Influence of Copolymer Composition on <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Performance of Celecoxib-PVP/VA Amorphous Solid Dispersions

Previous studies suggested that an amorphous solid dispersion with a copolymer consisting of both hydrophobic and hydrophilic monomers could improve the dissolution profile of a poorly water-soluble drug compared to the crystalline form. Therefore, this study investigated the influence of the copolymer composition of polyvinylpyrrolidone/vinyl acetate (PVP/VA) on the non-sink in vitro dissolution behavior and in vivo performance of celecoxib (CCX) amorphous solid dispersions. The study showed that the hydrophilic monomer vinylpyrrolidone (VP) was responsible for the generation of CCX supersaturation whereas the hydrophobic monomer vinyl acetate (VA) was responsible for the stabilization of the supersaturated solution. For CCX, there was an optimal copolymer composition around 50–60% VP content where further replacement of VP monomers with VA monomers did not have any biopharmaceutical advantages. A linear relationship was found between the in vitro AUC_0-4h and in vivo AUC_0-24h for the CCX:PVP/VA systems, indicating that the non-sink in vitro dissolution method applied in this study was useful in predicting the in vivo performance. These results indicated that when formulating a poorly water-soluble drug as an amorphous solid dispersion using a copolymer, the copolymer composition has a significant influence on the dissolution profile and in vivo performance. Thus, the dissolution profile of a drug can theoretically be tailored by changing the monomer ratio of a copolymer with respect to the required in vivo plasma-concentration profile. As this ratio is likely to be drug dependent, determining the optimal ratio between the hydrophilic (dissolution enhancing) and hydrophobic (crystallization inhibiting) monomers for a given drug is imperative.     

Effects of <Emphasis Type="Italic">CYP2C9</Emphasis> genetic polymorphisms on the pharmacokinetics of zafirlukast

Zafirlukast, a cysteinyl leukotriene receptor antagonist, is indicated for the treatment of patients with mild to moderate asthma. Zafirlukast is metabolized mainly by CYP3A4 and CYP2C9. We investigated the effects of the major CYP2C9 variant alleles in Asian populations, CYP2C9*3 and CYP2C9*13, on the pharmacokinetics of zafirlukast in healthy Korean subjects. A single 20-mg oral dose of zafirlukast was given to 23 Korean male subjects divided into two genotype groups according to CYP2C9 genotypes, CYP2C9EM (n = 11; CYP2C9*1/*1) and CYP2C9IM (n = 12; 9 and 3 carriers of CYP2C9*1/*3 and *1/*13, respectively). Zafirlukast concentrations were determined using a validated HPLC–MS/MS analytical method in plasma samples collected after the drug intake. Compared with the CYP2C9EM group, the C_max and AUC_inf of zafirlukast in the CYP2C9IM group were 1.44- and 1.70-fold higher, respectively (p < 0.01 and p < 0.0001). The CL/F of zafirlukast was 42.8 % lower in the CYP2C9IM group compared with the CYP2C9EM group (p < 0.001). Slightly higher C_max and AUC, and lower CL/F of zafirlukast were observed in subjects with the CYP2C9*1/*13 genotype compared with the CYP2C9*1/*3 genotype subjects. CYP2C9*3 and CYP2C9*13 alleles significantly affected the plasma concentrations of zafirlukast.     

In vitro antimicrobial and acetylcholinesterase inhibitory activities of coumarins from <Emphasis Type="Italic">Ferulago</Emphasis><Emphasis Type="Italic">carduchorum</Emphasis>

Ferulago carduchorum (Apiaceae) is an endemic plant of Iran. From the hexane and ethyl acetate extracts of F. carduchorum seven coumarins, one flavonoid and one steroid were isolated using column chromatography with silica gel and Sephadex LH₂₀ as the stationary phases. Antimicrobial activity of the isolated compounds was examined by a broth microdilution method. Acetylcholinesterase (AChE) inhibitory activity of isolated coumarins was also investigated. The isolated compounds were identified as suberosin, suberenol, bergapten, xanthotoxin, isopimpinellin, prantschimgin, β-sitosterol and hesperetin by comparison of their NMR and MS spectral data with those reported in the literature. Evaluation of the minimum inhibitory concentration (MIC) for each compound showed that hesperetin (flavonoid) was the most potent antimicrobial agent against a gram-positive bacterium (Staphylococcus aureus) and among the coumarins, bergapten had the best activity against S. aureus and Candida albicans. All coumarins inhibited AchE enzyme, in which xanthotoxin showed the most inhibitory among them (IC₅₀ = 39.64 µM). Our results indicate that isolated coumarins are effective against the tested bacterial strains and have AchE inhibitory activity suggesting their potential for commercial applications.     

Antioxidant <Emphasis Type="Italic">C</Emphasis>-glycosylflavones of <Emphasis Type="Italic">Drymaria cordata</Emphasis> (Linn.) Willd

A new C-glycosylflavone, drymaritin E (6-C-(3-keto-β-digitoxopyranosyl)-4′-O-(β-d-glucopyranosyl)-7-methoxyl-5,4′-dihydroxylflavone) 1 was isolated from the oily upper phase (SU) of the MeOH extract from aerial parts of Drymaria cordata together with two known compounds (cassiaoccidentalin A 2 and anemonin 3) and an inseparable mixture of two known C-glycosylflavones 5,4′-dihydroxy-7-methoxyflavone-6-C-(2′′-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside 4a and 5,7,3′,4′-tetrahydroxyflavone-6-C-(2′′-O-α-l-rhamnopyranosyl)-β-d-glucopyranoside 4b. The alkaline hydrolysis of 3 led to a new hemisynthetic derivative, sodium anemonate (sodium 2-((1’E) 2′-sodium-carboxylate-vinyl)-5-oxo-cyclohex-1-ene carboxylate) 3a. The chemical structures were determined by spectroscopic methods (¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMBC, HSQC, and NOESY) and mass spectrometry (ESI–MS). C-glycosylflavones had significant free radical-scavenging activities on the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). However, SU and compounds 3 and 3a exhibited no activity. In particular, compound 1 exhibited a concentration-dependent radical scavenging activity on DPPH with EC₅₀ of 31.43 µg/mL.     

The BioGIT System: a Valuable <Emphasis Type="Italic">In Vitro</Emphasis> Tool to Assess the Impact of Dose and Formulation on Early Exposure to Low Solubility Drugs After Oral Administration

The purpose of this study was to evaluate the usefulness of the in vitro biorelevant gastrointestinal transfer (BioGIT) system in assessing the impact of dose and formulation on early exposure by comparing in vitro data with previously collected human plasma data of low solubility active pharmaceutical ingredients. Eight model active pharmaceutical ingredients were tested; Lu 35-138C (salt of weak base in a HP-beta-CD solution, three doses), fenofibrate (solid dispersion, tablet, two doses), AZD2207 EQ (salt of weak base, capsule, three doses), posaconazole (Noxafil® suspension, two doses), SB705498 (weak base, tablets vs. capsules), cyclosporine A (Sandimmun® vs. Sandimmun® Neoral), nifedipine (Adalat® capsule vs. Macorel® tablet), and itraconazole (Sporanox® capsule vs. Sporanox® solution). AUC_0–0.75h values were calculated from the apparent concentration versus time data in the duodenal compartment of the BioGIT system. Differences in AUC_0–0.75h values were evaluated versus differences in AUC_0–1h and in AUC_0–2h values calculated from previously collected plasma data in healthy adults. Ratios of mean AUC_0–0.75h, mean AUC_0–1h, and mean AUC_0–2h values were estimated using the lowest dose or the formulation with the lower AUC_0–0.75h value as denominator. The BioGIT system qualitatively identified the impact of dose and of formulation on early exposure in all cases. Log-transformed mean BioGIT AUC_0–0.75h ratios correlated significantly with log-transformed mean plasma AUC_0–1h ratios. Based on this correlation, BioGIT AUC_0–0.75h ratios between 0.3 and 10 directly reflect corresponding plasma AUC_0–1h ratios. BioGIT system is a valuable tool for the assessment of the impact of dose and formulation on early exposure to low solubility drugs.     

Effect of the <Emphasis Type="Italic">CYP2D6*10</Emphasis> allele on the pharmacokinetics of clomiphene and its active metabolites

Clomiphene citrate, a selective estrogen receptor modulator, is metabolized into its 4-hydroxylated active metabolites, primarily by CYP2D6. In this study, we investigated the effects of the most common CYP2D6 variant allele in Asians, CYP2D6*10, on the pharmacokinetics of clomiphene and its two active metabolites (4-OH-CLO and 4-OH-DE-CLO) in healthy Korean subjects. A single 50-mg oral dose of clomiphene citrate was given to 22 Korean subjects divided into three genotype groups according to CYP2D6 genotypes, CYP2D6*wt/*wt (n = 8; *wt = *1 or *2), CYP2D6*wt/*10 (n = 8) and CYP2D6*10/*10 (n = 6). Concentrations of clomiphene and its metabolites were determined using a validated HPLC–MS/MS analytical method in plasma samples collected up to 168 h after the drug intake. There was a significant difference only in the C_max of clomiphene between three CYP2D6 genotype groups (p < 0.05). Paradoxically, the elimination half-life (t_1/2) and AUC of both active metabolites were all significantly increased in the CYP2D6*10 homozygous carriers, compared with other genotype groups (all p < 0.001). The AUC_inf of corrected clomiphene active moiety in CYP2D6*10/*10 subjects was 2.95- and 2.05-fold higher than that of CYP2D6*wt/*wt and *wt/*10 genotype groups, respectively (both p < 0.001). Along with the partial impacts on the biotransformation of clomiphene and its metabolites by CYP2D6 genetic polymorphism, further studies on the effects of other CYP enzymes in a multiple-dosing condition can provide more definite evidence for the inter-individual variabilities in clomiphene pharmacokinetics and/or drug response.     

Two different approaches for the prediction of <Emphasis Type="Italic">In Vivo</Emphasis> plasma concentration-time profile from <Emphasis Type="Italic">In Vitro</Emphasis> release data of once daily formulations of diltiazem hydrochloride

The aim of this study was to employ two different mathematical approaches: first, a convolution approach using computer software; second, a mathematical calculation exploiting Wagner-Nelson calculation to predict in vivo plasma concentration — time profile from the in vitro release study for the once daily formulations of a model drug diltiazem hydrochloride. The once daily extended release tablets (120 mg) were prepared by the wet granulation technique. Ethanol or ethanolic solutions of ethylcellulose (N22), were used as granulating agents along with hydrophilic matrix polymers like hydroxypropyl methylcellulose (HPMC) (K 15M). The granules showed satisfactory flow properties, compressibility, moisture content and drug content. All the tablet formulations showed acceptable properties and complied with pharmacopeial limits. The in vitro drug release study revealed that formula F7-T which contains drug: HPMC ratio 1:1 and 20 mg of ethylcellulose was able to sustain the drug release for 24 h and satisfied the USP dissolution limits. Fitting the in vitro drug release data to Korsmeyer-Peppas equation indicated that the mechanism of drug release could be zero-order. The capsule formulation F14-C which consists of drug: HPMC ratio 1:2, 12 mg of ethylcellulose and 20 mg of polyox 100 showed in vitro drug release similar to the tablet F7-T using the similarity factor (f ₂). The mechanism of drug release could be coupled diffusion, and polymer matrix relaxation. The percent dissolved data from the two formulations were used as input function to predict the in vivo plasma data by the two approaches (Convolution by Kinetica® software and Wagner-Nelson calculation). The two methods were validated by prediction of plasma data from in vitro release data of FDA approved 300 mg extended release capsule. Prediction errors were estimated for C _max and area under the curve (AUC) to determine the validity of the methods. The percent prediction error for each parameter is not exceeding 15%.     

Gender-Dependent Pharmacokinetics of Veratramine in Rats: <Emphasis Type="Italic">In Vivo</Emphasis> and <Emphasis Type="Italic">In Vitro</Emphasis> Evidence

Veratramine, a major alkaloid from Veratrum nigrum L., has distinct anti-tumor and anti-hypertension effects. Our previous study indicated that veratramine had severe toxicity toward male rats. In order to elucidate the underling mechanism, in vivo pharmacokinetic experiments and in vitro mechanistic studies have been conducted. Veratramine was administrated to male and female rats intravenously via the jugular vein at a dose of 50 μg/kg or orally via gavage at 20 mg/kg. As a result, significant pharmacokinetic differences were observed between male and female rats after oral administration with much lower concentrations of veratramine and 7-hydroxyl-veratramine and higher concentrations of veratramine-3-O-sulfate found in the plasma and urine of female rats. The absolute bioavailability of veratramine was 0.9% in female rats and 22.5% in male rats. Further experiments of veratramine on Caco-2 cell monolayer model and in vitro incubation with GI content or rat intestinal subcellular fractions demonstrated that its efficient passive diffusion mediated absorption with minimal intestinal metabolism, suggesting no gender-related difference during its absorption process. When veratramine was incubated with male or female rat liver microsomes/cytosols, significant male-predominant formation of 7-hydroxyl-veratramine and female-predominant formation of veratramine-3-O-sulfate were observed. In conclusion, the significant gender-dependent hepatic metabolism of veratramine could be the major contributor to its gender-dependent pharmacokinetics.     

Effects of diltiazem,a moderate inhibitor of CYP3A4, on the pharmacokinetics of tamsulosin in different <Emphasis Type="Italic">CYP2D6</Emphasis> genotypes

Tamsulosin, a selective antagonist of the α₁-adrenoceptor, is primarily metabolized by CYP3A4 and CYP2D6, and tamsulosin exposure is significantly increased according to the genetic polymorphism of CYP2D6. In this study, we investigated the effects of diltiazem, a moderate inhibitor of CYP3A4, on the pharmacokinetics of tamsulosin in subjects with different CYP2D6 genotypes. Twenty-three healthy Korean male subjects with CYP2D6*wt/*wt (*wt?=?*1 or *2) and CYP2D6*10/*10 were enrolled in the prospective, open-label, two-phase parallel pharmacokinetic study. On the first day of study (day 1), each subject received a single 0.2 mg oral dose of tamsulosin. After a washout period of 1 week, on day 8, the subjects were given a 60 mg oral dose of diltiazem three times daily for four days. On day 10, 1 h after the morning dose of diltiazem, they received a single 0.2 mg oral dose of tamsulosin. The pharmacokinetic parameters of tamsulosin in those with and without diltiazem treatment were compared in subjects with different CYP2D6 genotypes. After diltiazem treatment, the C_max and AUC_inf of tamsulosin in each CYP2D6 genotype group were significantly increased (p?<?0.0001 for all). The CL/F of tamsulosin was also significantly decreased after diltiazem treatment (both p?<?0.0001). However, diltiazem did not affect the t_1/2 of tamsulosin in each genotype group. In conclusion, diltiazem significantly increases exposure to tamsulosin regardless of the genotype of CYP2D6. Dose adjustment in the daily maintenance dose of tamsulosin may improve tolerability and safety in patients receiving diltiazem.     

Three new <Emphasis Type="Italic">C</Emphasis>-glycosyflavones with acetyl substitutions from <Emphasis Type="Italic">Swertia mileensis</Emphasis>

Three new acetylated C-glycosylflavones, 3″,6″-di-O-acetylswertiajaponin (1), 4″,6″-di-O-acetylswertiajaponin (2), and 6″-O-acetylswertiajaponin (3), together with six known compounds were isolated from the whole herb of Swertia mileensis. Their structures were elucidated on extensive NMR experiments and mass spectrometry studies. ¹H and ¹³C NMR data exhibited doublet signals at room temperature. Variable temperature ¹H NMR experiments were carried out to investigate the presence of rotational isomerism of C-glycosylflavones. All compounds showed potential antioxidant activities against apoptosis of H₂O₂-induced human embryo liver L02 cells.     

Moxifloxacin-gelrite <Emphasis Type="Italic">In Situ</Emphasis> ophthalmic gelling system against photodynamic therapy for treatment of bacterial corneal inflammation

In this study, six in situ gelling formulations based on Gelrite were prepared and evaluated for the retained ophthalmic delivery of Moxifloxacin (Mox). The effectiveness of the best developed formula G5 was compared with photodynamic therapy (PDT), the recent expanding approach for the treatment of ophthalmologic disorders after the assessment of optimum photodynamic inactivation parameters that permit efficient pathogens eradication. It was found that, Staphylococcus aureus (S. aureus) (Gram-positive) was more susceptible to effective lethal photosensitization that reaches 93.5% reduction in viable count than Escherichia coli (E. coli) (Gramnegative) of 76.1% using 3 mg/mL Hematoporphyrin (HP), illuminated by 630 nm Light Emitting Diode (LED) at 9 J/cm² and incubated for 15 min. Following topical instillation of G5 to rabbits corneas, higher amount of Mox was retained in the aqueous humor up to 24 h with significant 6-fold increase in the C_max and AUC_(0-∞) compared to vigamox® commercial eye drops. After post corneal infection with S. aureus, both approaches were effectively treating the infection without causing ocular irritation or collateral damage to corneal tissue where G5 showed remarkable improvement after four days compared to seven days of PDT treatment.     

Identification of <Emphasis Type="Italic">N</Emphasis>-arylsulfonylpyrimidones as anticancer agents

For confirming the role of five membered ring of imidazolidinone moiety of N-arylsulfonylimidazolidinones (7) previously reported with highly potent anticancer agent, a series of N-arylsulfonylpyrimidones (10a–g) and N-arylsulfonyltetrahydropyrimidones (11a–e) were prepared and their anti-proliferating activity was measured against human cancer cell lines (renal ACHN, colon HCT-15, breast MDA-MB-231, lung NCI-H23, stomach NUGC-3, and prostate PC-3) using XTT assay. Among them, 1-(1-acetylindolin-5-ylsulfonyl)-4-phenyltetrahydropyrimidin-2(1H)-one (11d, mean GI₅₀ = 3.50 µM) and ethyl 5-(2-oxo-4-phenyltetrahydropyrimidin-1(2H)-ylsulfonyl)-indoline-1-carboxylate (11e, mean GI₅₀ = 0.26 µM) showed best growth inhibitory activity against human cancer cell lines. Considering the activity results, N-arylsulfonyltetrahydropyrimidones (11) exhibited more potent activity compared to N-arylsulfonylpyrimidones (10) and comparable activity to N-arylsulfonylimidazolidinones (7). Especially, tetrahydropyrimidin-2(1H)-one analogs containing acylindolin-5-ylsulfonyl moiety at position 1 demonstrated their strong growth inhibitory activity against human cancer cell lines.     

Effects of genetic polymorphisms of <Emphasis Type="Italic">CYP2C19</Emphasis> on the pharmacokinetics of zolpidem

Zolpidem is indicated for the short-term treatment of insomnia and it is predominantly metabolized by CYP3A4, and to a lesser extent by CYP2C19, CYP1A2, and CYP2C9. Therefore, we evaluated the effects of CYP2C19 genetic polymorphisms on the pharmacokinetics of zolpidem in healthy male subjects. Thirty-two male subjects were recruited and all subjects were classified into three groups according to their genotypes: CYP2C19EM (CYP2C19*1/*1, n?=?12), CYP2C19IM (CYP2C19*1/*2 or *1/*3, n?=?10), and CYP2C19PM (CYP2C19*2/*2, *2/*3 or *3/*3, n?=?10). The pharmacokinetic parameters of zolpidem were compared in three CYP2C19 genotype groups after zolpidem administration with or without a CYP3A4 inhibitor at steady-state concentration. Plasma concentrations of zolpidem were determined up to 12 h after drug administration by liquid chromatography-tandem mass spectrometry method. The maximum plasma concentration (C_max) differed, but mean total area under the plasma concentration–time curve (AUC_inf), half-life (t_1/2), and apparent oral clearance (CL/F) of zolpidem administered alone did not significantly differ among the three different CYP2C19 genotype groups. Furthermore, when zolpidem was administered with a CYP3A4 inhibitor at steady-state concentration, there were no significant differences in any of the pharmacokinetic parameters of zolpidem in relation to CYP2C19 genotypes. In conclusion, we did not find any evidence for the impact of CYP2C19 genetic polymorphisms on the pharmacokinetic parameters of zolpidem.     

Effects of <Emphasis Type="Italic">CYP2C9</Emphasis> genetic polymorphisms on the pharmacokinetics of celecoxib and its carboxylic acid metabolite

Celecoxib, a selective cyclooxygenase (COX)-2 inhibitor, is used for the treatment of rheumatoid arthritis and osteoarthritis. The predominant hepatic metabolism of celecoxib to celecoxib carboxylic acid (CCA) is mediated mainly by CYP2C9. We investigated the effects of the major CYP2C9 genetic variants in Asian populations, CYP2C9*3 and CYP2C9*13, on the pharmacokinetics of celecoxib and its carboxylic acid metabolite in healthy Korean subjects. A single 200-mg oral dose of celecoxib was given to 52 Korean subjects with different CYP2C9 genotypes: CYP2C9EM (n = 26; CYP2C9*1/*1), CYP2C9IM (n = 24; CYP2C9*1/*3 and *1/*13), and CYP2C9PM (n = 2; CYP2C9*3/*3). Celecoxib and CCA concentrations in plasma samples collected up to 48 or 96 h after drug intake were determined by HPLC–MS/MS. The mean area under the plasma concentration–time curve (AUC_0–∞) of celecoxib was increased 1.63-fold (P < 0.001), and the apparent oral clearance (CL/F) of celecoxib was decreased by 39.6% in the CYP2C9IM genotype group compared with that of CYP2C9EM (P < 0.001). The overall pharmacokinetic parameters for celecoxib in CYP2C9*1/*13 subjects were similar to those in CYP2C9*1/*3 subjects. Two subjects with CYP2C9PM genotype both showed markedly higher AUC_0–∞, prolonged half-life, and lower CL/F for celecoxib than did subjects with CYP2C9EM and IM genotypes. CYP2C9*3 and CYP2C9*13 variant alleles significantly affected the plasma concentration of celecoxib.     

Safety of an injection with a mixture of extracts from <Emphasis Type="Italic">Herba Artemisiae annuae</Emphasis>, <Emphasis Type="Italic">Fructus Gardeniae</Emphasis> and <Emphasis Type="Italic">Flos Lonicerae</Emphasis>

Objective This study aimed to evaluate the safety for an injection with a mixture of extracts from Herba Artemisiae annuae, Fructus Gardeniae and Flos Lonicerae and to determine the risk factors that may affect its adverse drug reactions. Methods A drug-oriented prospective observational study was performed. Physicians filled in clinical observation forms with detailed information of the patients including general information, drug information, therapeutic effects and adverse drug events. The adverse drug reaction factors were analyzed by both mono-factor and multiple-factor logistic regression methods. Results From April to July 2007, we collected 12,427 observation forms from 46 hospitals in Jiangsu Province of China. Among the 11,707 observation forms we analyzed, 8,074 patients were children younger than 14 years old (69%). Among 51 reported adverse drug events, 45 cases were adverse drug reactions. The total adverse drug reaction incidence of the injection was 0.38%. While most adverse drug reactions were previously known (e.g., rash, pruritus, vomiting and diarrhea), we observed three new ADR symptoms: shiver, phlebitis and anhelation. All the adverse drug reactions were controlled very well through the follow-up therapy, and none of them was life threatening. The mono-factor analysis showed that adverse drug reactions of the injection were significantly correlated with total medication dose (P = 0.0049) and combination medication (P = 0.0143), especially with antimicrobial drugs (P = 0.0079) and macrolides (P = 0.0017). The multiple factor analysis confirmed these results: medication dosage and combination medication had a crucial impact on adverse drug reactions of the injection; the risk was increased by 24.8% (the estimated value of relative risk was 1.248, 95% confidence interval: 1.054–1.479) and 89% (1.890, 1.001–3.566), respectively. Conclusion The total adverse drug reaction incidence of the injection was 0.38% and lower than we expected. Moreover, we observed three new adverse drug reactions, none of which was severe.     

Time Scaling for <Emphasis Type="Italic">In Vitro-In Vivo</Emphasis> Correlation: the Inverse Release Function (IRF) Approach

In vitro-in vivo correlations (IVIVC) are methods used to create a link between biopharmaceutical properties such as dissolution and physiological response such as plasma concentration. Level A IVIVC defines 1:1 relationship between the percent absorbed in vivo and the percent dissolved in vitro. A successful level A IVIVC provides the capacity to predict in vivo behavior based only on in vitro data with application in formulation development and support of biowaivers recognized by regulatory agencies across the world. Level A regression may be complicated due to differences in time scales as well as the lack of coincident times of similar release in vitro and in vivo leading to approximate time-to-time links and subsequent loss of information. Here, a novel method to establish Levy’s plot and to provide time scaling for improved IVIVC predictive capacity is presented. The method is mathematically closed and is an inverse release function (IRF) characterizing the single (or more) phases of dissolution/absorption. It uses the complete set of information available from all time points both in vitro and in vivo. An extended-release formulation development situation is presented with three increasing release rate test products compared in a trial versus a reference product. First, the standard level A regression was made. Prediction errors for internal validation were higher than 10% for C_max. The IRF method was applied to obtain the in vitro times of percentage dissolved equivalent to percentage absorbed. The prediction errors from the IRF level A correlation were nearly negligible.     

Daytime <Emphasis Type="Italic">Ayahuasca</Emphasis> administration modulates REM and slow-wave sleep in healthy volunteers

Objectives

Ayahuasca is a traditional South American psychoactive beverage and the central sacrament of Brazilian-based religious groups, with followers in Europe and the United States. The tea contains the psychedelic indole N,N-dimethyltryptamine (DMT) and β-carboline alkaloids with monoamine oxidase-inhibiting properties that render DMT orally active. DMT interacts with serotonergic neurotransmission acting as a partial agonist at 5-HT_1A and 5-HT_2A/2C receptor sites. Given the role played by serotonin in the regulation of the sleep/wake cycle, we investigated the effects of daytime ayahuasca consumption in sleep parameters.

Measurements and results

Subjective sleep quality, polysomnography (PSG), and spectral analysis were assessed in a group of 22 healthy male volunteers after the administration of a placebo, an ayahuasca dose equivalent to 1 mg DMT kg^?1 body weight, and 20 mg d-amphetamine, a proaminergic drug, as a positive control. Results show that ayahuasca did not induce any subjectively perceived deterioration of sleep quality or PSG-measured disruptions of sleep initiation or maintenance, in contrast with d-amphetamine, which delayed sleep initiation, disrupted sleep maintenance, induced a predominance of ‘light’ vs ‘deep’ sleep and significantly impaired subjective sleep quality. PSG analysis also showed that similarly to d-amphetamine, ayahuasca inhibits rapid eye movement (REM) sleep, decreasing its duration, both in absolute values and as a percentage of total sleep time, and shows a trend increase in its onset latency. Spectral analysis showed that d-amphetamine and ayahuasca increased power in the high frequency range, mainly during stage 2. Remarkably, whereas slow-wave sleep (SWS) power in the first night cycle, an indicator of sleep pressure, was decreased by d-amphetamine, ayahuasca enhanced power in this frequency band.

Conclusions

Results show that daytime serotonergic psychedelic drug administration leads to measurable changes in PSG and sleep power spectrum and suggest an interaction between these drugs and brain circuits modulating REM and SWS.