## 1 Introduction  
The presence of pharmaceuticals in the environment is an alarming problem, yet their widespread use is essential for treating diseases in humans and animals [1]. Changes in clinical practice, a continuing increase in population, and higher incidences of chronic and age-related diseases are leading to a raised need and consumption of pharmaceuticals. This trend is evident in Organisation for Economic Co-operation and Development (OECD)countries--between 2000 and 2019, the consumption of antihypertensive drugs increased by an average of 65%, antidiabetic and antidepressant drugs doubled, while the increase in the uptake of lipid-modifying medicines was as much as 400% [2]. Furthermore, the expanding proportion of people aged 65 and older globally leads to aging populations in most countries, a key driver for the pharmaceutical market. The market has experienced significant growth since the beginning of the century, with linear growth and revenues of USD1.61 trillion worldwide in 2023. It is expected to grow further, with a compound annual growth rate (CAGR) of 7.6% from 2023 to 2030 [3]. Increased pharmaceutical production entails the risk of their release into the environment, both at the production and distribution stage and due to inappropriate use, disposal of unused or expired medicines, and inefficient treatment of wastewater and landfill leachate. As a result, active substances contained in medicines can accumulate in the environment, posing a potential threat to ecosystems and public health [4]. Furthermore, pharmaceuticals are processed in the body once they are taken in, and then between 30% and 90% of the dose taken is excreted unchanged or metabolized, mainly in feces or urine [5,6]. They end up in treatment plants and domestic wastewater treatment systems in these forms and subsequently enter ecosystems. Pharmaceuticals resist degradation, persist for a long time in the environment, and become transported along food chains. Recent work constantly indicates the presence of pharmaceuticals in soil [3,7, 8, 9, 10, 11], surface water [10, 12, 13], groundwater [13, 14], and even drinking water [15, 16, 17, 18, 19, 20]. Pharmaceuticals are also taken up by soil organisms [21] and plants [22, 23]. Their ubiquity raises concerns about possible environmental and human health risks [24], highlighting the need to monitor wastewater, the overriding source of pharmaceuticals in the environment. Wastewater treatment is a crucial component in protecting the environment and humans from the presence of pharmaceuticals in ecosystems and the following consequences. Nevertheless, conventional treatment methods do not entirely remove some drug residues, potentially leading to their presence in wastewater leaving treatment plants [1]. Hence, there is an urgent need for reliable and detailed methodologies to determine concentrations of pharmaceuticals in wastewater before they enter the environment and to realistically determine the effectiveness of the technology used at the treatment plant. Consequently, developing efficient analytical methods, including precise sample preparation, is becoming essential for effectively monitoring pharmaceutical residues in wastewater and evaluating treatment efficiency. Sample preparation is a critical step, affecting the quality of the results obtained by removing interferents from the matrix, stabilizing analytes, and ensuring compatibility with downstream analytical techniques. Many procedures have been developed for the preparation of aqueous samples, including wastewater, such as solid-phase extraction (SPE) [25, 26, 27], as well as microextraction techniques: dispersive liquid-liquid microextraction (DLLME) [28, 29, 30, 31], liquid microextraction using hollow fiber (HF-LPME) [32, 33, 34], ultrasound-assisted emulsification microextraction (USAEME) [35, 36, 37], and single-drop microextraction (SDME) [38, 39, 40] have been reported.