Correlations between interpersonal and cognitive difficulties: relationship to suicidal ideation in military suicide attempters.

BACKGROUND: Understanding suicidal ideation may help develop more effective suicide screening and intervention programs. The interpersonal and the cognitive-deficit theories seek to describe the factors leading to suicidal behavior. In the military setting it is common to find over- and under-reporting of suicidal ideation. This study sought to determine the relationship between these two models and determine to what degree their components can indirectly predict suicidal ideation. METHODS: Suicide attempters (n=32) were compared with non-suicidal psychologically treated peers (n=38) and controls (n=33), matched for sex and age (mean 19.7years). Pearson's analysis was used to quantify the relationship between the variables from the two models and hierarchal regression analysis was used to determine the explanation of suicidal ideation variance by these variables. RESULTS: Suicide attempters have more difficulties in problem-solving, negative emotion regulation and burdensomeness compared with their peers (P<.001). These variables are all closely correlated with each other and to suicide ideation (r>±0.5; P<.001). Prior suicide attempt, loneliness and burdensomeness together explain 65% (P<.001) of the variance in suicidal ideation. CONCLUSIONS: Suicidal ideation is strongly correlated with components of interpersonal and cognitive difficulties. In addition to assessing current suicidal ideation, clinicians should assess past suicide attempt, loneliness and burdensomeness.

Differentiating Army suicide attempters from psychologically treated and untreated soldiers: a demographic, psychological and stress-reaction characterization.

BACKGROUND: Suicide is the leading cause of death in most armies during peace-time. The recent dramatic rise in suicides in the US Army further focuses attention on the causes of suicidal behavior in the military. METHODS: This study investigated demographic characteristics, psychological profile and stress-related risk factors associated with suicide attempts in Israelis aged 18-21 years, who served in the Army in 2009. Soldiers who attempted suicide (N=60) were compared to soldiers treated by a mental health professional, but reported no suicidal behavior (N=58), and to controls (N=50). RESULTS: Suicide attempters had lower socioeconomic status and less cognitive ability compared with treated soldiers and untreated control soldiers. Only 25% of the suicide attempters had received mental healthcare prior to the attempt. The majority of the attempts were non-lethal (86.2%), and only 5.2% used firearms. Attempters had more previous suicide attempts (37.9%) and deliberate selfharm incidents (19.3%), compared to almost no such behaviors in the other two groups. Following the suicide attempt, 77% were diagnosed with moderate to severe mental disorders, 44.8% personality disorders and 8.6% mood disorders. Attempters reported higher levels of general stress compared to their peers in the other two groups. Being away from home and obeying authority were especially more stressful in attempters. CONCLUSIONS: Young soldiers are less prone to seek mental health assistance, despite suffering from higher levels of stress. Screening is required to detect soldiers at risk for suicidal behavior and preventive intervention will require active outreach.

Who needs individual bioequivalence studies for narrow therapeutic index drugs? A case for warfarin.

Warfarin is, among drugs, considered to have a narrow therapeutic index for which individual bioequivalence has been suggested. To establish the propriety of "switching," an individual bioequivalence study involving a replicate-design study and three "switchings" in healthy subjects was undertaken using the U.S.-brand warfarin sodium tablet and a generic product. A randomized, single-center, open-label, single-dose, four-way crossover replicate bioequivalence study was performed in 24 healthy male volunteers in which each subject received the same 5 mg warfarin test and reference tablets twice on different occasions under fasting conditions. Concentrations of warfarin in plasma were measured by a validated specific HPLC method. The individual pharmacokinetic parameters obtained with test and reference products were compared using pooled data and Liu's method. Bioequivalence was shown with both average and individual bioequivalence methods. The individual bioequivalence assessment did not show a subject-by-formulation interaction, nor did it add value to the bioequivalence assessment of warfarin.

Assessment of value and applications of in vitro testing of topical dermatological drug products.

The FDA recently issued a guidance covering practices of scaleup and post approval changes with semisolids (SUPAC-SS). This guidance outlines the steps that must be taken by a company to maintain certification of its semisolid dermatological products after quantitative changes have been made in their compositions and/or after changes have been made in the sourcing of their key ingredients, in their processing, in their batch sizes, and/or after their site of manufacture has been relocated. A key element within the guidance is a release test to be used to determine if the diffusional release of a drug found in a formulation is the same after changes have been made to the formulation as it was prior to implementing the changes. The AAPS-FDA sponsored workshop was set up to explore this qualifying test. The stated aims of the workshop were: a) to illustrate the methodology and techniques of in vitro release testing, b) to show the sensitivity of in vitro release with respect to manufacturing variables and to variations in components and composition (of specific formulations), c) to recognize in vitro release testing as a useful procedure for SUPAC documentation, d) to highlight and evaluate other applications of in vitro release testing, e) to explore the degree to which in vitro release testing and bioavailability may be related, and f) to evaluate the role of in vitro release testing of topical dosage forms as a tool to improve product quality.

A multiple-dose safety and bioequivalence study of a narrow therapeutic index drug: a case for carbamazepine.

BACKGROUND AND OBJECTIVES: Carbamazepine is among those drugs that have been considered to have a narrow therapeutic plasma concentration range, that is, a narrow therapeutic index. Although the US Food and Drug Administration has approved new generic products based on standard single-dose bioequivalence studies, several state formularies, including the New Jersey Drug Utilization Review Council, have recently established additional criteria for acceptance of bioequivalence of narrow therapeutic index drugs, limiting the use of some approved generic drugs in specific states. To further validate the adequacy of single-dose studies for the determination of bioequivalence of narrow therapeutic index drugs, a multiple-dose study was conducted that more closely reflected therapeutic use. METHODS: A single-center, multiple-dose, randomized, open-label, 2-way crossover bioequivalence study was conducted in 32 fasting volunteers at steady state. Subjects received the test and reference products as a 200 mg carbamazepine tablet 3 times a day in a crossover fashion. Concentrations of carbamazepine and carbamazepine-10,11-epoxide in plasma were measured by a validated specific HPLC method. RESULTS: A total of 28 subjects completed the study. Pharmacokinetic parameters and measures of fluctuation for both products at steady state were similar, with 90% and 95% confidence intervals falling within 90% and 110%. CONCLUSION: The multiple-dose study provided reliable safety and bioequivalence data under rigorous statistical conditions and confirmed bioequivalence of test and reference products determined by a single-dose study.

Existing and new criteria for bioequivalence evaluation of new controlled release (CR) products of carbamazepine.

While the three classical pharmacokinetic (PK) parameters, AUC, Cmax and tmax are adequate to assess bioequivalence of immediate release (IR) formulations, they are not designed to fully characterize the pharmacokinetic (PK) performance of controlled release (CR) formulations and provide only limited insight into the function of carbamazepine (CBZ) CR products. Thus, for reliable assessment of bioequivalence in CR formulations, there is a role for the use of additional criteria (parameters). The following are the proposed new parameters: MRT (mean residence time), Cmax/AUC, plateau time or POT (the time span associated with the concentrations within 25% of Cmax), tapical (the arithmetic mean of the times associated with POT) and Capical (the arithmetic mean of the concentrations within 25% of Cmax). The above proposed parameters, were utilized in a recent PK study of new CR products of CBZ (600 mg) designed for once daily dosing. The comparative PK analysis was conducted in a three-way crossover single dose studies of three CBZ CR formulations (Teril 600 CR tablet, CBZ 600 granulate and Timonil 600 Retard tablet). Teril 600 CR was found to be bioequivalent to Timonil 600 Retard while CBZ 600 granulate was not. This conclusion was reached utilizing both the classical and the proposed new parameters. The new parameters showed that CBZ 600 granulate has similar rate of absorption as the two 600 mg CR tablets, but its extent of absorption was lower. The new parameters examined in this paper are more attractive than the single point parameters, Cmax and tmax, for assessment of rate of absorption and the flatness of the plasma concentration versus time curve. Their potential benefit and practical utility was confirmed in this study, which demonstrated bioequivalence between a new CR and an innovator CBZ (600 mg) tablet. Absorption rate assessment is important in light of concentration-related side effects associated with CBZ therapy and the impact of fluctuations and the flatness of the CBZ plasma concentration curve on the drug efficacy and tolerability.

Criteria to assess in vivo performance and bioequivalence of generic controlled-release formulations of carbamazepine.

PURPOSE: Concern persists that the criteria used to establish bioequivalence of generic drugs may not adequately guarantee the interchangeability of antiepileptic medications (AEDs), particularly controlled-release (CR) formulations. We examined the utilization of several new parameters, in addition to AUC, peak plasma concentration (Cmax), and time to reach Cmax (tmax), for the assessment of bioequivalence and in vivo performance of CBZ and other CR products. These new parameters may offer additional information for evaluation of CR products that yield a prominent plateau in the plasma time-concentration curve. They include mean residence time (MRT), Cmax/AUC, plateau time or POT (the time span associated with the concentrations within 25% of Cmax), t(apical), and C(apical) (the arithmetic mean of the POT times and concentrations within 25% of Cmax, respectively). Additional parameters for multiple-dose studies include the percentage fluctuation and the flatness of the steady state-concentration curve. METHODS: These proposed parameters were used in two recent (single and multiple dose) two-way crossover studies of a new CR product of CBZ (Teril 400 CR) in comparison with Tegretol CR Divitab. RESULTS: Teril 400 CR was found to be bioequivalent to Tegretol CR Divitab, by using both the classic and the additional proposed parameters. Both CBZ CR products have similar rates of absorption and similar flatness of their plasma time-concentration curves as assessed by visual inspection and the proposed parameters. CONCLUSIONS: The additional parameters examined may supplement the traditional single-point parameters, Cmax and tmax, for assessment of rate of absorption and the flatness of the concentration curve. Their potential benefit and practical utility was confirmed in these two studies. Absorption-rate assessment is important in light of concentration-related side effects associated with CBZ therapy and the impact of fluctuations and the flatness of the CBZ plasma concentration curve on the drug efficacy and tolerability.

Analysis of enloplatin by liquid chromatography and of platinum by atomic absorption spectrometry in various biological fluids.

Analytical methods were developed and validated for the determination of enloplatin (an anticancer agent) in plasma by reversed-phase LC and for platinum (an elemental component of enloplatin) in plasma, plasma ultrafiltrate (PUF) and whole blood by flameless atomic absorption spectrometry (FAAS). The LC procedure involved protein precipitation with dilute perchloric acid. The supernatant was mixed with sodium phosphate buffer and injected into the LC system. A C18 or a cyano column was used, depending on sample matrix, with UV detection at 230 nm. The LC method was linear from 0.50 to 50.0 micrograms ml-1. Inter-day and intra-day precision (RSD%) and accuracy (relative error%) were < +/- 14%. The FAAS procedure utilized a graphite furnace, a hollow cathode platinum (Pt) lamp, and Zeeman background correction. An aliquot of plasma, PUF, or whole blood was mixed with a solution of Triton X-100 and Antifoam-B and injected into the FAAS system. The FAAS method showed goodness of fit from 0.05 to 10.0 micrograms Pt/ml. Inter-day and intra-day precision and accuracy were < +/- 15%. The methods were developed to support pharmacokinetic studies in humans, dogs and rats.

Dose proportionality of bisoprolol enantiomers in humans after oral administration of the racemate.

Dose proportionality of racemic bisoprolol and the stereoselectivity of its enantiomers were studied after single oral dosing of 5 to 40 mg of bisoprolol hemifumarate in eight healthy male volunteers in an open-label, randomized, four-way cross-over trial. There were dose-proportional increases in mean peak plasma concentration (Cmax) and area under the plasma concentration versus time curve (AUC) values for the racemate and the individual enantiomers. No statistically significant differences were detected between the mean half life (t 1/2), Cmax, and time to reach Cmax (tmax) of the R- and S-isomers at each of the four dose levels studied. These findings support dose proportionality and absence of stereoselective pharmacokinetics for bisoprolol in the dose range studied.

Pharmacokinetic comparison of leucovorin and levoleucovorin.

The pharmacokinetic values of d,l-leucovorin and l-leucovorin were compared in eight healthy volunteers following oral administration of 25 mg d,l-leucovorin and 12.5 mg l-leucovorin. Serum levels of l-5-formyltetrahydrofolate, l-5-methyltetrahydrofolate, and total reduced folates were measured by an established microbiological method. Pharmacokinetic data for both preparations were consistent with those previously reported for d,l-leucovorin, with essentially complete first pass metabolism to l-5-methyltetrahydrofolate, the active metabolite. No differences were found between the two preparations in serum concentrations of active folate fractions, AUC, or Cmax, or in clearance and volume of distribution estimates. These data suggest that after administration of 25 mg of d,l-leucovorin, the d-diastereoisomer has no significant effect on the standard pharmacokinetic measurements of the active l-folates.

Analytical methods validation: bioavailability, bioequivalence and pharmacokinetic studies. Conference report.

This is a summary report of the conference on Analytical Methods Validation: Bioavailability, Bioequivalence and Pharmacokinetic Studies. The conference was held from December 3 to 5, 1990 in the Washington, DC area and was sponsored by the American Association of Pharmaceutical Scientists, US Food and Drug Administration, Federation International Pharmaceutique, Health Protection Branch (Canada) and Association of Official Analytical Chemists. The purpose of the report is to represent our assessment of the major agreements and issues discussed at the conference. The report is also intended to provide guiding principles for validation of analytical methods employed in bioavailability, bioequivalence and pharmacokinetic studies in man and animals. The objectives of the conference were: 1. To reach a consensus on what should be required in analytical methods validation and the procedures to establish validation; 2. To determine processes of application of the validation procedures in the bioavailability, bioequivalence and pharmacokinetic studies; 3. To develop a report on analytical methods validation (which may be referred to in developing future formal guidelines). Acceptable standards for documenting and validating analytical methods with regard to processes, parameters or data treatments were discussed because of their importance in assessment of pharmacokinetic, bioavailability and bioequivalence studies. Other topics which were considered essential in the conduct of pharmacokinetic studies or in establishing bioequivalency criteria, including measurement of drug metabolites and stereoselective determinations, were also deliberated.

Pharmacokinetic principles in the design of immediate-release components in sustained-release formulations with zero-order release characteristics.

The potential advantages and disadvantages of incorporating an immediate-release (IR) component in sustained-release formulations with zero-order release characteristics (SR) are discussed. The dose of the IR component for SR doses other than the first one (DIS) should be less than that for the first SR dose (DI). Multiple dosing of an SR formulation with an IR component of dose DI may lead to unnecessary accumulation and fluctuation of plasma drug concentrations. An innovative and practical method for estimating the DI and DIS doses of this IR component is also presented.