Prevention strategies play a key role in the fight against HIV/AIDS. Vaginal and rectal microbicides hold great promise in tackling sexual transmission of HIV-1, but effective and safe products are yet to be approved and made available to those in need. While most efforts have been placed in finding and testing suitable active drug candidates to be used in microbicide development, the last decade also saw considerable advances in the design of adequate carrier systems and formulations that could lead to products presenting enhanced performance in protecting from infection. One strategy demonstrating great potential encompasses the use of nanosystems, either with intrinsic antiviral activity or acting as carriers for promising microbicide drug candidates. Polymeric nanoparticles, in particular, have been shown to be able to enhance mucosal distribution and retention of promising antiretroviral compounds. One important aspect in the development of nanotechnology-based microbicides relates to the design of pharmaceutical vehicles that allow not only convenient vaginal and/or rectal administration, but also preserve or even enhance the performance of nanosystems. In this manuscript, we revise relevant work concerning the selection of vaginal/rectal dosage forms and vehicle formulation development for the administration of microbicide nanosystems. We also pinpoint major gaps in the field and provide pertinent hints for future work.

Contamination of ground water as a consequence of soil leaching processes is an issue of major concern. In this context, a simulation of the soil leaching process was designed. A sequential injection (SI) method to monitor the soil leaching of iron complexes with in-line rain simulation for leachate production is described. The developed methodology comprises the SI determination of both iron(III) and 3-hydroxy-4-pyridinones iron(III) complexes, coupled to a mini soil column (mSC) for displaying in-line rain simulations. The described SI method enabled iron(III) determination within the range 2.0–35 µmol L⁻¹, with a detection limit of 0.42 µmol L⁻¹, and determination of iron(III) complexes in the range 1.0–45 µmol L⁻¹. It was successfully applied to leachates from laboratory scale soil columns (LSSC), with good precision for both iron(III) and iron complexes determinations: calculated relative standard deviation (RSD) of 5% and 6%, respectively. A step further in automation and miniaturization was attained with the incorporation of a mini soil column for the in-line leachate production. The system enabled the soil leachate production and assessment in less than 5 min, including determinations in triplicate.

Monitoring the soil/water interface has become fundamental for both environmental and agricultural studies. This work aimed to set up and monitor laboratory scale soil columns (LSSCs) for assessing nutrient levels and characterizing soil leachates using flow analysis methods. A flow analysis method was developed to determine calcium and magnesium concentrations, overcoming the disadvantages of conventional methods in terms of time consumption, waste production and cost. The LSSCs were set up with soil cores from distinct locations and with burned soil to verify if soil type or forest fires affect leaching behaviour. Leachates were obtained through rain simulations with rainwater. In order to establish valid comparisons, simulated rain was assessed before and after going through the LSSCs. The accommodation of both metals in the same sequential injection manifold was successfully attained, as well as the determination of ranges of calcium of 0.160–35.0 mg L⁻¹, and a range of magnesium of 0.160–8.00 mg L⁻¹. The developed method was successfully used to monitor different soil leachates, allowing for the assessment of both metal ions before and after going through the LSSCs. The limits of detection obtained for calcium and magnesium determinations were 7 and 8 μg L⁻¹, respectively. Effluent production equalled 1.8 mL for the assessment of magnesium and the smaller range of calcium and 2.0 mL for the larger range.