Real objects in horizontal projection often have a complex geometry. Their irregular shape causes issues during analyses and calculations that consider their geometry. The paper proposes the replacement of real-world objects with equivalent rectangles (ER). The paper also defines the geometric criteria of ER as well as ER parameters and methods for calculating them. The paper also demonstrates the difference in the duration of calculations for different types of rectangles (equivalent rectangle with the same area, surrounding rectangle with the smallest area, inscribed rectangle with the largest area). The presented approach has been illustrated with three case studies. The first one is the application of ER to underground mining cavities to determine post-mining deformations of the ground surface. In the second study, an ER was applied to analyse the geometry of agricultural parcels in a selected part of a rural settlement. ER can help assess whether the spatial layout is faulty and if a planning intervention is necessary. The third example describes a building’s geometry with an ER. Regarding the simplification of building’s geometry, it is crucial to replace a simplified building with a model that has the same centroid location and the same area. It is the perfect solution for rapid analyses of displaying objects on maps in various scales.

Currently, there is a tendency for new forms of carrier-drug systems to appear with prolonged and controlled release. However, in order to design medical or pharmaceutical devices, which have to be characterized by high quality and the assumed parameters in real conditions, it is necessary to analyze this process based on in vitro release (IVR) testing methods. For this purpose, extracorporeal studies are carried out, which enable the determination of the release profiles of active substances using a simulated tissue-like environment. Here, we focused on the release tests of poorly water-soluble compounds (salicylic acid and fluocinolone acetonide) from the dual drug delivery system using the flow-through cell method (USP4). Additionally, bio-hybrid hydrogel matrix containing the system of thermosensitive nanocarrier with salicylic acid and fluocinolone acetonide was subjected to the following investigations: physicochemical (swelling ability, gel fraction), morphological (SEM analysis) and structural using FT-IR spectroscopy. On the basis of results, we can conclude that the USP4 method may be suitable, especially for the release tests of poorly water-soluble components introduced into modern forms of drug administration, such as polymeric matrices, hydrogels, nano- and microcarriers as well as hybrid systems.