Sublingual tablets containing spray-dried carvedilol-loaded nanocapsules: development of an innovative nanomedicine.

The aim of this study was to propose the use of spray-dried mucoadhesive carvedilol-loaded nanocapsules in the formulation of sublingual tablets. There is no previous report describing the preparation of tablets containing spray-dried nanocapsules or tablets containing nanocapsules, neither prepared by direct compression nor for sublingual administration. Tablets of 6 mm of diameter and 2.7 ± 0.2 mm of height were obtained with a mean weight of 44 ± 4 mg, carvedilol content of 0.164 ± 0.017 mg, and a disintegration time less than 25 min. They were produced using a force of 4.7 ± 1.6 kgf. The release profile of carvedilol from the tablets was evaluated using the dialysis bag method. In parallel, the release of nanocapsules from the tablet structure into the release medium was evaluated using dynamic light scattering. Nanocapsules that were released from the tablets into the release medium exhibited similar particle size distributions after recovery as in their original liquid suspension, without losing their original ability to control drug release. Therefore, sublingual tablets may be produced from spray-dried drug-loaded nanocapsules using a direct compression technique, providing a useful pharmaceutical approach for drugs that undergo first pass metabolism, such as carvedilol.

Anti-HPV Nanoemulsified-Imiquimod: A New and Potent Formulation to Treat Cervical Cancer.

Cervical cancer is associated with the human papilloma virus (HPV) and nowadays is the fourth most frequent cancer among women. One of the treatments for this disease is based on the application of imiquimod. In this study, we postulated that the use of imiquimod in nanoemulsion results in a better antitumoral effect than the drug administered in its nonencapsulated form for the treatment of cervical cancer. Permeability studies using vaginal mucosa, as membrane, and in vitro studies involving cervical cancer cells (viability, clonogenic assay, and cell death analysis) were performed. We showed that low amount of encapsulated imiquimod permeated the vaginal mucosa. However, a higher percentage of cells died after the treatment with low amount (3.0 µmol L-1) of the formulation compared to the free drug. In addition, the innovative formulation presented a combinatory mechanism of cell death involving autophagy and apoptosis. Our results demonstrate that the imiquimod-loaded nanoemulsioncan be an alternative product for the treatment of cervical cancer validating the hypothesis.

Doxazosin nanoencapsulation improves its in vitro antiproliferative and anticlonogenic effects on breast cancer cells.

Doxazosin has been evaluated for the treatment of several types of cancer. Here, the antitumor effect of the nanoencapsulated form of doxazosin was evaluated in an in vitro model of breast cancer (MCF7 cell line). Doxazosin-loaded polymeric nanocapsules (DXZ-NC) were produced by interfacial deposition of preformed polymer with homogeneous aspect, spherical shape, mean diameter of about 130nm, positive zeta potential (+5mV), and encapsulation efficiency close to 35%. The Alamar Blue® assay and cell counting were carried out to assess cell viability and cell number, respectively. Mechanism of death was evaluated by Annexin/Propidium Iodide staining, while the long-term response was assessed using the clonogenic assay. Nuclear morphometric analysis was investigated using the NMA technique. A significant decrease in cell viability and clonogenicity was observed after the treatment with DXZ-NC when compared to the non-encapsulated drug. All treatments induced apoptosis as the main mechanism of toxicity. In conclusion, the nanoencapsulation of doxazosin improved its in vitro effects in MCF7 cells, without changing the mechanism of cell death underlying its toxicity. This approach was fundamental to reduce the long-term in vitro ability of the remaining tumor cells to form new colonies after the treatment, potentially reducing the risk of tumor recurrence.

3D printed tablets loaded with polymeric nanocapsules: An innovative approach to produce customized drug delivery systems.

The generation of multi-functional drug delivery systems, namely solid dosage forms loaded with nano-sized carriers, remains little explored and is still a challenge for formulators. For the first time, the coupling of two important technologies, 3D printing and nanotechnology, to produce innovative solid dosage forms containing drug-loaded nanocapsules was evaluated here. Drug delivery devices were prepared by fused deposition modelling (FDM) from poly(ε-caprolactone) (PCL) and Eudragit® RL100 (ERL) filaments with or without a channelling agent (mannitol). They were soaked in deflazacort-loaded nanocapsules (particle size: 138nm) to produce 3D printed tablets (printlets) loaded with them, as observed by SEM. Drug loading was improved by the presence of the channelling agent and a linear correlation was obtained between the soaking time and the drug loading (r2=0.9739). Moreover, drug release profiles were dependent on the polymeric material of tablets and the presence of the channelling agent. In particular, tablets prepared with a partially hollow core (50% infill) had a higher drug loading (0.27% w/w) and faster drug release rate. This study represents an original approach to convert nanocapsules suspensions into solid dosage forms as well as an efficient 3D printing method to produce novel drug delivery systems, as personalised nanomedicines.

Nanocarriers for optimizing the balance between interfollicular permeation and follicular uptake of topically applied clobetasol to minimize adverse effects.

The treatment of various hair disorders has become a central focus of good dermatologic patient care as it affects men and women all over the world. For many inflammatory-based scalp diseases, glucocorticoids are an essential part of treatment, even though they are known to cause systemic as well as local adverse effects when applied topically. Therefore, efficient targeting and avoidance of these side effects are of utmost importance. Optimizing the balance between drug release, interfollicular permeation, and follicular uptake may allow minimizing these adverse events and simultaneously improve drug delivery, given that one succeeds in targeting a sustained release formulation to the hair follicle. To test this hypothesis, three types of polymeric nanocarriers (nanospheres, nanocapsules, lipid-core nanocapsules) for the potent glucocorticoid clobetasol propionate (CP) were prepared. They all exhibited a sustained release of drug, as was desired. The particles were formulated as a dispersion and hydrogel and (partially) labeled with Rhodamin B for quantification purposes. Follicular uptake was investigated using the Differential Stripping method and was found highest for nanocapsules in dispersion after application of massage. Moreover, the active ingredient (CP) as well as the nanocarrier (Rhodamin B labeled polymer) recovered in the hair follicle were measured simultaneously, revealing an equivalent uptake of both. In contrast, only negligible amounts of CP could be detected in the hair follicle when applied as free drug in solution or hydrogel, regardless of any massage. Skin permeation experiments using heat-separated human epidermis mounted in Franz Diffusion cells revealed equivalent reduced transdermal permeability for all nanocarriers in comparison to application of the free drug. Combining these results, nanocapsules formulated as an aqueous dispersion and applied by massage appeare to be a good candidate to maximize follicular targeting and minimize drug penetration into the interfollicular epidermis. We conclude that such nanotechnology-based formulations provide a viable strategy for more efficient drug delivery to the hair follicle. Moreover, they present a way to minimize adverse effects of potent glucocorticoids by releasing the drug in a controlled manner and simultaneously decreasing interfollicular permeation, offering an advantage over conventional formulations for inflammatory-based skin/scalp diseases.

Trypanocidal activity of free and nanoencapsulated curcumin on Trypanosoma evansi.

This study aimed to evaluate in vitro and in vivo trypanocidal activity of free and nanoencapsulated curcumin against Trypanosoma evansi. In vitro efficacy of free curcumin (CURC) and curcumin-loaded in lipid-core nanocapsules (C-LNCs) was evaluated to verify their lethal effect on T. evansi. To perform the in vivo tests, T. evansi-infected animals were treated with CURC (10 and 100 mg kg(-1), intraperitoneally [i.p.]) and C-LNCs (10 mg kg(-1), i.p.) during 6 days, with the results showing that these treatments significantly attenuated the parasitaemia. Infected untreated rats showed protein peroxidation and an increase of nitrites/nitrates, whereas animals treated with curcumin showed a reduction on these variables. As a result, the activity of antioxidant enzymes (superoxide dismutase and catalase) differs between groups (P<0.05). Infected animals and treated with CURC exhibited a reduction in the levels of alanine aminotransferase and creatinine, when compared with the positive control group. The use of curcumin in vitro resulted in a better parasitaemia control, an antioxidant activity and a protective effect on liver and kidney functions of T. evansi-infected adult male Wistar rats.

Submicron polymeric particles prepared by vibrational spray-drying: Semisolid formulation and skin penetration/permeation studies.

Topical glucocorticoids (TG) such as dexamethasone (DEX) have been used for decades for the treatment of skin diseases. However, TG present well-documented side effects and their delivery to the skin is often insufficient. Therefore, many efforts have been undergone to improve the amount of drug delivered to the skin and to reduce side effects at the same time. In this work, the feasibility of DEX-submicron polymeric particles (SP) prepared by vibrational spray-drying as an approach to overcome the challenges associated with the topical administration of this drug class was evaluated. DEX was homogeneously dispersed in the SP matrix, according to confocal Raman microscopy analysis. Drug-loaded SP were incorporated into the oil phase of oil-in-water emulsions (creams). The formulation containing polymeric submicron particles (C-SP) showed controlled drug release kinetics and a significant drug accumulation in skin compared to formulations containing non-polymeric particles or free drug. DEX accumulation in the stratum corneum was evaluated by tape stripping and a depot effect over time was observed for C-SP, while the formulation containing the free drug showed a decrease over time. Similarly, C-SP presented higher drug retention in epidermis and dermis in skin penetration studies performed on pig skin in Franz diffusion cells, while drug permeation into the receptor compartment was negligible. It was demonstrated, for the first time, the advantageous application of submicron polymeric particles obtained by vibrational spray-drying in semisolid formulations for cutaneous administration to overcome challenges related to the therapy with TG such as DEX.

Penetration, photo-reactivity and photoprotective properties of nanosized ZnO.

The oxidizing capacity and skin penetration of a commercial nanosized ZnO, Nanosun™ (Micronisers-Australia), were evaluated in vitro using porcine skin. Nanosun™ was initially characterized regarding its photo-reactivity and size distribution. An assay using methylene blue was performed to confirm the Nanosun™ photo-reactivity by exposing the labile molecule to UVA irradiation in the presence and absence of the nanosized ZnO. The nanosized ZnO was photo-reactive, reducing the methylene blue concentration to 7% while its concentration remained constant in the control formulation (without ZnO). The product label states that the average particle size is 30 nm. X-ray diffraction, nitrogen sorption and UV-spectrophotometry confirmed the presence of nanometric particles of approximately 30 nm. On the other hand, laser diffractometry showed micrometric particles in the size distribution profile. These analyses indicated that the nanoparticles are arranged as agglomerates and aggregates of micrometric proportions ranging from 0.6 to 60 µm. The skin lipid peroxidation was determined by the formation of thiobarbituric acid reactive species (TBARS) and quantified by UV-spectrophotometry. When exposed to UVA radiation the nanosized ZnO applied porcine skin showed a lower production of TBARS (7.2 ± 1.5 nmol g(-1)) than the controls, the MCT applied porcine skin (18.4 ± 2.8 nmol g(-1)) and the blank porcine skin (14.0 ± 2.0 nmol g(-1)). The penetration of ZnO nanoparticles was studied by scanning electron microscopy and energy dispersive X-ray spectroscopy. The tested ZnO particles did not penetrate into viable layers of the intact porcine skin. The particles tend to accumulate on the skin folds and in these regions they may penetrate into the horny layer.

Nanoencapsulation of tacrolimus in lipid-core nanocapsules showed similar immunosuppressive activity after oral and intraperitoneal administrations.

Tacrolimus is widely used in the prophylaxis of solid-organ transplant rejection. Several studies have reported that tacrolimus has variable and poor bioavailability after oral administration, apart from adverse effects such as gastrointestinal disorders, hyperglycemia, nephro- and neurotoxicity. The aim of this work was to encapsulate tacrolimus (TAC) in lipid-core nanocapsules (LNC) as an oral strategy to deliver the drug. To validate our hypothesis, the pharmacodynamic effect of TAC-LNC was determined after oral and intraperitoneal (i.p.) administrations to mice. TAC-LNC had z-average diameter of 210 nm (unimodal), and 99.5% of encapsulation efficiency. In vitro sustained release was determined for TAC-LNC fitting an anomalous transport mechanism (n = 0.8). TAC-LNC demonstrated higher immunosuppressive activity after oral and i.p. administrations, when compared to the drug solution. TAC-LNC administered at 6.0 mg kg(-1) day(-1) showed equivalent percent reduction in lymphocyte when both routes of administration were used. After oral administration, drug nanoencapsulation allows reducing the dose by at least 40%. Furthermore, the nanoencapsulation of TAC in lipid-core nanocapsules showed pharmacodynamic effect similar for the oral and the i.p. routes. In conclusion, the lipid-core nanocapsules were able to improve the TAC deliver across the oral absorption barrier.

Co-encapsulation of resveratrol and curcumin in lipid-core nanocapsules improves their in vitro antioxidant effects.

Resveratrol and curcumin are natural antioxidants found in the human diet that have been used in the prevention and treatment of different diseases associated with oxidative stress. Aiming to improve the antioxidant effects of resveratrol and curcumin, lipid-core nanocapsules containing the combination of both polyphenols were developed. Physicochemical characteristics were evaluated and compared to the formulations containing each polyphenol individually. Co-encapsulation did not influence nanotechnological characteristics, and all formulations presented mean diameter around 200 nm, low polydispersity index, and encapsulation efficiency close to 100%. Nanoencapsulation increases the photostability of resveratrol and curcumin, and co-encapsulation improves resveratrol photostability. The in vitro antioxidant activity of polyphenols against HO radicals was enhanced by nanoencapsulation, and a better effect was observed after their co-nanoencapsulation. Also, nanocapsules exhibited controlled release profile, for both polyphenols. The results showed that the strategy to co-encapsulate resveratrol and curcumin is a promising approach to improve the performance of medicines used to prevent and treat diseases associated with oxidative stress.

Innovative approach to produce submicron drug particles by vibrational atomization spray drying: influence of the type of solvent and surfactant.

Spray drying is a technique used to produce solid particles from liquid solutions, emulsions or suspensions. Buchi Labortechnik developed the latest generation of spray dryers, Nano Spray Dryer B-90. This study aims to obtain, directly, submicron drug particles from an organic solution, employing this equipment and using dexamethasone as a model drug. In addition, we evaluated the influence of both the type of solvent and surfactant on the properties of the powders using a 3(2) full factorial analysis. The particles were obtained with high yields (above 60%), low water content (below 2%) and high drug content (above 80%). The surface tension and the viscosity were strongly influenced by the type of solvent. The highest powder yields were obtained for the highest surface tension and the lowest viscosity of the drug solutions. The use of ionic surfactants led to higher process yields. The laser diffraction technique revealed that the particles deagglomerate into small ones with submicrometric size, (around 1 µm) that was also observed by scanning electron microscopy. Interaction between the raw materials in the spray-dried powders was verified by calorimetric analysis. Thus, it was possible to obtain dexamethasone submicrometric particles by vibrational atomization from organic solution.

Antifungal activity of nanocapsule suspensions containing tea tree oil on the growth of Trichophyton rubrum.

The aim of this study was to evaluate, for the first time, the antifungal efficacy of nanocapsules and nanoemulsions containing Melaleuca alternifolia essential oil (tea tree oil) in an onychomycosis model. The antifungal activity of nanostructured formulations was evaluated against Trichophyton rubrum in two different in vitro models of dermatophyte nail infection. First, nail powder was infected with T. rubrum in a 96-well plate and then treated with the formulations. After 7 and 14 days, cell viability was verified. The plate counts for the samples were 2.37, 1.45 and 1.0 log CFU mL(-1) (emulsion, nanoemulsion containing tea tree oil and nanocapsules containing tea tree oil, respectively). A second model employed nails fragments which were infected with the microorganism and treated with the formulations. The diameter of fungal colony was measured. The areas obtained were 2.88 ± 2.08 mm(2), 14.59 ± 2.01 mm(2), 40.98 ± 2.76 mm(2) and 38.72 ± 1.22 mm(2) for the nanocapsules containing tea tree oil, nanoemulsion containing tea tree oil, emulsion and untreated nail, respectively. Nail infection models demonstrated the ability of the formulations to reduce T. rubrum growth, with the inclusion of oil in nanocapsules being most efficient.

Improved tretinoin photostability in a topical nanomedicine replacing original liquid suspension with spray-dried powder with no loss of effectiveness.

OBJECTIVE: The use of spray-dried powders containing tretinoin-loaded nanocapsules instead of the original liquid suspension, aimed at the preparation of dermatological nanomedicines with improved photostability, was investigated. METHODS: Powders were prepared using lactose as a drying adjuvant. Hydrogels were prepared using two approaches: dispersing Carbopol Ultrez 10 in an aqueous redispersion of the powder or incorporating the powder in previously formed hydrogels. RESULTS AND DISCUSSION: The photodegradation of tretinoin in hydrogels prepared with the powders showed similar half-life times (around 19.5 h) compared to preparations with the original liquid nanocapsules (20.7 ± 1.4 h), regardless of the preparation approach. In addition, the topical nanomedicines prepared with the spray-dried powders presented a significant improvement in tretinoin photostability compared to the formulation containing the non-encapsulated drug. CONCLUSION: This study verified that the addition of the spray-dried powders containing tretinoin-loaded lipid-core nanocapsules to hydrogels did not influence the photoprotection of the drug compared with the preparation procedure using the original liquid suspension.

Spray-dried powders containing tretinoin-loaded engineered lipid-core nanocapsules: development and photostability study.

The influence of the spray-drying process on the ability of engineered lipid-core nanocapsules to protect tretinoin against UV degradation was evaluated. This approach represents a technological alternative to improve the microbiological stability, storage and transport properties of such formulations. Tretinoin-loaded lipid-core nanocapsules or tretinoin-loaded nanoemulsion were dispersed in lactose (10% w/v) and fed in the spray-drier to obtain a solid product (spray-dried powder containing tretinoin-loaded nanocapsules or nanoemulsion--SD-TTN-NCL or SD-TTN-NE, respectively). SD-TTN-NE showed a lower (p < or = 0.05) percentage of encapsulation (89 +/- 1%) compared to SD-TTN-NCL (94 +/- 2%). Redispersed SD-TTN-NCL and SD-TTN-NE showed z-average sizes of 204 +/- 2 nm and 251 +/- 9 nm, which were close to those of the original suspensions (220 +/- 3 nm and 239 +/- 14 nm, respectively). Similar percentage of photodegradation were determined for tretinoin loaded in nanocapsules (26.15 +/- 4.34%) or in the respective redispersed spray-dried powder (28.73 +/- 6.19 min) after 60 min of UVA radiation exposure (p > 0.05). Our experimental design showed for the first time that spray-dried lipid-core nanocapsules are able to protect tretinoin against UVA radiation, suggesting that the drying process did not alter the supramolecular structure of the lipid-core nanocapsules. Such powders are potential intermediate products for the development of nanomedicines containing tretinoin.

Hydrogels containing rutin intended for cutaneous administration: efficacy in wound healing in rats.

OBJECTIVE: Development of a hydrogel containing rutin at 0.025% (w/w) and evaluation of its in vivo efficacy in cutaneous wound healing in rats. METHODS: Hydrogels were prepared using Carbopol Ultrez® 10 NF and an aqueous dispersion of rutin in polysorbate 80. Hydrogels were characterized by means of pH measurement, rheological and spreadability analysis and rutin content determination by liquid chromatography. The in vivo healing effect was evaluated through the regression of skin lesions in rats and by analysis of oxidative stress. RESULTS AND DISCUSSION: Hydrogels showed adequate pH values (5.50-6.50) and pseudoplastic non-Newtonian behavior. After 5 days of treatment of wounds, hydrogels containing rutin presented a higher decrease in the wound area compared to the control hydrogels. Analysis of the oxidative stress showed a decrease in lipid peroxidation and protein carbonyl content as well as an increase in catalase activity after the treatment with the hydrogel containing rutin. Furthermore, this treatment increased total protein levels. CONCLUSION: This study shows for the first time the feasibility of using dermatological formulations containing rutin to improve skin wound healing.

Improved efficacy in the treatment of contact dermatitis in rats by a dermatological nanomedicine containing clobetasol propionate.

We developed a dermatological nanomedicine containing clobetasol propionate-loaded nanocapsules and evaluated its efficacy in a model of contact dermatitis after topical administration in rats. Hydrogels containing clobetasol propionate-loaded lipid-core nanocapsules or nanoemulsion (HG-CP-NC and HG-CP-NE, respectively) were prepared to evaluate the influence of the polymeric wall. They presented adequate pH values (5.50-6.50) and drug content (0.5 mg g(-1)) and their rheograms exhibited a non-Newtonian pseudoplastic behavior. The best in vitro drug release control was obtained for HG-CP-NC (1.03±0.11 µg cm(-2) h) compared to the HG-CP-NE (1.65±0.19 µg cm(-2) h) and the hydrogels containing nonencapsulated drug (HG-CP) (2.79±0.22 µg cm(-2) h). A significant increase in NTPDase activity was observed in lymphocytes for the group treated with 0.05% HG-CP-NC every other day compared to the group treated with 0.05% HG-CP every day using the in vivo model of contact dermatitis. The nanoencapsulation of clobetasol in nanocapsules led to a better control of the drug release from the semisolid nanomedicine and provided better in vivo dermatological efficacy.

Innovative sunscreen formulation based on benzophenone-3-loaded chitosan-coated polymeric nanocapsules.

AIM: To evaluate the effect of cationic coating of polymeric nanocapsules in sunscreen formulations on the in vitro skin penetration of benzophenone-3. METHODS: Benzophenone-3-loaded nanocapsules were prepared by the interfacial deposition of poly(ε-caprolactone) and coated by using a chitosan solution. The nanoparticles were characterized and incorporated in hydrogels. The presence of nanoparticles in hydroxyethyl cellulose gels was observed by transmission electron microscopy and photon correlation spectroscopy. Penetration studies were carried out using Franz cells with porcine skin membranes. RESULTS: Benzophenone-3-loaded chitosan-coated nanocapsules presented a mean size of 202 ± 7 nm and positive zeta potential (+21 ± 1 mV), while these values for the uncoated nanocapsules were 175 ± 1 nm and -8 ± 1 mV. Penetration profiles showed that a higher amount of benzophenone-3 remained at the skin surface and a lower amount was found in the receptor compartment after the application of the formulation containing chitosan-coated nanocapsules compared to a formulation containing its free form. CONCLUSIONS: Hydrogel containing benzophenone-3 chitosan-coated nanocapsules represents an innovative formulation to overcome limitations of sunscreen daily use.

Lipid-core nanocapsules as a nanomedicine for parenteral administration of tretinoin: development and in vitro antitumor activity on human myeloid leukaemia cells.

Tretinoin-loaded conventional nanocapsules have showed a significant protection of this drug against UVC radiation. However, this formulation presents a limited stability on storage. We hypothesized that the association of tretinoin to lipid-core nanocapsules could increase the physicochemical stability of such formulations, focusing on the development of a reliable nanomedicine for parenteral administration. However, this advantage should still be accompanied by the known photoprotective effect of conventional polymeric nanocapsules against the exposure of tretinoin to UV radiation. Results showed that tretinoin-loaded lipid-core nanocapsules improved the physicochemical stability of formulations under storage, without changing their ability to protect tretinoin either against UVA or UVC radiation. In addition, the effect of nanoencapsulation on the antiproliferative and differentiation properties of tretinoin was studied on human myeloid leukemia cells (HL60 cells) showing that tretinoin-loaded lipid-core nanocapsules presents a longer antitumor efficiency compared to the free tretinoin. These results allow us to propose the current formulation (tretinoin-loaded lipid-core nanocapsules) as a promising parenteral nanomedicine for the treatment of acute promyelocytic leukaemia.

Tablets containing drug-loaded polymeric nanocapsules: an innovative platform.

The aim of the present work was to evaluate the feasibility to convert drug-loaded nanocapsule suspensions in a solid dosage form (tablets). Dexamethasone was used as a model drug due to its low aqueous solubility and fast drug release from conventional tablets. Granules containing dexamethasone-loaded nanocapsules were obtained by a wet granulation process using a dispersion of polyvinylpirrolidone/nanocapsules as a binder system. Granules were compressed in an eccentric compression machine (D-NC-T). A control formulation (tablets without nanocapsules) was also prepared (D-T). Tablets were characterized by means of mean weight, hardness, friability, diameter, thickness, disintegration time, drug content, morphological analysis by scanning electron microscopy (SEM), and in vitro drug release studies. D-NC-T showed adequate physicochemical characteristics according to the pharmacopeial requirements in terms of mean weight, hardness, friability, disintegration time and drug content. Intact nanocapsules in tablets were observed by SEM. In vitro drug release studies showed a slower release of dexamethasone from these tablets (D-NC-T) compared to the control formulation (D-T). Results showed that these tablets represent an interesting platform to the development of oral drug delivery systems containing polymeric nanocapsules.

Eficácia do óleo de citronela [Cymbopogon nardus (L. ) Rendle] no controle de ectoparasitas de bovinos / Efficacy of citronella [Cymbopogon nardus (L. ) Rendle] oil in the control of bovine ectoparasites

O objetivo desta pesquisa foi avaliar o efeito in vivo do óleo de citronela, no controle do carrapato bovino [Rhipicephalus (Boophilus) microplus], da mosca-dos-chifres (Haematobia irritans), da mosca-dos-estábulos (Stomoxys calcitrans) e da mosca doméstica (Musca domestica). Foram utilizadas 15 vacas da raça Holandês, distribuídas em três grupos de cinco animais cada um. Os tratamentos foram: controle negativo, amitraz a 0,025 por cento e óleo de citronela a 4 por cento. Para avaliação foram contadas fêmeas ingurgitadas de carrapato e moscas antes (média dos dias -3, -2, -1) e após a aplicação dos produtos nos dias 7, 14, 21 e 28; também foram coletadas amostras de sangue. Em 28 dias, houve necessidade de se reaplicar o amitraz e o fitoterápico para controlar a infestação com carrapato. A relação entre o número de aplicações foi de 1:2,5 para o amitraz e o óleo de citronela, respectivamente. A eficácia no controle do carrapato foi de 71,8 e 30,9 por cento para o amitraz e óleo de citronela a 4 por cento, respectivamente, na média pós-tratamento. Verificou-se baixo controle de moscas no tratamento constituído pelo fitoterápico. Não houve diferença entre os tratamentos para os parâmetros sanguíneos.

This study aimed to evaluate the in vivo effect of citronella oil on the control of bovine ticks [Rhipicephalus (Boophilus) microplus], horn flies (Haematobia irritans), stable flies (Stomoxys calcitrans) and houseflies (Musca domestica). Fifteen Holstein cows were allocated to three groups of five animals each. The treatments were: negative control, amitraz at 0.025 percent and citronella oil at 4 percent. Engorged female ticks and flies were counted before (mean of days -3, -2, -1) and at 7, 14, 21 and 28 days after treatment; blood samples were also collected. Within 28 days, amitraz and the phytotherapic agent had to be reapplied to control tick infestation. The relationship among the number of applications was 1:2.5 for amitraz and citronella oil, respectively. The efficacy of tick control was, on average, 71.8 and 30.9 percent for amitraz and citronella oil at 4 percent respectively, post-treatment. Lower control of flies was observed for the phytotherapic group. There was no difference among treatments for blood parameters.