Analysis of Adherence to Fluoxetine Treatment through its Plasma Concentration

Abstract Depression plays an important role in non-adherence to medical recommendations. Fluoxetine is a first line of depression treatment. This study aimed to evaluate adherence to drug therapy in fluoxetine users by different methods. A cross-section study was conducted with 53 depressed patients on fluoxetine for at least six months. Drug therapy adherence was assessed by validated questionnaires [Brief Medication Questionnaire (BMQ) and Morisky-Green test (MG)] and by the blood concentration of fluoxetine and its active metabolite norfluoxetine. Blood samples were taken before the daily first dose of fluoxetine. The plasmatic concentration of fluoxetine and norfluoxetine indicated that 58.5% volunteers were within the recommended therapeutic range and thus considered adherent to drug therapy. However, questionnaires indicated a non-adherent majority: 41.5% patients had a high degree of adherence in MG and only 13.2% were adherent to pharmacological treatment in BMQ. Most fluoxetine users showed a plasma concentration of fluoxetine and norfluoxetine within the therapeutic range, despite the low adherence to the drug therapy evaluated by the questionnaires. Thus, we suggest that plasma levels of fluoxetine and norfluoxetine could be used as the main method to check adherence to treatment.

Spectrophotometric and spectrofluorimetric determination of some selective serotonin reuptake inhibitors [SSRIs] through ternary complex formation with eosin and copper [II] in pharmaceuticals

Two simple, and sensitive, spectrophotometric and spectrofluorimetric procedures have been developed and validated for analysis of selective serotonin reuptake inhibitors [SSRIs] namely, fluoxetine hydrochloride [FX], fluvoxamine maleate [FV] and sertraline hydrochloride [SE]. Both methods were based on the formation of ternary complex between the cited drugs, eosin and copper sulphate, Spectrophotometrically, the complex was estimated by two procedures, the first procedure depends on the extraction of the ternary complex with chloroform. The second spectrophotometric one depends on the direct measurement of the complex after addition of sodium lauryl sulphat. The ternary complexes showed an absorption maximum at 530 nm for the three cited drugs. Different variables and parameters affecting the reactions were studied and optimized. The formed complexes obey Beer's law in concentration range 1-18, 1-16, 0.25-10 micro gml[-1] using the extractive method and 0.4-12, 0.5-14, 0.1-8 micro gml-1 using surfactant with good correlation coefficients. A fluorescence quenching method for the determination of the [SSRIs] through the formed ternary complexes was also investigated to enhance the sensitivity of the analysis. The formed fluorophores were measured at lambda E[x] 310 nm and lambda E[m]510nm for the three drugs. Regression analysis showed good correlation coefficients [0.9996-0.9999] over the concentration ranges 0.1-25, 0.1-15 and 0.1-12 micro gml-1 for FX, FV and SE, respectively. The proposed methods were validated and successfully applied to the analysis of the three drugs in drug substances and drug products with good accuracy. No interference was observed from common pharmaceutical excipients. The results were favorably in good agreement with those obtained by official methods