Bioadhesive 3D-Printed Skin Drug Delivery Polymeric Films: From the Drug Loading in Mesoporous Silica to the Manufacturing Process.

The alliance between 3D printing and nanomaterials brings versatile properties to pharmaceuticals, but few studies have explored this approach in the development of skin delivery formulations. In this study, clobetasol propionate (CP) was loaded (about 25% w/w) in mesoporous silica nanomaterial (MSN) to formulate novel bioadhesive and hydrophilic skin delivery films composed of pectin (5% w/v) and carboxymethylcellulose (5% w/v) by 3D printing. As a hydrophobic model drug, CP was encapsulated in MSN at a 3:1 (w/w) ratio, resulting in a decrease of CP crystallinity and an increase of its dissolution efficiency after 72 h (65.70 ± 6.52%) as compared to CP dispersion (40.79 ± 4.75%), explained by its partial change to an amorphous form. The CP-loaded MSN was incorporated in an innovative hydrophilic 3D-printable ink composed of carboxymethylcellulose and pectin (1:1, w/w), which showed high tensile strength (3.613 ± 0.38 N, a homogenous drug dose (0.48 ± 0.032 mg/g per film) and complete CP release after 10 h. Moreover, the presence of pectin in the ink increased the skin adhesion of the films (work of adhesion of 782 ± 105 mN·mm). Therefore, the alliance between MSN and the novel printable ink composed of carboxymethylcellulose and pectin represents a new platform for the production of 3D-printed bioadhesive films, opening a new era in the development of skin delivery systems.

Phenytoin-loaded lipid-core nanocapsules improve the technological properties and in vivo performance of fluidised bed granules.

Lipid-core nanocapsules (LNCs) were recently reported by our group as a suitable binder system to produce fluidised bed granules. However, there is still a lack of knowledge about the influence of using these nanocarriers loaded with a drug on the properties of the granules and their in vivo performance. Therefore, this study was designed to produce innovative fluidised bed granules containing phenytoin-loaded LNCs (LNCPHT) as a strategy to evaluate the influence of the presence of the drug-loaded nanocarriers on their in vitro and in vivo properties. Granules were produced using a mixture of maltodextrin and phenytoin (1:0.004 w/w) as substrate. They were prepared by fluid bed granulation using water or LNCPHT as the liquid binder, affording good yields (73-82%) of granules with low moisture content (<5%). Granules prepared with LNCPHT had larger mean size (122 µm) compared to maltodextrin primary particles (50 µm) due to the formation of solid bridges. Moreover, the use of LNCPHT as the liquid binder improved their powder flow properties. The nanocarriers were recovered after aqueous dispersion (3.00 mg.mL-1 of PHT) with a redispersibility close to 90%. After reconstitution in water, granules containing LNCPHT showed an improved dissolution behaviour compared to those prepared without them. In addition, they showed a higher mucoadhesive effect due to a combined effect of the LNCPHT and maltodextrin in the interactions with porcine intestinal mucosa. Regarding the in vivo studies, granules containing the combination of non-encapsulated PHT and PHT-loaded lipid-core nanocapsules increased the latency to seizures compared to placebo granules, showing effective anticonvulsant effect in mice. In conclusion, the use of drug-loaded nanocapsules as binder is an encouraging approach to produce fluidised bed mucoadhesive granules with improved technological properties and in vivo performance.

Liquid chromatography method to assay tretinoin in skin layers: validation and application in skin penetration/retention studies.

A liquid chromatography (LC) method for the quantification of tretinoin (TTN) in different matrices (adhesive tape, cotton and porcine skin layers, stratum corneum, viable epidermis, and dermis) was validated and applied in in vitro porcine skin penetration/retention studies. This study proposes, for the first time, a method for assaying TTN in separated porcine skin layers (stratum corneum, viable epidermis, and dermis). The skin studies were carried out using tape stripping and cutaneous retention techniques. The procedures for the extraction of TTN from dermatological formulations (creams and gels) and biological and non-biological matrices used with the tape stripping and retention techniques were also evaluated. The LC method consisted of a mobile phase composed of a mixture of methanol, water, and glacial acetic acid (85:15:1, v/v); a C18 column used as the stationary phase; a flow rate of 1.0 mL min-1; an injection volume of 100 µL; and TTN detection at 342 nm. The method was linear in the range of 0.05-15.00 µg mL-1 (r = 0.9999), and it was precise and accurate. The limit of detection (LOD) and limit of quantification (LOQ) were 0.0165 µg mL-1 and 0.0495 µg mL-1, respectively. TTN was extracted from different matrices, showing good precision [relative standard deviation (RSD) of <5%] and accuracy (89.4-113.9%). This method was successfully applied in the evaluation of TTN skin retention/permeation from dermatological formulations (cream and gel). A higher penetration of TTN through the skin was achieved with the gel rather than the cream, showing the influence of the dosage form. Therefore, the developed method can easily be applied in porcine skin penetration/retention studies of dermatological formulations containing TTN, and it is able to discriminate the behaviours of the different formulations.

Co-Nanoencapsulation of Vitamin D3 and Curcumin Regulates Inflammation and Purine Metabolism in a Model of Arthritis.

We analyzed the effects of a nanoencapsulated association of curcumin and vitamin D3 on purine metabolism enzymes in neutrophils, lymphocytes, and platelets in a model of adjuvant-induced arthritis (AIA) in rats. Following AIA induction, the animals were treated for 15 days with free and nanoencapsulated curcumin (4 mg/kg), nanocapsules of vitamin D3 (VD3) (15.84 IU/day), a nanoencapsulated combination of curcumin and VD3, vehicle, or blank nanocapsules. The animals were euthanized, and blood was collected to evaluate the activities of E-NTPDase, adenosine deaminase (ADA), and myeloperoxidase (MPO), as well as reactive oxygen species (ROS) levels and biochemical parameters. Also, the liver and kidney were collected for histological analysis. The changes in the activities of purinergic enzymes indicated that inflammation was significantly reverted by vitamin D3 and curcumin co-nanoencapsulation treatments in the arthritic rats. The reduction of inflammation was confirmed by the reduction in the signs and symptoms of AIA, as well as in MPO activity by all formulations. The treatments with nanocapsules reverted histological alterations in the kidney. Serum parameters were not altered by the induction or treatments. Our results suggest that co-nanoencapsulation of vitamin D3 and curcumin is an efficient alternative adjuvant treatment for rheumatoid arthritis as it reverts the changes in the purine metabolism and reduces arthritis-associated inflammation.

Chitosan hydrogels containing nanoencapsulated phenytoin for cutaneous use: Skin permeation/penetration and efficacy in wound healing.

Although phenytoin is an antiepileptic drug used in the oral treatment of epilepsy, its off-label use as a cutaneous healing agent has been studied in recent years due to the frequent reports of gingival hyperplasia after oral administration. However, the cutaneous topical application of phenytoin should prevent percutaneous skin permeation. Therefore, the aim of this study was to evaluate the in vitro skin permeation/retention and in vivo effects of nanocapsules and nanoemulsions loaded with phenytoin and formulated as chitosan hydrogels on the healing process of cutaneous wounds in rats. The hydrogels had adequate pH values (4.9-5.6) for skin application, drug content of 0.025% (w/w), and non-Newtonian pseudoplastic rheological behaviour. Hydrogels containing nanocapsules and nanoemulsions enabled improved controlled release of phenytoin and adhesion to skin, compared with hydrogels containing non-encapsulated phenytoin. In vitro skin permeation studies showed that phenytoin permeation to the receptor compartment, and consequently the risk of systemic absorption, may be reduced by nanoencapsulation without any change in the in vivo performance of phenytoin in the wound healing process in rats.

Tailoring structural properties of spray-dried methotrexate-loaded poly (lactic acid)/poloxamer microparticle blends.

Drug delivery systems can overcome cancer drug resistance, improving the efficacy of chemotherapy agents. Poly (lactic acid) (PLA) microparticles are an interesting alternative because their hydrophobic surface and small particle size could facilitate interactions with cells. In this study, two poloxamers (PLX 407 and 188) were applied to modulate the structural features, the drug release behavior and the cell viability from spray-dried microparticles. Five formulations with different PLA: PLX blend ratio (100:0, 75:25, 50:50, 25:50, and 0:100) were well-characterized by SEM, particle size analysis, FTIR spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction analysis (XRD). The spray-dried microparticles showed higher drug loading, spherical-shape, and smaller particle size. The type of poloxamer and blend ratio affected their structural and functional properties such as morphology, crystallinity, blend miscibility, drug release rate, and cell viability. The methotrexate (MTX), a model drug, was loaded in amorphous spray-dried microparticles. Moreover, the drug release studies demonstrated that PLX induced a leaching-effect of MTX from PLA: PLX blends, suggesting the formation of MTX/PLX micelles in aqueous medium. This finding was better established by cell viability assays. Therefore, biocompatible PLA: PLX blends showed promising in vitro results, and further in vivo studies will be performed to evaluate the performance of this chemotherapeutic agent.

Reconstituted spray-dried phenytoin-loaded nanocapsules improve the in vivo phenytoin anticonvulsant effect and the survival time in mice.

This study evaluated the in vivo anticonvulsant effect of a spray-dried powder for reconstitution containing phenytoin-loaded lipid-core nanocapsules. The effect of chitosan coating on redispersibility, gastrointestinal stability, and drug release from nanoparticles was evaluated during the development of the powders. Maltodextrin was used as adjuvant in the spray-drying process. Chitosan coating played an important role in redispersibility, and large particles (>100 µm) were obtained using the highest concentration of solids in the feed. However, after aqueous redispersion, volume-based particle size was reduced to about 1 µm. The release of nanoparticles from the surface of the spherical microagglomerates (roundness index = 0.75) was confirmed by SEM analysis. Powders reconstituted in water recovered partially the nanometric properties of the original suspensions and were stable for 24 h. Phenytoin-loaded chitosan-coated nanocapsules and their redispersed powders have good gastrointestinal stability, and are able to control drug release in simulated gastric and intestinal fluids. Besides that, the reconstituted powder containing chitosan-coated nanocapsules exhibited improved anticonvulsant activity against seizures induced by pilocarpine in mice, compared to the non-encapsulated drug, representing an important approach in anticonvulsant treatments for children and adults.