Marilisa Guimarães Lara

Mucoadhesive System Formed by Liquid Crystals for Buccal Administration of Poly(Hexamethylene Biguanide) Hydrochloride

Antimicrobial approaches are valuable in controlling the development of buccal diseases, but some antibacterial agents have a short duration of activity. Therefore, the development of prolonged delivery systems would be advantageous. Liquid crystalline systems comprising monoolein (GMO)/water have been considered to be a potential vehicle to deliver drugs to the buccal mucosa because of the phase properties that allow for controlled drug release as well as its mucoadhesive properties. Therefore, the aim of this study was to develop a GMO/water system for the slow release of poly(hexamethylene biguanide) hydrochloride (PHMB) on the buccal mucosa and test the properties of this system with regard to swelling, release profile, antimicrobial activity, and strength of mucoadhesion, with the overall goal of treating buccal infections. The tested systems were capable of modulating drug release, which is controlled by diffusion of the drug throughout the system. Furthermore, PHMB appeared to improve the mucoadhesive properties of the system and may synergistically act with the drug to promote antimicrobial activity against S. mutas and C. albicans, indicating that liquid crystals may be suitable for the administration of PHMB on the buccal mucosa. Therefore, this system could be proposed as a novel system for mucoadhesive drug delivery.

Celecoxib determination in different layers of skin by a newly developed and validated HPLC-UV method

A simple, rapid and sensitive analytical procedure for the measurement of celecoxib (CXB) levels in skin samples after in vitro penetration studies was developed and validated. In vitro permeability studies in porcine skin were performed for quantification of CXB at different layers of skin, the stratum corneum (SC) and epidermis plus dermis (EP + D) as well as in the acceptor solution (AS) to assess CXB permeation through skin. CXB was quantified by HPLC using a C18 column and UV detection at 251 nm. The mobile phase was methanol-water 72:28 (v/v) and the flow-rate was 0.8 mL/min. The CXB retention time was 5 min. The assay was linear for CBX in the concentration range of 0.1-3.0 μg/mL in the AS (drug permeated through skin) and 5.0-50.0 μg/mL for drug retained in SC and [EP + D] in vitro. The linear correlation coefficients for the different calibration curves were equal or greater than 0.99. Intra- and inter-assay variabilities were below 8.0%. Extraction of CXB from skin samples showed recoveries higher than 95.0% after 15 min of ultrasonic sound and centrifugation at 2500 rpm for 3 min. The method was considered appropriate for the assay of CXB in skin samples, after in vitro cutaneous penetration studies.

Liquid Crystalline Systems for Transdermal Delivery of Celecoxib: In Vitro Drug Release and Skin Permeation Studies

Liquid crystalline systems of monoolein/water could be a promising approach for the delivery of celecoxib (CXB) to the skin because these systems can sustain drug release, improve drug penetration into the skin layers and minimize side effects. This study evaluated the potential of these systems for the delivery of CXB into the skin based on in vitro drug release and skin permeation studies. The amount of CXB that permeated into and/or was retained in the skin was assayed using an HPLC method. Polarizing light microscopy studies showed that liquid crystalline systems of monoolein/water were formed in the presence of CXB, without any changes in the mesophases. The liquid crystalline systems decreased drug release when compared to control solution. Drug release was independent of the initial water content of the systems and CXB was released from cubic phase systems, irrespective of the initial water content. The systems released the CXB following zero-order release kinetics. In vitro drug permeation studies showed that cubic phase systems allowed drug permeation and retention in the skin layers. Cubic phase systems of monoolein/water may be promising vehicles for the delivery of CXB in/through the skin because it improved CXB skin permeation compared with the control solution.

In vitro and in vivo influence of penetration enhancers in the topical application of celecoxib.

Abstract Objective: We investigated the potential effects of oleic acid (OA) and glycerol monooleate (GMO) on the skin delivery of CXB. Methods: The influence of both OA and GMO (5.0% or 10.0%) on the in vitro skin permeability of CXB (2.0%) was evaluated using propylene glycol (PG) as a vehicle. Also the in vitro potential cytotoxicity and genotoxicity and in vivo assays (skin irritation in rabbits and topical anti-inflammatory activity by in mice) were conducted. Results: As expected, the amount of CXB that permeated through the skin was minimal, but drug retention on the viable skin (epidermis plus dermis) was higher in association with treatment with 5.0% OA or GMO compared to the control treatment, meaning that there was a localized effect of CXB in the skin. No formulation presented cytotoxic or genotoxic potential, suggesting safety for cutaneous application. In vivo skin irritation assays indicated that no formulation was irritating to the skin becomes its use possible for a prolonged time. In vivo anti-inflammatory experiments indicated that both edema and protein extravasation were inhibited with a maximum % inhibition of 53.5.0% and 61.0% for 5.0 % GMO, respectively, and 48.0% and 35.5% for 5.0% OA, respectively. Such formulations were able to inhibit around twofold the percentage of ear edema in mice compared to a commercial product reference diclofenac commercial formula. Conclusion: There is no topical formulation currently available that contains both CXB and 5.0% GMO or OA, suggesting them as potential adjuvants that improve the skin delivery of CXB.

Preparation and scaling up of a low phenylalanine enzymatic hydrolysate of bovine whey proteins

We describe the preparation of pancreatic enzymes hydrolysate of milk whey proteins containing low levels of aromatic amino acids. Pancreatin and trypsin/chymotrypsin (6.3% w/w protein) when used to hydrolyze whey proteins for 27 h at 37±2 oC, released 74% of the Phe, 100% of the Tyr and 100% of the Trp as free amino acids. Most of the free aromatic amino acids present in 2 kg hydrolysate were separated from the remaining peptides and other amino acids by gel filtration on a 15 liter Sephadex G-25 column eluted with 5% acetic acid at 60 liters h-1 at 25oC. The product, recovered in 37% yield, contained 0.70 mmol Phe, 0.41 mmol Tyr, and <0.01 mmol Trp/100 mmol recovered amino acids. The hydrolysate had a general amino acid composition similar to the whey proteins from which it was prepared and could be used as a nitrogen source for patients with phenylketonuria or tyrosinemia after the addition of appropriate aromatic amino acids.

Development of Intracanal Formulation Containing Silver Nanoparticles

This study aimed to synthetize, characterize and evaluate the antimicrobial properties of silver nanoparticles to be used in the development of a root intracanal formulation. Silver nanoparticles (AgNPs) were obtained by reduction of silver nitrate with sodium borohydride and characterized by UV-Visible spectrophotometry, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The antimicrobial activity of nanoparticle formulation was evaluated by determinations of the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against different bacterial species by the microdilution method, according to recommendations of the Clinical and Laboratory Standards Institute (CLSI). Three potential vehicles, hydroxyethylcellulose, Carbomer and polyethylene glycol were tested as carriers for formulations containing AgNPs. The efficiency of the synthesis method chosen to produce AgNPs was demonstrated by four characterization techniques. The nanoparticles showed antibacterial activity against all species tested. Incorporation of AgNPs into all experimental vehicles produced stable formulations but the one in hydroxyethylcellulose presented better physical proprieties. The results indicate that silver nanoparticles are potential antiseptic agents to be used in root canals and incorporation in adequate vehicles may favor a broader application.

In Vitro and In Vivo Evaluation of DMSO and Azone as Penetration Enhancers for Cutaneous Application of Celecoxib

BACKGROUND Celecoxib (CXB) has been explored as an anti-inflammatory or chemopreventive drug for topical treatment of skin diseases and cancer. OBJECTIVE The main aim of this work was to investigate the potential of dimethylsufoxide (DMSO) and Azone (AZ) as penetration enhancers (P.Es) for topical delivery of CXB. METHOD The in vitro studies, drug release, skin permeability and potential cytotoxicity/genotoxicity were carried out with formulations containing or not DMSO or AZ (5% and 10%). Skin irritation in rabbits and topical anti-inflammatory activity in mice were assayed in vivo. RESULTS Skin permeation was minimal while higher retention in stratum corneum (SC) and epidermis plus dermis was found (28.0 and 3-fold respectively) from 10.0% AZ compared to the control indicating a localized CXB effect. CXB associated to 5% or 10% DMSO has shown high drug permeation through skin with low retention. Associations of CXB with both enhancers were not cytotoxic or genotoxic, suggesting safety for cutaneous application. In vivo skin irritation assays of all formulations indicated mild irritation effects and, thus, possible use for longer periods. In vivo anti-inflammatory tests showed that ear edema could be inhibited by CXB associated with 5.0% DMSO (53.0%) or 10.0% AZ (40.0%). These inhibition values were almost 2-fold higher when compared to a commercial formula. CONCLUSION Although DMSO- associated CXB is an efficient edema inhibitor its high skin permeation suggests risks of systemic effects, whereas association to 10% AZ may improve topical delivery of the drug with good anti-inflammatory activity and no cytotoxic/genotoxic or significant skin irritation effects.