystals were prepared by high pressure homogenization, bead milling and cavi-precipitation. The nanocrystals produced by these methods were compared for particle size, saturation solubility and dissolution of the drug particles, and were subjected to stability testing. KEY FINDINGS: The X-ray diffraction study and microscopic pictures taken under polarized light indicated the crystalline nature of the nanocrystals produced by the three methods. As the crystalline state is relatively more stable than the amorphous state, a good physical stability was expected from the quercetin nanocrystals prepared. The high-pressure homogenized and bead-milled quercetin nanocrystals showed excellent physical stability when stored under refrigeration (4±2°C) and at room temperature (25±2°C) for 180 days. The dissolution properties were not significantly affected on storage at room temperature. However, increase in the storage temperature to 40±2°C led to physical instability. On the other hand, the cavi-precipitated quercetin nanocrystals exhibited a lower stability than the bead-milled and homogenized formulations and did not show the optimum zeta potential values as well. In the case of cavi-precipitated nanocrystals, recrystallization and agglomeration were responsible for the increasing particle size besides the Ostwald ripening phenomenon. The solvents used during cavi-precipitation might have competed with the surfactant for hydration leading to a partial dehydration of the surfactant, which subsequently affected the stability of the quercetin nanocrystals. CONCLUSIONS: High-pressure homogenized and bead-milled quercetin nanocrystals showed better physical stability than the cavi-precipitated ones. Freeze drying immediately after nanocrystal production can help to prevent their agglomeration and thus improve physical stability.

Carotenoid lutein: a promising candidate for pharmaceutical and nutraceutical applications.

Carotenoids play a major role in scavenging singlet oxygen and peroxyl radicals in human. Several studies have shown that lutein and zeaxanthin help to protect the skin and eyes from photodamage and offer several other health benefits. The potential benefits of using lutein as nutritional or cosmetic ingredient are reviewed in this paper. Recent advances in health and cosmetic care provided by lutein are also discussed. This review also mentions various drug carrier systems that have been studied for the delivery of lutein.

Fabrication of quercetin nanocrystals: comparison of different methods.

The main aim of this study was to prepare quercetin nanocrystals using three fabrication methods, viz. high-pressure homogenization, bead milling, and cavi-precipitation. The three fabrication methods were compared in terms of particle size, saturation solubility, and dissolution of the products obtained. The average particle size of the coarse quercetin was 50.1 µm. The three methods produced quercetin particles in the nanometre range (276-787 nm) and the smallest nanocrystals of around 276.7 nm were fabricated by bead milling. The particle size, polydispersity index, zeta potential, and saturation solubility values for the products fabricated by both high-pressure homogenization and bead mill were similar and thus both represented an efficient means to fabricate quercetin nanosuspensions. According to X-ray diffraction analysis, all nanocrystals were still in the crystalline state after being fabricated by the three methods. The cavi-precipitated product exhibited larger particle size and did not show an optimum stability as suggested by the zeta potential values. However, cavi-precipitated quercetin nanosuspension showed the higher saturation solubility due to the presence of ethanol. The bead milled products with the lowest particle size exhibited a saturation solubility of 25.59 ± 1.11 µg/ml, approximately nine times higher than coarse quercetin. Overall, the dissolution rates of the quercetin nanosuspensions fabricated by these three methods enhanced compared to the coarse quercetin.

Surface modified nevirapine nanosuspensions for viral reservoir targeting: In vitro and in vivo evaluation.

Most of the time HIV virus escape immunological burden exerted by antiretroviral drugs and develops resistance against therapy. For complete eradication of virus from body one has to use long term chemotherapies, which results in drug toxicity, drug resistance and eventually poor patient compliance. Nevirapine (NNRTI, non nucleoside reverse transcriptase inhibitor) nanosuspensions were developed and surface modified with serum albumin, polysaccharide and polyethylene glycol to enhance its targeting potential. The biodistribution studies revealed improved antiretroviral drug accumulation in various organs of rat for nanosuspensions as compared to the plain drug solution when administered intravenously. Nanosuspension after surface modification showed further enhancement in accumulation. Higher MRT values of surface coated nanosuspension in brain, liver and spleen as compared to pure drug solution ensured enhanced bioavailability and prolonged residence of the drug at the target site.

Lutein nanocrystals as antioxidant formulation for oral and dermal delivery.

Lutein is a well known antioxidant and anti-free radical used in cosmetic, nutraceutical industry with potential application in pharmaceutics as supportive antioxidant in treatments. As lipophilic molecule it is poorly soluble in water and has a low bioavailability. Lutein nanosuspension was prepared to enhance dissolution velocity, saturation solubility (C(s)), which are major factors determining oral bioavailability and penetration into the skin. High pressure homogenization (HPH) was used to prepare lutein nanosuspension. Particle size was determined by photon correlation spectroscopy (PCS) and laser diffractometry (LD). The lowest PCS diameter obtained was about 429 nm, the LD diameter 90% of 1.2 µm. The zeta potential was about -40 mV in water and -17 mV in the original dispersion medium. The 3 month storage study at different temperatures (4°C, 25°C, 40°C) confirmed physical stability despite the low zeta potential of -17 mV in original surfactant solution. A pronounced increase in saturation solubility by 26.3 fold was obtained for lutein nanocrystals compared to coarse powder. The lutein nanosuspension was converted into pellets and filled into hard gelatin capsules for nutraceutical use, showed a superior in vitro release (factor of 3-4). Lyophilized nanosuspension was prepared for subsequent incorporation into creams and gels. The lyophilized nanosuspension was very well re-dispersible (435 nm). Using cellulose nitrate membranes as in vitro model, permeation through this barrier was 14× higher for lutein nanocrystals compared to coarse powder. However, pig ear skin did not allow lutein to permeate but supported localization of the lutein in the skin where it should act anti-oxidatively.

Production and characterization of antioxidant apigenin nanocrystals as a novel UV skin protective formulation.

Flavonoids have many positive effects on various cell layers of the skin (e.g. anti-oxidant, anti-allergic and anti-inflammatory effects). However, the limiting factor of the use of flavonoids is their low water solubility. To overcome the poor solubility, apigenin nanosuspensions were prepared using the combination technology (CT), i.e. bead milling and subsequently high pressure homogenization. Distinct reduction in particle size was observed after each bead milling passage resulting in z-average (PCS) of 413 nm and a polydispersity index of 0.202. The LD data showed a similar pattern of particle size reduction reaching a diameter 99% (d(v)99%) of 0.515 µm. The antioxidant capacity of apigenin nanocrystals were almost doubled compared to the original coarse suspension. The developed smartCrystals can be easily incorporated into gels, which makes apigenin nanocrystals available for dermal application as efficient antioxidant.

Lipid nanocarriers for dermal delivery of lutein: preparation, characterization, stability and performance.

Topical application of lutein as an innovative antioxidant, anti-stress and blue light filter, which is able to protect skin from photo damage, has got a special cosmetic and pharmaceutical interest in the last decade. Lutein is poorly soluble, and was therefore incorporated into nanocarriers for dermal delivery: solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and a nanoemulsion (NE). Nanocarriers were produced by high pressure homogenization. The mean particle size was in the range of about 150 nm to maximum 350 nm, it decreased with increasing oil content of the carriers. The zeta potential in water was in the range -40 to -63 mV, being in agreement with the good short term stability at room temperature monitored for one month. In vitro release was studied using a membrane free model. Highest release in 24h was observed for the nanoemulsion (19.5%), lowest release (0.4%) for the SLN. Release profiles were biphasic (lipid nanoparticles) or triphasic (NE). In vitro penetration study with a cellulose membrane showed in agreement highest values for the NE (60% in 24h), distinctly lower values for the solid nanocarriers SLN and NLC (8-19%), lowest values for lutein powder (5%). Permeation studies with fresh pig ear skin showed that no (SLN, NLC) or very little lutein (0.4% after 24h) permeated, that means the active remains in the skin and is not systemically absorbed. The nanocarriers were able to protect lutein against UV degradation. In SLN, only 0.06% degradation was observed after irradiation with 10 MED (Minimal Erythema Dose), in NLC 6-8%, compared to 14% in the NE, and to 50% as lutein powder suspended in corn oil. Based on size, stability and release/permeation data, and considering the chemical protection of the lutein prior to its absorption into the skin, the lipid nanoparticles are potential dermal nanocarriers for lutein.

Present status of nanoparticle research for treatment of tuberculosis.

Nanotechnology has offered enormous improvement in field of therapeutics by means of designing of drug delivery systems and opened the possibility of controlling infections at the molecular level. Nanocarriers can cross biological barriers and are able to target cellular reservoirs of Mycobacterium tuberculosis (M. tuberculosis). Nanoparticle-based systems have significant potential for treatment and prevention of tuberculosis (TB). A variety of nanocarriers have been widely evaluated as potential drug delivery systems for various administration routes. Targeting the drugs to certain physiological sites such as the lymph nodes has emerged as a promising strategy in treating TB with improved drug bioavailability and reduction of the dosing frequency. Nanotechnology based rational targeting may improve therapeutic success by limiting adverse drug effects and requiring less frequent administration regimes, ultimately resulting in more patients compliance and thus attain higher adherence levels. The development of nanoparticle based aerosol vaccine is undergoing which could serve as new platform for immunization. Present article compiles the general physiological aspects of the infection along with the relevance nanocarriers used in prevention of tuberculosis.

20 years of lipid nanoparticles (SLN and NLC): present state of development and industrial applications.

In 1990, the lipid nanoparticles were invented in the laboratories, the first patent filings took place in 1991. The lipid nanoparticles were developed as alternative to traditional carriers such as polymeric nanoparticles and liposomes. After 20 years of lipid nanoparticles, the present state of development is reviewed - academic progress but also the development state of pharmaceutical products for the benefit of patients. Meanwhile many research groups are active worldwide, their results are reviewed which cover many different administration routes: dermal and mucosal, oral, intravenous/parenteral, pulmonary but also ocular. The lipid nanoparticles are also used for peptide/protein delivery, in gene therapy and various miscellaneous applications (e.g. vaccines). The questions of large scale production ability, accepted regulatory status of excipients, and - important for the public perception - lack of nanotoxicity are discussed, important pre-requisites for the use of each nanocarrier in products. Identical to the liposomes, the lipid nanoparticles entered first the cosmetic market, product examples are presented. Presently the pharmaceutical product development focuses on products for unmet needs and on niche products with lower development costs (e.g. ocular delivery), which can be realized also by smaller companies. A pharmaceutical perspective for the future is given, but also outlined the opportunities for non-pharmaceutical use, e.g. in nutraceuticals.

In vitro protein adsorption studies on nevirapine nanosuspensions for HIV/AIDS chemotherapy.

Nevirapine is a poorly water-soluble antiretroviral drug. Intravenous nevirapine nanosuspensions (NS) (457 ± 10 nm) were prepared by high-pressure homogenization. NS were surface modified by stabilizer adsorption, e.g., serum albumin, polysaccharide and polyethylene glycol (PEG) 1000. The NS were characterized for mean particle size, particle size distribution and polydispersity index. The targeting potential of the nonmodified and three surface-modified NS to the mononuclear phagocytic system (MPS) cells that serve as potent viral reservoirs was assessed by in vitro protein adsorption studies using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The adsorption patterns were qualitatively identical, but showed quantitative differences. The relatively adsorbed high amounts of immunoglobulins indicate uptake by liver and spleen, observed quantitative differences (e.g., the amount of dysopsonin albumin and apolipoproteins) can modulate the organ distribution. Controlled in vitro optimization of the protein adsorption by surface modification of the nanocrystals can reduce the number of animals required for in vivo studies and accelerate development of targeted nanoparticles. FROM THE CLINICAL EDITOR: In this study, intravenous nevirapine (a poorly water-soluble antiretroviral drug) nanosuspensions were prepared by high-pressure homogenization and characterized.

Formulation development and in vitro evaluation of didanosine-loaded nanostructured lipid carriers for the potential treatment of AIDS dementia complex.

The purpose of this article was to investigate the feasibility of incorporating didanosine (DDI) into nanostructured lipid carriers (NLC) for potential treatment of AIDS dementia complex. Aqueous DDI-free and DDI-loaded NLC were manufactured using hot high-pressure homogenization. The lipid matrix contained a mixture of Precirol® ATO 5 and Transcutol® HP. Photon correlation spectroscopy revealed that the mean particle size for all formulations was below 250 nm with narrow polydispersity indices. In addition, the d99% values for all formulations determined using laser diffractometry were below 400 nm with the span values ranging from 0.84 to 1.0. The zeta potential values ranged from -18.4 to -11.4 mV and the encapsulation efficiency of NLC for DDI ranged from 33.02% to 78.34%. These parameters remained relatively constant for all formulations tested following storage for 2 months at 25°C indicating that all the formulations were relatively stable. Differential scanning calorimetry revealed a decrease in the degree of crystallinity of NLC in all formulations developed relative to the bulk lipid material. In addition, wide-angle X-ray scattering showed that NLC in all formulations tested existed in a single ß-modification form and that DDI that had been incorporated into the NLC appeared to be molecularly dispersed in the lipid matrices. Images of the NLC formulations obtained using transmission electron microscopy revealed that all formulations contained a mixture of spherical and nonspherical particles irrespective of the amount of DDI that was added during the manufacture of the formulations.

Nanocrystals: industrially feasible multifunctional formulation technology for poorly soluble actives.

Poor solubility of new drugs and their related low oral bioavailability and general delivery problems are becoming a major challenge. Nanocrystals being a kind of "universal" formulation approach for these molecules are reviewed in this paper regarding the industrial feasibility, i.e. industrially available production processes (bottom-up and top-down technologies), regulatory aspects and nanotoxicology. This article also includes second generation nanocrystals (<<100 nm) as smartCrystals. The status of products on the market and in clinical phases is presented. The different special features of nanocrystals, which are exploited in different products, are described (tablets, capsule, aqueous nanosuspension). The main focus is given for oral and intravenous products. However, the potential and delivery strategies for other administration routes are discussed, i.e. dermal and mucosal, ocular, pulmonary and targeted delivery (e.g. via differential protein adsorption to the brain). In addition, the potential of the nanocrystal technology for delivery of poorly soluble, non-pharmaceutical actives is highlighted, i.e. in cosmetics or nutraceuticals.