Formulation of a neutral solution of ciprofloxacin upon complexation with aluminum

Systemic exposure, tissue distribution, and disease evolution of a high solubility ciprofloxacin-aluminum complex in a murine model of septicemia induced by salmonella enterica serotype Enteritidis

A new pharmaceutical derivative obtained by stoichiometric complexation of ciprofloxacin (CIP) with aluminum (CIP-complex) has been investigated and reported in this study. Such product has high solubility in the gastrointestinal pH range and was successful in the development of optimized formulations while maintaining its antimicrobial potency. The systemic exposure, tissue distribution, and the disease evolution after given CIP-complex were assessed. The systemic exposure and distribution in intestines, lungs, and kidneys after a single intragastric administration of CIP-complex and CIP given alone, used as reference, were performed in Balb-C mice at a dose of 5 mg CIP/kg. For the assessment of the disease evolution assay, mice were infected with a virulent strain of Salmonella enterica serotype Enteritidis and treated intragastrically once or twice daily during 5 consecutive days with solutions of CIP-complex or the reference. Clinical follow up and survival was measured during 15 days post inoculation and health state was scored during this period from 0 to 5. CIP-complex showed a 32% increase in C(max), an earlier T(max), and a smaller AUC(0-12) than the reference. Maximum tissue concentrations (0.5-1 h) were significantly higher in CIP-complex (447% in intestine, 93% in kidney, and 44% in lungs). In the infection model used in this study, survival in CIP-complex versus CIP groups was 40% versus 20% (twice-daily administration) and 30% versus 0% (once-daily administration). Health state of the survivors of CIP-complex group (5/5) was higher than CIP group (3/5). The greater effectiveness of CIP-complex is attributed to the higher levels of CIP in the intestine. Our results supported the fact that CIP-complex is a promising candidate to develop dose-efficient formulations of CIP for oral administration.

Mass spectrometic study of speciation in aluminium-fluoroquinolone solutions

Fluoroquinolones (FQLs) are synthetic antibacterial agents containing a 4-oxo-1,4-dihydroquinoline skeleton. When concomintantly administered with other drugs which may contain metal ions, particularly Al(3+) (antacids, phosphate binders, vaccines etc) they may form metal-drug complexes. Pharmacokinetic studies showed that aluminium-quinolone interactions lead to reduced bio- availability and altered activity of the drug with possible development of the toxic effects of aluminum ion. Reliable speciation in Al(3+) - quinolone systems at micromolar concentration level is needed to better understand pharmaco- and toxicokinetics of the FQLs in the presence of Al. In this work, the speciation in solutions containing Al(3+) and FQL family members (fleroxacin, moxifloxacin and ciprofloxacin) was studied by electrospray mass spectrometry (ESI-MS), ESI-MS/MS, and laser desorption ionization (LDI) MS. The dominating species identified in all the three Al(3+)-FQL solutions, at ca 30-50 µmol L(-1) total Al concentration and 2:1 to 1:3 metal-to-ligand ratio in the pH range 3.0- 6.0, were the ions related to the complexes AlL(2+), AlL(2)(+) and AlL(3)(0) (L = ligand in the monodeprotonated form). Mixed protonated and hydroxo complexes were also formed at lower and higher pH values respectively and, as expected, dimeric and polymeric species were not observed in ESI spectra. LDI measurements confirmed the existence of the mononuclear complexes found by ESI, and indicated the formation of polymeric species. The ion [2Al(3+) +5(-)](+) was identified with all three FQLs. This ionic species most probably arises from Al(2)L(2) by clustering with free ligand anions. Comparison of literature potentiometric data with mass spectral data indicated good agreement between speciation schemes. The obtained results suggest the presence of strong interaction between FQLs and Al(3+) which may be important in affecting absorption of these drugs in the gastrointestinal tract.

Biowaiver monographs for immediate release solid oral dosage forms: ciprofloxacin hydrochloride

Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of new multisource and reformulated immediate release (IR) solid oral dosage forms containing ciprofloxacin hydrochloride as the only active pharmaceutical ingredient (API) are reviewed. Ciprofloxacin hydrochloride's solubility and permeability, its therapeutic use and index, pharmacokinetics, excipient interactions and reported BE/bioavailability (BA) problems were taken into consideration. Solubility and BA data indicate that ciprofloxacin hydrochloride is a BCS Class IV drug. Therefore, a biowaiver based approval of ciprofloxacin hydrochloride containing IR solid oral dosage forms cannot be recommended for either new multisource drug products or for major scale-up and postapproval changes (variations) to existing drug products.

Ciprofloxacin surf-plexes in sub-micron emulsions: a novel approach to improve payload efficiency and antimicrobial efficacy

The aim of this study was to investigate antimicrobial efficacy and pharmacokinetic profile of ciprofloxacin (CFn) loaded oil-in-water (o/w) submicron emulsion (SE-CFn). This study emphasized on development of hydrophobic ion-pair complexes of CFn with sodium deoxycholate (SDC) [CFn-SDC], which was incorporated in the core of SE (SE-CFn-SDC). SE-CFn-SDC was characterized for globulet size (278±12 nm), zeta potential (-25.3±1 mV), viscosity (2.6±0.3 cP), transmission electron microscopy (TEM), drug entrapment and for in vitro release profile. The entrapment efficiency (EE) was significantly improved (≥80%; p≤0.05) on ion-pairing while it was merely 27.2±3.1% for free CFn. The cytotoxicity studies of formulations on J774 macrophage cells showed that more than 90±3% of cells were viable, even at high concentration (100 μg/ml). SE-CFn-SDC was further modified with cationic inducer chitosan (SE-CH-CFn-SDC), which showed almost twofold and fourfold enhancement in antimicrobial efficacy as compared to SE-CFn-SDC and SE-CFn, respectively when tested in vitro against E. coli, S. aureus, and P. aeruginosa. When tested in male Balb/c mice, the AUC(0-24h) of SE-CH-CFn-SDC (23.27±2.8 h μg/ml) was found to be 1.7-fold and 5-fold higher as compared to SE-CFn-SDC (13.17±0.88 h μg/ml) and CFn solution (4.70±0.77 h μg/ml), respectively. The study demonstrates that surfactant based ionic complex formation incorporated in surface modified submicron emulsion is a promising approach to improve payload efficiency of poorly water soluble drugs with improved antimicrobial efficacy and pharmacokinetic profile.

NMR and IR characterization of the aluminium complexes of norfloxacin and ciprofloxacin fluoroquinolones

A set of new aluminium complexes of norfloxacin (NOR) and ciprofloxacin (CIP) that show an improvement in their pharmaceutical properties were studied using solution and solid-state nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The complexes synthesized with two different methods were compared. One of these methods will allow formulation of the compounds at production scale. High-resolution (13)C spectra were obtained with the cross-polarization and magic angle spinning (CP-MAS) experiment. These spectra were assigned by comparing them with the solution data of the pure drug and by using a quaternary carbon edition technique. The carbon relaxation times in the rotating frame, T(1rhoC), were measured for all the complexes. A two-exponential decay evidences that the complexes are nonhomogeneous. The short T(1rhoC) values are in the range 320-1100 micros and the long values in the range 1.8-7 ms. (27)Al MAS NMR spectra revealed an octahedral coordination between the aluminium ion and oxygens of the pure drug, supporting a 3:1 ligand:metal stoichiometry in both CIP and NOR complexes. The stretching and deformation modes of carboxylic acid and carboxylate and keto groups were analyzed by IR. This technique shows that the same modes are present in the aluminium complexes obtained by the two methods and that the coordination of the fluoroquinolone to aluminium occurs through the 4-keto and 3-carboxylic groups.

Polyamidoamine (PAMAM) dendrimers as biocompatible carriers of quinolone antimicrobials: An in vitro study

Quinolones, an expanding class of clinically established potent antibiotics, is not freely soluble in water which prevents the design of liquid dosage forms and restricts their use in topical applications. In the present study we investigated the potential of polyamidoamine (PAMAM) dendrimers as drug carriers of quinolones (nadifloxacin and prulifloxacin) by aqueous solubility and antibacterial activity studies. Results showed that the aqueous solubility of nadifloxacin and prulifloxacin was significantly increased by PAMAM dendrimers. Microbiology studies showed that nadifloxacin and prulifloxacin still exhibit their strong antimicrobial activities in the presence of dendrimers. These studies indicated that PAMAM dendrimers might be considered as biocompatible carriers of quinolones under suitable conditions.

Release kinetics and up-take studies of model fluoroquinolones from carbomer hydrogels

Hydrogels of carbomer (C) loaded with model slightly soluble fluoroquinolone antimicrobials (AMFQ), norfloxacin (I) and ciprofloxacin (II) were prepared to evaluate their physical and delivery properties. Thus, dispersions of 0.25% of C loaded with 0.2-0.5 mol equivalents of AMFQ and 0.2-0.5 mol equivalents of NaOH yielded pseudoplastic hydrogels with a high negative electrokinetic potential and good physical stability. Concentration of AMFQ in the hydrogels was, respectively, 7.2 and 34 times higher than I and II aqueous solubility, indicating a high increase in aqueous compatibility. Release of AMFQ in bicompartimetal Franz type cell occurred by zero order kinetics. Delivery rate constant (k(0)) was five to six times higher as water was replaced by NaCl solution as receptor medium. Release in agar dishes revealed that, even under high dilution, delivery remains modulated. Intestinal absorption flux coefficient in everted rat intestine (k(U)) were measured with reference solutions (RS) of free AMFQ (k(U)(RS) II>k(U)(RS) I) and with hydrogels (H), in which the pattern was reversed since k(U)(H) I>k(U)(H) II. As expected k(U)(H) II was 0.55 times lower than k(U)(RS) II. However, k(U)(H) I was 1.37 times higher than its reference, which cannot be explained from the analysis of k(0) and k(U)(RS) alone. Hydrogels C-AMFQ behave as a reservoir of AMFQ able to deliver it at a constant rate and would be useful to design topical and or systemic dosage forms.