Md. Mofazzal Hossain

Practically water insoluble Simvastatin has been accused for being poorly absorbed from gastro intestinal tract. With an aim to improve the solubility and dissolution characteristics of the drug, solid dispersion and surface solid dispersion were prepared by using different water soluble and insoluble carrier at different ratio. Dispersions were made by solvent evaporation technique and undergo drug content test, compatibility by FT-IR, DSC thermal study and in vitro drug release study. FT-IR and DSC thermographs showed the compatibility of the drug and carrier in the incorporated ratio. All the preparations were found to improve the dissolution behavior of Simvastatin significantly compare to the binary physical mixtures and the pure drug. The suitability of solid dispersion and surface solid dispersion technique was evaluated. Also the efficacy of the carriers to improve the dissolution behavior was compared. Tablets were formulated by incorporating dispersions and were subjected to various physical tests including thickness, diameter, hardness, average weight and disintegration time. Their release pattern was compared with compressed matrix of drug and two brand products available in Bangladesh market. Their drug release pattern was further characterized with mean dissolution time (MDT), fractional dissolution time (T50% and T80%) and percent dissolution efficiency. Tablets made of dispersion with HPMC, sodium starch glycolate and croscarmellose sodium were found to have better release rate and extent than the drug and the brand products.

Atorvastatin Tablet is one of the best selling drugs in the world, but still it suffers inadequate bioavailability problem from oral dosage. An attempt was taken to evaluate the floating drug delivery system for Atorvastatin by incorporating it in different grades of Carbomer matrix. Direct compression technique was selected and different once daily formulations were designed. The tablets were successfully floated over prolonged time and released the drug at a controlled fashion depending on the grade and quantity of Carbomer used. The tablets were evaluated for different physical tests including weight variation, friability, hardness, diameter and thickness. The compatibility between drug and polymers were confirmed by FT-IR spectra. Buoyancy characteristics of the tablets were determined by observing lag time, swelling index and total buoyancy period. The mechanism of drug release from the matrixes was assumed by fitting the release profile with different mathematical equations. Formulation F-5 and F-10 were found to release the drug at most sustaining manner and also had the longest total floating time. 

An immediate action of Metformin HCl is essential for emergency treatment of diabetes. With an objective of finding the best suitable disintegrant for immediate release tablet of Metformin HCl, different formulations were prepared by incorporating varying ratios of three widely used superdisintegrants both by intra and extra granularly. Wet granulation method was adopted to formulate the tablets by using Maize Starch as diluent; Povidone k-30 as binder; Sodium Starch Glycolate/Kollidon CL/Crosscarmellose Sodium as superdisintegrants in different concentration (2-3.5%), Aerosil-200 as flow promoter and Magnesium Stearate as lubricant. To evaluate the rheological properties of powdered blend, some pre-compression characteristics including bulk and tapped densities, compressibility index, Hausner’s ratio, angle of repose were studied. The compressed tablets were evaluated for hardness, thickness, diameter, friability, drug content, weight variation, in vitro dispersion time, in vitro disintegration time, in vitro wetting time and finally for in vitro dissolution studies. It was found that wetting time, dispersion time and the disintegration time of the tablets were governed by the type and quantity of the superdisintegrants. In vitro drug release data obtained at phosphate buffer at pH 6.8 also found reliant on successful incorporation of right disintegrating agent. Higher the disintegrant ratio in the formulation, lower the disintegration time and hence, higher percentage of drug release was obtained. Based upon results of different studies, Sodium Starch Glycolate has been proven successful in rapid disintegration of tablets and enhancing dissolution behavior.