Hidrogelovi za vaginalnu primjenu lijekova

The vaginal route of drug administration has been used for achieving local and systemic drug effects. The rate and extent of drug absorption after intravaginal application may be altered by vaginal physiology, age, stage in the menstrual cycle, pathological condition and formulation factors. Among a variety of vaginal dosage forms available, hydrogels offer several advantages such as hydrophilicity, biocompatibility, good distribution and retention, appropriate drug release and acceptability by patients. They have been mostly used for the treatment of vaginal dryness and local delivery of antimicrobial drugs, microbicides, contraceptives and labor inducers. However, hydrogels have also potential for systemic delivery of hormones, vaccines, proteins and peptides. This paper summarizes potentials, current use and research on hydrogels as vaginal drug delivery systems

Liposomes for (trans)dermal drug delivery: the skin-PVPA as a novel in vitro stratum corneum model in formulation development

Penetration potential of vesicles destined for trans(dermal) administration remains to be of great interests both in respect to drug therapy and cosmetic treatment. This study investigated the applicability of the phospholipid vesicle-based permeation assay (PVPA) as a novel in vitro skin barrier model for screening purposes in preformulation studies. Various classes of liposomes containing hydrophilic model drug were examined, including conventional liposomes (CLs), deformable liposomes (DLs) and propylene glycol liposomes (PGLs). The size, surface charge, membrane deformability and entrapment efficiency were found to be affected by the vesicle lipid concentration, the presence of the surfactant and propylene glycol. All liposomes exhibited prolonged drug release profiles with an initial burst effect followed by a slower release phase. The permeation of the drug from all of the tested liposomes, as assessed with the mimicked stratum corneum – PVPA model, was significantly enhanced as compared to the permeability of the drug in solution form. Although the DLs and the PGLs exhibited almost the same membrane elasticity, the permeability of the drug delivered by PGLs was higher (6.2 x 10^-6 cm/s) than DLs (5.5 x 10^-6 cm/s). Therefore, this study confirmed both the potential of liposomes as vesicles in trans(dermal) delivery and potential of the newly developed skin- PVPA for the screening and optimization of liposomes at the early preformulation stage

In vitro skin models as a tool in optimization of drug formulation

(Trans)dermal drug therapy is gaining increasing importance in the modern drug development. To fully utilize the potential of this route, it is important to optimize the delivery of active ingredient/drug into/through the skin. The optimal carrier/vehicle can enhance the desired outcome of the therapy therefore the optimization of skin formulations is often included in the early stages of the product development. A rational approach in designing and optimizing skin formulations requires well-defined skin models, able to identify and evaluate the intrinsic properties of the formulation. Most of the current optimization relies on the use of suitable ex vivo animal/human models. However, increasing restrictions in use and handling of animals and human skin stimulated the search for suitable artificial skin models. This review attempts to provide an unbiased overview of the most commonly used models, with emphasis on their limitations and advantages. The choice of the most applicable in vitro model for the particular purpose should be based on the interplay between the availability, easiness of the use, cost and the respective limitation