Thoracic Spinal Anesthesia for Laparoscopic Cholecystectomy: An Observational Feasibility Study.

BACKGROUND: The expanding horizons of the application of Segmental Thoracic Spinal anesthesia in day-to-day anesthesia practice prompted us to perform this study in a large subset of healthy patients with the aim of determining the feasibility, safety, advantages, and complications of this mode of anesthesia. MATERIAL AND METHODS: The prospective observational study was conducted from April 2020 to March 2022, 2.146 patients with symptoms of cholelithiasis and planned for laparoscopic cholecystectomy were included in this study, and 44 patients from this study were excluded due to pre-defined exclusion criteria. The patients belonging to ASA lIl, lV, severe cardiovascular or renal disability, on beta blockers, coagulation anomaly, spinal deformities, or previous spine surgeries were not included in the study. The patients exhibiting allergy to local anesthetics, requiring more than two attempts for the procedure, patchy or inadequate effects after spinal anesthesia, or change in the plan of surgery intraoperatively were also excluded from the study. All other patients were given subarachnoid block at T10-T11 intervertebral space with 26G Quincke needle and Inj. Bupivacaine Heavy (0.5%) 2.4 mL with 5µg of Dexmedetomidine. Intraoperative parameters, number of attempts, the incidence of paresthesia during the procedure intraoperative and postoperative complications, and patient satisfaction were evaluated and recorded. RESULTS: Spinal anesthesia was successful in 2,074 patients and was achieved in a single attempt of procedure in 92% of patients. The incidence of paresthesia during needle insertion was 5.8%. Hypotension was observed in 18% of patients, bradycardia (13%), and nausea (10%) in a few patients, with shoulder tip pain in only 6% of patients. The majority of patients (94%) were "very satisfied" with the procedure. There were no episodes of any adverse event during the postoperative period. CONCLUSION:  Thoracic spinal anesthesia is a regional anesthesia technique practically feasible for healthy patients undergoing laparoscopic cholecystectomy with a manageable incidence of intraoperative complications and no evidence of any neurological complications. It has the advantage of providing manageable hemodynamics, minimal postoperative complication, and an acceptable degree of patient satisfaction.

Opportunities and Challenges in Developing a Cryptosporidium Controlled Human Infection Model for Testing Antiparasitic Agents.

Cryptosporidiosis is a leading cause of moderate-to-severe diarrhea in low- and middle-income countries, responsible for high mortality in children younger than two years of age, and it is also strongly associated with childhood malnutrition and growth stunting. There is no vaccine for cryptosporidiosis and existing therapeutic options are suboptimal to prevent morbidity and mortality in young children. Recently, novel therapeutic agents have been discovered through high-throughput phenotypic and target-based screening strategies, repurposing malaria hits, etc., and these agents have a promising preclinical in vitro and in vivo anti-Cryptosporidium efficacy. One key step in bringing safe and effective new therapies to young vulnerable children is the establishment of some prospect of direct benefit before initiating pediatric clinical studies. A Cryptosporidium controlled human infection model (CHIM) in healthy adult volunteers can be a robust clinical proof of concept model for evaluating novel therapeutics. CHIM could potentially accelerate the development path to pediatric studies by establishing the safety of a proposed pediatric dosing regimen and documenting preliminary efficacy in adults. We present, here, perspectives regarding the opportunities and perceived challenges with the Cryptosporidium human challenge model.

Telbivudine vs tenofovir in hepatitis B e antigen-negative chronic hepatitis B patients: OPTIMA roadmap study.

AIM: To make efficacy and safety comparison of telbivudine-raodmap and tenofovir-roadmap in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients. METHODS: This was the first prospective, randomised, two-arm, open-label, non-inferiority study in HBeAg-negative CHB patients that compared telbivudine and tenofovir administered as per roadmap concept. Patients were treated up to 24 wk and, depending on virologic response, continued the same therapy or received add-on therapy up to 104 wk. Eligible patients received an additional 52 wk of treatment in the extension period (i.e., up to 156 wk). Patients who developed virologic breakthrough (VB) while on monotherapy also received add-on therapy. The primary efficacy endpoint was the rate of patients achieving hepatitis B virus (HBV) DNA < 300 copies/mL at week 52. Secondary efficacy endpoints included the rates of HBV DNA < 300 and < 169 copies/mL, HBV DNA change from baseline, alanine aminotransferase normalisation, hepatitis B surface antigen (HBsAg) loss, HBsAg seroconversion, VB, and emergence of resistance at various timepoints throughout the study. Safety and estimated glomerular filtration rate (eGFR) were also analysed. RESULTS: A total of 241 patients were randomised. Non-inferiority of telbivudine arm to tenofovir arm was demonstrated at week 52 (± 7 d window), with over 91% of patients in each treatment arm achieving HBV DNA level < 300 copies/mL. Both arms were similar in terms of key secondary efficacy variables at weeks 104 and 156. The percentage of patients achieving HBV DNA < 300 copies/mL remained high and was similar in the telbivudine and tenofovir arms at both weeks 104 and 156. Over 82% of patients in both arms achieved alanine aminotransferase normalisation at week 52, and this percentage remained high at weeks 104 and 156. Telbivudine treatment progressively reduced serum HBsAg levels from baseline while no change was reported in quantitative HBsAg during therapy with tenofovir. Both treaments showed acceptable safety profiles. The telbivudine arm showed eGFR improvement unlike the tenofovir arm. CONCLUSION: Efficacy was shown for both telbivudine-roadmap and tenofovir-roadmap regimens in HBeAg-negative CHB patients over 156 wk. Telbivudine arm was associated with renal improvement.

Remnant lipoprotein size distribution profiling via dynamic light scattering analysis.

BACKGROUND: Remnant lipoproteins (RLP) are a metabolically derived subpopulation of triglyceride-rich lipoproteins (TRL) in human blood that are involved in the metabolism of dietary fats or triglycerides. RLP, the smaller and denser variants of TRL particles, are strongly correlated with cardiovascular disease (CVD) and were listed as an emerging atherogenic risk factor by the AHA in 2001. METHODS: Varying analytical techniques used in clinical studies in the size determination of RLP contribute to conflicting hypotheses in regard to whether larger or smaller RLP particles contribute to CVD progression, though multiple pathways may exist. RESULTS: We demonstrated a unique combinatorial bioanalytical approach involving the preparative immunoseparation of RLP, and dynamic light scattering for size distribution analysis. CONCLUSIONS: This is a new facile and robust methodology for the size distribution analysis of RLP that in conjunction with clinical studies may reveal the mechanisms by which RLP cause CVD progression.

Safety and tolerability of cell culture-derived and egg-derived trivalent influenza vaccines in 3 to <18-year-old children and adolescents at risk of influenza-related complications.

BACKGROUND: This descriptive, non-comparative, phase III study evaluated the safety and tolerability of cell culture-derived (TIVc) and egg-derived (TIV) seasonal influenza vaccines in children at risk of influenza-related complications. METHODS: Four hundred and thirty subjects were randomized 2:1 to TIVc or TIV. Subjects aged 3 to <9 years received one dose (if previously vaccinated, n=89) or two doses (if not previously vaccinated, n=124) of the study vaccines; the 9 to <18-year-olds (n=213) received one dose. Reactogenicity was assessed for 7 days after vaccination; safety was monitored for 6 months. RESULTS: After any vaccination, the most frequently reported solicited local adverse event (AE) was tenderness/pain (TIVc 44%, 66%, 53% and TIV 56%, 51%, 65% in the age groups 3 to <6 years, 6 to <9 years, and 9 to <18 years, respectively) and the systemic AE was irritability (22% TIVc, 24% TIV) in 3 to <6-year-olds and headache in 6 to <9-year-olds (20% TIVc, 13% TIV) and 9 to <18-year-olds (21% TIVc, 26% TIV). There were no cases of severe fever (≥40°C). No vaccine-related serious AEs were noted. New onset of chronic disease was reported in ≤1% of subjects. CONCLUSION: TIVc and TIV had acceptable tolerability and similar safety profiles in at-risk children (NCT01998477).

Safety and tolerability of a cell culture derived trivalent subunit inactivated influenza vaccine administered to healthy children and adolescents: A Phase III, randomized, multicenter, observer-blind study.

BACKGROUND: Cell culture-derived inactivated influenza vaccines (TIVc) are necessary for scale and predictability of production to meet global demand. This study compared the safety and tolerability of TIVc with an egg-derived trivalent influenza vaccine (TIVf) in 4-17 yearolds. METHODS: A Phase 3 observer blind, multicenter study enrolled 2055 healthy participants randomized 2:1 to receive either TIVc or TIVf, respectively (1372 TIVc and 683 TIVf evaluable subjects). Participants received one dose each on Days 1 and 28 (4-8 year-olds not previously vaccinated [NPV]) or one dose on Day 1 (4-8 and 9-17 yearolds previously vaccinated [PV]). Solicited adverse events (AEs) occurring within 7 days after each vaccination were assessed; participants were followed up for 6 months after their last dose for safety. RESULTS: Most solicited and unsolicited AEs were mild to moderate with <1% in the severe category. No withdrawals due to AEs, deaths or vaccine-related SAEs were reported. TIVc and TIVf were similar in percentages of participants reporting solicited reactions in 4-8 years NPV group after the 1st dose: local reactions, TIVc: 48%, TIVf: 43%; systemic reactions, TIVc: 34%, TIVf: 32%; percentages were lower following the 2nd dose in TIVc; local reactions: TIVc: 40%; TIVf: 43%; systemic reactions: TIVc: 21%; TIVf: 22%. In 4-17 years PV group, solicited reactions were lower following TIVf, local reactions: TIVc: 53%; TIVf: 43%; systemic reactions: TIVc: 37%, TIVf: 30%. Injection-site pain was the most common solicited reaction, and was similar following TIVc and TIVf in 4-8 yearolds (TIVc: 56%; TIVf: 55%), and lower following TIVf in 9-17 years group (TIVc: 52%; TIVf: 42%). Reporting of unsolicited AEs was similar for TIVc and TIVf across the two age groups. CONCLUSION: TIVc was well tolerated and had a safety and reactogenicity profile similar to that of TIVf in healthy 4-17 yearolds (NCT01857206).

Non-inferiority of mammalian cell-derived quadrivalent subunit influenza virus vaccines compared to trivalent subunit influenza virus vaccines in healthy children: a phase III randomized, multicenter, double-blind clinical trial.

OBJECTIVES: The safety and immunogenicity of mammalian cell-derived quadrivalent influenza vaccine (QIVc) as compared with trivalent influenza vaccines (TIV1c/TIV2c) was evaluated in children aged ≥4 to <18 years. METHODS: Two thousand three hundred and thirty-three subjects were randomized 2:1:1 to receive either one or two doses of study vaccine depending on previous vaccination status. Hemagglutination inhibition antibody responses for all four influenza strains were performed 3 weeks after the last dose. Reactogenicity and safety were also assessed (ClinicalTrials.gov: NCT01992107). RESULTS: QIVc met the non-inferiority criteria against all four vaccine strains and demonstrated superiority for both influenza B strains over the unmatched B lineage included in the comparator vaccines, when geometric mean titers and seroconversion rates were compared at 3 weeks after the last vaccination. Similar percentages of subjects experienced solicited and unsolicited adverse events (AEs) across all subgroups. Unsolicited AEs, serious AEs, medically attended AEs, and new onset chronic disease were reported in comparable percentages of subjects in all study groups. No vaccine-related serious AEs or deaths occurred. CONCLUSIONS: QIVc demonstrated a similar safety profile and immunogenicity responses against all four vaccine strains without signs of immune interference on addition of an alternate lineage B strain compared with TIV1c/TIV2c and may provide broader protection against both influenza B lineages in children.

Comparison of azithromycin plus chloroquine versus artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in children in Africa: a randomized, open-label study.

BACKGROUND: This randomized, open-label study was conducted to establish the non-inferiority of a combination of azithromycin (AZ) and chloroquine (CQ) to artemether-lumefantrine (AL) for treatment of uncomplicated malaria in children from six sites in sub-Saharan Africa. METHODS: Children with uncomplicated Plasmodium falciparum malaria between six and 59 months of age were randomized 1:1 to either AZCQ (30 mg/kg AZ + 10 mg/kg CQ base) or AL per prescribing information for three days (Days 0, 1, 2). Each site could enrol in the study population once the treatment of uncomplicated malaria in five children five to 12 years of age was deemed to be effective and well tolerated. The primary efficacy evaluation was the proportion of subjects in both the modified intent-to-treat (MITT) and per-protocol (PP) populations with an adequate clinical and parasitological response (PCR corrected) at Day 28. Non-inferiority was concluded if the lower bound of the 95% confidence interval comparing the two groups was 10 percentage points or greater. RESULTS: A total of 255 children were enrolled in the efficacy analysis (AZCQ, n = 124; AL, n = 131). The PCR corrected clearance rates were 89% (AZCQ) versus 98% (AL) for MITT, a difference of -9.10 (95% confidence interval; -16.02, -2.18) and 93% (AZCQ) versus 99% (AL) for PP, a difference of -6.08 (-12.10, -0.05). Early and late treatment failures were more common in subjects receiving AZCQ. Adverse events were more common in subjects treated with AZCQ. Drug concentrations obtained at specified time points following AZCQ administration had a large coefficient of variation partially due to sparse sampling with sample collection time window. CONCLUSIONS: In this study, non-inferiority of AZCQ to AL was not demonstrated. TRIAL REGISTRATION: ClinicalTrials.gov NCT00677833 .

Efficacy and safety of a combination of azithromycin and chloroquine for the treatment of uncomplicated Plasmodium falciparum malaria in two multi-country randomised clinical trials in African adults.

BACKGROUND: Given increasing rates of resistance to existing therapy, new options for treatment and prophylaxis of malaria are needed. METHODS: Two randomised, comparative, non-inferiority studies were conducted in Africa, one double-blinded and one open-label. Adults with fever, a positive peripheral blood smear, and a positive rapid diagnostic test for Plasmodium falciparum were randomised in both studies to either azithromycin (AZ) 1,000 mg plus chloroquine (CQ) 600-mg base (AZCQ 1,000 mg) once daily for three days or mefloquine hydrochloride (MQ) 1,250 mg (split dose). In the first study, an additional regimen of AZ 500 mg plus CQ 600-mg base (AZCQ 500 mg) once daily for three days was included. All study participants were hospitalised until three consecutive daily blood smears were negative for asexual P. falciparum parasitaemia. Study participants were evaluated weekly for 42 days, with Day 28 polymerase chain reaction (PCR)-corrected parasitological clearance rate as primary endpoint. RESULTS: A total of 467 subjects were randomised in the two studies. At 28 days' follow-up, PCR-corrected parasitological clearance rates in the per protocol population in the first study were 101/103 (98%) with AZCQ 1,000 mg compared with 102/103 (99%) with MQ (95% confidence interval [CI]: -5.2, 3.3). The AZCQ 500-mg regimen was stopped during an interim study review (six [86%] clearance of seven evaluable; two lost to follow-up). In the second study, clearance rates were similar: AZCQ 1,000 mg 107/107 (100%) vs MQ 111/112 (99%; 95% CI: -1.8, 3.6). Among the participating countries, in vitro CQ resistance based on pfcrt mutation frequency in the baseline isolates across both studies ranged from 20.8% (Zambia) to 96.1% (Uganda). Serious adverse events (AEs; all causality) were observed more frequently with MQ compared with AZCQ (four vs one, respectively), though discontinuations for AEs were similar (four vs three, respectively). Common AEs in the AZ-containing arms included pruritus, vomiting, dizziness, and headache. CONCLUSIONS: Among adults with symptomatic uncomplicated falciparum malaria in Africa, the combination of AZ 1,000 mg and CQ 600-mg base once daily for three days resulted in Day 28 PCR-corrected parasitological clearance rates of ≥98% and was non-inferior to treatment with MQ. AZCQ was well tolerated. TRIAL REGISTRATION: ClinicalTrials.gov identifiers NCT00082576 and NCT00367653.

Population pharmacokinetics of azithromycin and chloroquine in healthy adults and paediatric malaria subjects following oral administration of fixed-dose azithromycin and chloroquine combination tablets.

BACKGROUND: Population pharmacokinetics (PK) of azithromycin (AZ) and chloroquine (CQ) following administration of fixed-dose combination tablet formulations of AZ and CQ (AZCQ) was evaluated using data from two studies: 1) in children with symptomatic uncomplicated falciparum malaria in sub-Saharan Africa; and 2) in healthy adults in the United States. METHODS: Study 1 included paediatric subjects randomized to either AZCQ or artemether-lumefantrine treatment in Cohort 1 (age 5-12 years) and Cohort 2 (age 6-59 months). Dosing of AZCQ was approximately 30 mg/kg AZ and 10 mg/kg CQ once daily for 3 days (for ≥20 kg weight: AZ/CQ 300/100 mg per tablet; 5 to <20 kg weight: AZ/CQ 150/50 mg per tablet). Study 2 included adults randomized to receive either two AZCQ tablets (AZ/CQ 250/155 mg per tablet) or individual commercial tablets of AZ 500 mg and CQ 300 mg. Serum AZ and plasma CQ concentrations from both studies were pooled. Population PK models were constructed using standard approaches to evaluate the concentration-time data for AZ and CQ and to identify any covariates predictive of PK behaviour. RESULTS: A three-compartment PK model with linear clearance and absorption adequately described AZ data, while a two-compartment model with linear clearance and absorption and an absorption lag adequately described CQ data. No overall bias or substantial model misspecification was evident using diagnostic plots and visual predictive checks. Body weight as an allometric function was the only covariate in the final AZ and CQ PK models. There were significantly lower AZ (0.488 vs 0.745 [mg•h/L]/[mg/kg], p < 0.00001) and CQ (0.836 vs 1.27 [mg•h/L]/[mg/kg], p < 0.00001) exposures (AUCinf) normalized by dose (mg/kg) in children compared with the adults. CONCLUSIONS: The PK of AZ and CQ following administration of AZCQ was well described using a three- and two-compartment model, respectively. AZ and CQ exhibited linear absorption and clearance; the model for CQ included an absorption lag. Weight was predictive of exposure for both AZ and CQ. Assuming equivalent dosing (mg/kg), AZ and CQ exposure in children would be expected to be lower than that in adults, suggesting that children may require a higher dose (mg/kg) than adults to achieve the same AZ and CQ exposure.

Novel tripod amphiphiles for membrane protein analysis.

Integral membrane proteins play central roles in controlling the flow of information and molecules across membranes. Our understanding of membrane protein structures and functions, however, is seriously limited, mainly due to difficulties in handling and analysing these proteins in aqueous solution. The use of a detergent or other amphipathic agents is required to overcome the intrinsic incompatibility between the large lipophilic surfaces displayed by the membrane proteins in their native forms and the polar solvent molecules. Here, we introduce new tripod amphiphiles displaying favourable behaviours toward several membrane protein systems, leading to an enhanced protein solubilisation and stabilisation compared to both conventional detergents and previously described tripod amphiphiles.

Creative solutions to extraordinary challenges in clinical trials: methodology of a phase III trial of azithromycin and chloroquine fixed-dose combination in pregnant women in Africa.

BACKGROUND: Malaria in pregnancy is one of the most common preventable causes of maternal and neonatal morbidity and mortality in sub-Saharan Africa. To prevent its adverse effects, such as maternal anaemia, placental parasitaemia and low birth weight (LBW) neonates, the World Health Organization recommends effective malaria case management, use of insecticide-treated bed nets and intermittent preventive therapy in pregnancy (IPTp). Sulphadoxine-pyrimethamine (SP) has been the standard for IPTp in several countries, but parasite resistance to SP is growing. Therefore, new IPTp therapies are urgently needed. One candidate being evaluated for IPTp is a fixed-dose combination of azithromycin and chloroquine (AZCQ). This paper describes the challenges and the innovative solutions implemented in designing and conducting a pivotal AZCQ-IPTp trial, sponsored by Pfizer Inc and co-funded by Pfizer Inc and the Medicines for Malaria Venture. METHODS: The AZCQ-IPTp pivotal trial is a multicentre, multicountry, phase III, open-label, randomized superiority study of AZCQ-IPTp versus SP-IPTp in pregnant women of sub-Saharan Africa. The trial was designed to meet stringent regulatory agency scientific advice and IPTp policy makers' recommendations, and incorporates an innovative adaptive design to manage programme risk, maintain the operating characteristics of the study and optimize resources. The trial's novel composite primary endpoint is the proportion of participants with a suboptimal pregnancy outcome (abortion [≤28 weeks], stillbirths [>28 weeks], premature [<37 weeks] deliveries, LBW [<2,500 g] live neonates, missing neonatal birth weight data or loss to follow-up). The study employs a prospective group sequential design with three unblinded analyses when 50%, 70% and 100% of participants achieve the primary endpoint; the study team will remain blinded to the analyses until after the completion of the study. The number of participants randomized will be adaptive, based on the blinded review of the observed pooled primary endpoint data across the two treatment arms, when approximately 1,000 participants complete the primary endpoint assessments. RESULTS: This study is ongoing and expected to complete in 2014. CONCLUSION: This report describes the unique challenges and innovative solutions implemented in designing and conducting this pivotal AZCQ-IPTp trial, which may serve as a prototype for future IPTp and other studies involving similar conditions.

Glutathione-S-transferase M1 and T1 genes and gastric cancer: a case control study in North Indian population.

BACKGROUND: Difference in the capacity of xenobiotic metabolising enzymes might be an important factor in genetic susceptibility to cancer. METHODS: A case control study involving forty one gastric cancer patients and one hundred and thirty controls was carried out to determine the frequency of GSTM1 and GSTT1 null genotypes. The frequency of GSTM1 and GSTT1 null genotype was observed by carrying out multiplex PCR. RESULTS: There was no difference in the frequencies of the GSTM1 and GSTT1 null and the combined GSTM1 and GSTT1 null genotype between patients and control. CONCLUSIONS: Our data suggest that GSTM1 and GSTT1 status may not influence the risk of developing gastric cancer.

In vivo and in vitro antimalarial properties of azithromycin-chloroquine combinations that include the resistance reversal agent amlodipine.

Evidence of emerging Plasmodium falciparum resistance to artemisinin-based combination therapies, documented in western Cambodia, underscores the continuing need to identify new antimalarial combinations. Given recent reports of the resurgence of chloroquine-sensitive P. falciparum parasites in Malawi, after the enforced and prolonged withdrawal of this drug, and indications of a possible synergistic interaction with the macrolide azithromycin, we sought to further characterize chloroquine-azithromycin combinations for their in vitro and in vivo antimalarial properties. In vitro 96-h susceptibility testing of chloroquine-azithromycin combinations showed mostly additive interactions against freshly cultured P. falciparum field isolates obtained from Mali. Some evidence of synergy, however, was apparent at the fractional 90% inhibitory concentration level. Additional in vitro testing highlighted the resistance reversal properties of amlodipine for both chloroquine and quinine. In vivo experiments, using the Peters 4-day suppressive test in a P. yoelii mouse model, revealed up to 99.9% suppression of parasitemia following treatment with chloroquine-azithromycin plus the R enantiomer of amlodipine. This enantiomer was chosen because it does not manifest the cardiac toxicities observed with the racemic mixture. Pharmacokinetic/pharmacodynamic analyses in this rodent model and subsequent extrapolation to a 65-kg adult led to the estimation that 1.8 g daily of R-amlodipine would be required to achieve similar efficacy in humans, for whom this is likely an unsafe dose. While these data discount amlodipine as an additional partner for chloroquine-based combination therapy, our studies continue to support azithromycin as a safe and effective addition to antimalarial combination therapies.

Glutathione S-transferase M1 and T1 polymorphism and response to neoadjuvant chemotherapy (CAF) in breast cancer patients.

PURPOSE: Response to neoadjuvant chemotherapy (NACT) for breast cancer patients cannot be predicted; however, polymorphism of the glutathione S-transferase genes GSTM1 and GSTT1 can modify the response to chemotherapy. The aim of this study was to establish whether there is an association between the polymorphism of GSTM1 and GSTT1 and response to NACT. METHODS: The subjects of this study were 45 patients with locally advanced breast cancer (LABC), who received the cyclophosphamide, adriamycin, and 5-fluorouracil (CAF) regimen as NACT. We analyzed the relationship between the genotypes and responses to chemotherapy. RESULTS: The response rates to chemotherapy were better, although not significantly so, in patients with the GSTM1 and GSTT1 null genotypes (odds ratio [OR] 2.06 and 1.45). Similar findings were noted in patients with either or both of the null genotypes (OR 2.67 and 1.16). Among the responders, patients with the GSTM1 and GSTT1 null genotypes had higher rates of complete response following chemotherapy than those with one or more active allele (OR 1.8 and 1.3), although the difference was not significant. CONCLUSIONS: There was an association between the polymorphism of glutathione S-transferases and responses to chemotherapy, but the differences were not significant. However, larger studies are needed to investigate the role and efficiency of GST polymorphism in predicting response to chemotherapy.

Effects of food on a gastrically degraded drug: azithromycin fast-dissolving gelatin capsules and HPMC capsules.

PURPOSE: Commercial azithromycin gelatin capsules (Zithromax®) are known to be bioequivalent to commercial azithromycin tablets (Zithromax®) when dosed in the fasted state. These capsules exhibit a reduced bioavailability when dosed in the fed state, while tablets do not. This gelatin capsule negative food effect was previously proposed to be due to slow and/or delayed capsule disintegration in the fed stomach, resulting in extended exposure of the drug to gastric acid, leading to degradation to des-cladinose-azithromycin (DCA). Azithromycin gelatin capsules were formulated with "superdisintegrants" to provide fast-dissolving capsules, and HPMC capsule shells were substituted for gelatin capsule shells, in an effort to eliminate the food effect. METHODS: Healthy volunteers were dosed with these dosage forms under fasted and fed conditions; pharmacokinetics were evaluated. DCA pharmacokinetics were also evaluated for the HPMC capsule subjects. In vitro disintegration of azithromycin HPMC capsules in media containing food was evaluated and compared with commercial tablets and commercial gelatin capsules. RESULT: When the two fast-dissolving capsule formulations were dosed to fed subjects, the azithromycin AUC was 38.9% and 52.1% lower than after fasted-state dosing. When HPMC capsules were dosed to fed subjects, the azithromycin AUC was 65.5% lower than after fasted-state dosing. For HPMC capsules, the absolute fasting-state to fed-state decrease in azithromycin AUC (on a molar basis) was similar to the increase in DCA AUC. In vitro capsule disintegration studies revealed extended disintegration times for commercial azithromycin gelatin capsules and HPMC capsules in media containing the liquid foods milk and Ensure®. CONCLUSION: Interaction of azithromycin gelatin and HPMC capsules with food results in slowed disintegration in vitro and decreased bioavailability in vivo. Concurrent measurement of serum azithromycin and the acid-degradation product DCA demonstrates that the loss of azithromycin bioavailability in the fed state is largely (and probably entirely) due to gastric degradation to DCA. Capsules can provide a useful and elegant dosage form for almost all drugs, but may result in a negative food effect for drugs as acid-labile as azithromycin.

Maltose-neopentyl glycol (MNG) amphiphiles for solubilization, stabilization and crystallization of membrane proteins.

The understanding of integral membrane protein (IMP) structure and function is hampered by the difficulty of handling these proteins. Aqueous solubilization, necessary for many types of biophysical analysis, generally requires a detergent to shield the large lipophilic surfaces of native IMPs. Many proteins remain difficult to study owing to a lack of suitable detergents. We introduce a class of amphiphiles, each built around a central quaternary carbon atom derived from neopentyl glycol, with hydrophilic groups derived from maltose. Representatives of this maltose-neopentyl glycol (MNG) amphiphile family show favorable behavior relative to conventional detergents, as manifested in multiple membrane protein systems, leading to enhanced structural stability and successful crystallization. MNG amphiphiles are promising tools for membrane protein science because of the ease with which they may be prepared and the facility with which their structures may be varied.

Clinical pharmacokinetics and gastrointestinal tolerability of a novel extended-release microsphere formulation of azithromycin.

BACKGROUND AND OBJECTIVE: A novel oral, extended-release, microsphere formulation of azithromycin (AZSR) was developed to improve the gastrointestinal tolerability profile while allowing administration of an entire treatment course of azithromycin in a single dose. Several phase I clinical pharmacology studies were conducted to (i) identify a well-tolerated single-dose formulation that met a predefined exposure target; and (ii) evaluate the effect of food and antacid on the absorption of this formulation. Of these, five pivotal studies are described here. METHODS: The pharmacokinetic profile of AZSR was compared with that of the commercially available immediate-release azithromycin formulation (AZM) in an open-label, crossover, single-dose study (Study A), and their gastrointestinal tolerability profiles were compared in an observer-blind, parallel group, single-dose study (Study B). The effects of food (a high-fat meal and a standard meal) and antacid (a single 20 mL dose of Maalox Regular Strength, containing magnesium hydroxide, aluminium hydroxide and simethicone) on the absorption of azithromycin from AZSR were evaluated in three separate open-label, crossover, single-dose studies (Studies C, D and E). Healthy adult subjects were enrolled in all five studies, and all subjects were evaluable for tolerability. The dose used for all azithromycin formulations was 2.0 g. Serum azithromycin concentrations were determined using a validated high-performance liquid chromatography/electrochemical detection method, and pharmacokinetic parameters were analysed using noncompartmental methods. RESULTS: 377 subjects received a single 2.0 g dose of azithromycin as AZSR and/or AZM in the five studies. Compared with AZM, AZSR had a slower absorption rate (57% decrease in the mean peak concentration [C(max)] and an approximate 2.5-hour delay in the time to reach C(max) [t(max)]), with a mean relative bioavailability of 82.8%, which met the predefined exposure target (at least 80% bioavailability relative to AZM). Compared with AZM, AZSR was associated with significantly lower rates of nausea and vomiting. A high-fat meal increased the mean area under the serum concentration-time curve [AUC] from time zero to 72 hours post-dose (AUC(72 h)) by 23% and increased the C(max) of azithromycin by 115%. A standard meal increased the mean C(max) by 119% but had no clinically significant effect on the AUC(72 h). AZSR appeared to be better tolerated in the fasted state than in the fed state. The AUC(72 h) and C(max) of AZSR were not significantly affected by co-administration with a single dose of antacid. CONCLUSIONS: The extended-release microsphere formulation of azithromycin, AZSR, allows administration of an entire therapeutic course of azithromycin as a well-tolerated single 2.0 g dose. This formulation should be administered on an empty stomach and can be co-administered with antacids.