## 1 Introduction  
Copper-tin alloys, widely known as bronzes, are among the earliest alloys developed by humans, which have been endlessly used over the centuries in art, architecture, and various industrial and marine applications. Bronzes are relatively resistant to corrosion because they spontaneously develop thin layers of corrosion products on their surface, designated as 'patinas', which tend to be extremely stable [1, 2], protecting the metals against corrosion and offering an aesthetically pleasant appearance [3]. However, bronze can undergo significant corrosion when exposed to aggressive humid environments, containing chlorides, carbonates, nitrates, or sulphate ions, such as seawater in marine atmosphere or acid rainwater encountered in industrial urban areas affected by increased air pollution [4, 5]. The application of corrosion inhibitors is one of the most feasible approaches for protecting metals against corrosion [6]. Various organic compounds containing heteroatoms (N, S, P and O), polar functional groups, and/or \(\pi\) electrons in conjugated multiple bonds have been long recognized as efficient corrosion inhibitors of metals in many aggressive media [7, 8]. The anticorrosion effectiveness of these organic compounds depends on their ability to adsorb on the metal surface and form protective layers that further prevent the corrosion process. Despite their extensive use, most of the synthetic chemicals exploited as corrosion inhibitors are expensive, non-biodegradable, and often hazardous to humans and the environment. For instance, the most effective corrosion inhibitor for bronzes--benzotriazole (BTA)--is suspected to be potentially carcinogenic and has toxic effects on the aquatic organisms [9]. In recent years, in view of increasing ecological awareness, the research goals in the corrosion inhibitors field were directed toward the development and exploration of new inexpensive and effective molecules with high biodegradability, non-bioaccumulative behavior, and negligible environmental impact. Such examples of environmentally friendly corrosion inhibitors are amino acids [10; 11; 12], plant extracts [13; 14], natural polymers [15], ionic liquids [16], and carbohydrates [17]. Various pharmaceutical medicines are also regarded as greener approaches for replacing the traditional harmful corrosion inhibitors [18; 19; 20], as many drugs are generally less toxic and more biodegradable compared to synthetic chemicals. However, most of the drugs are expensive, and their application as corrosion inhibitors is appropriate only when they become pharmaceutical wastes due to expiration, unuse, recall, damage, or contamination [21]. Currently, pharmaceutical wastes can be found in the municipal sewage effluents, surface waters, ground water, and even in drinking water [22; 23], representing a major environmental concern that is likely to be exacerbated in the future given the expected increase in drug usage. The primary sources of pharmaceutical pollution include wastewater from human and veterinary consumption and excretion, the improper disposal of unused or expired medications, and effluents from pharmaceutical industries [24; 25]. Numerous studies [26; 27; 28] have reported that the most common pharmaceutical contaminants in aquatic systems are antibiotics; analgesics; non-steroidal anti-inflammatory drugs; anticancer, antidiabetic, and antifungal drugs; antihistamines; antidiuretics; beta-blockers; opioid pain medications; and hormones. A comprehensive study [29] monitoring 61 pharmaceutical products, sampled from 1052 sites in 258 rivers across 104 countries, revealed that over 25% of the analyzed sites were contaminated with at least one active pharmaceutical ingredient at harmful levels. The highest contamination levels were observed in low- to middle-income countries from sub-Saharan Africa, South Asia, and South America.