Growing restrictions and bans on animal testing for chemical safety assessment under different regulations have led to an increasing use of alternative methods. Read-across is one of the major approaches used for this purpose, which relies on the identification of toxicological hazards of a data-poor or untested (target) chemical from data on other already-tested (source) similar chemicals. This requires the target substance to be first assigned to a group or category of ‘similar’ chemicals. The ‘similarity’ may be in terms of structural features alone, or in combination with certain rules that are based on mechanistic and/or toxicological aspects. In this regard, the OECD QSAR toolbox—a major free-access in silico platform—is widely used to derive toxicity predictions for a range of (eco) toxicological endpoints. The Toolbox allows the user to identify a set of similar chemicals (analogues) by computational ‘profilers’ that incorporate different structural alerts, or a combination of structural alerts and physicochemical and/or toxicokinetic rules relevant to a specific toxicological endpoint. The overall aim of this study was to assess the performance of the in silico profilers provided in the OECD QSAR Toolbox for reliability for identifying chemical analogues for category formation in a number of high-quality databases on mutagenicity, carcinogenicity, and skin sensitisation. The study also aimed to identify the reasons for any limitations in the performance of the profilers, and propose ways to improve their overall accuracy. The results showed that whilst some structural alerts are fit-for-purpose as such within the acceptable limits, others need refinement or a consideration for their possible exclusion from the profiler. Such refinements are imperative for a reliable use of the profilers in read-across and grouping/categorisation for classification, labelling and risk assessment of chemicals.

Perfumes are widely used products; however, several fragrance substances used in perfuming are well-established allergenic substances and have been attributed to various adverse health reactions. The nature and significance of perfume sensitivity reactions have not been thoroughly investigated. Therefore, this study aimed to identify the prevalence, nature, and associated risk factors of self-reported perfume sensitivity among the general population in Saudi Arabia. A nationally representative cross-sectional study was conducted among adults in Saudi Arabia in October 2020. Significant associated risk factors were explored using multivariate regression analyses. A total of 1078 participants completed the survey, with a mean age of 36.7 years (SD ± 10.36). Perfume sensitivity reactions were reported in 14.6% of participants. From among these participants, 17.8% reported moderate to severe reactions. Respiratory and skin symptoms were the most reported reactions, with total rates of 40.1% and 35.7%, respectively. History of asthma (OR = 3.2, 95%CI 1.88–4.37, p < 0.001) and the use of counterfeit perfume products (OR = 1.9, 95%CI 1.23–2.94, p < 0.003) were significantly associated with a higher risk of perfume sensitivity. Our study revealed that a considerable number of the general population in Saudi Arabia has experienced adverse health reactions due to perfume products. The enormous volume of the perfume market thus necessitates further quantitative analysis studies to determine the presence of allergenic fragrance substances in perfumes.

Background: Drug shortages represent a growing challenge to healthcare systems worldwide, affecting treatment continuity and patient outcomes. This study assessed the burden and perceived impact of drug shortages from both healthcare professionals’ and patients’ perspectives in a Saudi tertiary hospital. Methods: A cross-sectional survey was conducted in April 2025 at King Abdulaziz Medical City, Riyadh, Saudi Arabia. Convenience sampling was used to recruit healthcare professionals with at least two years of experience and adult outpatients. Structured questionnaires assessed shortage frequency, affected drug classes, perceived impacts, and management practices. The findings were descriptively analyzed and compared with the Saudi Food and Drug Authority (SFDA) national shortage data for the corresponding 12-month period. Results: A total of 230 healthcare professionals and 243 patients participated. Among healthcare professionals, 89.1% reported experiencing at least one drug shortage, with 38.3% encountering shortages more than ten times annually. Anti-infectives (36.5%) and analgesics (35.7%) were the most frequently reported classes. The most common response was prescribing alternative medications (77.4%), with 55.3% perceived as adequately effective and 30.8% as less effective. Delayed care was the most frequently reported consequence (44.0%). Among patients, 30.9% reported experiencing shortages, 46.7% reported some degree of health impact, and 28.1% incurred additional costs. Awareness and utilization of the SFDA reporting system were low in both groups. Comparison with SFDA data revealed discrepancies between hospital-reported and nationally reported shortages. Conclusions: Drug shortages were frequently reported and associated with perceived clinical and economic consequences. Gaps between hospital experiences and national reporting highlight limitations in current surveillance systems. Strengthening reporting mechanisms, communication, and supply chain coordination may improve the management of drug shortages.