Natubhai. Patel

The study aim was concerned with formulation and in vitro evaluation of mucoadhesive buccal patch of carvedilol, which is extensively metabolized by liver. During last few years mucoadhesive dosage forms have promoted an area of drug delivery system that renders the treatment more effective and safe, not only for topical disorders but also for systemic problems. Therefore the present investigation is concerned with the development of the bucco-mucoadhesive patches, which were designed to prolong the buccal residence time, to increase penetration through buccal mucosa and thus increase the bioavailability. Various formulations were developed by using release rate controlling patches forming polymers like HPMC (K15, K4), HPC-L, Sodium alginate, PVP K30& Carbopol 934P in  alone & various combinations by solvent casting technique using plasticizer glycerol. For unidirectional release, backing layer prepared using ethyl cellulose 2.5%w/v dissolve in isopropyl alcohol and acetone. Glycerol used as a plasticizer was casted on the patches. The patches were evaluated for their thickness uniformity, folding endurance, weight uniformity, content uniformity, swelling behaviour, tensile strength, and surface pH, In vitro release studies, in vitro residence time, in vitro diffusion study. Patches exhibited drug release (diffusion) in the range of 75.69% to 96.53%. Kinetic models i.e. Higuchi, Korsemeyer-peppas, zero order were applied on data of diffusion release to explain release. The optimized formulation (F1) shows the zero order release.

The objective of this study was to develop and evaluate controlled porosity osmotic pump tablet (CPOP) system to deliver Verapamil HCl inacontrolledmannerupto24 h. The porous osmotic pump contains pore forming water soluble additives in the coating membrane, which after coming in contact with water, dissolve, resulting in an in situ formation of a microporous structure. Mannitol was used as an osmotic agent and cellulose acetate (CA) was used as semipermeable membrane. Polyethylene glycol 400(PEG-400) was employed as a pore forming agent as well as plasticizer for controlling membrane porosity. The influences of drug: osmogent ratio, concentration of PEG-400 and membrane thickness on the release profiles were investigated using 23 full factorial design and optimized batch was investigated in different environmental media and stirring rates. It was found that drug release rate increased with the amount of osmogent due to the increased water uptake, and hence increased driving force for drug release. This could be retarded by the proper concentration of channelling agent and membrane thickness in order to achieve the desired zero order release profile. This system was found to deliver Verapamil HCl at a zero order rate for24 h. The optimized formulations were subjected to stability studies as per ICH guidelines at different temperature and humidity conditions.

The objective of this study was to develop and evaluate a pulsatile drug delivery system based on drug-containing core tablet, which were coated with a swelling layer. Core tablets of Salbutamol Sulphate were prepared by direct compression using a croscarmellose sodium as disintegrant, micro crystalline cellulose as diluent and other. Core tablets were evaluated for uniformity of weight and thickness, hardness, friability, disintegration and dissolution. Compression coating over the prepared core tablets were done using various grade of HPC. Different formulae S1 to S9 were prepared using different coat % weights gain and polymer ratio. The compression forces were kept constant by adjusting constant distance between the upper and lower punches. The prepared Salbutamol Sulphate tablets were evaluated for the Lag time and in vitro release characteristics at variant pH media mimicking the gastrointestinal media. The results showed that the developed core tablets of Salbutamol Sulphate comprised excellent physical characteristics and complied with the USP criteria. For the pulsatile system, a quick releasing core was formulated in order to obtain a rapid drug release after the rupture of the polymer coating. The lag time prior to the rapid drug release phase increased with increasing % coating level. Key word: disintegrant, swelling layer, pulsatile release tablets, compression coating, lag time.

The present study involves the formulation and evaluation of buccal tablets of venlafaxine hydrochloride, an antidepressant drug belongs to class SNRI(serotonin-nonepinephrine reuptake inhibitor)has high first pass metabolism, So buccal drug delivery has been considered an alternative to the oral dosing for compound subjected to degradation in the gastrointestinal tract or to first pass metabolism. An attempt has been made to developed muccoadhesive buccal tablets comprising of drug containing mucoadhesive layers and drug free backing layer ethyl cellulose of to release the drug for extended period of time with reduction in dosing frequency, dose related side effects and improve bioavaibility of drug. Tablets of Venlafaxine Hydrochloride were prepared by direct compression using muccoadhesive polymers Carbopol 934-P and HPMC K4M.Buccal tablets were evaluated by different parameters such as thickness, hardness, weight uniformity, content uniformity, swelling index, surface pH, ex vivo bioadhesive strength, in vitro drug release, ex vivo drug permeation and FTIR studies. The modified in vitro assembly was used to measure the bioadhesive strength of tablets with fresh goat buccal mucosa as model tissue. In order to determine the mode of release, the data was subjected to Krosmeyer and Peppas diffusion model. All the formulations followed Fickian release mechanism. Tablet containing Carbopol 934P and HPMC K4M in the ratio of 1:1(25%) had maximum in vitro drug release for 8 hrs.