Tetracycline-niosomesversus Tetracycline hydrochloride-niosomes: How to Modulate Encapsulation and Percutaneous Permeation Properties

Nowdays, the design of the optimalniosomal formulation may ensure the best performance in terms of physico-chemical properties and drug skin permeation. Our study want to propose the loading of Tetracycline or Tetracycline hydrocholoride drugs as strategy to modulate niosomes properties, with particular emphasis on encapsulation and percutaneous permeation behavior. Niosomes were prepared from mixtures of nonionic commercial surfactants with different final value of hydrophile- lipophile balance (HLB). Significant increase in size respect to the corresponding empty vesicles occurred when drugs were encapsulated, while the presence of glyceryl monostearate resulted in a reduction of the diameter. Drugs entrapment efficiencies were found to be directly related to the chemical properties of the system: tetracycline showed better affinity for lipophilic matrices, while tetracycline hydrochloride was better encapsulated in hydrophilic ones. Finally we found drugs permeation across the skin was affected by many variables, such as bilayer composition, niosomes size, nature of the drugs and their entrapment efficiency, where by depending on the intended effect (topical or systemic) the opportune formulation may be selected.