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Objectives We characterized and compared the in-vivo absorption of topotecan into the aqueous humor after instillation of aqueous and ointment formulations. Methods A lanolin/petrolatum ointment was used. New Zealand rabbits were instilled with topotecan solution (6 μg, group A), a single 10 μg dose of topotecan ointment (group B) or with five 10 μg doses of topotecan ointment (group C). Aqueous humor samples were collected at different times. Corneal samples were collected only for group A. Topotecan was quantified using HPLC, and pharmacokinetic parameters were calculated. Acute corneal epithelial toxicity was assessed after multiple instillations of topotecan ointment. Key findings Total topotecan maximum aqueous humor concentration ( Cmax) was 16.1, 69.9 and 287 ng/ml in group A, B and C, respectively. A single dose of topotecan ointment increased threefold and sevenfold the aqueous humor Cmax, and exposure compared to the aqueous formulation. Aqueous humor concentrations from group C eyes were substantially above the cytotoxic concentration for retinoblastoma cells. No corneal toxicity was evident after ointment instillation. Conclusions Topotecan penetrated into the aqueous humor of the rabbit eye after multiple doses of an ointment in concentrations pharmacologically active against retinoblastoma cells without eliciting acute toxicity. Topotecan ointment may translate to the clinical treatment of anterior segment disseminated retinoblastoma. [ABSTRACT FROM AUTHOR]

Objective. Determine the status of analytical laboratories that quantify immunosuppressants in transplant patients who are under therapeutic drug monitoring (TDM) for these drugs in Argentina in order to identify potential perfectible areas for action. Methods. A survey of the clinical and analytical TDM centers in Argentina was conducted between September 2013 and November 2014 under the direction of the Garrahan Hospital Clinical Pharmacokinetics Unit and the National Unified Central Institute for Ablation and Implant Coordination. Results. A nationally representative sample of 27 clinical and analytical centers was identified, of which 45% were public hospitals. Most of these centers (95%) monitor ciclosporin and tacrolimus, and to a lesser extent, sirolimus and everolimus; a small number of them also monitor mycophenolic acid. The median number of samples of these five drugs analyzed per month was 251 (range: 10-2024). Nearly 60% of the samples were analyzed in private institutions. Only four of the respondents (17%) reported values within the therapeutic margin. Of all the centers, 92% use immunoassay as the analytical methodology. Of the bioanalytical installations that have their own facilities, 68% reported that they also have their own quality assurance program. Conclusions. TDM of immunosuppressants is a recommended practice for transplant patients in Argentina. Initiatives need to be taken at the national level to develop uniform guidelines for analytical laboratories that include TDM-related quality assurance processes with regulatory force. There is also a need to train technical and professional personnel and to invite the participation of public and private organizations in the regulatory, public health, and research areas. [ABSTRACT FROM AUTHOR]

Objective Determine the status of analytical laboratories that quantify immunosuppressants in transplant patients who are under therapeutic drug monitoring (TDM) for these drugs in Argentina in order to identify potential perfectible areas for action. Methods A survey of the clinical and analytical TDM centers in Argentina was conducted between September 2013 and November 2014 under the direction of the Garrahan Hospital Clinical Pharmacokinetics Unit and the National Unified Central Institute for Ablation and Implant Coordination. Results A nationally representative sample of 27 clinical and analytical centers was identified, of which 45% were public hospitals. Most of these centers (95%) monitor ciclosporin and tacrolimus, and to a lesser extent, sirolimus and everolimus; a small number of them also monitor mycophenolic acid. The median number of samples of these five drugs analyzed per month was 251 (range: 10-2024). Nearly 60% of the samples were analyzed in private institutions. Only four of the respondents (17%) reported values within the therapeutic margin. Of all the centers, 92% use immunoassay as the analytical methodology. Of the bioanalytical installations that have their own facilities, 68% reported that they also have their own quality assurance program. Conclusions TDM of immunosuppressants is a recommended practice for transplant patients in Argentina. Initiatives need to be taken at the national level to develop uniform guidelines for analytical laboratories that include TDM-related quality assurance processes with regulatory force. There is also a need to train technical and professional personnel and to invite the participation of public and private organizations in the regulatory, public health, and research areas.