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Today, the world of science is constantly challenged with new genomics, which in turn is responsible for new disease-causing targets. Hence, there is a need for developing drugs acting against such targets. Computational methods are proving to be a mainstay in the drug discovery process, mainly through virtual screening. This review discusses about the recent advancements in structure-based drug design with reference to Virtual Screening along with its procedures from ligand preparation and protein preparation, docking, scoring function, databases, and virtual (VS) algorithms. Application of Structure-based VS in combination with other virtual screening techniques has also been highlighted in this review. [ABSTRACT FROM AUTHOR]

Context: The mucoadhesive gel formulations are helpful to prolong the residence time at the nasal absorption site and thereby facilitate the uptake of drug. Sumatriptan succinate has oral bioavailability of 15% and undergoes hepatic metabolism, hence it is suitable for nasal administration. Objective: The objective of the investigation was to develop a mucoadhesive in situ gel to improve the bioavailability of the sumatriptan succinate. Materials and methods: Deacetylated gellan gum was used as gelling agent. In situ gel was formulated by ion activation mechanism in simulated nasal fluid. A 32 factorial design was found suitable to optimize batch. In vivo study was carried out in Spraugue-Dawley rats, and drug was estimated in plasma by UPLC-MS. Result: The optimized batch showed drug release of 98.57% within 5 h followed by Peppas model of drug release. Ex vivo studies on sheep nasal mucosa showed 93.33% within 5 h. In histopathological study, optimized batch was found to be safe and stable in accelerated stability study for three months. Optimized formulation, F7 has shown absolute bioavailability, which was found to be 164.70%. Drug targeting index for brain tissues was found to be 1.866. Discussion: Concentration of the gelling polymer was compromised for satisfactory gel strength and an acceptable viscosity. The release depended on viscosity of formulation. Drug targeting index indicates sumatriptan can reach to brain via olfactory pathway. Conclusion: In situ gel proved to be suitable for administration of sumatriptan succinate through nasal route. The ease of administration coupled with less frequent administration enhances patient compliance. [ABSTRACT FROM AUTHOR]

Osmotically controlled oral drug delivery system utilizes osmotic pressure for controlled delivery of active agents. This drug delivery system overcomes the numerous problems associated with matrix and reservoir types of controlled drug delivery system. Osmotic system achieves zero order drug release which is independent of pH of gastrointestinal tract, presence or absence of food, agitation, hydrodynamic conditions and concentration of drug. Sandwiched Osmotic Tablet System (SOTS) formulation consists of two layers of drug (theophylline) sandwitching a push layer (polyethylene oxide 301 or croscarmellose sodium) coated with cellulose acetate as semipermeable membrane and two delivery orifices drilled on both sides of tablet. This system is suitable for drugs causing local irritation. A successful attempt of formulation development of SOTS of theophylline was made. Hydroxy propyl methyl cellulose K100M was incorporated in drug layer to determine its effect on drug release. All the formulations were evaluated for hardness, friability, drug content and in vitro drug release. All the formulations showed zero order kinetics of drug release except F2 shows Korsemeyer-Peppas and F3 shows Hixon-Crowell kinetics of drug release. The formulation F4 showed 98.02% drug release within 24 hrs and was further subjected to accelerated stability testing for 3 months. The formulation F4 was found to be stable with no significant change in the drug content and drug release. [ABSTRACT FROM AUTHOR]

The dry powder inhaler formulation of Clindamycin HCl microspheres was prepared for treatment of respiratory diseases. Chitosan was used as the polymer due to its compatibility with respiratory tract. The chitosan microspheres of Clindamycin HCl were prepared by spray drying method. The microspheres formed were blended with a carrier (spray dried lactose Inhalac®250). The microspheres showed the particle size in the range of 1.7-1.8 μm & spherical shape required for dpi formulation. 74% - 94% of drug was released at 120 minutes. The blend of microspheres with the carrier also showed good flow properties. Overall, spray drying is less complicated technique for the preparation of respirable microspheres. [ABSTRACT FROM AUTHOR]

Solution layering technique was used to prepare pellets of Salbutamol Sulphate. A multiparticulate system was prepared with pH independent and pH dependent coatings, and evaluated as pulsatile drug delivery system. Salbutamol sulphate release was studied from methacrylate coated pellets from non pareils. Morphology was studied using Scanning Electron Microscopy for the characterization of prepared pellets. Combination of Eudragit RSPO (pH independent) and Eudragit L100 (pH dependent) was used for coating of the pellets. Different concentrations of this polymeric combination were loaded on to the drug-loaded pellets. The aim of this study was to investigate the effect of physicochemical properties of the polymers on the release profile of Salbutamol sulphate from the pellets dosage form. The in-vitro study suggested that Eudragit RSPO and Eudragit L100 at 10% coating level led to an optimum pulsatile release behavior. The coated pellets prepared by solution layering technology successfully released drug after specific lag time indicating pulsatile drug delivery. It was revealed that Eudragit RSPO has the effect to retard drug release. The results generated in this study showed that proper selection of polymeric materials based on their physicochemical properties is important in designing pellets dosage form with suitable dissolution profile.