Enhancement of oral bioavailability of an HIV-attachment inhibitor by nanosizing and amorphous formulation approaches

BMS-488043 is an HIV-attachment inhibitor that exhibited suboptimal oral bioavailability upon using conventional dosage forms prepared utilizing micronized crystalline drug substance. BMS-488043 is classified as a Biopharmaceutics Classification System (BCS) Class-II compound with a poor aqueous solubility of 0.04 mg/mL and an acceptable permeability of 178 nm/s in the Caco2 cell-line model. Two strategies were evaluated to potentially enhance the oral bioavailability of BMS-488043. The first strategy targeted particle size reduction through nanosizing the crystalline drug substance. The second strategy aimed at altering the drug's physical form by producing an amorphous drug. Both strategies provided an enhancement in oral bioavailability in dogs as compared to a conventional formulation containing the micronized crystalline drug substance. BMS-488043 oral bioavailability enhancement was 5- and 9-folds for nanosizing and amorphous formulation approaches, respectively. The stability of the amorphous coprecipitated drug prepared at different compositions of BMS-488043/polyvinylpyrrolidone (PVP) was evaluated upon exposure to stressed stability conditions of temperature and humidity. The drastic effect of exposure to humidity on conversion of the amorphous drug to crystalline form was observed. Additionally, the dissolution behavior of coprecipitated drug was evaluated under discriminatory conditions of different pH values to optimize the BMS-488043/PVP composition and produce a stabilized, amorphous BMS-488043/PVP (40/60, w/w) spray-dried intermediate (SDI), which was formulated into an oral dosage form for further development and evaluation.     

Effect of Rifampin on the Pharmacokinetics of Apixaban,an Oral Direct Inhibitor of Factor Xa

Objective

Apixaban is a substrate of cytochrome P450 3A4 (CYP3A4) and P-glycoprotein. The effects of rifampin, a strong inducer of CYP3A4 and P-glycoprotein, on the pharmacokinetics of oral and intravenous apixaban were evaluated in an open-label, randomized, sequential crossover study.

Methods

Twenty healthy participants received single doses of apixaban 5 mg intravenously on day 1 and 10 mg orally on day 3, followed by rifampin 600 mg once daily on days 5–15. Finally, participants received single doses of apixaban 5 mg intravenously and 10 mg orally separately on days 12 and 14 in one of two randomized sequences.

Results

Apixaban, given intravenously and orally, was safe and well tolerated when administered in the presence and absence of rifampin. Apixaban absolute oral bioavailability was 49 % when administered alone and 39 % following induction by rifampin. Rifampin reduced apixaban area under the plasma concentration–time curve from time zero to infinity (AUC_∞) by 39 % after intravenous administration and by 54 % after oral administration. Rifampin induction increased mean clearance by 1.6-fold for intravenous apixaban and mean apparent clearance by 2.1-fold for oral apixaban, indicating rifampin affected both pre-systemic and systemic apixaban elimination pathways.

Conclusion

Co-administration of apixaban with rifampin reduced apixaban exposure via both decreased bioavailability and increased systemic clearance.

     

Molecular evidence and functional expression of P-glycoprotein (MDR1) in human and rabbit cornea and corneal epithelial cell lines

PURPOSE: Efflux pumps such as P-glycoprotein (P-gp; MDR1) are believed to be a major barrier to drug delivery. The purpose of this work was to determine whether cornea and corneal epithelial cells expresses the functionally active P-gp efflux pump. METHOD: Cultured rabbit primary corneal epithelial cells (rPCECs) and a corneal cell line (Statens Seruminstitut rabbit cornea [SIRC] cells) were selected as the model. Rhodamine-123 (Rho-123), a P-gp substrate, was used as a P-gp probe. To confirm gene expression, RT-PCR was performed with appropriate pairs of primers for rabbit and human MDR1. Subcloning, sequencing, and protein sequence determination were performed to confirm P-gp. RESULTS: Permeability of [(3)H] cyclosporin A (CsA) across SIRC cells was found at 1.74 x 10(-6) cm/s in the apical-to-basolateral and 5.1 x 10(-6) cm/s in the basolateral-to-apical directions. Uptake of Rho-123 across both SIRC cells and rPCECs was time and temperature dependent. Rho-123 uptake in SIRC cells was 14.4 picomoles/mg protein and in the presence of CsA (10 micro M) was 70.8 picomoles/mg protein at 3 hours. Uptake in rPCECs was the highest at 3 hours. Western blot analysis indicated a 170-kDa band confirming the presence of P-gp. Human cornea was also checked for the presence of P-gp. RT-PCR data indicated one single band, which was subcloned and sequenced to confirm the presence of P-gp. The protein sequence deduced from the fragment product indicated more than 89% homology with human MDR1. CONCLUSIONS: Functional and molecular characterization showed the existence of P-gp in human cornea, rabbit cornea, and a rabbit corneal cell line. This knowledge of the existence of P-gp will help in development of better ocular drug delivery strategies.     

A new polyene with antimycotic activity produced by a streptomycete from the rhizosphere of an indoor plant

From the rhizosphere of a potted Sanseviera trifasciata, a Streptomyces griseus strain with a broad antifungal activity was isolated; in the soil of this plant, a sole hyphomycete, Aspergillus niger, was found in pure culture at 37 degrees C. This streptomycete produced a polyene, belonging to the pentaene group. It was found to inhibit, in vitro, the growth of all the 123 strains tested; the strains belonging to the genera Aspergillus, Cryptococcus, Candida, Trichophyton, Epidermophyton, Microsporum, Penicillium and Mucor. An antimycotic activity of this substance was also found to be present after i.v. administration to white mice infected with Cr. neoformans. Toxicological tests will have to show if this polyene could be considered as a candidate antimycotic drug. The soil of potted indoor plants is discussed as a possible habitat for streptomycetes with defined antifungal activities.     

Candida albicans-Serumpräzipitine bei Blutspenderr Auffällige serologische und kulturelle Candida albicans-Befunde bei Alkoholikern

Für serologische Untersuchungen dienten Seren von freiwilligen Blutspendern als Negativkontrolle. Bei 5 von 105 solcher Spender gelang der Nachweis präzipitierender Antikörper (AK) mit Hilfe 2 verschiedener Candida albicans-Antigene, und zwar dem sogenannten Proteolyse-Kulturfiltrat-Antigen und dem herkömmlichen SABOURAUD Dextrose-Kulturfiltrat-Antigen. Die anschließend durchgeführte Untersuchung von Rachenabstrich, Sputum und Stuhl auf C. albicans verlief ebenfalls positiv. Die isolierten C. albicans-Stämme zeigten in Serumalbumin-Agar stärkste Proteolyseaktivität. Bei 4 dieser 5 Blutspender handelte es sich um schwere Alkoholiker. Diese vorläufigen Befunde werden im Hinblick auf die Pathogenese der Candida-Mykosen und die Gesundheitskontrolle des Blutspenders diskutiert.

Summary

Sera from voluntary blood donors served as negative controls in serological studies. In 5 out of 105 donors, precipitating antibody to 2 different C. albicans antigens (so called proteolyzed culture filtrate antigen and conventional S abouraud dextrose culture filtrate antigen) could be demonstrated. Subsequent examination of throat swabs, sputum and stools for yeastlike fungi was also positive. In serum-albumin agar, the C. albicans strains isolated were exhibiting very high proteolytic activity. 4 of the 5 donors involved proved to be severely addicted to alcohol and suffering from latent disease. These preliminary findings are discussed in respect of the pathogenesis of Candida mycoses and health control of blood donors.     

Phase I–IIa study of BMS-690514, an EGFR,HER-2 and -4 and VEGFR-1 to -3 oral tyrosine kinase inhibitor,in patients with advanced or metastatic solid tumours

PurposeBMS-690514 is a potent, reversible oral inhibitor of epidermal growth factor receptor (EGFR/HER-1), HER-2 and -4, and vascular endothelial growth factor receptors (VEGFRs)-1 to -3 offering targeted inhibition of tumour growth and vascularisation in a single agent. This phase I–IIa study was designed to identify the maximum tolerated dose (MTD) and assess safety, antitumour activity, pharmacokinetics and pharmacodynamics of BMS-690514.Patients and methodsIn phase I, patients with advanced solid tumours received escalating doses of once-daily BMS-690514. In phase IIa, erlotinib-naïve (cohort A) or erlotinib-resistant (cohort B) patients with advanced non-small-cell lung cancer (NSCLC) received BMS-690514 once-daily at the MTD.ResultsIn phase I (n = 28), the MTD was determined to be 200 mg daily. BMS-690514 was rapidly absorbed and highly metabolised after repeated oral administration with minimum drug accumulation. In phase IIa (n = 62), the most frequent treatment-related adverse events were diarrhoea and acneiform rash. Adverse events that led to >1 discontinuation were diarrhoea (n = 4; 4%) and rash (n = 2; 2%). Disease control (?4 months) and objective response rates, respectively, were 43.3% and 3.3% (cohort A) and 22.6% and 3.2% (cohort B). Six of 21 (29%) NSCLC patients with wild-type EGFR achieved disease control versus seven of 10 (70%) patients with EGFR mutations (including T790M). At MTD, BMS-690514 modulated pharmacodynamic biomarkers associated with inhibition of VEGFR- and EGFR-signalling pathways.ConclusionThis phase I–IIa study suggests that BMS-690514 has manageable safety profile and antitumour activity in patients with NSCLC at 200 mg/d, including those with EGFR mutations conferring resistance to erlotinib.