Simple and Selective HPLC-UV/Vis Bioanalytical Method to Determine Aluminum Phthalocyanine Chloride in Skin Permeation Studies.

Considering the feasibility of the aluminum phthalocyanine chloride (AlPcCl) application in the topical photodynamic therapy of cutaneous tumors and the lack of HPLC methods capable of supporting skin permeation experiments using this compound, the aim of this study was to obtain a simple and selective chromatographic method for AlPcCl determination in skin matrices. A HPLC-UV/Vis method was developed using a normal-phase column operating at 30°C, an isocratic mobile phase of methanol : phosphoric acid (0.01 M) at 1.5 mL/min, and detection at 670 nm. The method exhibited (i) selectivity against various contaminants found in the different skin layers, (ii) high drug extraction capacity from the hair follicle (>70%) and remaining skin (>80%), and (iii) low limits of detection and of quantification (0.03 and 0.09 µg/mL, resp.). The method was also linear in the range from 0.1 to 5.0 µg/mL (r = 0.9994) and demonstrated robustness with regard to experimental chromatographic parameters according to a factorial design. Lastly, the developed method was successfully tested in in vitro skin permeation studies of AlPcCl, proving its effectiveness in the development of pharmaceutical delivery systems containing this drug for topical photodynamic therapy of skin cancers.

Influence of monoolein on progesterone transdermal delivery

abstract This work aimed to investigate in vitro the influence of monoolein (MO) on progesterone (PG) transdermal delivery and skin retention. Information about the role of MO as an absorption enhancer for lipophilic molecules can help on innovative product development capable of delivering the hormone through the skin in a consistent manner, improving transdermal therapy of hormonal replacement. MO was dispersed in propylene glycol under heat at concentrations of 0% (control), 5% w/w, 10% w/w and 20% w/w. Then, 0.6% of PG (w/w) was added to each formulation. Permeation profile of the hormone was determined in vitro for 48 h using porcine skin in Franz diffusion cells. PG permeation doubled when 5% (w/w) of MO was present in formulation in comparison to both the control and higher MO concentrations (10% and 20% w/w). An equal trend was observed for PG retention in stratum corneum (SC) and reminiscent skin (E+D). PG release rates from the MO formulations, investigated using cellulose membranes, revealed that concentrations of MO higher than 5% (w/w) hindered PG release, which indeed negatively reflected on the hormone permeation through the skin. In conclusion, this work demonstrated the feasibility of MO addition (at 5% w/w) in formulations as a simple method to increase transdermal PG delivery for therapies of hormonal replacement. In contrast, higher MO concentrations (from 10% to 20% w/w) can control active release, and this approach could be extrapolated to other lipophilic, low-molecular-weight molecules.

resumo Este trabalho teve como objetivo investigar in vitro a influência de monooleína (MO) na permeação transdérmica de progesterona (PG), bem como sobre a retenção cutânea desse hormônio a fim de (i) liberar de maneira mais consistente hormônio através da pele para melhorar a terapia transdérmica de reposição hormonal e (ii) trazer mais informações sobre o papel da MO como promotor da absorção cutânea de moléculas lipofílicas, tema ainda pouco explorado na literatura. MO foi dispersa em propilenoglicol, a concentrações de 0% (controle), 5%, 10% e 20% (p/p). Adicionou-se, em seguida, 0,6% (p/p) de PG a cada uma das formulações. O perfil de permeação do hormônio foi então determinado in vitro durante 48 h, utilizando pele de porco em células de difusão do tipo Franz. MO a 5% (p/p) foi capaz de duplicar a permeação de PG em comparação ao controle e às concentrações mais elevadas de MO, assim como a retenção de PG no estrato córneo (SC) e epiderme e derme remanescentes (E+D). A velocidade de liberação de PG a partir das formulações foi investigada usando membranas de celulose e este estudo revelou que concentrações de MO superiores a 5% (p/p) impediram a liberacão de PG, o que de fato refletiu de forma negativa na permeação cutânea do hormônio. Concluindo, este trabalho demonstrou a viabilidade da adição de MO a uma formulação como um método simples para aumentar a permeação transdérmica de PG para uso em terapias de reposição hormonal. Por outro lado, altas concentrações de MO (de 10% a 20% p/p) controlam a liberação de PG e este efeito pode ser extrapolado para outras moléculas lipofílicas de baixa massa molecular.

Chitosan nanoparticles for targeting and sustaining minoxidil sulphate delivery to hair follicles.

This work developed minoxidil sulphate-loaded chitosan nanoparticles (MXS-NP) for targeted delivery to hair follicles, which could sustain drug release and improve the topical treatment of alopecia. Chitosan nanoparticles were obtained using low-molecular weight chitosan and tripolyphosphate as crosslink agent. MXS-NP presented a monomodal distribution with hydrodynamic diameter of 235.5 ± 99.9 nm (PDI of 0.31 ± 0.01) and positive zeta potential (+38.6 ± 6.0 mV). SEM analysis confirmed nanoparticles average size and spherical shape. A drug loading efficiency of 73.0 ± 0.3% was obtained with polymer:drug ratio of 1:1 (w/w). Drug release through cellulose acetate membranes from MXS-NP was sustained in about 5 times in comparison to the diffusion rate of MXS from the solution (188.9 ± 6.0 µg/cm(2)/h and 35.4 ± 1.8 µg/cm(2)/h). Drug permeation studies through the skin in vitro, followed by selective recovery of MXS from the hair follicles, showed that MXS-NP application resulted in a two-fold MXS increase into hair follicles after 6h in comparison to the control solution (5.9 ± 0.6 µg/cm(2) and 2.9 ± 0.8 µg/cm(2)). MXS-loading in nanoparticles appears as a promising and easy strategy to target and sustain drug delivery to hair follicles, which may improve the topical treatment of alopecia.