Dried blood spot analysis of gabapentin as a valid alternative for serum: a bridging study.

We evaluated the applicability of a validated GC-MS method for the determination of gabapentin in dried blood spots (DBS). Important for the acceptance of DBS sampling as an alternative sampling strategy is the possibility to base solid conclusions on the quantification. Therefore, bridging studies -studies in which the correlation between both DBS and a reference matrix (e.g. serum) is evaluated statistically- need to be conducted. To this end, a comparative study was set up to quantify gabapentin in both blood (DBS) and serum samples. Statistically significant differences between DBS and serum concentrations were found (p<0.001). A mean blood-to-serum ratio of 0.85 was observed, which is in line with expectations. Calculated serum concentrations (obtained by dividing the DBS concentrations by 0.85) demonstrated a good correlation with measured serum concentrations, with 87% of samples fulfilling the criterion for incurred sample reanalysis. Furthermore, our data indicate a good correlation between capillary and venous concentrations. Conclusively, this study demonstrated that DBS are a valid alternative to serum for the determination of gabapentin.

Microwave-assisted on-spot derivatization for gas chromatography-mass spectrometry based determination of polar low molecular weight compounds in dried blood spots.

Dried blood spot (DBS) sampling and analysis is increasingly being applied in bioanalysis. Although the use of DBS has many advantages, it is also associated with some challenges. E.g. given the limited amount of available material, highly sensitive detection techniques are often required to attain sufficient sensitivity. In gas chromatography coupled to mass spectrometry (GC-MS), derivatization can be helpful to achieve adequate sensitivity. Because this additional sample preparation step is considered as time-consuming, we introduce a new derivatization procedure, i.e. "microwave-assisted on-spot derivatization", to minimize sample preparation of DBS. In this approach the derivatization reagents are directly applied onto the DBS and derivatization takes place in a microwave instead of via conventional heating. In this manuscript we evaluated the applicability of this new concept of derivatization for the determination of two polar low molecular weight molecules, gamma-hydroxybutyric acid (GHB) and gabapentin, in DBS using a standard GC-MS configuration. The method was successfully validated for both compounds, with imprecision and bias values within acceptance criteria (<20% at LLOQ, <15% at 3 other QC levels). Calibration lines were linear over the 10-100µg/mL and 1-30µg/mL range for GHB and gabapentin, respectively. Stability studies revealed no significant decrease of gabapentin and GHB in DBS upon storage at room temperature for at least 84 days. Furthermore, DBS-specific parameters, including hematocrit and volume spotted, were evaluated. As demonstrated by the analysis of GHB and gabapentin positive samples, "microwave-assisted on-spot derivatization" proved to be reliable, fast and applicable in routine toxicology. Moreover, other polar low molecular weight compounds of interest in clinical and/or forensic toxicology, including vigabatrin, beta-hydroxybutyric acid, propylene glycol, diethylene glycol, 1,4-butanediol and 1,2-butanediol, can also be detected using this method.

Attitudes of physicians and pharmacists towards International Non-proprietary Name prescribing in Belgium.

International Non-proprietary Name (INN) prescribing is the use of the name of the active ingredient(s) instead of the brand name for prescribing. In Belgium, INN prescribing began in 2005 and a major policy change occurred in 2012. The aim was to explore the opinions of Dutch-speaking general practitioners (GPs) and pharmacists. An electronic questionnaire with 39 five-point Likert scale statements and one open question was administered in 2013. Multivariate analysis was performed with multiple linear regression on a sum score for benefit statements and for drawback statements. Answers to the open question were qualitatively analysed. We received 745 valid responses with a representable sample for both subgroups. Participants perceived the motives to introduce INN prescribing as purely economic (to reduce pharmaceutical expenditures for the government and the patient). Participants accepted the concept of INN prescribing, but 88% stressed the importance of guaranteed treatment continuity, especially in older, chronic patients, to prevent patient confusion, medication non-adherence and erroneous drug use. In conclusion, the current way in which INN prescribing is applied in Belgium leads to many concerns among primary health professionals about patient confusion and medication adherence. Slightly adapting the current concept of INN prescribing to these concerns can turn INN prescribing into one of the major policies in Belgium to reduce pharmaceutical expenditures and to stimulate rational drug prescribing.

Operational rules for the implementation of INN prescribing.

PURPOSE: The aim is to describe the process, principles and results of the International Nonproprietary Name (INN) prescribing project in Belgium. The purpose of this project was to operationalize electronic INN prescribing for outpatient care in daily medical practice and to develop a factual database which can be used in electronic INN prescribing applications. METHODS: The operationalization process consisted of three phases: (1) expert consultation, (2) review by regulatory authorities and (3) test phase with stakeholders and end-users. RESULTS: The INN prescribing project resulted into (1) operational rules for electronic INN prescribing and (2) a reference database to be implemented in commercial medical software. The operational rules for electronic INN prescribing define valid INN groups as sets of equivalent medicinal products, described by three elements: the therapeutic moiety (the active part of the therapeutic ingredient) or combination of therapeutic moieties, the strength (with standardized denominators), and the method of administration (with simplified but standardized options). The operational rules also define two categories of exemptions for INN prescribing: INN groups where the first choice of treatment should be continued throughout the therapy period (NO SWITCH) and medicinal product groups not suitable for INN prescribing (NO INN). The reference database is the result of the virtual classification of the Belgian therapeutic arsenal into INN groups, according to the operational rules. CONCLUSIONS: Defining the operational rules for INN prescribing for and with different stakeholders was a difficult yet feasible assignment. The INN prescribing project resulted into explicit operational rules and a reference database. The Belgian experience may provide important information for other countries planning to operationalize or refine electronic INN prescribing. It can also be used for a thorough evaluation of the impact of the new concept of INN prescribing on daily practice and on medical education.

Ramadan fasting and diabetes: an observational study among Turkish migrants in Belgium.

AIMS: To investigate (i) Ramadan participation, (ii) provision of Ramadan-related advice by healthcare providers, (iii) medication use during Ramadan fasting among Turkish migrants with diabetes in Belgium. METHODS: This pilot observational study was conducted among a convenience sample of 52 Turkish migrants with diabetes in Belgium. Two questionnaires collected information on socio-demographic characteristics, diabetes-related characteristics, current hypoglycaemic medication with dosing regimen, participation in the past Ramadan, reasons for (non-)participation, use of hypoglycaemic medication during the past Ramadan, advice from their healthcare providers about fasting during Ramadan and follow-up of this advice. RESULTS: Sixteen patients (31%) had fasted during the past Ramadan. Main reason for Ramadan participation was reinforcement of faith (12/15), while the main reason for non-participation was having diabetes (34/36). About 56% of the study population had received recommendations from their healthcare provider(s) about fasting and diabetes during Ramadan. The most commonly provided advice was not to participate in Ramadan, followed by modification of drug therapy. Only 3 patients ignored the advice of their health professionals. In addition, only 60% of those who actually fasted received recommendations about intake of diabetes medication during the Ramadan. Most fasters continued their medication dose unchanged (87% of OHA users and 80% of the insulin users). CONCLUSIONS: This pilot study found a low prevalence of Ramadan fasting among Turkish migrants with diabetes in Belgium. We also found that provision of advice by healthcare providers could be improved. Larger scale studies are warranted to confirm these findings.