Eyes are delicate and most vital organs of the body whose defence mechanism restricts entry of exogenous substance. Conventional drug delivery systems get washed off within a short period of time that usually cause poor bioavailability and therapeutic responses because high tear fluid turnover and dynamics cause rapid elimination of the drug from the eye. In-situ gelling ophthalmic drug delivery system is one of the new methods that is developed to overcome this bioavailability problems. In-situ gelling systems are viscous polymerbased liquids that exhibit sol-to-gel phase transition on the ocular surface due to a change in a specific physicochemical parameter like temperature, ionic strength, or pH triggered in-situ systems. Using this formulation of pH triggered in-situ gel systems, the release of drug can be sustained for longer periods of time, therapeutically more efficacious, non-irritant and stable than conventional eye drops.

Transdermal drug delivery system (TDDS) shows promising results when compared with oral drug delivery system mainly by eliminating the first pass metabolism and by improving the bioavailability of drug. Hydrophilic gels are networks of polymer chains that are sometimes found as colloidal gels in which water is the dispersion medium.  Ibuprofen, non-steroidal anti-inflammatory drug used to relieve pain, reduces fever and anti-inflammation. The purpose of present research is to demonstrate the influence of various enhancers (transcutol and stearylamine) in various concentrations on percutaneous permeation of ibuprofen hydrophilic gel from HPMC K4M & HPMC K100M gel formulation. Gelling agents at various concentrations were preliminary screened for gel consistency. The control and the prepared gels were evaluated for clarity, homogeneity, spreadability, extrudability, drug content, invitro diffusion, ex-vivo permeation, skin irritation, anti-inflammatory activity and stability studies.  All formulations have shown better physicochemical properties. Ex-vivo skin permeation studies reveals that the (IBU29) formulated using HPMC K4M 6%, transcutol 40% and stearylamine 4% as permeation enhancers has shown maximum drug release of 86.4 % for 24hrs. Permeability parameters like flux were found to be 1940.68±0.06µg/cm²/hr, permeability coefficient was found 31 ×10^-3cm/hr and Q₂₄ was found to be 5240.82±0.06µg/cm² and enhancement ratio of 13.06 over pure drug. Skin irritation studies showed irritation potential of “0” score thus providing to be non-irritant. The anti-inflammation studies were performed with inflammation induced by carrageenan 1% w/v solution. Optimized formulation (IBU29) showed highest reduction of inflammation comparable to marketed preparation BRUGESIC GEL^®. The formulations were stable at room temperature for 1 month.

Hydroxyapatite is the inorganic constituent present in the bone and it is used as a drug delivery carrier in hard tissue regeneration applications. Hydroxyapatite was prepared by simple precipitation technique and the effect of experimental parameters on the phase formation was studied. Calcium nitrate tetra hydrate and diammonium hydrogen phosphate were taken as the calcium and phosphate source. The calcined powders were characterized by Fourier – Transform Infrared spectroscopy to identify the functional groups present in the product and also analyzed by powder X-ray diffraction to identify the phases present in the product. Results showed that the product formed is pure hydroxyapatite and it confirms that aging time and pH of the system plays a significant role in the phase formation.

The present work describes the optimization of spray dried powder of solid lipid-based nanosystems to improve drug stability, surface modification and to obtain nanosystems after redispersion. Chitosan coated solid lipid nanoparticles containing bromocriptine mesylate (cBMSLN) were prepared by high pressure homogenization technique following by chitosan addition. For spray drying, response surface methodology with central composite rotatable design was to optimize 3 parameters: inlet temperature, pump rate and feed concentration. From regression analysis, powder yield, moisture content and size of redispersed nanoaggregates as responses were fitted well with linear, quadratic and quadratic equation models, respectively. Spherical powders with size of 4-5 µm and 70% yield were obtained at optimum parameters which were also used to prepare powder of chitosan coated nanostructured lipid carriers containing BM (cBMNLC). Amorphous characteristics were confirmed from powder XRD patterns and DSC chromatograms in all prepared powders. Redispersion of powders yielded nanosystems of some original nanosize and a greater portion of larger size. Smoother surface of NLC systems was observed, so was with chitosan coating. Drug entrapment was >85% but significantly decreased in chitosan coated formulations while drug retention after spray drying showed opposite results. After storage, spray dried powder could retain higher drug content than the original nanosystems. Obviously, NLC systems had better drug stability results than SLN systems. It could be concluded that redispersible spray dried powders of chitosan coated lipid-based nanosystems especially NLC systems were successfully obtained with surface modification, nanoaggregate size range and improved drug stability.

Cinnarizine is a piperazine derivative, antiallergic with antihistamine, sedative, and calcium-channel blocking activity. It is used for the symptomatic treatment of nausea and vertigo caused by Meniere’s disease and other vestibular disorders and for the prevention and treatment of motion sickness. The present study is focused on making fast dissolving wafers of solid dispersion incorporated Cinnarizine to enhance the bioavailability, dissolution of the drug and increasing the patient compliance. Fast dissolving films of Cinnarizine can be considered suitable for clinical use in the treatment of allergic rhinitis and other conditions of allergies, where a quicker onset of action is desirable along with the convenience of administration. Seven formulations of fast releasing wafers of solid dispersion incorporated Cinnarizine, dispersed in two different polymers; HPMC and PVA by solvent casting method were prepared. Solid dispersion was prepared by solvent evaporation method to enhance the solubility, dissolution rate and consequently, the bioavailability of Cinnarizine. These wafers were evaluated for various parameters like thickness uniformity, weight uniformity, folding endurance, swelling index, percentage moisture absorption, content uniformity, ex vivo permeation studies etc. The cumulative percentage amount of drug diffused was higher for fast releasing wafer made of 3% HPMC. The release kinetics data indicates that the release of drug from fast releasing wafer F4 follows first order release kinetics and model fits to Higuchi which is indicative of the diffusion mechanism of drug release. The mechanism of drug release was found to be non-Fickian. From all of these findings it was concluded that HPMC K4M is the best fast releasing wafer forming polymer.