Cold processed oil-in-water emulsions for dermatological purpose: formulation design and structure analysis.

The aim of this work is to develop, optimize and characterize cold process emulsions that are stable at acidic pH. The main surfactant was selected according to the hydrophilic lipophilic balance (HLB) concept and surface tension, whereas polymers were selected by viscoelastic measurements and analytical centrifugation. It was showed that the inclusion of methyl vinyl ether/maleic anhydride copolymer crosslinked with decadiene (PVM/MA) increased the storage modulus (G') of the gels (23.

The relevance of polymeric synthetic membranes in topical formulation assessment and drug diffusion study.

Synthetic membranes are composed of thin sheets of polymeric macromolecules that can control the passage of components through them. Generally, synthetic membranes used in drug diffusion studies have one of two functions: skin simulation or quality control. Synthetic membranes for skin simulation, such as the silicone-based membranes polydimethylsiloxane and Carbosil, are generally hydrophobic and rate limiting, imitating the stratum corneum.

Comparison of the in vitro release characteristics of mucosal freeze-dried wafers and solvent-cast films containing an insoluble drug.

Drug release characteristics of freeze-dried wafers and solvent-cast films prepared from sodium carboxymethylcellulose have been investigated and compared. In vitro drug dissolution studies were performed using an exchange cell and drug release was measured by UV spectroscopy at 272 nm using distilled water. The dissolution profiles of hydrochlorothiazide from the wafers and films were compared by determining the rates of drug release, estimated from the % release versus time profiles and calculating their difference (f(1)) and similarity (f(2)) factors.

Influence of hydration state and homologue composition of magnesium stearate on the physical chemical properties of liquid paraffin lipogels.

Lipogels were prepared by dispersing mixed (60:40 C(16)-C(18)) and pure (C(18)) homologue magnesium stearate (MgSt) in liquid paraffin, using three methods of preparation, i.e. addition of water at 95 °C during cooling cycle (method 1), homogenisation upon cooling (method 2) or cooling without addition of water or homogenisation (method 3).

Validation of a static Franz diffusion cell system for in vitro permeation studies.

Over the years, in vitro Franz diffusion experiments have evolved into one of the most important methods for researching transdermal drug administration. Unfortunately, this type of testing often yields permeation data that suffer from poor reproducibility. Moreover, this feature frequently occurs when synthetic membranes are used as barriers, in which case biological tissue-associated variability has been removed as an artefact of total variation.