Insilico Screening of Pentacyclic Triterpenoids against Vascular Dementia Target's.

Vascular dementia (VaD) accounts to 30% of cases and is predicted as second most common form of dementia after Alzheimer's disease by WHO. Earlier studies reported that plant-derived pentacyclic triterpenoids possess a wide range of pharmacological activities but these compounds are not extensively studied for their neuroprotective potential against VaD. This in silico approach was designed to screen 20 pentacyclic triterpenoid plant compounds against known targets of VaD using Flare software. S-Adenyl homocysteine hydrolase, Acetylcholinesterase, and Butyrylcholinesterase were selected as important VaD targets, and various parameters like intermolecular interaction energies, binding energy, and dock scores were analyzed and compared between selected ligands. Our results showed that Ursolic acid has lowest binding energy when docked with most of the target proteins, and among all 20 pentacyclic triterpenoids studied, only three ligands Betulinic acid, Ambolic acid, and Madecassic acid, showed better binding energy scores, and they can be shortlisted as lead compounds to further study their therapeutic potential against VaD using in vitro and in vivo animal models.

3D QSAR based Virtual Screening of Flavonoids as Acetylcholinesterase Inhibitors.

In an attempt to develop therapeutic agents to treat Alzheimer's disease, a series of flavonoid analogues were collected, which already had established acetylcholinesterase (AChE) enzyme inhibition activity. For each molecule we also collected biological activity data (Ki). Then, 3D-QSAR (quantitative structure-activity relationship model) was developed which showed acceptable predictive and descriptive capability as represented by standard statistical parameters r2 and q2. This SAR data can explain the key descriptors which can be related to AChE inhibitory activity. Using the QSAR model, pharmacophores were developed based on which, virtual screening was done and a dataset was obtained which loaded as a prediction set to fit the developed QSAR model. Top 10 compounds fitting the QSAR model were subjected to molecular docking. CHEMBL1718051 was found to be the lead compound. This study is offering an example of a computationally-driven tool for prioritisation and discovery of probable AChE inhibitors. Further, in vivo and in vitro testing will show its therapeutic potential.

Pharmacokinetics/pharmacodynamics of L-ornithine phenylacetate in overt hepatic encephalopathy and the effect of plasma ammonia concentration reduction on clinical outcomes.

Hepatic encephalopathy (HE) is a serious neurocognitive complication of liver dysfunction, often associated with elevated plasma ammonia. Ornithine phenylacetate (OP), a potent ammonia scavenger, is being evaluated for the treatment of acute/overt HE. The pharmacokinetics and pharmacodynamics of OP in patients with HE were characterized in this phase IIb study (NCT01966419). Adult patients hospitalized with an overt HE episode, cirrhosis, and plasma ammonia above the upper limit of normal (ULN) who failed to improve after 48 hours' standard care were randomly assigned to continuous intravenous OP (10, 15, or 20 g/day, based on Child-Turcotte-Pugh score) or matching placebo for 5 days. Plasma levels of ornithine and phenylacetic acid (PAA) and plasma/urinary levels of phenylacetylglutamine (PAGN) (primary metabolite of PAA) were regularly assessed; plasma ammonia level was the primary pharmacodynamic variable. PAA demonstrated dose-dependent pharmacokinetics; ornithine and PAGN levels increased with dose. PAGN urinary excretion represented ~50%-60% of administered PAA across all doses. Mean reduction in plasma ammonia with OP at 3 hours postinfusion was significantly greater versus placebo (p = 0.014); and time to achieve plasma ammonia less than or equal to the ULN was significantly reduced (p = 0.028). Achievement of clinical response based on HE stage was associated with a greater reduction in mean plasma ammonia level (p = 0.009). OP effects on plasma ammonia were consistent with its proposed mechanism of action as a primary ammonia scavenger, with a significant association between reduced plasma ammonia and improvement in HE stage. OP should be further evaluated as a promising treatment for hyperammonemia in patients with overt HE.

In Silico and In Vivo Studies on Quercetin as Potential Anti-Parkinson Agent.

Parkinson's disease (PD) is a major cause of morbidity and mortality among older individuals. Several researchers have suggested that iron chelators which cross the blood-brain barrier (BBB) might have clinical efficacy in treating PD. Therefore, efforts are made not only in order to improve the effect of L-dopa but also to introduce drugs which provide anti-parkinsonian and neuroprotective effects. In this study, quercetin, a flavonoid, exhibited noticeable neuroprotective effects via iron induced-oxidative stress-dependent apoptotic pathways. Our results suggested that quercetin significantly decreased the catalepsy and exhibited neuroprotective effects in rotenone-induced Parkinson. A model of rotenone-induced Parkinsonism in rats produced the decrease in glutathione, SOD, catalase, and serum iron concentration and the increase in H2O2 and lipid peroxidation activity. Quercetin efficiently halted the deleterious toxic effects of L-dopa, revealing normalization of catalepsy and rotarod score, in addition to amelioration of neurochemical parameters, indicating benefit of both symptomatic and neuroprotective therapies. In silico molecular docking studies have also shown that quercetin could be an ideal potential drug target for aromatic L-amino acid decarboxylase and human catechol-O-methyltransferase. In conclusion, quercetin possesses strong iron-chelating abilities and could be recommended as a disease-modifying therapy when administered in combination with L-dopa, early on in the course of Parkinson's disease.

Randomized Population Pharmacokinetic Analysis and Safety of Intravenous Acetaminophen for Acute Postoperative Pain in Neonates and Infants.

Intravenous administration of acetaminophen is an alternative to the oral and rectal routes, which may be contraindicated in particular clinical settings. This randomized, placebo-controlled study of intravenous acetaminophen (Ofirmev, Mallinckrodt Pharmaceuticals, Bedminster, New Jersey) in neonate and infant patients with acute postoperative pain assessed pharmacokinetics (PK) and safety, in addition to efficacy and pharmacodynamics of repeated doses administered over 24 hours. Neonate and infant patients (<2 years of age) who were undergoing surgery or had experienced a traumatic injury and were expected to need pain management for at least 24 hours were enrolled. Subjects were randomly assigned to receive intravenous acetaminophen low dose, intravenous acetaminophen high dose, or placebo. A population PK model of intravenous acetaminophen was updated by combining 581 samples from the current study of 158 neonate and infant subjects with results from a previously developed model. The individual predicted-versus-observed concentrations plots showed that the structural PK model fit the blood and plasma acetaminophen concentration-versus-time profiles in the active and placebo groups. Terminal elimination half-life was prolonged in neonates and younger infants and in intermediate and older infants similar to values in adults. When compared with placebo, total rescue opioid consumption was similar and significantly fewer intravenous acetaminophen patients prematurely discontinued because of treatment-emergent adverse events (P < .01). For intravenous acetaminophen, neonates receiving 12.5 mg/kg every 6 hours had PK profiles similar to younger, intermediate, and older infants, adolescents, and adults weighing <50 kg receiving 15 mg/kg every 6 hours and adults ≥ 50 kg receiving 1000 mg every 6 hours.

Design, synthesis and biological evaluation of theophylline containing variant acetylene derivatives as α-amylase inhibitors.

A novel pharmacophore with theophylline and acetylene moieties was constructed by using a fragment-based drug design and a series of twenty theophylline containing acetylene conjugates were designed and synthesized, and all the compounds were evaluated by enzyme-based in vitro α-amylase inhibition activity. The in vitro evaluation revealed that most of the compounds displayed good inhibitory activities, and among them nine analogs 13-15, 20, 21 and 24-27 were exhibited more or nearly as equipotent inhibitory activity with IC50 values 1.11 ±â€¯0.07, 1.14 ±â€¯0.17, 1.07 ±â€¯0.01 and 1.21 ±â€¯0.03, 1.33 ±â€¯0.09, 1.17 ±â€¯0.01, 1.05 ±â€¯0.02, 1.61 ±â€¯0.04, 1.02 ±â€¯0.03 µM respectively, as compared with standard, acarbose 1.37 ±â€¯0.26 µM. Further, molecular docking simulation studies were done to identify the interactions and binding mode of synthesized analogs at binding site of α-amylase enzyme (PBD ID: 4GQR). Among the synthesized analogs, two compounds 25 and 27 were selected on the basis of α-amylase inhibition activity and evaluated for in vivo anti-diabetic activity by High Fat Diet-Streptozotocin (HFD-STZ) model in normal rats. At the dose of 10 mg/kg, bw, po these compounds have significantly reduced Plasma Glucose level in rats as compared to pioglitazone. The anti-diabetic activity results showed that the animal treated with the compounds 25 and 27 could better reverse and control the progression of the disease compared to the standard.

In vitro binding and receptor-mediated activity of terlipressin at vasopressin receptors V1 and V2.

Terlipressin, a synthetic, systemic vasoconstrictor with selective activity at vasopressin-1 (V1) receptors, is a pro-drug for the endogenous/natural porcine hormone [Lys8]-vasopressin (LVP). We investigated binding and receptor-mediated cellular activities of terlipressin, LVP, and endogenous human hormone [Arg8]-vasopressin (AVP) at V1 and vasopressin-2 (V2) receptors. Cell membrane homogenates of Chinese hamster ovary cells expressing human V1 and V2 receptors were used in competitive binding assays to measure receptor-binding activity. These cells were used in functional assays to measure receptor-mediated cellular activity of terlipressin, LVP, and AVP. Binding was measured by [3H]AVP counts, and the activity was measured by fluorometric detection of intracellular calcium mobilization (V1) and cyclic adenosine monophosphate (V2). Binding potency at V1 and V2 was AVP>LVP>>terlipressin. LVP and terlipressin had approximately sixfold higher affinity for V1 than for V2. Cellular activity potency was also AVP>LVP>>terlipressin. Terlipressin was a partial agonist at V1 and a full agonist at V2; LVP was a full agonist at both V1 and V2. The in vivo response to terlipressin is likely due to the partial V1 agonist activity of terlipressin and full V1 agonist activity of its metabolite, LVP. These results provide supportive evidence for previous findings and further establish terlipressin pharmacology for vasopressin receptors.

Pharmacokinetics of Oral and Intravenous Paracetamol (Acetaminophen) When Co-Administered with Intravenous Morphine in Healthy Adult Subjects.

BACKGROUND AND OBJECTIVE: Several features favor paracetamol (acetaminophen) administration by the intravenous rather than the oral route in the postoperative setting. This study compared the pharmacokinetics and bioavailability of oral and intravenous paracetamol when given with or without an opioid, morphine. METHODS: In this randomized, single-blind, parallel, repeat-dose study in healthy adults, subjects received four repeat doses of oral or intravenous 1000 mg paracetamol at 6-h intervals, and morphine infusions (0.125 mg/kg) at the 2nd and 3rd intervals. Comparisons of plasma pharmacokinetic profiles were conducted before, during, and after opioid co-administrations. RESULTS: Twenty-two subjects were included in the pharmacokinetic analysis. Observed paracetamol peak concentration (C max) and area under the plasma concentration-time curve over the dosing interval (AUC0-6) were reduced when oral paracetamol was co-administered with morphine (reduced from 11.6 to 7.25 µg/mL and from 31.00 to 25.51 µg·h/mL, respectively), followed by an abruptly increased C max and AUC0-6 upon discontinuation of morphine (to 13.5 µg/mL and 52.38 µg·h/mL, respectively). There was also a significantly prolonged mean time to peak plasma concentration (T max) after the 4th dose of oral paracetamol (2.84 h) compared to the 1st dose (1.48 h). However, pharmacokinetic parameters of paracetamol were not impacted when intravenous paracetamol was co-administered with morphine. CONCLUSIONS: Morphine co-administration significantly impacted the pharmacokinetics of oral but not intravenous paracetamol. The abrupt release of accumulated paracetamol at the end of morphine-mediated gastrointestinal inhibition following oral but not intravenous administration of paracetamol suggests that intravenous paracetamol provides a better option for the management of postoperative pain. CLINICALTRIALS. GOV IDENTIFIER: NCT02848729.

Evaluation of the tamper-resistant properties of biphasic immediate-release/extended-release oxycodone/acetaminophen tablets.

CONTEXT: Abuse potential of extended-release (ER) opioid tablets increases if tampering causes rapid opioid release. OBJECTIVE: To evaluate the susceptibility to tampering of biphasic immediate-release (IR)/ER oxycodone (OC)/acetaminophen (APAP) tablets compared with IR OC/APAP tablets. MATERIALS AND METHODS: IR/ER OC/APAP and IR OC/APAP tablets were tested at room temperature and after heating, freezing and microwaving. Resistance to crushing was tested using manual and powered tools (e.g. spoons, mortar and pestle, blender, coffee grinder). Tampered tablets were tested for suitability for snorting, OC extraction in solvents and ease of drawing into a syringe. Dissolution of IR/ER OC/APAP in gastric fluid with and without ethanol was tested to determine the potential for facilitating precipitous release of opioid from the tablet. RESULTS: IR/ER OC/APAP tablets were more crush resistant than IR OC/APAP tablets. Heating, freezing and microwaving had no effect on crush resistance of IR/ER OC/APAP tablets. Although a mortar and pestle pulverized IR/ER OC/APAP tablets, upon contact with solvent, the powder formed a thick gel judged unsuitable for absorption through the nasal mucosa and could not be drawn into a syringe. In contrast, powder from crushed IR OC/APAP tablets dissolved readily, was judged suitable for snorting, and was easily drawn into a syringe. Dissolution of IR/ER OC/APAP tablets in gastric fluid was slowed by the addition of ethanol. DISCUSSION: IR/ER OC/APAP tablets are resistant to crushing and dissolution compared with IR OC/APAP tablets. CONCLUSION: IR/ER OC/APAP tablets may have less potential for abuse involving tampering compared with IR OC/APAP tablets.

Correlation of Subjective Effects with Systemic Opioid Exposure from Fixed-Dose Combinations of Oxycodone/Acetaminophen in Recreational Users of Prescription Drugs.

OBJECTIVE: To correlate abuse-related pharmacodynamic measures and pharmacokinetic measures after administering immediate-release/extended-release and immediate-release oxycodone/acetaminophen fixed-dose combination analgesicsDesign. Randomized, double-blind, active- and placebo-controlled, 7-way crossover studySetting. Contract research organizationSubjects. Nondependent recreational users of prescription opioids. METHODS: Participants received single doses of intact immediate-release/extended-release and immediate-release oxycodone/acetaminophen 15/650 mg, intact immediate-release/extended-release and immediate-release oxycodone/acetaminophen 30/1,300 mg, crushed immediate-release/extended-release and immediate-release oxycodone/acetaminophen 30/1,300 mg, and placebo. Measures of pharmacodynamics (pupillometry, drug liking, drug high, good drug effects) and pharmacokinetics were assessed predose and up to 24 hours postdose, and correlations between pharmacokinetic parameters and pharmacodynamic data were explored. RESULTS: Of 61 participants, 55 completed all 7 treatments. Intact immediate-release/extended-release oxycodone/acetaminophen produced 50% lower oxycodone peak plasma concentration (Cmax) than immediate-release oxycodone/acetaminophen. Median oxycodone time to Cmax (tmax) was significantly longer (P<0.001) for intact immediate-release/extended-release oxycodone/acetaminophen than immediate-release oxycodone/acetaminophen. The pharmacokinetics of crushed immediate-release/extended-release and immediate-release oxycodone/acetaminophen (30/1,300 mg) followed a similar pattern. Crushing did not shorten the median oxycodone tmax for immediate-release/extended-release oxycodone/acetaminophen (30/1,300 mg). Strong correlations were observed between oxycodone Cmax and area under the curve from time 0 to time x peak effects and area under the subjective effect curve from time 0 to time x for all subjective effects (R2=0.711-0.997). CONCLUSION: Immediate-release/extended-release oxycodone/acetaminophen produced lower oxycodone Cmax and longer tmax than immediate-release oxycodone/acetaminophen. Lower oxycodone concentrations, particularly at earlier time points, were strongly correlated with lesser positive subjective drug effects.

Pooled Post Hoc Analysis of Population Pharmacokinetics of Oxycodone and Acetaminophen Following Multiple Oral Doses of Biphasic Immediate-Release/Extended-Release Oxycodone/Acetaminophen Tablets.

OBJECTIVE: To examine whether biphasic immediate-release (IR)/extended-release (ER) oxycodone (OC)/acetaminophen (APAP) 7.5/325-mg tablets have clinically relevant variability in population pharmacokinetics (PK). DESIGN: Post hoc analysis of 2 phase 1 randomized, open-label, multiple-dose crossover studies. SETTING: Single contract research organization clinic. SUBJECTS: Men and women aged 18 to 55 years with a body mass index of 19 to 30 kg/m(2) and body weight ≥ 59 kg. METHODS: Fasted participants (N = 96) received 2 tablets of IR/ER OC/APAP 7.5/325 mg (total dose, 15/650 mg) every 12 hours for 4.5 days. Population PK analysis was performed using nonlinear mixed effects modeling and evaluated 6 population variables. RESULTS: The average PK estimates for OC were 75 L/hour for clearance (CL/F), 756 L for volume of distribution (V/F), and 0.581 per hour for absorption rate constant (Ka ). Body weight was a statistically significant source of variability in V/F for OC at steady state. Average estimates for APAP were 25 L/hour for CL/F and 119 L for V/F. Sex was identified as a statistically significant source of variability in CL/F with predicted values for APAP of 25 L/hour in men and 21 L/hour in women. Body weight affected variability in V/F, with a predicted value of 193 L in men and 174 L in women for a 72-kg participant at steady state. CONCLUSIONS: Dose adjustments of < 50% are not clinically relevant for IR/ER OC/APAP 7.5/325-mg tablets considering the approved dose of 1 to 2 tablets every 8 to 12 hours; thus, adjustment may be necessary for large deviations from normal body weight but not for sex.

Single-dose pharmacokinetics of 2 or 3 tablets of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (MNK-155) under fed and fasted conditions: two randomized open-label trials.

BACKGROUND: Biphasic immediate-release (IR)/extended-release (ER) hydrocodone bitartrate (HB)/acetaminophen (APAP) 7.5/325-mg tablets are formulated with gastroretentive ER drug delivery technology that has been associated with clinically meaningful food effects in other approved products. Two phase 1 studies evaluated potential effects of food on single-dose pharmacokinetics of IR/ER HB/APAP tablets. METHODS: These were single-center, open-label, randomized, single-dose, 3-period crossover studies in healthy volunteers (aged 18-55 years). IR/ER HB/APAP was administered as a single 2-tablet dose (study 1) or 3-tablet dose (study 2) under fed (high- and low-fat) and fasted conditions. Area under the plasma concentration-time curve from 0 h to time t (AUC0-t) and from time 0 extrapolated to infinity (AUC0-inf) and maximum observed plasma concentration (Cmax) of hydrocodone and APAP under fed versus fasted conditions were compared using analysis of variance. A 90% confidence interval of the geometric least squares mean ratio fully contained within 80 to 125 % indicated no treatment difference. Safety and tolerability were assessed. RESULTS: Forty of 48 participants in study 1 and 21 of 30 in study 2 completed all treatments. In both studies, under fed (high- or low-fat meal) versus fasted conditions, 90% CIs for AUC0-t and AUC0-inf for both hydrocodone and APAP were entirely contained within the bioequivalent range (80-125%), indicating that high- and low-fat meals did not affect the extent of exposure. In both studies, a high-fat meal did not affect the Cmax for hydrocodone. Hydrocodone Cmax was not affected by a low-fat meal in study 1 but increased by approximately 19% in study 2. A high-fat meal decreased APAP Cmax by approximately 20 % (study 1) and 13 % (study 2); a low-fat meal decreased APAP Cmax by 22% (study 1) and 21% (study 2). Approximately 50% of participants in both studies reported ≥1 treatment-emergent adverse event (TEAE), with no notable difference based on food intake. There were no serious or severe AEs. The most common TEAEs were nausea, vomiting, and dizziness. CONCLUSIONS: Pharmacokinetic and safety findings were similar regardless of food intake. TEAEs were consistent with those reported with low-dose combination opioids. IR/ER HB/APAP can be administered without regard to food. TRIAL REGISTRATION: ClinicalTrials.gov NCT02561650 and NCT02561741 .

Single- and multiple-dose pharmacokinetics of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (MNK-155) compared with immediate-release hydrocodone bitartrate/ibuprofen and immediate-release tramadol HCl/acetaminophen.

OBJECTIVE: To characterize the single-dose and steady-state pharmacokinetics (PK) of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (IR/ER HB/APAP), IR HB/ibuprofen, and IR tramadol HCl/APAP. METHODS: In this single-center, open-label, randomized, four-period crossover study, healthy participants received four treatments under fasted conditions: 1) a single dose of two IR/ER HB/APAP 7.5/325 mg tablets (15/650 mg total dose) on day 1, followed by two tablets every 12 hours (q12h) beginning on day 3; 2) a single dose of IR HB/ibuprofen 15/400 mg (divided as one 7.5/200 mg tablet at hour 0 and 6), followed by one tablet every 6 hours (q6h) beginning on day 3; 3) a single dose of IR tramadol HCl/APAP 75/650 mg (divided as one 37.5/325 mg tablet at hour 0 and 6), followed by one tablet q6h beginning on day 3; and 4) a single dose of three IR/ER HB/APAP 7.5/325 mg tablets (22.5/975 mg total dose) on day 1, a three-tablet initial dose at 48 hours followed by two-tablet doses q12h beginning on day 3. Hydrocodone and APAP single-dose and steady-state PK were assessed. Adverse events were monitored. RESULTS: The PK analysis was carried out on 29 of 48 enrolled participants who completed all treatment periods. Single-dose hydrocodone exposure was similar for IR/ER HB/APAP 22.5/975 mg and IR HB/ibuprofen 15/400 mg; time to maximum observed plasma concentration was shorter and half-life was longer for IR/ER HB/APAP (22.5/975 mg and 15/650 mg) vs IR HB/ibuprofen. Single-dose APAP exposure was similar for IR/ER HB/APAP 15/650 mg and IR tramadol HCl/APAP 75/650 mg. Steady-state hydrocodone and APAP exposures were similar between treatments. Adverse events were similar for each treatment and typical of low-dose combination opioid analgesics. With dosing q12h, IR/ER HB/APAP had half as many concentration peaks and troughs as the comparators treated q6h. CONCLUSION: With dosing q12h, IR/ER HB/APAP provided similar peak and total steady-state hydrocodone and APAP exposure vs IR comparators.

Comparison of single-dose and multiple-dose pharmacokinetics between two formulations of hydrocodone bitartrate/acetaminophen: immediate-release versus biphasic immediate-release/extended release.

OBJECTIVE: This study aimed to compare the single-dose and steady-state pharmacokinetics (PK) of biphasic immediate-release (IR)/extended-release (ER) hydrocodone bitartrate (HB)/acetaminophen (APAP) and IR HB/APAP. SETTING: The study was conducted in a contract research center. PARTICIPANTS: The study included healthy adults. INTERVENTIONS: In a three-way crossover study, Study 1, participants received the following treatments: (A1) a single dose of IR/ER HB/APAP 7.5/325 mg one tablet, followed by one tablet every 12 hours (q12h); (B1) a single dose of IR/ER HB/APAP 7.5/325 mg two tablets, followed by two tablets q12h; (C1) a single dose of IR HB/APAP 7.5/325 mg two tablets (one tablet at hours 0 and 6), followed by one tablet q6h. In a two-way crossover study, Study 2, participants received the following treatments: (A2) an initial dose of IR/ER HB/APAP 7.5/325 mg three tablets, followed by two tablets q12h; (B2) three doses of IR HB/APAP 7.5/325 mg one tablet q4h, followed by one tablet q6h. MAIN OUTCOME MEASURES: PK values were compared, and adverse events were assessed. RESULTS: Single-dose and steady-state area under the concentration-time curves for hydrocodone and APAP were similar for IR/ER and IR HB/APAP; the steady-state peak plasma concentrations (C max) at steady state were also similar, but single-dose C max for hydrocodone was lower for IR/ER HB/APAP. For most PK parameters, 90% confidence intervals for geometric least squares mean ratios were not meaningfully different (80%-125%). Steady state was achieved in 2-3 days for IR/ER HB/APAP and in 2 days for IR HB/APAP. Median time to C max was longer for IR/ER HB/APAP versus IR HB/APAP (P,0.05). Adverse events were similar across treatments. CONCLUSION: PK outcomes and tolerability were similar for IR/ER HB/APAP and IR HB/APAP.

Frog intestinal perfusion to evaluate drug permeability: application to p-gp and cyp3a4 substrates.

To evaluate the reliability of using in situ frog intestinal perfusion technique for permeability assessment of carrier transported drugs which are also substrates for CYP enzymes. Single Pass Intestinal Perfusion (SPIP) studies were performed in frogs of the species Rana tigrina using established method for rats with some modifications after inducing anesthesia. Effective permeability coefficient (P eff) of losartan and midazolam was calculated in the presence and absence of inhibitors using the parallel-tube model. Peff of losartan when perfused alone was found to be 0.427 ± 0.27 × 10(-4)cm/s and when it was co-perfused with inhibitors, significant change in P eff was observed. Peff of midazolam when perfused alone was found to be 2.03 ± 0.07 × 10(-4)cm/s and when it was co-perfused with inhibitors, no significant change in P eff was observed. Comparison of P eff calculated in frog with that of other available models and also humans suggested that the P eff-values are comparable and reflected well with human intestinal permeability. It is possible to determine the P eff-value for compounds which are dual substrates of P-glycoprotein and CYP3A4 using in situ frog intestinal perfusion technique. The calculated P eff-values correlated well with reported P eff-values of probe drugs. comparison of the P eff-value of losartan obtained with that of reported human's P eff and Caco 2 cell data, and comparison of the P eff-value of midazolam with that of reported rat's P eff, we could conclude that SPIP from model can be reliably used in preclinical studies for permeability estimation. This model may represent a valuable alternative to the low speed and high cost of conventional animal models (typically rodents) for the assessment of intestinal permeability.

Pooled post hoc analysis of population pharmacokinetics of oxycodone and acetaminophen following a single oral dose of biphasic immediate-release/extended-release oxycodone/acetaminophen tablets.

This analysis evaluated the single-dose population pharmacokinetics (PK) of biphasic immediate-release (IR)/extended-release (ER) oxycodone (OC)/acetaminophen (APAP) 7.5/325 mg tablets administered under fasted conditions and the effects of a meal on their single-dose population PK. Data were pooled from four randomized, single-dose crossover trials enrolling healthy adult (18-55 years old) participants (three trials) and nondependent recreational users of prescription opioids (one trial) with a body weight of ≥59 kg. Participants received IR/ER OC/APAP 7.5/325 mg tablets in single doses of 7.5/325 mg (one tablet), 15/650 mg (two tablets), or 30/1,300 mg (four tablets) under fasted or fed conditions. Six variables were examined: sex, race, age, weight, height, and body mass index. Single-dose population PK was analyzed using first-order conditional estimation methods. A total of 151 participants were included in the analysis under fasted conditions, and 31 participants were included in the fed analysis. Under fasted conditions, a 10% change in body weight was accompanied by ~7.5% change in total body clearance (CL/F) and volume of distribution (V/F) of OC and APAP. Black participants had 17.3% lower CL/F and a 16.9% lower V/F of OC compared with white participants. Under fed conditions, the absorption rate constant of OC and APAP decreased significantly, although there was no effect on CL/F and V/F. Considering that the recommended dose for IR/ER OC/APAP 7.5/325 mg tablets is two tablets every 12 hours, adjustments of <50% are not clinically relevant. Dose adjustment may be necessary for large deviations from average body weight, but the small PK effects associated with race and consumption of a meal are not clinically relevant.

Human abuse potential of immediate-release/extended-release versus immediate-release hydrocodone bitartrate/acetaminophen: a randomized controlled trial in recreational users of prescription opioids.

BACKGROUND: The abuse potential of prescription opioids is well established. This study compared positive, subjective drug effects of single, equal doses of biphasic immediate release (IR)/extended release (ER) hydrocodone bitartrate (HB)/acetaminophen (acetyl-p-aminophenol [APAP]) 7.5/325 mg tablets versus IR HB/APAP 7.5/325-mg tablets and placebo. METHODS: Healthy adult recreational users of prescription opioids entered this randomized, double-blind, double-dummy, active- and placebo-controlled, seven-way crossover study. Participants received single, total doses of IR/ER HB/APAP 22.5/975 mg (intact; three active tablets) and 45/1950 mg (intact and crushed [encapsulated]; six active tablets), IR HB/APAP 22.5/975 mg (intact; three active tablets) and 45/1950 mg (intact and crushed [encapsulated]; six active tablets), and placebo. Peak subjective effects (E(max)); time to peak effects (TE(max)); and area under the drug-effect curves for drug liking, high, and good drug effects were measured using visual analog scales. Median values with 95% confidence interval (CI) were compared using analysis of variance. RESULTS: Among completers (n = 52), IR/ER HB/APAP produced delayed and lower peak effects compared to equal doses of IR HB/APAP. Comparing intact tablets, the drug liking E(max) (median [95% CI]) was significantly lower for IR/ER HB/APAP 45/1950 mg (78.0 [73.0, 81.0]) than an equal dose of IR HB/APAP (89.5 [85.0, 93.0]; difference, -8.5 [-12.0, -6.0]; P < 0.001). Similar results were observed for intact IR/ER HB/APAP and IR HB/APAP 22.5/975 mg. Crushing IR/ER HB/APAP 45/1950 mg delayed these effects compared with an equal dose of crushed IR HB/APAP and intact IR/ER HB/APAP. CONCLUSION: IR/ER HB/APAP resulted in lower subjective positive drug effects than an equal dose of IR HB/APAP. Crushing IR/ER HB/APAP also delayed the onset of subjective effects compared with intact IR/ER HB/APAP. These findings suggest that biphasic IR/ER HB/APAP has lower abuse potential than IR HB/APAP in single equal doses. REGISTRATION: This Phase I clinical trial conducted in the USA was not registered.

Pharmacokinetics and bioavailability of oxycodone and acetaminophen following single-dose administration of MNK-795, a dual-layer biphasic IR/ER combination formulation, under fed and fasted conditions.

BACKGROUND: XARTEMIS™ XR (formerly MNK-795) is a combination oxycodone (OC) and acetaminophen (APAP) analgesic with both immediate-release and extended-release (ER) components (ER OC/APAP). The tablets are designed with gastric-retentive ER oral delivery technology that releases the ER component at a controlled rate in the upper gastrointestinal tract. Because consumption of food has demonstrated an impact on the pharmacokinetics (PK) of some marketed products using gastric-retentive ER oral delivery technology, a characterization of the effects of fed (high- and low-fat diets) versus fasted conditions on the PK of ER OC/APAP was performed. METHODS: This Phase I study used an open-label randomized single-dose three-period six-sequence crossover single-center design. Healthy adult participants (n=48) were randomized to receive two tablets of ER OC/APAP under three conditions: following a high-fat meal; following a low-fat meal; and fasted. Plasma concentration versus time data from predose throughout designated times up to 48 hours postdose was used to estimate the PK parameters of oxycodone and APAP. RESULTS: Thirty-one participants completed all three treatment periods. Both oxycodone and APAP were rapidly absorbed under fasted conditions. Total oxycodone and APAP exposures (area under the plasma drug concentration-time curve [AUC]) from ER OC/APAP were not significantly affected by food, and minimal changes to maximum observed plasma concentration for oxycodone and APAP were also noted. However, food marginally delayed the time to maximum observed plasma concentration of oxycodone and APAP. There was no indication that tolerability was affected by food. CONCLUSION: The findings from this study suggest that ER OC/APAP can be administered with or without food.

Comparison of subjective effects of extended-release versus immediate-release oxycodone/acetaminophen tablets in healthy nondependent recreational users of prescription opioids: a randomized trial.

BACKGROUND: Prescription opioids have substantial abuse potential. This study compared the positive subjective drug effects of a newly developed extended-release (ER) oxycodone (OC)/acetaminophen (acetyl-para-aminophenol [APAP]) formulation with those of immediate-release (IR) OC/APAP. METHODS: This randomized, double-blind, active- and placebo-controlled, 7-way crossover study enrolled healthy volunteers who were recreational prescription opioid users. The protocol was approved by an institutional review board and all participants provided written informed consent. Participants received single doses of intact ER and IR OC/APAP 15/650 mg, intact ER and IR OC/APAP 30/1300 mg, crushed ER and IR OC/APAP 30/1300 mg, and placebo. Peak subjective effects (Emax), time to Emax, and area under the drug-effect curves for drug liking, drug high, and good drug effects were measured using visual analogue scales. Least squares means with 95% confidence interval were compared using analysis of variance. RESULTS: Among completers (N = 55), intact ER OC/APAP produced delayed and lower peak effects versus IR OC/APAP. Comparing intact tablets, the drug liking Emax (least squares means [95% confidence interval]) was significantly lower for OC/APAP 30/1300 mg (76.4 [72.8 to 80.0]) than for IR OC/APAP 30/1300 mg (85.6 [81.9 to 89.2]; difference, -9.2 [-13.1 to -5.2]; P < 0.001). Similar results were observed for intact ER and IR OC/APAP (15 mg/650 mg). Crushing ER OC/APAP 30/1300 mg further delayed these effects compared with the same dose of crushed IR OC/APAP and intact ER OC/APAP. CONCLUSIONS: Extended-release OC/APAP produced lower subjective drug effects than IR OC/APAP. Crushing ER OC/APAP further delayed onset of subjective effects compared with intact ER OC/APAP. The ER OC/APAP may be less attractive for abuse than IR OC/APAP. CLINICAL TRIAL REGISTRATION: This phase 1 study conducted in the United States was not registered.

Biodistribution of diclofenac following repeated topical applications of two diclofenac sodium formulations to minipigs.

This study evaluated diclofenac concentrations in plasma, selected hind limb tissues and synovial fluid after repeated topical applications of two diclofenac formulations. Group 1 Gottingen minipigs (n = 18) were administered diclofenac sodium 2.0% topical solution twice daily on days 1-6 and once on day 7. Group 2 minipigs (n = 18) were administered diclofenac sodium 1.5% topical solution four times daily on days 1-6 and twice on day 7. Approximately 20 mg of diclofenac was applied daily to a 10 × 15 cm dosing site centered over the patella of the right knee. Plasma and tissue samples were collected throughout and analysed for diclofenac concentrations using liquid chromatography with tandem mass spectrometry. On day 1, diclofenac sodium 2.0% topical solution produced higher plasma concentrations compared with the 1.5% formulation; however, after 24 h and throughout the remainder of the dosing period, plasma concentrations appeared similar, except at the 72 h time point. Twenty-four hours after the final application, skin treated with diclofenac sodium 2.0% topical solution retained a significantly (p < 0.02) greater amount of diclofenac than the 1.5% formulation. Generally, both formulations produced similar diclofenac concentrations in synovial fluid, underlying muscle, tendon and bone 24 h after the last application. The 2.0% diclofenac formulation applied twice daily delivered similar amounts of diclofenac as the 1.5% formulation administered four times daily. The skin retained a significant portion of the applied dose to serve as a depot for continuous diffusion of diclofenac into underlying tissues and systemic circulation.