Developing Transdermal Applications of Ketorolac Tromethamine Entrapped in Stimuli Sensitive Block Copolymer Hydrogels.

PURPOSE: In order to obtain dermal vehicles of ketorolac tromethamine (KT) for the local treatment of inflammation and restrict undesirable side effects of systemic levels hydrogels (HGs) of poloxamer and carbomer were developed. METHODS: KT poloxamer based HG (KT-P407-HG) and KT carbomer based HG (KT-C940-HG) were elaborated and characterized in terms of swelling, degradation, porosity, rheology, stability, in vitro release, ex vivo permeation and distribution skin layers. Finally, in vivo anti-inflammatory efficacy and skin tolerance were also assessed. RESULTS: HGs were transparent and kept stable after 3 months exhibiting biocompatible near neutral pH values. Rheological patterns fitted to Herschel-Bulkley for KT-C940-HG and Newton for KT-P407-HG due to its low viscosity at 25°C. Rapid release profiles were observed through first order kinetics. Following the surface the highest concentration of KT from C940-HG was found in the epidermis and the stratum corneum for P407-HG. Relevant anti-inflammatory efficacy of KT-P407-HG revealed enough ability to provide sufficient bioavailability KT to reach easily the site of action. The application of developed formulations in volunteers did not induce any visual skin irritation. CONCLUSIONS: KT-P407-HG was proposed as suitable formulation for anti-inflammatory local treatment without theoretical systemic side effect.

Cytotoxic Evaluation of (2S)-5,7-Dihydroxy-6-prenylflavanone Derivatives Loaded PLGA Nanoparticles against MiaPaCa-2 Cells.

The search for new alternatives for the prevention and treatment of cancer is extremely important to minimize human mortality. Natural products are an alternative to chemical drugs, since they are a source of many potential compounds with anticancer properties. In the present study, the (2S)-5,7-dihydroxy-6-prenylflavanone (semi-systematic name), also called (2S)-5,7-dihydroxy-6-(3-methyl-2-buten-1-yl)-2-phenyl-2,3-dihydro-4H-1-Benzopyran-4-one (CAS Name registered) (1) was isolated from Eysenhardtia platycarpa leaves. This flavanone 1 was considered as the lead compound to generate new cytotoxic derivatives 1a, 1b, 1c and 1d. These compounds 1, 1a, 1b, 1c, and 1d were then loaded in nanosized drug delivery systems such as polymeric nanoparticles (NPs). Small homogeneous spherical shaped NPs were obtained. Cytotoxic activity of free compounds 1, 1a, 1b, 1c, and 1d and encapsulated in polymeric NPs (NPs1, NPs1a, NPs1b, NPs1c and NPs1d) were evaluated against the pancreatic cancer cell line MiaPaCa-2. The obtained results demonstrated that NPs1a and NPs1b exhibited optimal cytotoxicity, and an even higher improvement of the cytotoxic efficacy was exhibited with the encapsulation of 1a. Based on these results, NPs1a were proposed as promising anticancer agent candidates.

Development of Clotrimazole Multiple W/O/W Emulsions as Vehicles for Drug Delivery: Effects of Additives on Emulsion Stability.

Multiple emulsions have attracted considerable attention in recent years for application as potential delivery systems for different drugs. The aim of the present work is to design a new formulation containing clotrimazole (CLT) loaded into multiple emulsions by two-step emulsification method for transdermal delivery. Different ingredients and quantities like primary and secondary co-emulsifiers and the nature of oily phase were assayed in order to optimize the best system for good. Resulting formulations were characterized in terms of droplet size, conductivity, pH, entrapment efficiency, rheological behavior, and stability under various storage conditions for 180 days. pH values of multiple emulsions containing CLT ranged from 7.04 ± 0.03 to 6.23 ± 0.04. Droplet size increased when increasing concentration of sorbitan stearate. The addition of polysorbate 80 resulted in significant decrease of oil droplet size comparing with those prepared without this. CLT entrapment efficiency ranged between 85.64% and 97.47%. All formulations exhibited non-Newtonian pseudoplastic flow with some apparent thixotropic behavior. Cross and Herschel-Bulkley equations were the models that best fitted experimental data. In general, the addition of 1% polysorbate 80 resulted in a decrease of viscosity values. No signals of optical instability were observed, and physicochemical properties remained almost constant when samples were stored at room temperature after 180 days. On the contrary, samples stored at 40°C exhibited pronounced increase in conductivity values 24 h after elaboration and some of them were unstable after 180 days of storage. JMLP01 was proposed as an innovative and stable system to incorporate CLT as active pharmaceutical ingredient.

Melatonin Delivery: Transdermal and Transbuccal Evaluation in Different Vehicles.

PURPOSE: Melatonin (MLT) could be candidate drug for treatment of several diseases because of its high antioxidant and anticarcinogenic activity and its important biological roles. The aim of this study was to assess the influence of different vehicles on the permeation of MLT through buccal and skin tissues. METHODS: Formulations were characterized in terms of rheology, drug release and permeation through human skin as well as porcine buccal mucosa. Irradiation experiments were also performed. RESULTS: The lowest amount of MLT released was from oral adhesive paste Orabase® (OB) and the highest from the emulsion system Montanov® 68 (M68). Skin permeation revealed high pattern for Carbopol® 940 (C940) and M68, and poor for poloxamer 407 (P407) and Pluronic® lecithin organogel (PLO). Statistical differences of MLT remaining in skin between M68 vs C940 (p < 0.05) and M68 vs PLO (p < 0.05) were observed. Transmucosal results showed that sodium carboxymethylcellulose (NaCMC) was the best and OB the worst vehicle. P407 and PLO followed similar behaviour. Photostability studies revealed high percentage of degradation of MLT in solution which was also similar when was loaded in OB. The rest of formulations showed low rates of degradation. CONCLUSIONS: C940 or M68 and NaCMC can be proposed as formulations for a potential systemic effect of MLT by skin and buccal mucosa routes, respectively. However, if the intended objective is to obtain local action in the skin and buccal mucosa, the proposed formulations are M68 or P407 and PLO.

Release profile and transscleral permeation of triamcinolone acetonide loaded nanostructured lipid carriers (TA-NLC): in vitro and ex vivo studies.

Nanostructured lipid carriers (NLC) have been developed for sustained release of triamcinolone acetonide (TA), a corticosteroid commonly indicated for macular edema, neovascularization, and other ocular inflammatory disorders. TA-NLC were prepared by high-pressure homogenization and characterized for in vitro release by dialysis bag. Ex vivo permeation profile was assessed using rabbit sclera isolated and mounted in Franz diffusion cells. TA-NLC were placed in episcleral donor compartment and choroidal side was perfused with HEPES buffer. Tissue sections underwent drug wash-out, following analysis by validated RP-HPLC of drug content and perfused fractions collected over 24 hours. Drug release followed one-order kinetics and permeability studies confirmed that TA is able to diffuse across rabbit sclera in sustained profile, following zero-order kinetics. Strong tissue binding was observed, providing a drug depot. These findings are of potential use when designing future TA therapy strategies for ocular diseases of posterior segment.

Melatonin nanogel promotes skin healing response in burn wounds of rats.

Aim: Development of a melatonin nanogel intended for wound healing (WH) application. Materials & methods: The main components of the nanogel were poloxamer 407, chitosan and hyaluronic acid. The nanogel was characterized by the assessment of physical interactions, swelling, wettability, rheological properties and internal structure. The drug release, antimicrobial efficacy against different strains and biocompatibility with human keratinocytes were also tested. Finally, the WH efficacy was evaluated in rats. Results: The nanogel showed optimal physicochemical properties and an internal network of interconnected channels from which melatonin was released following first order kinetics. Antimicrobial activity was similar to commercial reference material and it promoted epidermis growth with evident wound contraction. Conclusion: Melatonin nanogel can be proposed as a promising system for WH.

Development of a buccal doxepin platform for pain in oral mucositis derived from head and neck cancer treatment.

This study describes the development of semisolid formulations containing doxepin (DOX) for pain relief in oral mucositis, frequently related to chemotherapy and/or radiotherapy treatments in patients with head and neck cancer. Chemical permeation enhancers were evaluated and selected according to the results obtained from rheological studies, drug release, and drug permeation and retention through buccal mucosa. Finally, the selected formulation was compared in vivo, with a reference DOX mouthwash, whose clinical efficacy had been previously reported. The obtained findings showed that an orabase® platform loading transcutol® (10%) and menthol (5%) for the buccal vehiculization of DOX exhibited a decreased elastic and viscous behavior improving its application. The main drug release mechanism could be considered as diffusion according to Higuchi model. Obtained DOX permeation rates were considered optimal for an analgesic effect and far below to an antidepressant activity. Similar in vivo plasma concentrations were found for the semisolid formulation and the reference mouthwash. However, DOX amounts retained in the mucosa of animals for the semisolid formulation were higher than the reference, which let us hypostatize even stronger potential local therapeutic effect with additional advantages such as, mucoadhesive properties, absence of alcohol, some degree of freshness, as well as, drug palatability improvement.

In vitro, ex vivo and in vivo characterization of PLGA nanoparticles loading pranoprofen for ocular administration.

Pranoprofen (PF) is a NSAID considered as a safe anti-inflammatory treatment for strabismus and/or cataract surgery. The drug has been formulated in poly (lactic/glycolic) acid (PLGA) nanoparticles (PF-F1NPs with cPF 1.5mg/mL, PF-F2NPs with cPF 1mg/mL) produced by solvent displacement technique and tested the in vitro cytotoxicity, ex vivo corneal permeation, in vivo ocular tolerance and in vivo anti-inflammatory efficacy of PF-F1NPs, PF-F2NPs, in comparison to eye drops conventional dosage form (Oftalar(®), PF 1mg/mL) and free drug solution (PF dissolved in PBS, 1.5mg/mL). The mean particle size of both formulations was around 350nm, with polydispersity index below 0.1, and a net negative charge of -7.41mV and -8.5mV for PF-F1NPs and PF-F2NPs, respectively. Y-79 human retinoblastoma cell line was used to evaluate the cytotoxicity of PF-F1NPs and PF-F2NPs, which were compared to blank NPs and free drug solution (PF dissolved in PBS, 1.5mg/mL). Concentrations up to 75µg/mL exhibited no toxicity to Y-79 cells, whereas at 150µg/mL a decrease of about 80% on the cell viability was observed after exposing the cells to PF-F1NPs. When treating the Y-79 cells with concentrations of PF-F2NPs between 1µg/mL to 100µg/mL, the cell viability was similar to control values after 24h and 48h of exposure. An ex vivo corneal permeation study was carried out in New Zealand rabbits. A very similar profile has been observed for the permeation of PF through the cornea when administered as eye drops and as free drug solution, which was kept much lower in comparison to PF-NPs formulations. The permeated amount of PF from the PF-F1NPs was slightly smaller than from PF-F2NPs, attributed to the increase of viscosity of the formulations with the increase of cPVA concentration. New Zealand white rabbits were also used to evaluate the irritancy of PF-F1NPs and PF-F2NPs, which demonstrated to be well-tolerated to the eye (i.e. the mean total score (MTS) was 0). PF-F2NPs exhibited the highest QP (amounts of PF permeated in the cornea) and significantly reduced the ocular edema compared to the tested formulations. The QR (amounts of PF retained in the cornea) of the PF-F1NPs was greater than that obtained for PF-F2NPs.

Ex vivo permeation of carprofen from nanoparticles: A comprehensive study through human, porcine and bovine skin as anti-inflammatory agent.

The purpose of this study was the development of poly(d,l-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) for the dermal delivery of carprofen (CP). The developed nanovehicle was then lyophilized using hydroxypropyl-ß-cyclodextrin (HPßCD) as cryoprotectant. The ex vivo permeation profiles were evaluated using Franz diffusion cells using three different types of skin membranes: human, porcine and bovine. Furthermore, biomechanical properties of skin (trans-epidermal water loss and skin hydration) were tested. Finally, the in vivo skin irritation and the anti-inflammatory efficacy were also assayed. Results demonstrated the achievement of NPs 187.32 nm sized with homogeneous distribution, negatively charged surface (-23.39 mV) and high CP entrapment efficiency (75.38%). Permeation studies showed similar diffusion values between human and porcine skins and higher for bovine. No signs of skin irritation were observed in rabbits. Topically applied NPs significantly decreased in vivo inflammation compared to the reference drug in a TPA-induced mouse ear edema model. Thus, it was concluded that NPs containing CP may be a useful tool for the dermal treatment of local inflammation.

Biopharmaceutical profile of hydrogels containing pranoprofen-loaded PLGA nanoparticles for skin administration: In vitro, ex vivo and in vivo characterization.

Pranoprofen (PF)-loaded nanoparticles (PF-F1NPs and PF-F2NPs) have been formulated into blank hydrogels (HG_PF-F1NPs and HG_PF-F1NPs) or into hydrogels composed of 3% azone (HG_PF-F1NPs-Azone and HG_PF-F2NPs-Azone), as innovative strategy to improve the biopharmaceutical profile of the selected non-steroidal anti-inflammatory drug (Pranoprofen, PF) for topical application. The purpose of this approach has been to increase the contact of PF with the skin, improve its retention in deeper layers, thus enhancing its anti-inflammatory and analgesic effects. The physicochemical characterization of the developed hydrogels showed a non-Newtonian behaviour, typical of semi-solid formulations for skin administration, with sustained release profile. The results obtained from ex vivo skin human permeation and in vivo anti-inflammatory efficacy studies suggest that topical application of HG_PF-F2NPs has been more effective in the treatment of oedema on the skin' surface in comparison to other hydrogels. No signs of skin irritancy have been detected for all the semi-solid formulations containing 0% or 3% azone.

Enhanced topical delivery of hyaluronic acid encapsulated in liposomes: A surface-dependent phenomenon.

In the present study, we investigated the release and permeation of hyaluronic acid (HA) encapsulated in liposomes when deposited onto two surfaces: cellulose, a model widely used for investigating transport of drugs; and human skin, a natural biointerface used for transdermal drug delivery. We prepared and characterised liposomes loaded with HA and liposomes incorporating two penetration enhancers (PEs): the non-ionic surfactant Tween 80, and Transcutol P, a solubilising agent able to mix with polar and non-polar solvents. In vitro and ex vivo permeation assays showed that PEs indeed enhance HA-release from liposomes. Since one of the possible mechanisms postulated for the action of liposomes on skin is related to its adsorption onto the stratum corneum (SC), we used atomic force microscopy (AFM) topography and force volume (FV) analysis to investigate the structures formed after deposition of liposome formulations onto the investigated surfaces. We explored the possible relationship between the formation of planar lipid structures on the surfaces and the permeation of HA.

Design and elaboration of freeze-dried PLGA nanoparticles for the transcorneal permeation of carprofen: Ocular anti-inflammatory applications.

This work aimed the design and development of poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) for the ocular delivery of Carprofen (CP) by a central rotatable composite design 2(3)+ star. NPs showed adequate size for ocular administration (189.50 ± 1.67 nm), low polydispersity (0.01 ± 0.01), negative charge surface (-22.80 ± 0.66 mV) and optimal entrapment efficiency (74.70 ± 0.95%). Physicochemical analysis confirmed that CP was dispersed inside the NPs. The drug release followed a first order kinetic model providing greater sustained CP release after lyophilization. Ex vivo permeation analysis through isolated rabbit cornea revealed that a sufficient amount of CP was retained in the tissue avoiding excessive permeation and thus, potential systemic levels. Ex vivo ocular tolerance results showed no signs of ocular irritancy, which was also confirmed by in vivo Draize test. In vivo ocular anti-inflammatory efficacy test confirmed an optimal efficacy of NPs and its potential application in eye surgery.

Nanoemulsions (NEs), liposomes (LPs) and solid lipid nanoparticles (SLNs) for retinyl palmitate: effect on skin permeation.

The aim of this study was to develop biocompatible lipid-based nanocarriers for retinyl palmitate (RP) to improve its skin delivery, photostability and biocompatibility, and to avoid undesirable topical side effects. RP loaded nanoemulsions (NEs), liposomes (LPs) and solid lipid nanoparticles (SLNs) were characterized in terms of size, surface electrical charge, pH, drug encapsulation efficiency and morphology. Spherical-shaped nanocarriers with a negatively charged surface (>|40|mV) and mean size lower than 275 nm were produced with adequate skin compatibility. The rheological properties showed that aqueous dispersions of SLNs followed a non-Newtonian behavior, pseudoplastic fluid adjusted to Herschel-Bulkley equation, whereas LPs and NEs exhibited a Newtonian behavior. SLNs offered significantly better photoprotection than LPs and NEs for RP. The cumulative amount of drug permeated through human skin at the end of 38 h was 6.67 ± 1.58 µg, 4.36 ± 0.21 µg and 3.64 ± 0.28 µg for NEs, LPs and SLNs, respectively. NEs flux was significantly higher than SLNs and LPs: NEs (0.37 ± 0.12 µg/h) > LPs (0.15 ± 0.09 µg/h) > SLNs (0.10 ± 0.05 µg/h). LPs offered significant higher skin retention than NEs and SLNs. Finally, even though all developed nanocarriers were found to be biocompatible, according to histological studies, NE was the system that most disrupted the skin. These encouraging findings can guide in proper selection of topical carriers among the diversity of available lipid-based nanocarriers, especially when a dermatologic or cosmetic purpose is desired.

Design of nanosuspensions and freeze-dried PLGA nanoparticles as a novel approach for ophthalmic delivery of pranoprofen.

Pranoprofen (PF)-loaded poly (lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were optimized and characterized as a means of exploring novel formulations to improve the biopharmaceutical profile of this drug. These systems were prepared using the solvent displacement technique, with polyvinyl alcohol (PVA) as a stabilizer. A factorial design was applied to study the influence of several factors (the pH of the aqueous phase and the stabilizer, polymer and drug concentrations) on the physicochemical properties of the NPs. After optimization, the study was performed at two different aqueous phase pH values (4.50 and 5.50), two concentrations of PF (1.00 and 1.50 mg/mL), three of PVA (5, 10, and 25 mg/mL), and two of PLGA (9.00 and 9.50 mg/mL). These conditions produced NPs of a size appropriate particle size for ocular administration (around 350 nm) and high entrapment efficiency (80%). To improve their stability, the optimized NPs were lyophilized. X-ray, FTIR, and differential scanning calorimetry analysis confirmed the drug was dispersed inside the particles. The release profiles of PF from the primary nanosuspensions and rehydrated freeze-dried NPs were similar and exhibited a sustained drug delivery pattern. The ocular tolerance was assessed by an HET-CAM test. No signs of ocular irritancy were detected (score 0).

Improving ex vivo skin permeation of non-steroidal anti-inflammatory drugs: enhancing extemporaneous transformation of liposomes into planar lipid bilayers.

Transdermal delivery of active principles is a versatile method widely used in medicine. The main drawback for the transdermal route, however, is the low efficiency achieved in the absorption of many drugs, mostly due to the complexity of the skin barrier. To improve drug delivery through the skin, we prepared and characterized liposomes loaded with ibuprofen and designed pharmaceutical formulations based on the extemporaneous addition of penetration enhancer (PE) surfactants. Afterwards, permeation and release studies were carried out. According to the permeation studies, the ibuprofen liposomal formulation supplemented with PEs exhibited similar therapeutic effects, but at lower doses (20%) comparing with a commercial formulation used as a reference. Atomic force microscopy (AFM) was used to investigate the effect caused by PEs on the adsorption mechanism of liposomal formulations onto the skin. Non-fused liposomes, bilayers and multilayered lipid structures were observed. The transformation of vesicles into planar structures is proposed as a possible rationale for explaining the lower doses required when a liposome formulation is supplemented with surfactant PEs.