Biomedical subjects

Buchi N Nalluri

Publications and source records attributed to Buchi N Nalluri.

4 recordsLinked to original sources

PubMed2005

Transdermal delivery of naltrexone and its active metabolite 6-beta-naltrexol in human skin in vitro and guinea pigs in vivo.

The aim of the present study was to evaluate the transdermal delivery of 6-beta-naltrexol (NTXOL), the active metabolite of naltrexone (NTX), across human skin and guinea pig skin in vitro and in hairless guinea pigs in vivo. NTXOL may be responsible for much of NTX's pharmacologic activity. In vitro diffusion studies on NTXOL were compared with similar studies on NTX using a formulation of propylene glycol and buffer in a flow-through diffusion cell system. In vivo guinea pig studies were carried out involving topical application of both drugs in patches containing identical formulations. The in vitro flux of NTX was about 2.3- and 5.6-fold higher than for NTXOL across guinea pig skin and human skin, respectively. NTXOL lag times were longer than NTX in both skin types. In vivo studies in guinea pigs showed that the steady-state plasma level of NTX was twofold greater than NTXOL, which correlated well with in vitro data. The results of the present study indicated that substantial levels of NTX and NTXOL could be delivered via the transdermal route, although the plasma levels of NTXOL were significantly less than NTX. Further transdermal formulation development will be investigated for permeation enhancement.

Administration, Cutaneous↗

PubMed2005

In vitro release studies on matrix type transdermal drug delivery systems of naltrexone and its acetyl prodrug.

Matrix type acrylic adhesive transdermal patches of naltrexone (NTX) and its 3-O-acetyl ester prodrug were prepared and evaluated for drug content, thickness, and in vitro release characteristics. Among the four DURO-TAK adhesive polymers (87-2516, 87-2054, 87-2501, and 87-2582) tested, 87-2516 proved to be the most suitable and compatible polymer for the transdermal delivery of NTX from NTX and prodrug patches. A linear relationship was observed for release flux (F) and cumulative amount (Mt) values versus 1%, 2%, and 3% drug loading at equimolar levels. The release of NTX from the patches showed a good correlation (R2>0.99) for Mt vs. square root t profiles, indicating that a Higuchian matrix diffusion mechanism of drug release from the transdermal adhesive patches was obtained. Overall, the amounts of NTX released from the prodrug patches were significantly higher than from the NTX patches, at all three drug loading levels.

Acetylation↗

PubMed2004

Development and validation of a liquid chromatography-mass spectrometry method for the quantitation of naltrexone and 6beta-naltrexol in guinea pig plasma.

A quantitative liquid chromatographic-electrospray ionization mass spectrometry method for the determination of naltrexone and 6beta-naltrexol in guinea pig plasma has been developed and validated using naloxone as an internal standard. A single step precipitation-extraction technique was carried out to extract the plasma samples using acetonitrile:ethyl acetate (1:1, v/v). The chromatographic separation was performed on a C(18) column using a mobile phase consisting of 35:65 (v/v) acetonitrile:2 mM ammonium acetate with 0.01 mM ammonium citrate at a flow rate of 0.25 mL/min. The analyte was detected after positive electrospray ionization using selected ion monitoring (SIM) mode. The mean recoveries for naltrexone, naltrexol, and naloxone were 91.7, 89.3, and 99.0%, respectively. The lower limit of quantification (LLOQ) for naltrexone and 6beta-naltrexol was 1.25 ng/mL, and the limit of detection (LOD) was 0.75 ng/mL. The method was applied to a pharmacokinetic study in order to assess the drug disposition of naltrexone in guinea pigs.

Animals↗

PubMed2003

Physicochemical characterization and dissolution properties of nimesulide-cyclodextrin binary systems.

The objective of this work is physicochemical characterization of nimesulide-cyclodextrin binary systems both in solution and solid state and to improve the dissolution properties of nimesulide (N) via complexation with alpha-, beta, and gamma-cyclodextrins (CDs). Detection of inclusion complexation was done in solution by means of phase solubility analysis, mass spectrometry, and 1H nuclear magnetic resonance (1H-NMR) spectroscopic studies, and in solid state using differential scanning calorimetry (DSC), powder x-ray diffractometry (X-RD), scanning electron microscopy (SEM), and in vitro dissolution studies. Phase solubility, mass spectrometry and 1H-NMR studies in solution revealed 1:1 M complexation of N with all CDs. A true inclusion of N with beta-CD at 1:2 M in solid state was confirmed by DSC, powder X-RD and SEM studies. Dissolution properties of N-CD binary systems were superior when compared to pure N.

Anti-Inflammatory Agents, Non-Steroidal↗