Green Extracts and UPLC-TQS-MS/MS Profiling of Flavonoids from Mexican Oregano (Lippia graveolens) Using Natural Deep Eutectic Solvents/Ultrasound-Assisted and Supercritical Fluids.

Mexican oregano (Lippia graveolens) is an important source of bioactive compounds, such as flavonoids. These have presented different therapeutic properties, including antioxidant and anti-inflammatory; however, their functionality is related to the quantity and type of compounds, and these characteristics depend on the extraction method used. This study aimed to compare different extraction procedures to identify and quantify flavonoids from oregano (Lippia graveolens). Emerging and conventional technologies include maceration with methanol and water, and ultrasound-assisted extraction (UAE) using deep eutectic solvents (DES) such as choline chloride-ethylene glycol, choline chloride-glycerol, and choline chloride-lactic acid. Supercritical fluid extraction using CO2 as a solvent was also studied. Six different extracts were obtained and the total reducing capacity, total flavonoid content, and antioxidant capacity by ABTS•+, DPPH•, FRAP, and ORAC were evaluated. In addition, flavonoids were identified and quantified by UPLC-TQS-MS/MS. Results showed that UAE-DES had the best extraction effect and antioxidant capacity using colorimetric methods. However, maceration-methanol was superior in compound content, and highlighting naringenin and phloridzin were the major compounds. In addition, this extract was microencapsulated by spray drying, which provided a protection feature of their antioxidant potential. Oregano extracts are rich in flavonoids and the microcapsules present promising results for future research.

Three- and six-month efficacy and safety of phentermine in a Mexican obese population.

OBJECTIVE: Mexico has the second largest prevalence of obesity among adults worldwide, a condition especially affecting the low-income population. There is a pressing need to improve therapeutic options for weight loss. Phentermine is an old and low-cost agent given as an adjuvant therapy for obesity for a 12-week period, at an initial dose of 15 mg or 30 mg. However, there are no precise guidelines on the suitability of both the starting dose and the continuation of treatment for 6 months. The aim of this study was to evaluate the 3- and 6-month efficacy and safety of phentermine in obese Mexican patients to elucidate the aforementioned. MATERIALS AND METHODS: In this prospective, multi-center, open-label study, 932 obese adults received 15 mg or 30 mg phentermine once daily for 6 months. RESULTS: 30 mg phentermine was more effective than 15 mg phentermine in improving anthropometric variables in the 3-month follow-up, but not after completing the 6-month treatment period. Nearly 40% of 3-month non-responders reached a body weight reduction of at least 5% at 6 months. Conversely, ~ 65% and 25% of 3-month responders maintained or improved, respectively, their body weight reduction with long-term phentermine. Potential tolerance as weight regain was ~ 10% from 3 to 6 months. None of the doses increased cardiovascular risk, although mild-to-moderate adverse events were more frequent with 30 mg phentermine. CONCLUSION: 30 mg phentermine was more effective than 15 mg phentermine after 3 months, but not at 6 months of treatment. An important number of subjects could benefit following the therapy from 3 to 6 months.

Pharmacokinetic evaluation of two pirfenidone formulations in patients with idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonitis.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease characterized by an abnormal activation of lung epithelium and fibroblasts, as well as an excessive accumulation of extracellular matrix. Pirfenidone was introduced as a therapeutic option for IPF and chronic hypersensitive pneumonitis (cHP), a related disease. However, high plasma concentrations, which can be achieved even at recommended doses, are frequently associated with adverse events. Hence, an extended release formulation (XP), yielding lower peak plasma concentrations, has been developed. The aim of this study was to compare the pharmacokinetic properties of XP with those of the immediate (IR) formulation in patients with IPF or cHP. Data were analyzed using two pharmacokinetic approaches, conventional non compartmental analysis and a population analysis using the nonlinear mixed effects model technique. Results observed with both approaches were consistent. Drug exposure was similar with both formulations. However, XP exhibited less concentration fluctuations and a longer mean resident time. These results suggest that XP could be a feasible option to reduce adverse events associated to pirfenidone elevated concentrations. Nevertheless, efficacy studies are required to fully document the therapeutic potential of XP.

Rapid and sensitive determination of levofloxacin in microsamples of human plasma by high-performance liquid chromatography and its application in a pharmacokinetic study.

A rapid, sensitive and simple high-performance liquid chromatographic assay with ultraviolet detection was developed for the quantification of levofloxacin in microsamples (100 µL) of human plasma. The extraction procedure included a protein precipitation technique and a short chromatographic running time (4.5 min). Analyses were carried out on a Symmetry C18 column using a mixture of acetonitrile and 0.01 m potassium dihydrogen aqueous solution (pH 3.4; 14:86 v/v) as mobile phase. The method provided specificity and was linear (r ≥ 0.9992) over the concentration range 0.1-12 µg/mL. The average absolute recovery was 93.59%. The intra- and inter-day coefficients of variation were <6%. Additionally, levofloxacin was stable in all evaluations. The usefulness of this method was demonstrated in a pharmacokinetic study of levofloxacin in healthy adult volunteers. The present method offers two main advantages: (a) the use of microsamples reduces the total volume of blood to be collected from patients; and (b) it provides a good cost-effectiveness ratio. It is concluded that the method is rapid, simple, sensitive, economical and suitable for the determination of levofloxacin in human plasma using a small volume of sample.

Relationship between blood levels and the anti-hyperalgesic effect of ketoprofen in the rat.

The relationship between blood levels of ketoprofen and its anti-hyperalgesic effects was examined in rat using the carrageenan-evoked thermal hyperalgesia model. Female adult Wistar rats were injected with carrageenan into the plantar surface of the right hind paw. Immediately after, rats were administered with ketoprofen po and hindpaw withdrawal latency measured and micro-whole blood samples were obtained over six hours via a cannula inserted in the caudal artery. Ketoprofen levels were measured by HPLC. Ketoprofen concentration increased in a dose-dependent manner and was reflected in dose-dependent anti-hyperalgesic effect. The pharmacokinetic and pharmacodynamic parameters expressed as mean ± s.e.m. following administration of 1, 3.2, and 10 mg/kg ketoprofen were: Cmax 1.27 ± 0.08, 3.44 ± 0.20 and 11.76 ± 0.81 µg/mL; AUClast 4.16 ± 0.17, 11.63 ± 0.65 and 28.15 ± 1.32 µg h/mL; and Emax observed (AUCE ): 65.41 ± 7.79, 92.06 ± 6.46 and 98.42 ± 7.53%. A direct relationship between blood concentrations and the anti-hyperalgesic effect of ketoprofen followed a maximum effect model equation. The results indicate that the anti-hyperalgesic effect of ketoprofen in the carrageenan pain model can be predicted by the pharmacokinetic properties of ketoprofen.

Bioequivalence of two oral formulations of glyburide (glibenclamide).

Glyburide (glibenclamide) is a sulfonylurea derivative that is very widely used in the treatment of type II diabetes mellitus. Currently, there are several pharmaceutical formulations available in Mexico containing this drug, however, very limited information about their bioavailabilities is known. The purpose of this study was to compare the bioavailability of two formulations of glyburide used in Mexico, Daonil and Gen-Glybe. Twenty-four Mexican healthy volunteers participated in this study that was carried out following the recommendations of the Declaration of Helsinki. Subjects received a dose of 10 mg of glyburide (two tablets of 5 mg) under fasting conditions in two separate sessions using a randomized crossover design with a one week washout period. Plasma samples were obtained at selected times over 24 hours and stored frozen until analyzed. Pharmacokinetic parameters were obtained and values (mean +/- S.E.M.) were as follows: Cmax 273.32 +/- 25.84 versus 294.83 +/- 27.12 ng/ml; tmax 3.03 +/- 0.23 versus 2.87 +/- 0.24 h; and AUC24h 1396.66 +/- 130.18 versus 1557.99 +/- 140.24 ng x h/ml, for Daonil and Gen-Glybe tablets, respectively. Pharmacokinetic parameters were compared using analysis of variance for a cross-over design and ratios of AUC24h and Cmax and 90% confidence intervals were obtained. As confidence intervals did not exceed the limits of acceptance (80--125%) for Cmax and AUC24h, it is concluded that the formulations tested are bioequivalent.

Kainic acid does not modify the oral pharmacokinetics of carbamazepine in rats.

Carbamazepine (CBZ) is a widely used antiepileptic agent that frequently interacts with other drugs. Recently, it has been reported that CBZ is able to modify the disturbed sleep patterns induced by kainic acid in epileptics. As a pharmacokinetic-pharmacodynamic characterization in the same animal is not possible due to the stress induced by blood sampling, it is important to establish if kainic acid is able to modify the pharmacokinetics of CBZ. Two groups of seven rats were used in this study. Animals received an oral dose of 50 mg/kg of CBZ alone or with 10 mg/kg of kainic acid. Blood samples (0.1 mL) were obtained at selected times for 12 hr and stored frozen until analyzed by HPLC. Pharmacokinetic parameters were: Cmax 6.51 +/- 1.32 and 6.63 +/- 0.95 microg/mL, tmax 3.55 +/- 0.98 and 1.82 +/- 0.59 hr, AUC 66.61 +/- 28.16 and 73.54 +/- 15.35 microg x h/mL and t1/2 7.16 +/- 2.55 and 5.80 +/- 1.37 hr. No statistically significant difference was observed in any parameter indicating that kainic acid is not able to modify oral pharmacokinetics of CBZ and pharmacokinetic-pharmacodynamic studies may be carried out using two groups of animals, one for the pharmacodynamics and another for the pharmacokinetic evaluation.

Comparative bioavailability of two oral suspensions of naproxen sodium.

The bioavailability of naproxen sodium (CAS 26159-34-2) after administration of two oral suspensions, reference or test (Pactens), was compared in 24 healthy subjects. The volunteers received an oral dose of 250 mg (10 ml) in two separate sessions under fasting conditions according to a randomized cross-over design and blood samples were obtained at selected times for a period of 72 h. Plasma samples were analyzed by a high-performance liquid chromatographic method for determination of naproxen. Individual plasma concentration against time curves were constructed and pharmacokinetic parameters were obtained by non-compartmental techniques. The parameters obtained (mean +/- S.E.M.) were: C(max) 43.93 +/- 1.83 and 44.91 +/- 2.15 microg/ml, t(max) 2.38 +/- 0.21 and 1.83 < or = 0.19 h, AUC(72 h) 721.73 +/- 18.47 and 722.55 +/- 19.07 microg x h/ml for reference and test formulations, respectively. Maximal concentration, AUC(72 h) and AUC(infinity). were log transformed and compared by analysis of variance and ratios; in addition, 90% confidence limits were obtained. As confidence limits were included in the 80-125% range and the probability of exceeding these intervals was always lower than 0.05, it is concluded that the formulations tested are bioequivalent.

Further evidence for interethnic differences in the oral pharmacokinetics of meloxicam.

INTRODUCTION: Meloxicam is a nonsteroidal anti-inflammatory agent used widely in therapeutics. It is mainly metabolised by the cytochrome P450 enzyme (CYP) 2C9, with minor involvement of CYP3A4. So far, no information on the oral pharmacokinetics of this drug in adult Mexicans is available. The purpose of this study was to evaluate the oral pharmacokinetics of meloxicam in Mexican subjects. METHODS: Twenty-four healthy male subjects received an oral dose of meloxicam 7.5mg after fasting for 10 hours. Blood samples were drawn from a suitable forearm vein and plasma obtained. The meloxicam concentration was evaluated by a high-performance liquid chromatographic method and pharmacokinetic parameters were obtained by non-compartmental techniques. Pharmacokinetic parameters obtained in this study were compared with those reported under similar conditions in other populations in order to establish if interethnic differences in the pharmacokinetics of meloxicam exist. RESULTS: After administration of meloxicam, plasma levels increased to a maximum concentration (C(max)) of 0.702 +/- 0.027 (mean +/- SEM) microg/mL with a time to reach C(max) of 4.77 +/- 0.65h. The area under the plasma concentration versus time curve was 24.82 +/- 1.23 microg . h/mL. The clearance was about 4.8 mL/min and the volume of distribution 9.8 +/- 0.36L. When these parameters were compared with those reported in German and Indian subjects, a reduced clearance and volume of distribution were evident in Mexicans. However, clearance and volume of distribution obtained in this study were very similar to those reported in Chinese subjects. CONCLUSIONS: The oral pharmacokinetic parameters of meloxicam in healthy Mexican subjects compared with historic controls reported in other populations showed a reduced clearance and volume of distribution when compared with German subjects, whereas no differences between Mexican and Chinese subjects were observed. These results suggest that there are interethnic differences in the pharmacokinetics of meloxicam.