Influence of Sodium CMC and HPMC on the Physical Characteristics of Ofloxacin Floating Matrix Tablets.

Aims: Sustained release floating drug delivery systems or gastro retentive drug delivery systems enables prolonged and continuous input of drug to the upper part of gastrointestinal tract and improves the bioavailability of medication. A new strategy is proposed for the development of floating drug delivery systems of Fluoroquinolone antibiotic, Ofloxacin, a potent moiety for treating UTI’s. Methodology: Various rate retarding polymers like HPMC K4M, HPMC 5 cps and swelling agent as Sodium carboxymethyl cellulose in different proportions were tried and optimized to achieve the drug release for 8 hr. All the formulations were evaluated for floating properties, swelling characteristics and in vitro drug release studies. The in vitro drug release was found to be matrix diffusion controlled. Optimized formulation was subjected to intermediate stability studies at various combinations of temperature and humidity according to ICH guidelines. Results: Lower hardness and higher thickness decreased the floating lag time and increased floating duration. Based on drug release studies, formulation F5 was optimized as the best formulation because it released about 89.27 ±2.6% of the drug at the end of 8 hr while other formulations released not more than 80 ±2.2%. This may be due to high NaCMC content which might have caused excessive channeling, thereby giving a burst release. Optimized formulation F5 was found to follow zero order kinetics with r2 value of 0.993. Conclusion: In conclusion we have been proved that HPMC K4M has retarded the drug release, while HPMC 5cps has facilitated high buoyancy time for the tablets. NaCMC has influenced as channeling agent. Formulation F5 was optimized for its long buoyancy time, prolonged duration of drug release, zero order and diffusion controlled drug release kinetics which can assure 100% bioavailability.

Infecciones respiratorias adquiridas en la comunidad: relación con agentes etiológicos y antibióticos con especial atención a levofloxacino / Community acquired respiratory infections: relationship to causal agents and antibiotics with special focus on levofloxacine

Los microorganismos involucrados en infecciones del tracto respiratorio alto y bajo, incluyen tanto bacterias "típicas" tales como Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes y Moraxella catarrhalis, y bacterias "atípicas", como Mycoplasma pneumoniae, Chlamydia pneumoniae y Legionella pneumophila. El primer grupo ha adquirido resistencia, tanto a nivel mundial como nacional, a los antimicrobianos de uso habitual en el tratamiento de estas infecciones, como son penicilina, ampicilina, cotrimoxazol, cefuroxima y cefotaxima, entre otros. Debido a lo anterior, se han desarrollado nuevas moléculas siendo una de ellas levofloxacino, una nueva quinolona, levoisómero de D-L racemato de ofloxacino. Este compuesto posee un amplio espectro "in vitro" contra bacteria Gram positivas, incluyendo S. pneumoniae resistente a penicilina, bacterias Gram negativas, bacterias atípicas y algunas bacterias anaerobias. Su biodisponibilidad en forma oral es de 100 por ciento. Es metabolizada en el hígado y su excreción a nivel renal es de 80 por ciento. En estudios clínicos levofloxacino ha demostrado eficacia y seguridad incluso con erradicación microbiológica demostrada en infecciones respiratorias adquiridas en la comunidad, lo que la convierte en una alternativa real de tratamiento