Evaluation of methotrexate-loaded surfactants, ceramides and cholesterol-based lamellar phases as a topical treatment for psoriasis.

OBJECTIVE: Psoriasis is a chronic inflammatory skin disorder. Oral or subcutaneous methotrexate (MTX) is a first-line antipsoriatic treatment, whose adverse effects can be observed even at low doses. To minimize systemic side effects, antipsoriatic drugs should be administered topically, since they could permeate the stratum corneum. As liquid crystals with lamellar phase (LP) can be helpful in promoting skin permeation, this work evaluated two MTX-loaded LPs (C1CH and C1CHCE), based on stearic acid, cholesterol and ceramides, like topical treatments for mice with imiquimod-induced psoriasis. METHODS: C1CH and C1CHCE were topically administered to mice with imiquimod-induced psoriasis. Dexamethasone cream was used as positive treatment control. Skin histology and inflammation biomarkers were assessed. KEY FINDINGS: C1CH and C1CHCE exhibited marked immunomodulatory effects and induced extensive microstructural skin remodelling on the epidermis and dermis. These formulations increased keratinization score, epidermis thickness, inflammatory infiltrate, hair follicle hypertrophy and vascular congestion in the dermis. C1CH and C1CHCE also attenuated IL-10 upregulation and upregulated IL-1, IFN-γ, TNF-α and prostaglandin E2 levels, as well as myeloperoxidase, N-acetyl-ß-d-glucosaminidase and cyclooxygenase 2 activity compared with untreated psoriatic animals. CONCLUSION: Although liquid crystals have been reported as good options for carrying topical drugs, they need to be carefully assessed on a case-by-case basis.

Influence of the ionic strength on the physicochemical properties of methotrexate-loaded chitosan polyelectrolyte complexes

Abstract Polyelectrolyte complexes (PECs) as drug delivery systems are widely explored since they are easily obtained by coacervation and biopolymers can be associated. However, particle distribution is a challenging critical parameter that has been infrequently focused. This work evaluated the effect of NaCl concentration on the physicochemical properties of PECs based on chitosan and hypromellose loaded with methotrexate. The particle size, zeta potential and polydispersity index (PdI) were determined by DLS, besides of drug entrapment efficiency (EE) and in vitro drug release profile determination. Particle size decreased while NaCl concentration rised, achieving a narrower size distribution of (345±79 nm) and PdI (0.285±0.067) with 200 mmol/L NaCl. The higher the NaCl concentration, the lower the zeta potential at acid pH. The EE was kept similar ((28.2±4.5) %) from 0 to 300 mmol/L NaCl, while 400 mmol/L NaCl impaired the drug entrapment. The addition of (200 and 300) mmol/L NaCl did not affect the drug release profile, but it was faster with (100 or 400) mmol/L. In conclusion, the addition of 200 mmol/L NaCl reduced particle size and PdI with no changes in the EE and drug release. Therefore, the ionic strength plays an important role on PECs development.

Preclinical Evaluation of Polymeric Nanocomposite Containing Pregabalin for Sustained Release as Potential Therapy for Neuropathic Pain.

This study offers a novel oral pregabalin (PG)-loaded drug delivery system based on chitosan and hypromellose phthalate-based polymeric nanocomposite in order to treat neuropathic pain (PG-PN). PG-PN has a particle size of 432 ± 20 nm, a polydispersity index of 0.238 ± 0.001, a zeta potential of +19.0 ± 0.9 mV, a pH of 5.7 ± 0.06, and a spherical shape. Thermal and infrared spectroscopy confirmed nanocomposite generation. PG-PN pharmacokinetics was studied after a single oral dose in male Wistar rats. PG-PN showed greater distribution and clearance than free PG. The antinociceptive effect of PG-PN in neuropathic pain rats was tested by using the chronic constriction injury model. The parameter investigated was the mechanical nociceptive threshold measured by the von Frey filaments test; PG-PN showed a longer antinociceptive effect than free PG. The rota-rod and barbiturate sleep induction procedures were used to determine adverse effects; the criteria included motor deficit and sedative effects. PG-PN and free PG had plenty of motors. PG-PN exhibited a less sedative effect than free PG. By prolonging the antinociceptive effect and decreasing the unfavorable effects, polymeric nanocomposites with pregabalin have shown promise in treating neuropathic pain.

Preclinical study of methotrexate-based hydrogels versus surfactant based liquid crystal systems on psoriasis treatment.

Psoriasis is an autoimmune, inflammatory and chronic skin disease in which cell growth and proliferation are increased, causing erythema, lesions and skin's peeling. Oral methotrexate (MTX) is the first-choice drug when phototherapy or retinoid treatment are not effective. Topical administration can be advantageous to better orientate the drug's delivery; however, the stratum corneum performs as a barrier for hydrofilic drugs penetration. This study sought to evaluate two different types of vehicles for MTX on the psoriasis treatment - hydrogel and liquid crystal systems (LCs). Lamellar and hexagonal liquid crystalline phases were selected from a ternary phase diagram based on polysorbate 80, isopropyl miristate and water. The hydrogel was based on alkylated carbomer (ACH). Rheological analysis showed ACH was more elastic than lamellar and hexagonal phases. ACH interacted better with pig skin than LCs in bioadhesion assay. Preclinical study revealed the ACH decreased inflammation in mice with induced psoriasis, being as effective as dexamethasone to regulate epidermis thickness, COX-2 and myeloperoxidase activity and TNF-α level, while LCs demonstrated inflammatory effect. Therefore, MTX-loaded hydrogel based platforms are indicated for local treatment of psoriasis and present great potential for further studies.

The liquid crystalline phase behaviour of a nasal formulation modifies the brain disposition of donepezil in rats in the treatment of Alzheimer's disease.

Although nanoparticles, polymeric micelles, liposomes, nanoemulsions, and microemulsions were extensively evaluated as formulations for nasal administration of drugs, lyotropic liquid crystal (LLC) mesophases have been few studied. The phase transition from a low-viscosity microemulsion to a more viscous LLC may improve the mucoadhesion of the formulation. Donepezil is a drug administered orally in the treatment of Alzheimer's disease, and with gastrointestinal side effects that are typical of acetylcholinesterase inhibitors. Based on this, donepezil administration by nasal pathway using a mucoadhesive LLC may be a feasible alternative. A colloidal formulation was selected from a ternary diagram, combining CETETH-10, oleic acid, and water (40:45:15, w/w). Donepezil was incorporated into the formulation, and the characterisation included in vitro studies, such as mucoadhesion and drug release. Pharmacokinetics in Wistar rats included evaluations by the nasal pathway with donepezil incorporated into microemulsion. A phase transition from an isotropic to an anisotropic system was observed after the swelling of the microemulsion with artificial nasal fluid (12-20 %). The release of donepezil in vitro occurred in a sustained manner. Significant levels of donepezil were achieved in the brain after nasal administration of the microemulsion, as a promising strategy for the treatment of Alzheimer's disease.

Preclinical evaluation of methotrexate-loaded polyelectrolyte complexes and thermosensitive hydrogels as treatment for rheumatoid arthritis.

This work proposes new methotrexate (MTX) loaded drug delivery systems (DDS) to treat rheumatoid arthritis via the intra-articular route: a poloxamer based thermosensitive hydrogel (MTX-HG), oligochitosan and hypromellose phthalate-based polyelectrolyte complexes (MTX-PEC) and their association (MTX-PEC-HG). MTX-PEC showed 470 ± 166 nm particle size, 0.298 ± 0.108 polydispersity index, +26 ± 2 mV and 74.3 ± 5.8% MTX efficiency entrapment and particle formation was confirmed by infrared spectroscopy and thermal analysis. MTX-HG and MTX-PEC-HG gelled at 36.7°C. MTX drug release profile was prolonged for MTX-HG and MTX-PEC-HG, and faster for MTX-PEC and free MTX. The in vivo effect of the MTX-DDSs systems was evaluated in induced arthritis rats as single intra-articular dose. The assessed parameters were the mechanical nociceptive threshold, the plasmatic IL-1ß level and histological analysis of the tibiofemoral joint. MTX-HG and MTX-PEC-HG performance were similar to free MTX and worse than oral MTX, used as positive control. All DDSs showed some irritative effect, for which further studies are required. MTX-PEC was the best treatment on recovering cartilage damage and decreasing allodynia. Thus, MTX-PEC demonstrated potential to treat rheumatoid arthritis, with the possibility of decreasing the systemic exposure to the drug.

Mucoadhesive nanostructured lipid carriers as a cannabidiol nasal delivery system for the treatment of neuropathic pain.

The therapeutic potential of cannabidiol (CBD) has been explored to treat several pathologies, including those in which pain is prevalent. However, the oral bioavailability of CBD is low owing to its high lipophilicity and extensive first-pass metabolism. Considering the ability of the nasal route to prevent liver metabolism and increase brain bioavailability, we developed nanostructured lipid carriers (NLCs) for the nasal administration of CBD. We prepared particles with a positively charged surface, employing stearic acid, oleic acid, Span 20Ⓡ, and cetylpyridinium chloride to obtain mucoadhesive formulations. Characterisation of the CBD-NLC dispersions showed uniform nano-sized particles with diameters smaller than 200 nm, and high drug encapsulation. The mucoadhesion of cationic particles has been related to interactions with negatively charged mucin. Next, we added in-situ gelling polymers to the CBD-NLC dispersion to obtain a CBD-NLC-gel. A thermo-reversible in-situ forming gel was prepared by the addition of PluronicsⓇ. CBD-NLC-gel was characterised by its gelation temperature, rheological behaviour, and mucoadhesion. Both formulations, CBD-NLC and CBD-NLC-gel, showed high mucoadhesion, as assessed by the flow-through method and similar in vitro drug release profiles. The in vivo evaluation showed that CBD-NLC dispersion (without gel), administered intranasally, produced a more significant and lasting antinociceptive effect in animals with neuropathic pain than the oral or nasal administration of CBD solution. However, the nasal administration of CBD-NLC-gel did not lessen mechanical allodynia. These findings demonstrate that in-situ gelling hydrogels are not suitable vehicles for highly lipophilic drugs such as CBD, while cationic CBD-NLC dispersions are promising formulations for the nasal administration of CBD.

Novel Insights to Enhance Therapeutics With Acyclovir in the Management of Herpes Simplex Encephalitis.

Acyclovir is an antiviral drug poorly absorbed in the gastrointestinal tract due to its hydrophilicity, with low oral bioavailability (~20%). Although acyclovir is prescribed in the management of herpes simplex encephalitis (HSE), the disease has a poor prognosis, particularly if the treatment is delayed, reaching mortality rates of 70% if left untreated. Thus, high acyclovir doses are administered by intravenous (IV) infusion, usually at a dosage of 10 mg kg-1 8-hourly in adults with normal renal function. However, the mortality related to HSE treated with acyclovir remains high (~20%) and permanent sequelae are commonly reported after 1 year (~50%). This review analyzed clinical trials following IV acyclovir administration. Novel insights aiming to improve drug bioavailability were reviewed, including acyclovir or its prodrugs, leading to the systemic distribution of the drug or drug targeting. Much research effort has been made to improve antiviral therapy, searching for delivery systems increasing acyclovir bioavailability by non-invasive pathways, such as oral and nasal pathways, or parenterally administered nanotechnology-based systems leading to drug targeting. Nanocarriers administered by non-invasive pathways represent feasible alternatives to treat HSE, even though not be industrially manufactured yet.

Serum analysis in women and in vitro skin assay for the assessment of exposure to parabens in antiperspirants.

The present study assessed the exposure to methylparaben (MP) and propylparaben (PP) from antiperspirants in serum of 24 women aged 20-30 years old and an in vitro skin assay. An effective liquid chromatography-tandem mass spectrometry method for the determination of MP and PP levels in serum was developed and validated in the range of 10-100 µg/L; the method was fast, simple, sensitive, linear, precise, and accurate. In addition, a simple and rapid liquid chromatography-ultraviolet detection method for the determination of MP and PP levels in antiperspirants was developed and validated in the range of 2-26 mg/L, which presented satisfactory linearity, precision, and accuracy. Using these two methods, 20 commercial antiperspirants were evaluated, and only three showed MP and PP in the formulation. The antiperspirant containing 0.2% and 0.1% w/w MP and PP, respectively, was given to the volunteers, to estimate the internal dose, and submitted to a pig ear skin permeation assay in Franz diffusion cells, presenting a permeation flux of 32% for MP and 71% for PP. In this assay, both MP and PP permeated the skin; however, there was no correlation between antiperspirant use and paraben serum concentration in the volunteers. Graphical abstract.

Evaluation of polyelectrolyte and emulsion covalent crosslink of chitosan for producing mesalasine loaded submicron particles

This study evaluates various techniques for producing mesalamine (5ASA)-loaded particles employing chitosan as a biopolymer: (1) the polyelectrolyte complexation of chitosan with phthalate hypromelose (HP), (2) the chemical crosslinking of chitosan with genipin and (3) the water-in-oil emulsion method associated with chemical crosslinking with genipin. Systems were characterized by dynamic light scattering, zeta potential (ζ), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and a drug release profile. Method (1) was efficiently produced unloaded nanoparticles (491 nm, PdI=0.26 and ζ = 23.2), but the conditions for chitosan and HP cross-linking enhanced the precipitation of 5ASA. Method (2) caused the degradation of the drug. Method 3 produced sub-micron and microparticles, thereby varying the agitation method; 3 h magnetic agitation resulted in 2692 nm, Pdi = 0.6 and ζ = 46, while Ultra-Turrax, 5 min produced submicron particles (537 nm, PdI = 0.6). The percentage yield was approximately 50%, which is very satisfactory considering the impossibility of encapsulating 5ASA using other methods. FTIR showed the covalent interaction of chitosan and genipin. The drug release was rapid in acidic fluid, but in neutral pH a slower release was obtained in the initial stage, followed by rapid release, which may ensure the controlled release of 5ASA in the colon.