Using genetics to investigate the association between lanosterol and cataract.

Background: Cataract is one of the most prevalent causes of blindness worldwide. Whilst surgery is the primary treatment for cataracts, it is not always an available option, particularly in developing countries. Non-surgical methods of treatment would increase treatment availability for more patients. Several studies have investigated how topical application of oxysterols, such as lanosterol, may break down aggregated proteins and restore lens transparency. However, the results are conflicting and inconclusive. Aim: In this study, we focus on combining genetic evidence for associations between lanosterol related genetic variation and cataract to explore whether lanosterol is a potentially suitable drug treatment option. Method: Using data from 45,449 available cataract cases from the UK Biobank, with participant ages ranging from 40-69, we conducted a genetic association study (GWAS) to assess the risk of cataract. Cataract cases were defined using diagnostic and operation codes. We focused on genetic variants in the lanosterol synthase gene region. We also compared our results with previously published genetic associations of phytosterol-to-lanosterol ratios. Finally, we performed a genetic risk score analysis to test the association between lanosterol within the cholesterol synthesis pathway and the risk of cataract. Results: No statistically significant single nucleotide polymorphisms (SNPs) associations with cataract were observed in the gene region of lanosterol synthase at a multiple testing adjusted significance threshold of p < 0.05/13. The comparison between cataract risk and genetic association of 8 phytosterol-to-lanosterol GWAS results also showed no evidence to support lanosterol's protective properties for cataract risk. No statistically significant association was found between the lanosterol within the cholesterol synthesis pathway genetic risk score and cataract outcomes (OR = 1.002 p = 0.568). Conclusion: There was no evidence observed for genetic associations between lanosterol and cataract risk. Our results do not support lanosterol's potential role in treating cataracts. Further research may be needed to address the effect of lanosterol on specific cataract subtypes.

Exploring the contribution of lifestyle to the impact of education on the risk of cancer through Mendelian randomization analysis.

Educational attainment (EA) has been linked to the risk of several types of cancer, despite having no expected direct biological connection. In this paper, we investigate the mediating role of alcohol consumption, smoking, vegetable consumption, fruit consumption and body mass index (BMI) in explaining the effect of EA on 7 cancer groupings. Large-scale genome wide association study (GWAS) results were used to construct the genetic instrument for EA and the lifestyle factors. We conducted GWAS in the UK Biobank sample in up to 335,024 individuals to obtain genetic association data for the cancer outcomes. Univariable and multivariable two-sample Mendelian randomization (MR) analyses and mediation analyses were then conducted to explore the causal effect and mediating proportions of these relations. MR mediation analysis revealed that reduced lifetime smoking index accounted for 81.7% (49.1% to 100%) of the protective effect of higher EA on lower respiratory cancer. Moreover, the effect of higher EA on lower respiratory cancer was mediated through vegetable consumption by 10.2% (4.4% to 15.9%). We found genetic evidence that the effect of EA on groups of cancer is due to behavioural changes in avoiding well established risk factors such as smoking and vegetable consuming.

Higher Waist Hip Ratio Genetic Risk Score Is Associated with Reduced Weight Loss in Patients with Severe Obesity Completing a Meal Replacement Programme.

Background: A better understanding of the influence of genetic factors on the response to lifestyle interventions in people with obesity may allow the development of more personalised, effective and efficient therapeutic strategies. We sought to determine the influence of six obesity-related genetic risk scores on the magnitude of weight lost by patients with severe obesity who completed a dietary intervention. Methods: In this single-centre prospective cohort study, participants with severe and complicated obesity who completed a 24-week, milk-based meal replacement programme were genotyped to detect the frequency of common risk alleles for obesity and type 2 diabetes-related traits. Genetic risk scores (GRS) for six of these traits were derived. Participants with a potentially deleterious monogenic gene variant were excluded from the analysis. Results: In 93 patients completing the programme who were not carrying a known obesity-related gene mutation, 35.5% had diabetes, 53.8% were female, mean age was 51.4 ± 11 years, mean body mass index was 51.5 ± 8.7 and mean total weight loss percent at 24 weeks was 16 ± 6.3%. The waist-hip ratio (WHR) GRS was inversely associated with percentage total weight loss at 24 weeks (adjusted ß for one standard deviation increase in WHR GRS -11.6 [-23.0, -0.3], p = 0.045), and patients in the lowest tertile of WHR GRS lost more weight. Conclusions: Patients with severe and complicated obesity with a genetic predisposition to central fat accumulation had less weight loss in a 24-week milk-based meal replacement programme, but there was no evidence for influence from the five other obesity-related genetic risk scores on the response to dietary restriction.

Repo-Man/protein phosphatase 1 SUMOylation mediates binding to lamin A and serine 22 dephosphorylation.

Lamin A phosphorylation/de-phosphorylation is an important process during cells division as it allows for nuclear envelope (NE) disassembly at mitotic entry and its re-assembly during mitotic exit. Several kinases have been identified as responsible for these phosphorylations, but no protein phosphatase has been implicated in their reversal. One of the mitotic phosphosites in lamin A responsible for its dynamic behaviour is serine 22 (S22) which is de-phosphorylated during mitotic exit. Recent evidence has also linked the nuclear pool of lamin A S22ph in interphase to gene expression regulation. Previous work suggested that the phosphatase responsible for lamin A S22 de-phosphorylation is chromatin bound and interacts with lamin A via SUMO-SIM motives. We have previously reported that Repo-Man/protein phosphatase 1 (PP1) is a chromatin-associated phosphatase that regulates NE reformation. Here we propose that Repo-Man/PP1 phosphatase mediates lamin A S22 de-phosphorylation. We indeed show that depletion of Repo-Man leads to NE defects, causes hyperphosphorylation of lamin A S22 that can be rescued by a wild-type but not a SUMOylation-deficient mutant. Lamin A and Repo-Man interact in vivo and in vitro, and the interaction is mediated by SUMOylation. Moreover, the localization of Repo-Man/PP1 to the chromatin is essential for lamin A S22 de-phosphorylation.

Mendelian randomisation analyses of UK Biobank and published data suggest that increased adiposity lowers risk of breast and prostate cancer.

Breast (BCa) and prostate (PrCa) cancer are the first and second most common types of cancer in women and men, respectively. We aimed to explore the causal effect of adiposity on BCa and PrCa risk in the UK Biobank and published data. We used Mendelian randomisation (MR) to assess the causal effect of body mass index (BMI), body fat percentage (BFP), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) on BCa and PrCa risk. We found that increased BMI, WC and HC decreased the risk of breast cancer (OR 0.70 per 5.14 kg/m2 [0.59-0.85, p = 2.1 × 10-4], 0.76 per 12.49 cm [60-0.97, p = 0.028] and 0.73 per 10.31 cm [0.59-0.90, p = 3.7 × 10-3], respectively) and increased WC and BMI decreased the risk of prostate cancer (0.68 per 11.32 cm [0.50-0.91, p = 0.01] and 0.76 per 10.23 kg/m2 [0.61-0.95, p = 0.015], respectively) in UK Biobank participants. We confirmed our results with a two-sample-MR of published data. In conclusion, our results suggest a protective effect of adiposity on the risk of BCa and PrCa highlighting the need to re-evaluate the role of adiposity as cancer risk factor.

No Evidence That Genetic Variation at the Klotho Locus Is Associated With Longevity in Caucasians from the Newcastle 85+ Study and the UK Biobank.

The demographics of Western populations are changing, with an increase in the proportion of older adults. There is evidence to suggest that genetic factors may influence the aging process: studying these may lead to interventions to help individuals live a longer and healthier life. Evidence from several groups indicates that Klotho (KL), a gene encoding a single-pass transmembrane protein that acts as an FGF23 co-receptor, may be associated with longevity and healthy aging. We aimed to explore this area further by comparing the genotype counts in 642 long-lived individuals from the Newcastle 85+ Study with 18 295 middle-aged Newcastle-based controls from the UK Biobank to test whether variants at the KL gene locus are over- or under-represented in older individuals. If KL is associated with longevity, then we would expect the genotype counts to differ between the 2 cohorts. We found that the rs2283368 CC genotype and the rs9536338 C allele, but not the KL-VS haplotype, were associated with reaching very old age. However, these associations did not replicate in the remainder of the UK Biobank cohort. Thus, our results do not reliably support the role of KL as a longevity factor.

Age at Natural Menopause and Blood Pressure Traits: Mendelian Randomization Study.

Observational studies suggest that early onset of menopause is associated with increased risk of hypertension. Whether this association is causal or due to residual confounding and/or reverse causation remains undetermined. We aimed to evaluate the observational and causal association between age at natural menopause (ANM) and blood pressure traits in Caucasian women. A cross-sectional and one-sample Mendelian randomization (MR) study was conducted in 4451 postmenopausal women from the CoLaus and Rotterdam studies. Regression models were built with observational data to study the associations of ANM with systolic and diastolic blood pressure (SBP/DBP) and hypertension. One-sample MR analysis was performed by calculating a genetic risk score of 54 ANM-related variants, previously identified in a genome-wide association study (GWAS) on ANM. In the two-sample MR analysis we used the estimates from the ANM-GWAS and association estimates from 168,575 women of the UK Biobank to evaluate ANM-related variants and their causal association with SBP and DBP. Pooled analysis from both cohorts showed that a one-year delay in menopause onset was associated with 2% (95% CI 0; 4) increased odds of having hypertension, and that early menopause was associated with lower DBP (ß = -1.31, 95% CI -2.43; -0.18). While one-sample MR did not show a causal association between ANM and blood pressure traits, the two-sample MR showed a positive causal association of ANM with SBP; the last was driven by genes related to DNA damage repair. The present study does not support the hypothesis that early onset of menopause is associated with higher blood pressure. Our results suggest different ANM-related genetic pathways could differently impact blood pressure.

Non-redundant functions of H2A.Z.1 and H2A.Z.2 in chromosome segregation and cell cycle progression.

H2A.Z is a H2A-type histone variant essential for many aspects of cell biology, ranging from gene expression to genome stability. From deuterostomes, H2A.Z evolved into two paralogues, H2A.Z.1 and H2A.Z.2, that differ by only three amino acids and are encoded by different genes (H2AFZ and H2AFV, respectively). Despite the importance of this histone variant in development and cellular homeostasis, very little is known about the individual functions of each paralogue in mammals. Here, we have investigated the distinct roles of the two paralogues in cell cycle regulation and unveiled non-redundant functions for H2A.Z.1 and H2A.Z.2 in cell division. Our findings show that H2A.Z.1 regulates the expression of cell cycle genes such as Myc and Ki-67 and its depletion leads to a G1 arrest and cellular senescence. On the contrary, H2A.Z.2, in a transcription-independent manner, is essential for centromere integrity and sister chromatid cohesion regulation, thus playing a key role in chromosome segregation.

No evidence that vitamin D is able to prevent or affect the severity of COVID-19 in individuals with European ancestry: a Mendelian randomisation study of open data.

BACKGROUND: Upper respiratory tract infections are reportedly more frequent and more severe in individuals with lower vitamin D levels. Based on these findings, it has been suggested that vitamin D can prevent or reduce the severity of COVID-19. METHODS: We used two-sample Mendelian randomisation (MR) to assess the causal effect of vitamin D levels on SARS-CoV-2 infection risk and COVID-19 severity using publicly available data. We also carried out a genome-wide association analysis (GWA) of vitamin D deficiency in the UK Biobank (UKB) and used these results and two-sample MR to assess the causal effect of vitamin D deficiency on SARS-CoV-2 infection risk and COVID-19 severity. RESULTS: We found no evidence that vitamin D levels causally affect the risk of SARS-CoV-2 infection (ln(OR)=0.17 (95% CI -0.22 to 0.57, p=0.39)) nor did we find evidence that vitamin D levels causally affect COVID-19 severity (ln(OR)=0.36 (95% CI -0.89 to 1.61, p=0.57)). Based on our GWA analysis, we found that 17 independent variants are associated with vitamin D deficiency in the UKB. Using these variants as instruments for our two-sample MR analyses, we found no evidence that vitamin D deficiency causally affects the risk of SARS-CoV-2 infection (ln(OR)=-0.04 (95% CI -0.1 to 0.03, p=0.25)) nor did we find evidence that vitamin D deficiency causally affects COVID-19 severity (ln(OR)=-0.24 (95% CI -0.55 to 0.08, p=0.14)). CONCLUSIONS: In conclusion, we found no evidence that vitamin D is protective against SARS-CoV-2 infection or COVID-19 severity. Our data support the recent statement by the National Institute for Health and Care Excellence that the use of vitamin D supplementation to mitigate COVID-19 is not supported by the available data.

H2A Histone Family Member X (H2AX) Is Upregulated in Ovarian Cancer and Demonstrates Utility as a Prognostic Biomarker in Terms of Overall Survival.

Background: H2AX can be of prognostic value in breast cancer, since in advanced stage patients with high levels, there was an association with worse overall survival (OS). However, the clinical relevance of H2AX in ovarian cancer (OC) remains to be elucidated. Methods: OC H2AX expression studied using the TCGA/GTEX datasets. Subsequently, patients were classified as either high or low in terms of H2AX expression to compare OS and perform gene set enrichment. qRT-PCR validated in-silico H2AX findings followed by immunohistochemistry on a tissue microarray. The association between single nucleotide polymorphisms in the area of H2AX; prevalence and five-year OC survival was tested in samples from the UK Biobank. Results: H2AX was significantly overexpressed in OCs compared to normal tissues, with higher expression associated with better OS (p = 0.010). Gene Set Enrichment Analysis demonstrated gene sets involved in G2/M checkpoint, DNA repair mTORC1 signalling were enriched in the H2AX highly expressing OCs. Polymorphisms in the area around the gene were associated with both OC prevalence (rs72997349-C, p = 0.005) and worse OS (rs10790282-G, p = 0.011). Finally, we demonstrated that H2AX gene expression correlated with γ-H2AX staining in vitro. Conclusions: Our findings suggest that H2AX can be a novel prognostic biomarker for OC.

Outcomes of Silicone Ahmed Glaucoma Valve Implantation in Refractory Pediatric Glaucoma.

PURPOSE: The purpose of this study was to report the outcomes of Silicone Ahmed Glaucoma Valve (AGV) implantation in the management of refractory pediatric glaucoma. METHODS: Between 2007 and 2015, 76 eyes of 64 children aged 16 years or younger underwent AGV implantation. We included 65 eyes of 53 children with follow up ≥6 months; 24 eyes had primary congenital glaucoma (PCG) and 41 eyes had secondary pediatric glaucoma (SPG). Success was defined as IOP>5 and ≤21 mm Hg with or without topical antiglaucoma medications; considered failure, when repeat glaucoma surgery was need or loss of light perception. Primary outcome measure was success of AGV in refractory pediatric glaucomas and secondary outcome measure was comparison of outcomes in PCG and SPG. RESULTS: The median age at AGV implantation was 3 years (interquartile range, 2, 12), and median follow up was 27 months (15, 39). The overall cumulative success probability was 88% [95% confidence interval (CI), 76%-94%] at 1 year and was maintained up to 4 years. The success probability in PCG was 91% (80.8%-100%), and SPG was 83% (72%-96%) at 1 year and 4 years (P=0.49). Among the preoperative factors, number of previous intraocular surgeries (hazard ratio of 2.24; 95% CI, 1.14-4.37, was significantly associated with failure; P=0.01). Tube-related complications (16%) were similar in both the groups. One eye in each group had sight-threatening complication. CONCLUSIONS: AGV implantation had good success rate in refractory pediatric glaucoma. The success rates were similar in PCG and SPG as were the complications. Number of prior intraocular surgeries was a risk factor for failure.

Loss of the proprioception and touch sensation channel PIEZO2 in siblings with a progressive form of contractures.

Dominant mutations in PIEZO2, which codes for the principal mechanotransduction channel for proprioception and touch sensation, have been found to cause different forms of distal arthrogryposis. Some observations suggest that these dominant mutations induce a gain-of-function effect on the channel. Here, we report a consanguineous family with three siblings who showed short stature, scoliosis, gross motor impairment, and a progressive form of contractures involving the distal joints that is distinct from that found in patients with dominant mutations in PIEZO2. These siblings also displayed deficits in proprioception and touch sensation. Whole-exome sequencing performed in the three affected siblings revealed the presence of a rare homozygous variant (c.2708C>G; p.S903*) in PIEZO2. This variant is predicted to disrupt PIEZO2 function by abolishing the pore domain. Sanger sequencing confirmed that all three siblings are homozygous whereas their parents and an unaffected sibling are heterozygous for this variant. Recessive mutations in PIEZO2 thus appear to cause a progressive phenotype that overlaps with, while being mostly distinct from that associated with dominant mutations in the same gene.

Comparative analysis of serum malondialdehyde, antioxidant vitamins and immunoglobulin levels in patients suffering from generalized anxiety disorder.

The relationship between the elevated levels of serum malondialdehyde, depleted level of antioxidants (vitamin A, E and C) and altered level of immunoglobulins (IgA, IgG and IgM) in several psychiatric disorders has been established by various experimental evidences over the past few years. But previously no study was carried out to determine these components in patients suffering from generalized anxiety disorder (GAD) in Bangladesh. This study was conducted to compare the serum concentration of these components in GAD patients and healthy volunteers; matched by socioeconomic and sociodemographic parameters. Serum level of malondialdehyde and vitamin C were determined by UV spectrophotometric method, vitamins A and E were detected by RP-HPLC method whereas immunoglobulin levels were determined by turbidimetric method. Data were analyzed by independent t-test, Pearson's correlation and regression analysis. Significantly lower level of vitamin E (p<0.05) and significantly higher level of vitamin C were found in GAD patients than the healthy controls, whereas the change of vitamin A was insignificant. Serum malondialdehyde content was significantly higher (p<0.05) and IgM level was significantly (p<0.05) higher than that of the controls. Change in concentrations of IgG and IgA were insignificant (p>0.05). Pearson's correlation coefficient suggested that there were some significant positive and negative correlations among these tested components. Our study reveals that GAD patients have considerably higher level of malondialdehyde, immunoglobulins and altered level of antioxidant vitamins. These findings may play a key role in the diagnosis and treatment of GAD patients.

Determination of serum antioxidant vitamins, glutathione and MDA levels in panic disorder patients.

There are sufficient experimental evidences to establish the relationship between the elevated level of malondealdehyde (MDA)-the lipid peroxidation product and depleted level of antioxidants (Vitamin A, E, C and glutathione) in several psychiatric disorders. But previously no study was carried out to determine these components in panic disorder (PD) patients of Bangladesh. This study was conducted to assess the serum concentration of antioxidant vitamins, MDA and glutathione in 54 panic disorder patients and 52 healthy volunteers. Patients were recruited from Bangabandhu Sheikh Mujib Medical University, Bangladesh by random sampling. Serum level of MDA, glutathione and vitamin C were determined by UV spectrophotometric method whereas Vitamins A and E were detected by RP-HPLC method. Data were analyzed by independent t test and Pearson's correlation analysis. It had been found that the PD patients had low level of antioxidants like vitamin A (p=0.041) and vitamin E (p=0.018) than the healthy controls whereas the change of vitamin C is not significant. It had been found that the MDA content was significantly higher (p<0.05) in PD patients than that of controls. There was no significant difference for the glutathione content between the 2 groups. Pearson's correlation coefficient suggested that there were significant negative correlation between the glutathione level and vitamin C (p=0.013) and a positive correlation between the vitamin E and vitamin A (p=0.020) in patient group. Our study reveals that panic disorder patients have considerably higher level of MDA, lower level of antioxidant vitamins and glutathione than the healthy control subjects.

Interaction of nalbuphine hydrochloride with deoxyribonucleic acid measured by fluorescence quenching.

The interaction of nalbuphine hydrochloride with calf thymus deoxyribonucleic acid was investigated by absorption and fluorescence titration techniques. Hypochromic effect was observed in the absorption spectra of nalbuphine. The fluorescence quenching of nalbuphine by DNA was found to be static according to Stern-Volmer constant at different temperature (2.257×103 L/mol and 1.678×103 L/mol at 298 K and 308 K respectively; binding constants (K) between calf thymus DNA and nalbuphine were 2.081×103 and 8.26×101 at 298 K and 308 K respectively). The binding numbers (n) were 0.9955 and 0.6762 with the standard deviation of 0.225 at 2 different temperatures which indicates mol ratio of Nalbuphine and DNA remains unchanged at different temperatures (298 K and 308 K). The binding affinity of nalbuphine to DNA was calculated at different temperatures and the stoichiometry of binding was characterized to be about 1 nalbuphine molecule per nucleotide. Calibration for nalbuphine, based on quenching titration data, was linear in the concentration range 6.3×10-6 to 6.4×10-4 mol/L. And these binding forces also indicate the binding site of Nalbuphine to be at the minor groove of DNA.

Resistant hypertension: underlying causes and treatment.

Resistant hypertension (RH) is defined as failure to achieve goal blood pressure while receiving a 3 drug regimen at optimal doses that includes a diuretic. The exact prevalence of resistant hypertension is unknown which may vary from 5% to 50%. Patient or clinician-related factors contributing to resistant hypertension include patient's non-adherence to antihypertensive therapy, White-coat effect and pseudo-hypertension and life style factors (Obesity, alcohol, smoking, dietary sodium etc). Several drugs may induce pre-existing hypertension where non-steroidal anti-inflammatory drugs are usually the most common due to their frequent use; whereas oral contraceptives, sympathomimetics (decongestants, anorectics), adrenal steroids and antineoplastic drugs targeting the vascular endothelial growth factor (VEGF) pathway has a good deal of contribution to resistant hypertension. Most common secondary causes of resistant hypertension are obstructive sleep apnea, renal artery stenosis, renal parenchymal disease, and primary aldosteronism while some uncommon causes such as pheochromocytoma, Cushing's disease, thyroid and parathyroid dysfunction; and aortic coarctation also contribute to resistant hypertension. Both pharmacological and non-pharmacological treatments are available for the management of resistant hypertension. This article reviews the prevalence, symptoms, causes and treatment of resistant hypertension.

Primary and revision THA using a stemless metaphyseal-loading implant above distorted proximal femoral anatomy.

Total hip arthroplasty is well established as a successful treatment for end stage arthritis, with a wide variety of components currently available. Using traditional stemmed implants in patients with a distorted proximal femur can be technically challenging with an increased risk of complications. We present seven patients with distorted proximal femoral anatomy or failed hip arthroplasty in whom a short, metaphyseal loading implant was utilised. At minimum two-year follow-up there have been no complications with all stems stable and well fixed radiologically. Average improvement in Oxford Hip Score is 32. We suggest that a short, metaphyseal loading prosthesis can be considered in cases where a conventional stemmed implant may not be suitable due to challenging proximal femoral anatomy.

CYP3A genotypes in Bangladeshi tuberculosis patients.

The purpose of this study is to investigate the genotype and allelic frequencies of CYP3A in Bangladeshi Tuberculosis (TB) patients which may help for individualized drug dosing and improved therapeutics. Genotyping was done using the extracted genomic DNA from 90 TB patients followed by amplification of target alleles by Polymerase Chain Reaction (PCR). Amplified alleles were then digested by restriction enzymes followed by gel electrophoresis & sequencing to identify the targeted alleles namely CYP3A4*1B, CYP3A4*2, CYP3A4*4, CY3A4*5, CYP3A4*6, CYP3A4*10, CYP3A4*18, and CYP3A5*3. In TB patients, no samples were positive for CYP3A4*2, CYP3A4*4, CYP3A4*5, CYP3A4*6, CYP3A4*10, and CYP3A4*18 alleles. One sample was found to be heterozygous for CYP3A4*1B (1.11%). The wild homozygous (CYP3A5*1/*1) genotype frequency was 7.78%, the heterozygous (CYP3A5*1/*3) frequency was 42.22% and the homozygous mutant (CYP3A5*3/*3) frequency was 50% in Bangladeshi TB patients. The absence of the common polymorphic gene suggests that there will be no impact of CYP3A drug metabolizing enzymes on antituberculosis drugs.

Conversion of a long distally fixed uncemented revision femoral stem to a proximally fixed implant following fatigue fracture.

There has been increasing focus on bone conservation through proximal fixation in primary hip arthroplasty. However, the debate regarding fixation in revision arthroplasty and which factors influence implant choice remains less clear-cut. We report a case involving fatigue fracture of a long, distally well-fixed, uncemented revision stem. This was revised to a proximally fixed implant. This case highlights a number of issues when considering the choice of implant in hip revision surgery and raises the issue of bone conservation in revision surgery. We would suggest that in both primary and revision hip arthroplasty meticulous pre-operative consideration of the choice of implant should be undertaken, especially in the younger patient with higher expectations and functional demands.

Bioavailability of omeprazole 20 mg capsules containing omeprazole 22.5% enteric coated pellets versus a reference product in healthy Bangladeshi male subjects: an open-label, single-dose, randomized-sequence, two-way crossover study.

OBJECTIVE: Omeprazole 20 mg enteric coated capsule formulation is generally prepared either with omeprazole 8.5% or omeprazole 7.5% enteric coated pellets to accommodate in capsule Shell 2, but the use of omeprazole 22.5% enteric coated pellets in capsule Shell 5 for the same amount of omeprazole is a new concept and for the first time in the Bangladesh market. This study was conducted to compare the relative bioavailability and pharmacokinetic properties of two omeprazole 20 mg capsule formulations namely Xeldrin®20 (ACI Ltd., Bangladesh) encapsulated with omeprazole 22.5% enteric coated pellets, as test product and Losec®20 (AstraZeneca, Wilmington, DE, USA) as reference product and to assess whether these formulations meet the FDA requirement for bioequivalence. MATERIALS AND METHODS: 24 non-smoking healthy Bangladeshi male subjects participated in this open-label, randomized-sequence, single- dose, two-way crossover study. Subjects were randomly assigned to receive test formulation, followed by reference formulation or vice versa, as a single dose of 20 mg capsule after 12 h overnight fasting. A washout period of 1 week was maintained between the treatments. Blood samples were collected before study drug administration (baseline) and at 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 9.0, and 12.0 h after study drug administration. Serum omeprazole concentrations were determined using a validated HPLC method with UV detection. The pharmacokinetic parameters were determined by the non-compartmental method. The two formulations were to be considered bioequivalent if the 90% confidence intervals (CI) for the ln-transformed ratios of pharmacokinetic parameters were within the predetermined equivalence range of 80 - 125% according to the guidelines of the US Food and Drug Administration (FDA). Tolerability was assessed on the basis of adverse effects, monitoring vital signs, ECG and laboratory tests at baseline and after completion of the study with the assistance of registered physicians. RESULTS: All 24 subjects completed the study without any adverse effect reported. After administering a single dose of 20 mg of each omeprazole formulation, the obtained mean (SD) values for the test and reference products were 608.40 (116.37) and 588.56 (98.36) ng/ml for Cmax; 1.83 (0.25) and 2.00 (0.30) h for tmax; 1,635.77 (581.25) and 1,639.58 (652.54) h-ng/ml for AUC0-12; and 1,721.12 (572.07) and 1,805.58 (856.39) h-ng/ml for AUC(0-∞) respectively. The mean t(1/2) was 3.33 (1.61) and 3.57 (1.24) h for test and reference product respectively. From paired t-test, no significant differences were observed (p > 0.05) for any pharmacokinetic parameters. The point estimates (90% CI) for the test/reference ratios of the ln-transformed AUC(0-12), AUC(0-∞) and C(max) mean values were 100.73% (91.40 -111.01%), 98.29% (88.45 -109.24%) and 103.06% (99.05 - 07.24%) respectively, which fell within the predetermined FDA bioequivalence range of 80 - 125%. CONCLUSION: This single-dose study found that the test (Xeldrin®20) and reference (Losec®20) 20 mg capsule formulations of omeprazole in these fasting healthy male Bangladeshi subjects met the FDA regulatory criteria for bioequivalence.