A Novel Method for Rapid Non Destructive Determination of O/W Creams Stability

Colloidal carriers for benzathine penicillin G: nanoemulsions and nanocapsules

The main purpose of this work is to formulate benzathine penicillin G nanoemulsion and nanocapsules, to evaluate their physicochemical and stabilising characteristics, and to determine their antimicrobial activity and penicillin in vitro release kinetics. Nanoemulsions were produced by the spontaneous emulsification approach and nanocapsules of poly (D,L-lactic acid-co-glycolic acid) polymer (PLGA) were prepared by the method of interfacial deposition of a pre-formed polymer. A 207+/-8 nm mean diameter nanoemulsion formulation maintained stability for more than 5 months at 4 degrees C. Stable nanocapsules with 224+/-58 nm mean diameter were obtained, which remained stabilised over 120 days at 4 degrees C. The penicillin encapsulation ratio in the nanocapsules was 85%. The in vitro release profiles indicated that penicillin released from the nanoemulsion was similar to the one observed from nanocapsules. However it can be clearly deduced from the in vitro kinetic analysis that the antibiotic cannot be protected in colloidal delivery systems. Nevertheless, stable formulations obtained in this investigation supply a potential dosage form to encapsulate more easily soluble drugs.

The effect of temperature on the conductivity of gels and emulsions prepared from cetrimide and cetostearyl alcohol

The conductivity of gels and emulsions containing cetrimide, cetostearyl alcohol, liquid paraffin and water has been studied over the temperature range +35 to -10 degrees C. All samples froze at temperatures below -5 degrees C and exhibited hysteresis on rewarming to room temperature with an initial increase in conductivity up to 15 degrees C followed by a decrease to 25 degrees C. The amount of hysteresis was dependent on the cetostearyl alcohol content and appeared to be related to changes in the microstructure of the liquid crystalline network.