Characterization, Antioxidant and Antibacterial Potentials of Tamarindus indica L. Fruit Pulp Extract Loaded O/W Nanoemulsions

Abstract The main purposes of the current study were to formulate o/w nanoemulsions as a carrier for Tamarindus indica (tamarind) fruit pulp extract and to study the antioxidant and antibacterial potentials of nanoemulsions containing tamarind extract, focusing on cosmetic/hygiene applications. The o/w nanoemulsions using a mixture of Tween 80 and Span 80 as an emulsifier (5%w/w) were prepared by a high pressure homogenization process. Two concentrations of sweet tamarind extract, 3.3 and 6.6%w/w, based on the bioactivity study, were incorporated into the blank nanoemulsions to produce loaded nanoemulsions, F1-3.3TE (3.3%) and F1- 6.6TE (6.6%). As compared with the unloaded nanoemulsion, both tamarind extract loaded nanoemulsions showed reduced pH and significantly increased viscosity. Overall, the loaded nanoemulsions had droplet sizes of approximately 130 nm, zeta potential around -38 mV and polydispersity index (PDI) values less than 0.2. The nanoemulsion F1-3.3TE had better stability (e.g. significantly greater % tartaric acid content and lesser PDI value) than the nanoemulsion F1-6.6TE did. The antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay revealed that the nanoemulsions F1-3.3TE and F1-6.6TE had scavenging activities of 81.66 ± 0.77% and 63.80 ± 0.79%, respectively. However, antioxidant activity of these two formulations decreased under stress conditions (heating-cooling cycles). Such incidence did not occur for their antibacterial properties investigated by agar well diffusion technique. The two formulations exhibited inhibition zones of approximately 24.0-27.7 mm against Staphylococcus aureus and Staphylococcus epidermidis, responsible for malodor of underarms. The results suggest the potential of using sweet tamarind pulp extract loaded nanoemulsions as hygiene products.

The correlation of urinary levels of albuterol and its metabolites isomers following inhalation from a dry powder inhaler and in vitro particle size characterisation.

This study was designed to analyse the two enantiomers of abuterol in urine after the inhalation of a single dose of racemic albuterol from three dry powder inhalers by human volunteers. Urine samples were collected over 24h and analysed by HPLC-with fluorescence detection. Albuterol and its metabolites in urine could only have resulted from pulmonary absorption because gastrointestinal absorption was prevented. Unchanged albuterol and its conjugated metabolites were detected in the urine of healthy volunteers at much higher levels than in the urine of the asthmatics. Also, the amount of S-(+)-isomer excreted in urine was higher than that of the R-(--)-isomer. These differences did not arise as a consequence of either the formulation or the inter-conversion of two isomers in the urine. There is a relationship between the improvement of mid-expiratory flow (FEF(25-75)) and the amount of R-(--)-albuterol remaining to be excreted. The elimination rate constants of the parent drug in healthy volunteers of both R-(--)- and S-(+)-isomers were higher than those of the respective conjugated metabolites. The mean S/R ratio of the parent drug was about unity initially and increased to about 1.5 in the urine collected between 12 and 24h. The values of S/R ratio of the conjugated metabolites in the healthy volunteers were in the range 1.2-2.4, with the value increasing over the time of collection before reaching a plateau. This also occurred with the asthmatics, but the ratios were higher, in the range of 2.0-4.5. In summary, the urinary level of albuterol following in vivo inhalation was found to correlate with in vitro deposition data from the dry powder inhaler.

The study of in vitro-in vivo correlation: pharmacokinetics and pharmacodynamics of albuterol dry powder inhalers.

The pharmacokinetics and pharmacodynamics of albuterol were studied following inhalation of three different in-house dry powder formulations in healthy volunteers and in asthmatics. Albuterol in plasma was measured using liquid chromatography-mass spectrometry (LC-MS). The plasma concentration time profiles were fitted to a two-compartment model with first-order kinetics. Oral absorption of swallowed albuterol was eliminated by oral dosing of 560 mg activated charcoal 1 h prior to albuterol aerosol administration. The peak concentration was reached within 15-20 min. Mean peak concentrations in healthy volunteers (six males and six females) were 1.74 +/- 0.34, 2.01 +/- 0.35, and 2.59 +/- 0.27 ng/mL following inhalation of formulations with fine particle doses (FPDs) of 100, 120, and 160 microg of albuterol, respectively. The corresponding peak plasma concentrations of 1.23 +/- 0.29, 1.37 +/- 0.13, and 1.53 +/- 0.11 ng/mL were obtained when asthmatics (six males and six females) were dosed with the same three formulations. The FPD of each formulation correlated well with the area under the curve of plasma concentration-time (AUC(0-8)) profile. Plasma potassium did not show any significant change over a period of 8 h. The forced vital capacity (FVC), the force expiratory volume in 1 s (FEV(1)), and mid expiratory flow (FEF(25-75)) did not correlate with FPD for the three different formulations.