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At least 469 records · Page 26Linked to original sources
PubMed1997

Estimating a delay distribution from incomplete data, with application to reporting lags for AIDS cases.

Statistical inference for the probability distribution of a reporting delay is considered when delays are recorded only after a certain point in time tau. A method is proposed which utilizes data on incidences arising prior to tau. By a suitable choice of parameters we find explicit expressions for maximum likelihood estimates and standard errors. An application to reporting delay data on Australian AIDS diagnoses demonstrates that inclusion of data on AIDS diagnoses made prior to tau results in significant gains in the precision of estimates. A simulation study indicates for this data set that there is minimal bias in the estimates and the large sample formulae for the standard errors give good estimates of the standard deviation of the estimators.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Bivariate logistic regression: modelling the association of small for gestational age births in twin gestations.

Clustered binary responses, such as disease status in twins, frequently arise in perinatal health and other epidemiologic applications. The scientific objective involves modelling both the marginal mean responses, such as the probability of disease, and the within-cluster association of the multivariate responses. In this regard, bivariate logistic regression is a useful procedure with advantages that include (i) a single maximization of the joint probability distribution of the bivariate binary responses, and (ii) modelling the odds ratio describing the pairwise association between the two binary responses in relation to several covariates. In addition, since the form of the joint distribution of the bivariate binary responses is assumed known, parameters for the regression model can be estimated by the method of maximum likelihood. Hence, statistical inferences may be based on likelihood ratio tests and profile likelihood confidence intervals. We apply bivariate logistic regression to a perinatal database comprising 924 twin foetuses resulting from 462 pregnancies to model obstetric and clinical risk factors for the association of small for gestational age births in twin gestations.

Adolescent↗
PubMed1999

Sample size and power issues in estimating incremental cost-effectiveness ratios from clinical trials data.

It is becoming increasingly more common for a randomized controlled trial of a new therapy to include a prospective economic evaluation. The advantage of such trial-based cost-effectiveness is that conventional principles of statistical inference can be used to quantify uncertainty in the estimate of the incremental cost-effectiveness ratio (ICER). Numerous articles in the recent literature have outlined and compared various approaches for determining confidence intervals for the ICER. In this paper we address the issue of power and sample size in trial-based cost-effectiveness analysis. Our approach is to determine the required sample size to ensure that the resulting confidence interval is narrow enough to distinguish between two regions in the cost-effectiveness plane: one in which the new therapy is considered to be cost-effective and one in which it is not. As a result, for a given sample size, the cost-effectiveness plane is divided into two regions, separated by an ellipse centred at the origin, such that the sample size is adequate only if the truth lies on or outside the ellipse.

Antineoplastic Agents↗
PubMed1999

Bioequivalence evaluation of lomefloxacin 400 mg tablets (Lomax versus Maxaquin in healthy human volunteers.

This study represents the results of a randomized, single dose, two-treatment, two-period crossover study in 18 healthy male volunteers to assess the bioequivalence of two tablets of 400 mg lomefloxacin. The two formulations were: Lomax(R) (Julphar, United Arab Emirates) as the test formulation and Maxaquin(R) (Searle, S.A., UK) as the reference formulation. The study was conducted at the College of Pharmacy, King Saud University, Riyadh, Saudi Arabia, jointly with King Khalid University Hospital, Riyadh, Saudi Arabia. After overnight fasting the two products were administered as a single dose on two treatment days separated by a 1 week washout period. Serial blood samples were collected thereafter, for a period of 48 h. Plasma harvested from blood was analysed for lomefloxacin by a sensitive, reproducible and accurate HPLC method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max,) T(max), T(1/2), K(elm) and C(max)/AUC(0-infinity) were determined from plasma concentrations for both formulations and found to be in good agreement with reported values. Statistical modules applied to AUC(0-t), AUC(0-infinity) and C(max) revealed no significant difference in the two tested products. Based on these statistical inferences it was concluded that Lomax(R) is bioequivalent to Maxaquin(R).

Adult↗
PubMed2000

Bioequivalence evaluation of norfloxacin 400 mg tablets (Uroxin and Noroxin) in healthy human volunteers.

A bioequivalence study of two oral formulations of 400 mg norfloxacin was carried out in 18 healthy volunteers according to a single dose, two-sequence, cross-over randomized design at College of Pharmacy, King Saud University, Riyadh, Saudi Arabia, jointly with King Khalid University Hospital. The two formulations were: Uroxin (Julphar, United Arab Emirates) as test and Noroxin (Merck Sharpe & Dohme, BV, Netherlands). Both test and reference formulations were administered to each subject after an overnight fasting on 2 treatment days separated by 1 week wash-out period. After dosing, serial blood samples were collected for a period of 24 h. Plasma harvested from blood, was analysed for norfloxacin by a sensitive, reproducible and accurate HPLC method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max), T(max), T(1/2), and K(el) were determined from plasma concentrations for both the formulations and found to be in good agreement with reported values. AUC(0-t), AUC(0-infinity), and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on ANOVA; 90% confidence interval for test/reference ratio of these parameters were found within a bioequivalence acceptance range of 80-125%. Based on these statistical inferences, it was concluded that Uroxin is bioequivalent to Noroxin.

Adult↗
PubMed2026

Molecular dynamics simulations of positively selected codons in FcγRI reveal novel biochemical binding properties.

FcγRI is a high-affinity receptor for IgG, associated with autoimmune disease pathology and determines clinical responses to antibody-based immunotherapies. FcγRI has a complex evolutionary history that is not fully understood, and to address this we explored signatures of positive selection in the receptor's functional gene, FCGR1A, using codon-based selection tests on aligned 1-1 orthologous sequences from placental mammals (n = 32). Signatures of positive selection have occurred at several locations within the gene, with two sites (H148 (M2a ω 0.997 & M8 ω = 0.993)) and (W149 (M2a ω = 0.999 & M8 ω = 1.000)) exhibiting highest posterior probabilities, suggesting strong evidence of positive selection; these positions are known to form one of the FcγRI-IgG binding interfaces. We employed ancestral reconstruction to statistically infer prior codon sequences at these sites and identified ancestral H148P and W149R codons at different nodes in the phylogeny. Employing molecular dynamics simulations, we determined how evolutionary changes at these sites may have influenced the binding of FcγRI-IgG of modern-day Homo sapiens. Measuring RMSD, free energy, radius of gyration, hydrogen bond formation, and analyzing free energy landscapes, we demonstrate that structural instability between mutant structures vs the WT counterpart; however, overall binding potential increases at position 148, yet decreases at 149 in potential. H148P protonation at physiological pH remains similar, yet during acidotic calculations, protonation is likely reduced, with predicted reduction in affinity for IgG. While ancestral W149R substitutions demonstrate an implication for electron conjugation. Examining key sites at this binding FcγRI-IgG interface, our data demonstrate that these two codons have evolved in humans to be relatively insensitive to shifts in pH promoting a more stable interaction with the Fc portion of IgG during diseases that promote acidosis.

Receptors, IgG↗
PubMed2000

Bioequivalence evaluation of two brands of cefuroxime 500 mg tablets (Cefuzime and Zinnat) in healthy human volunteers.

A bioequivalence study of two oral formulations of 500 mg cefuroxime axetil was carried out in 24 healthy volunteers following a single dose, standard two-treatment cross-over design at the College of Pharmacy, King Saud University, Riyadh, Saudi Arabia, working jointly with King Khalid University Hospital. The two formulations used were Cefuzime (Julphar, United Arab Emirates) as the test and Zinnat (Glaxo Wellcome, England) as the reference product. Both test and reference tablets were administered to each subject after an overnight fasting on two treatment days separated by a 1-week washout period. After dosing, serial blood samples were collected for a period of 8 h. Plasma harvested from blood was analysed for cefuroxime by a sensitive, reproducible and accurate high pressure liquid chromatography (HPLC) method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max), T(max), T(1/2) and K(el) were determined from plasma concentrations of both formulations and found to be in good agreement with reported values. AUC(0-t), AUC(0-infinity) and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on an analysis of variance (ANOVA); 90% confidence interval for test/reference ratio of these parameters were found within bioequivalence acceptance range of 80-125%. Based on these statistical inferences, it was concluded that Cefuzime is bioequivalent to Zinnat.

Adult↗
PubMed2001

Bioequivalence assessment of Azomycin (Julphar, UAE) as compared to Zithromax (Pfizer, USA)--two brands of azithromycin--in healthy human volunteers.

Two studies have been performed to assess the relative bioavailability of Azomycin (Julphar, UAE) as compared with Zithromax (Pfizer, USA) at the International Pharmaceutical Research Center (IPRC), Amman, Jordan. One study involved Azomycin capsules and the other Azomycin suspension. Each study enrolled 24 volunteers and in both studies, after an overnight fasting, the two brands of azithromycin were administered as single dose on two treatment days separated by a 2 weeks washout period. After dosing, serial blood samples were collected for a period of 192 h. Plasma harvested from blood, was analysed for azithromycin by HPLC coupled with electrochemical detection. Various pharmacokinetic parameters including AUC(0-t,) AUC(0-infinity,) C(max), T(max), T(1/2) and K(elm) were determined from plasma concentrations for both formulations and found to be in good agreement with the reported values. AUC(0-t), AUC(0-infinity) and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on ANOVA; 90% confidence intervals for the test/reference ratios of these parameters were found within the bioequivalence acceptance range of 80-125%. Based on these statistical inferences it was concluded that Azomycin capsule is bioequivalent to Zithromax capsule and Azomycin suspension is bioequivalent to Zithromax suspension.

Administration, Oral↗
PubMed2002

Bioequivalence evaluation of two brands of gliclazide 80 mg tablets (Glyzide & Diamicron)--in healthy human volunteers.

A randomized, two-way, crossover, bioequivalence study in 24 fasting, healthy, male volunteers was conducted to compare two brands of gliclazide 80 mg tablets, Glyzide (Julphar, UAE) as test and Diamicron (Servier Industries, France) as reference product. The study was performed at the International Pharmaceutical Research Centre (IPRC), in joint venture with Speciality Hospital, Amman, Jordan. The drug was administered with 240 ml of 20% glucose solution after a 10 h overnight fasting. After dosing, serial blood samples were collected for a period of 48 h. Plasma harvested from blood was analyzed for gliclazide by validated HPLC method. Various pharmacokinetic parameters including AUC(0-t), AUC(0- proportional, variant), C(max), T(max), T(1/2), and elimination rate constant were determined from plasma concentrations of both formulations. Statistical modules (ANOVA and 90% confidence intervals) were applied to AUC(0-t), AUC(0- proportional, variant), and C(max) for bioequivalence evaluation of the two brands which revealed no significant difference between them, and 90% CI fell within US FDA accepted bioequivalence range of 80-125%. Based on these statistical inferences, Glyzide was judged bioequivalent to Diamicron.

Adolescent↗
PubMed2002

Bioequivalence evaluation of two brands of metformin 500 mg tablets (Dialon & Glucophage)--in healthy human volunteers.

A randomized, two-way, crossover study was conducted in 24 fasting, healthy, male volunteers to compare the bioavailability of two brands of metformin 500 mg tablets; Dialon (Julphar, UAE) as test and Glucophage (Lipha Pharmaceutical Industries, France) as reference product. The study was performed at the International Pharmaceutical Research Centre (IPRC), in joint venture with Al-Mowasah Hospital, Amman, Jordan. The drug was administered with 240 ml of water after a 10-h overnight fasting on two treatment days separated by 1-week washout period. After dosing, serial blood samples were collected for a period of 30 h. Plasma harvested from blood was analyzed for metformin by validated HPLC method with UV-visible detector capable to detect metformin in the range of 0.05-5.0 microg/ml with limit of quantitation of 0.05 microg/ml. Various pharmacokinetic parameters including AUC(0-t), AUC(0-proportional to), C(max), T(max), T(1/2), and lambda(Z) were determined from plasma concentrations of both formulations and found to be in good agreement with reported values. AUC(0-t), AUC(0-proportional to) and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on ANOVA; 90% confidence interval (97.9-110.8% for AUC(0-t), 97.4-110.7% for AUC(0-proportional to); 95.3-110.5% for C(max)) of test/reference ratio for these parameters were found within bioequivalence acceptance range of 80-125%. Based on these statistical inferences, it was concluded that Dialon is bioequivalent to Glucophage.

Adolescent↗
PubMed2003

Pharmacokinetics and bioequivalence evaluation of two simvastatin 40 mg tablets (Simvast and Zocor) in healthy human volunteers.

The pharmacokinetics of two brands of simvastatin 40 mg tablets were compared in 24 healthy human volunteers after a single oral dose in a randomized cross-over study, conducted at IPRC, Amman, Jordan. Reference (Zocor, MSD, Netherlands) and test (Simvast, Julphar, UAE) products were administered to fasted volunteers; blood samples were collected at specified time intervals, plasma separated and analyzed for simvastatin and its active metabolite (beta-hydoxy acid) using a validated LC-MS/MS method at Cartesius Analytical Unit, Institute of Biomedical Sciences - USP, Sao Paulo, Brazil. The pharmacokinetic parameters AUC(0-t), AUC(0-variant), C(MAX), T(MAX), T(1/2) and elimination rate constant were determined from plasma concentration-time profile for both formulations and were compared statistically to evaluate bioequivalence between the two brands, using the statistical modules recommended by FDA. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range for bioequivalence. Based on these statistical inferences it was concluded that the two brands exhibited comparable pharmacokinetic profiles and that Julphar's Simvast is bioequivalent to Zocor of MSD, Netherlands.

Administration, Oral↗
PubMed2003

Bioequivalence evaluation of two brands of furosemide 40 mg tablets (Salurin and Lasix) in healthy human volunteers.

A randomized, two-way, crossover, bioequivalence study was conducted in 24 fasting, healthy, male volunteers to compare two brands of furosemide 40 mg tablets, Salurin (Julphar, UAE) as test and Lasix (Hoechst AG, Germany) as reference product. The study was performed at the International Pharmaceutical Research Centre (IPRC), in a joint venture with Al-Mowasah Hospital, Amman, Jordan. One tablet of either formulation was administered with 240 ml of water after a 10 h overnight fast. After dosing, serial blood samples were collected for a period of 12 h. Plasma harvested from blood was analysed for furosemide by a validated HPLC method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max), T(max), T(1/2), and elimination rate constant were determined from plasma concentrations of both formulations. Statistical modules (ANOVA and 90% confidence intervals) were applied to AUC(0-t), AUC(0-infinity), and C(max) to assess the bioequivalence of the two brands which revealed no significant difference between them, and 90% CI fell within the US FDA accepted bioequivalence range of 80%-125%. Based on these statistical inferences, Salurin was found to be bioequivalent to Lasix.

Administration, Oral↗
PubMed2003

Bioequivalence evaluation of two brands of enalapril 20 mg tablets (Narapril and Renitec) in healthy human volunteers.

The bioequivalence of two brands of enalapril 20 mg tablets was demonstrated in 24 healthy human volunteers after a single oral dose in a randomized cross-over study, conducted at IPRC, Amman, Jordan. Reference (Renitec, MSD, Netherlands) and test (Narapril, Julphar, UAE) products were administered to fasted male volunteers; blood samples were collected at specified time intervals, plasma separated and analysed for enalapril and its active metabolite (enalaprilat) using a validated LC-MS/MS method at Cartesius Analytical Unit, Institute of Biomedical Sciences, USP, Sao Paulo, Brazil. The pharmacokinetic parameters AUC(0-t), AUC(0-infinity), Cmax, Tmax, T(1/2) and elimination rate constant were determined from plasma concentration-time profile for both formulations and were compared statistically to evaluate bioequivalence between the two brands, using the statistical modules recommended by FDA. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range for bioequivalence. Based on these statistical inferences it was concluded that the two brands exhibited comparable pharmacokinetic profiles and that Julphar's Narapril is bioequivalent to Renitec of MSD, Netherlands.

Adolescent↗
PubMed2004

Bioequivalence evaluation of two brands of aceclofenac 100 mg tablets (Aceclofar and Bristaflam) in healthy human volunteers.

A randomized, two-way, crossover, bioequivalence study in 24 fasting, healthy, male volunteers was conducted to compare two brands of aceclofenac 100 mg tablets, Aceclofar (Julphar, UAE) as test and Bristaflam (Bristol Myers Squibb, Egypt) as the reference product. The drug was administered with 240 ml of water after a 10 h overnight fast on two treatment days separated by 1 week washout period. After dosing, serial blood samples were collected for a period of 24 h. Plasma harvested from blood was analysed for aceclofenac by a validated HPLC method with UV-visible detection capable of detecting aceclofenac in the range 0.2-8.0 microg/ml with the limit of quantitation as 0.2 microg/ml. Various pharmacokinetic parameters including AUC(0-t), AUC(0- infinity ), C(max), T(max), T(1/2), and lambda(Z) were determined from plasma concentrations for both formulations and found to be in good agreement with reported values. AUC(0-t), AUC(0- infinity), and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on ANOVA; 90% confidence interval (100.0%-106.4% for AUC(0-t), 100.2%-106.8% for AUC(0- infinity ); 83.3%-102.8% for C(max)) of test/reference ratio for these parameters were found to be within the bioequivalence acceptance range of 80%-125%. Based on these statistical inferences, it was concluded that Aceclofar is bioequivalent to Bristaflam.

Administration, Oral↗
PubMed2005

Comparative bioavailability of two brands of atenolol 100 mg tablets (Tensotin and Tenormin) in healthy human volunteers.

A bioequivalence study of two oral formulations of 100 mg atenolol was carried out in 24 healthy volunteers following a single dose, two-sequence, cross-over randomized design at the International Pharmaceutical Research Centre (IPRC), as a joint venture with Al-Mowasah Hospital, Amman, Jordan. The two formulations were Tensotin (Julphar, UAE) as test and Tenormin (Zeneca, UK) as reference product. Both test and reference tablets were administered with 240 ml of water to each subject after an overnight fast on 2 treatment days separated by a 1 week washout period. After dosing, serial blood samples were collected for a period of 36 h. Whole blood was analysed for atenolol by a sensitive, reproducible and accurate HPLC method with fluorescence detection capable of detecting atenolol in the range of 20-1600 ng/ml with a limit of quantitation of 20 ng/ml. Various pharmacokinetic parameters including AUC0-t, AUC0-proportional to), Cmax, Tmax, T1/2 and lambdaZ were determined from blood concentrations of both formulations and found to be in good agreement with reported values. AUC0-t, AUC0-proportional to), and Cmax were tested for bioequivalence after log-transformation of data using ANOVA and 90% confidence interval and were found within the acceptable range of 80%-125%. Based on these statistical inferences, it was concluded that Tensotin is bioequivalent to Tenormin.

Administration, Oral↗
PubMed2005

Bioequivalence assessment of Lovrak (Julphar, UAE) compared with Zovirax (Glaxo Wellcome, UK)--Two brands of Acyclovir--in healthy human volunteers.

Two studies were performed to assess the relative bioavailability of Lovrak (Julphar, UAE) compared with Zovirax (Glaxo Wellcome, UK) at the International Pharmaceutical Research Center (IPRC), Amman, Jordan. One study involved acyclovir tablets and the other acyclovir suspension. Each study enrolled 24 volunteers and in both studies, after an overnight fasting, the two brands of acyclovir were administered as a single dose on 2 treatment days separated by 1 week washout period. After dosing, serial blood samples were collected for a period of 16 h. Plasma harvested from blood, was analysed for acyclovir by an HPLC method with UV detection. Various pharmacokinetic parameters including AUC0-t, AUC0-infinity, Cmax, Tmax, T1/2 and Kelm were determined from plasma concentrations for both formulations and found to be in good agreement with the reported values. AUC0-t, AUC(0-proportional to), and Cmax were tested for bioequivalence after log-transformation of data. No significant difference was found based on ANOVA; 90% confidence intervals for the test/reference ratio of these parameters were found within the bioequivalence acceptance range 80%-125%. Based on these statistical inferences it was concluded that a Lovrak tablet is bioequivalent to a Zovirax tablet and that Lovrak suspension is bioequivalent to Zovirax suspension.

Acyclovir↗
PubMed2005

Comparative pharmacokinetics of two tablet formulations of Losartan: bioequivalence assessment.

The pharmacokinetic profiles of two brands of losartan 50 mg tablets were compared in 24 healthy adult volunteers after a single oral dose in a randomized cross-over study. The study was conducted at the ACDIMA Center for Bioequivalence & Pharmaceutical Studies, Amman, Jordan. The reference (Cozaar, MSD, The Netherlands) and test (Blosart, Julphar, UAE) products were administered to fasting volunteers. Blood samples were collected at specified time intervals, and the plasma separated and analysed for losartan and its active metabolite (losartan carboxylic acid) using a validated HPLC method with fluorescence detection. Pharmacokinetic parameters AUC(0-t), AUC(0-alpha), C(max), T(max), T(1/2), elimination rate constant, MRT, Cl/F and Vss/F were determined from plasma concentration-time profiles of both formulations and found to be in good agreement with reported values. Three parameters (AUC(0-t), AUC(0-alpha), and C(max)) were compared statistically to evaluate the bioequivalence between the two brands, using statistical modules recommended by the FDA. Analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range (80%-125%) for bioequivalence. Based on these statistical inferences it was concluded that the two formulations exhibited comparable pharmacokinetic profiles and that Julphar's Blosart is bioequivalent to Cozaar of MSD, The Netherlands.

Adult↗
PubMed2005

Bioequivalence evaluation of two brands of fluoxetine 20 mg capsules (Flutin and Prozac) in healthy human volunteers.

A bioequivalence study of two oral formulations of 20 mg fluoxetine was carried out in 24 healthy volunteers following a single dose, two-sequence, crossover randomized design at International Pharmaceutical Research Centre (IPRC), Amman, Jordan. The two formulations were Flutin capsules (Julphar, UAE) as test and Prozac capsules (Eli Lilly, UK) as reference product. Test and reference capsules were administered to each subject after an overnight fasting on two treatment days separated by a 28 day washout period. After dosing, serial blood samples were collected for a period of 360 h. Plasma harvested from blood was analysed for fluoxetine by a sensitive, reproducible and accurate LC-MS method. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max), T(max), T(1/2), and lambda(Z) were determined from plasma concentrations for both formulations and found to be in good agreement with reported values. AUC(0-t), AUC(0-infinity) and C(max) were tested for bioequivalence after log-transformation of data. No significant difference was found based on ANOVA; 90% confidence interval (94.60%-106.41% for AUC(0-t), 94.6%-108.14% for AUC(0-infinity); 91.88%-103.65% for C(max)) for test/reference ratio of these parameters were found within FDA acceptance range of 80%-125%. Based on these statistical inferences, it was concluded that Flutin is bioequivalent to Prozac and can be used interchangeably in medical practice.

Adult↗