Selective determination of acidic pharmaceuticals in wastewater using molecularly imprinted solid-phase extraction.

The determination of acidic pharmaceuticals, such as non-steroidal anti-inflammatory drugs NSAIDs and clofibric acid (metabolite of clofibrate), at low ngL(-1) levels in wastewater requires highly selective and sensitive analytical procedures. The removal of matrix components during sample preparation results in significant benefits towards reducing the matrix effects during LC-MS analysis. Therefore this work describes a simple method to enrich and clean up NSAIDs and clofibric acid from sewage water using molecularly imprinted solid-phase extraction (MISPE). Final analysis was performed by liquid chromatography-tandem mass spectrometry. The performance of this method has been evaluated in fortified tap and sewage water in terms of recovery, precision, linearity, and method quantification limit. Recovery for all compounds ranged in all matrices between 84 and 116% with intra-day R.S.D. values below 11.5%. Matrix effect evaluation demonstrated that even complex sample matrixes, such as pond or sewage water did not showed significant ion suppression/enhancement compared to tap water. The performance of the method was further emphasized by the study of pond water, which receives treated water from a sewage treatment plant in south Sweden. Raw sewage and treated water were also tested. In those samples, all acidic pharmaceuticals were detected in concentration above method quantification limits ranging from 5.1 to 5153.0ngL(-1).

Repeat prescriptions: refill adherence in relation to patient and prescriber characteristics, reimbursement level and type of medication.

BACKGROUND: Repeat prescribing used in long-term pharmacotherapy is often associated with inadequate patient medication, including non-adherence. In this paper we explore patients' drug refill adherence with repeat prescriptions and relate refill data to patient age and gender, type of prescriber, type of prescribed drug, and reimbursement level. METHODS: During one week of 2002, copies of 3636 repeat prescriptions filled at 16 large Swedish pharmacies were collected. Satisfactory refill adherence was defined as dispensed refills covering 80-120% of the prescribed treatment time. Under- and oversupplying were defined as <80% and >120% coverage, respectively. RESULTS: The average level of refill adherence was 57%, and the level of under- and oversupplying 21% and 22%, respectively. There was no gender difference. Patients who were exempt from payment had higher oversupplies than others (33% versus 19%), and patients of general practitioners had higher refill adherence than patients of hospital physicians. The highest refill adherence was observed for contraceptives (81%) and the lowest for anti-asthmatics, proton pump inhibitors and non-steroidal anti-inflammatory drugs (30-40%). CONCLUSIONS: Refill non-adherence includes both under- and oversupplying and may vary due to different attitudes between prescribers and between patients. Different therapeutic indications and reimbursement systems are other apparent causes. These observations should be considered in programs aiming to assist patients in following medication prescriptions.