Protoporphyrin IX (PpIX) loaded PLGA nanoparticles for topical Photodynamic Therapy of melanoma cells.

INTRODUCTION: Nanoparticles (Np) can increase drug efficacy and overcome problems associated with solubility and aggregation in a solution of PpIX. PURPOSE: Evaluate if Np interferes in the photophysical and photobiological capacity of the PpIX comparing with free PpIX intended for topical PDT of melanoma. METHODS: In vitro photophysical evaluation of Np-PpIX was carried out through singlet oxygen (1O2) quantum yield. In vitro cytotoxicity and phototoxicity assays have used murine melanoma cell culture. RESULTS: The quantum yield of singlet oxygen has shown that Np did not influence the formation capacity of this reactive species. In the dark, all PpIX-Nps concentrations were less cytotoxic compared to free drugs. At a higher light dose (1500 mJ.cm2) 3.91 µg / mL PpIX had similar % viable cells for free and Np (∼34 %) meaning Nps did not interfere in the photodynamic effect of PpIX. However, at 7.91 µg / mL the phototoxicity increased for both (5.8 % viable cells for free versus 21.7 % for Nps). Despite the higher phototoxicity of free PpIX at this concentration, greater cytotoxicity in the dark was obtained (∼49 % viable cells for free versus ∼90.6 % Np) which means Nps protect the tumor tissue from the photodynamic action of PpIX. CONCLUSIONS: Np is a potential delivery system for melanoma skin cancer, since it maintained the photophysical properties of PpIX and excellent in vitro phototoxicity effect against melanoma cells, reducing cell viability ∼80 % (7.91 µg / mL PpIX in Nps) and provides safe PDT (due to lower cytotoxicity in the dark).

Copaiba Oil: Chemical Composition and Influence on In-vitro Cutaneous Permeability of Celecoxib.

BACKGROUND: Use of topical or transdermal administration of Celecoxib (Cxb) is an interesting strategy in cutaneous treatments since it reduces or avoids side effects of the oral route. However, Cxb´s high lipophilicity and the stratum corneum (SC) barrier impair cutaneous penetration. OBJECTIVE: Evaluation of copaiba oil (C.O) as a potential skin penetration enhancer (P.E) for Cxb. METHODS: The chemical composition of C.O was evaluated by GC-MS. Both in-vitro release and permeability assay of Cxb in Polyethylene glycol 400/ propylene glycol (PEG 400/PG) vehicle associated to C.O (1-50% w/w) were determined in a modified diffusion cell fitted with a synthetic hydrophobic membrane and pig ear skin as model, respectively. RESULTS: GC-MS analysis of C.O showed that it is composed of sesquiterpenes (68.65%) and diterpenes (22.26%). Formulations containing 25% C.O (F4) and 50% C.O (F5) have shown in-vitro burst release in the first 2 h, but only F4 released 100% of drug after 24 h. The highest Cxb permeation across skin was obtained from F4 and the highest skin retentions for F4 and F5 in the stratum corneum and epidermis plus dermis. CONCLUSION: The increased Cxb permeability through skin and its retention for an extended time (24h) at 25% C.O suggest that it could be a promising adjuvant for the development of transdermal formulations of Cxb.

α-Bisabolol improves 5-aminolevulinic acid retention in buccal tissues: Potential application in the photodynamic therapy of oral cancer.

CONTEXT: 5-Aminolevulinic acid (5-ALA) is a prodrug used in photodynamic therapy (PDT) of tumors, including cancer of the oral mucosa. 5-ALA poorly penetrates oral tissues due to its high hydrophilicity, which impairs its local effects in PDT. OBJECTIVES: To examine whether α-bisabolol (α-Bis) influences the 5-ALA permeability in the porcine buccal mucosa, to an extent that improves its application in PDT (which requires low permeation and high retention in the buccal mucosa). METHODS: In vitro permeability studies with 5-ALA (1% and 10% w/w) associated with α-Bis (1% to 20% w/w) in propylene glycol were carried out at 4h and 24h using porcine buccal mucosa in a modified Franz cell system. The in vitro release profiles (0.5 to 48h) of the selected formulation and its respective control were determined using artificial membranes. Samples of buccal mucosa treated with the formulation were submitted to histopathological analysis, using a routine optical microscopy technique. RESULTS: The association of 1% 5-ALA and 5% α-Bis provided the best results; after 4h of treatment with this formulation, the 5-ALA permeation was low and its retention in the mucosa was six-fold higher than that promoted by the control formulation (5-ALA alone). Histological analysis of the porcine buccal mucosa evidenced that 5% α-Bis altered the tissue morphology, which probably promoted 5-ALA retention. We concluded that 5% α-Bis is a potential adjuvant in formulations containing 5-ALA that could improve its retention after topical oral administration for the PDT treatment of cancer.

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.