Solvent evaporation

Nimodipine, a poorly soluble drug, was considered to be fit for solid dispersions to improve its solubility and bioavailability. Our study intended to prepare Nimodipine solid dispersions by solvent evaporation method using various novel polymers. Solubility and dissolution studies indicate that Kolliwax RH 40 and SLS is the most suitable polymer. The solubility studies were corresponded with dissolution data and the formulation SD15 was found to be having highest drug release of about 98.96±5.15% in about 90 minutes. In-vitro release data from several formulations containing XRD and SEM studies indicate no crystallinity in the optimized formulation SD15. FTIR studies suggested good drug excipient compatibility between all components of prepared formulation. From in vivo bioavailability studies, Cmax of the optimized formulation SD15 was 4.34±0.08ng /ml, was significantly higher as compared to pure drug suspension, i.e., 2.78±0.35ng/ml. Tmax of optimized formulation was decreased significantly when compared with pure drug (1.00±0.05hr, 2.00±0.01hr), AUC0-? and AUC0-t for optimized solid dispersion formulation was significantly higher (p<0.05) as compared to pure drug suspension. The present study demonstrated that formulation of Nimodipine solid dispersion by solvent evaporation technique is a highly effective strategy for enhancing the bioavailability of poorly water soluble Nimodipine.

  Controlled release of drug from micrometrics is of the particular therapeutic importance for oral medication in patients. There are various approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion. One such approach is using microparticles as carriers for drugs. The idea behind a controlled drug delivery system is to incorporate the drug within a polymeric carrier that controls the release rate of the drug. Various processes, such as diffusion, erosion, and/or swelling can be involved in the control of the overall drug release rate, resulting in a broad spectrum of possible release profiles. Solvent evaporation and extraction based processes are required for the preparation of microparticles. The microparticles show lower percentage compressibility but good flowability, hence a capsule dosage form was thought to be suitable. The microparticle formulation was optimized with respect to size distribution and increased drug loading. The microparticles was physically evaluated with respect to bulk density, angle of repose, and percent compressibility, drug content, swelling study and in-vitro release study. Polyvinyl alcohol is proposed as a polymer to be used for the present controlled release formulation development. The intent of the paper is to highlight the potential of microparticles as a vital dosage form in novel drug delivery.   Key words: Microparticles, Sustain release, Solvent evaporation, Release profile, Therapeutic range, Compressibility