PubMed · 9442946
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D McKelvey. 1998. Using the fentanyl patch.. https://pubmed.ncbi.nlm.nih.gov/9442946/
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The skin permeation and partitioning of a fluorinated quinolone antibacterial agent, enoxacin, in liposomes and niosomes, after topical application, were elucidated in the present study. In vitro percutaneous absorption experiments were performed on nude mouse skin with Franz diffusion cells. The influence of vesicles on the physicochemical property and stability of the formulations were measured. The enhanced delivery across the skin of liposome and niosome encapsulated enoxacin had been observed after selecting the appropriate formulations. The optimized formulations could also reserve a large amount of enoxacin in the skin. A significant relationship between skin permeation and the cumulative amount of enoxacin in the skin was observed. Both permeation enhancer effect and direct vesicle fusion with stratum corneum may contribute to the permeation of enoxacin across skin. Formulation with niosomes demonstrated a higher stability after 48 h incubation compared to liposomes. The inclusion of cholesterol improved the stability of enoxacin liposomes according to the results from encapsulation and turbidity. However, adding negative charges reduced the stability of niosomes. The ability of liposomes and niosomes to modulate drug delivery without significant toxicity makes the two vesicles useful to formulate topical enoxacin.
A reservoir-type transdermal delivery system of testosterone (TS) was developed using an ethanol/water (70:30) cosolvent system as the vehicle. The maximum permeation rate achieved by 70% (v/v) of ethanol was further increased from 2.69 to 47.83 microg/cm(2)/h with the addition of 1.0% dodecylamine as the skin permeation enhancer. The permeation rate of TS through the ethylene vinyl acetate (EVA) membrane was observed to increase as the vinyl acetate content in the copolymer increased. Addition of 1.0% (w/w) gelling agent, hydroxypropyl methlycellulose (HPMC), in the reservoir formulation resulted in desirable rheological properties with an insignificant effect on the skin permeation rate of TS. Thus, a new transdermal delivery system for TS was formulated using EVA membrane coated with a pressure-sensitive adhesive (Duro-Tak 87-2510) and HPMC as a gelling agent. This experimental patch showed comparable plasma concentration profiles in the in vivo study when compared with a commercial product, Androderm(R). Moreover, the results suggested the possibility of further enhancing the permeation rate of TS by controlling the composition of the reservoir formulation.
The effect of the solvent systems water, ethanol (EtOH), propylene glycol (PG) and their binary combinations was studied on the ex vivo permeation profile of the opioid receptor antagonist, naloxone, through rat skin. Fourier transform-infrared (FT-IR) spectroscopic studies were done to investigate the effect of enhancers on the biophysical properties of the stratum corneum (SC), in order to understand the mechanism of permeation enhancement of naloxone by the solvent systems used. The flux of naloxone was found to increase with increasing concentrations of EtOH, upto 66% in water, and PG upto 50% in water. The maximum flux of 32.85 microg cm(-2) h(-1) was found with 33% PG in EtOH. The FT-IR spectra of SC treated with EtOH showed peak broadening at 2920 cm(-1) at all concentrations of EtOH studied indicating that EtOH increases the translational freedom (mobility) of lipid acyl chains. Theoretical blood levels well above the therapeutic concentration of naloxone can be achieved with the solvent system comprising 33% PG in EtOH and hence, provides flexibility in choice of patch size depending on the addiction status of the patient to be treated.