At present 40% of the drugs within the development pipelines, and approximately 60 % of the drugs coming directly from synthesis area unit poorly soluble. Solubility is one of the important parameter to obtain desired concentration of drug in systemic circulation. Liquisolid compacts technique is a new and promising approach to overcome this consequence and that can change the dissolution rate of water insoluble drugs and increase the bioavailability of the drugs. This technique is an efficient method for formulating water insoluble and water soluble drugs. This technique relies upon the admixture of drug loaded solutions with applicable carrier and coating materials. Liquisolid system is characterized by flow behaviour, wettability, powder bed hydrophilicity, saturation solubility, drug content, differential scanning calorimetry, Fourier transform infra-red spectroscopy, powder X-ray diffraction, scanning electron microscopy, in-vitro release and in-vivo evaluation. This review article explains the preparation, classification and application of liquisolid system.

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Objective: The objective of the present investigation was to improve the solubility and dissolution rate of poorly soluble drug meloxicam by its ternary inclusion complexation with natural polymers and beta-cyclodextrin (β-CD) by kneading. Methods: Equimolar physical mixture (1:1) was prepared by homogeneously kneading drug and β-CD using a solution of agar and pectin in water to get a paste, then paste was dried overnight to get inclusion complex. Inclusion complex was evaluated for drug content, the yield of the adsorption process, Fourier-transform infrared (FTIR), differential scanning calorimeter (DSC), powder X-ray diffractometry (PXRD), scanning electron microscopy (SEM), dissolution, and stability studies. Results: The phase solubility diagrams exhibit AL showing a linear increase of drug solubility and indicating the formation of soluble complexes. The FTIR and DSC show compatibility between meloxicam and β-CD, while slight broadening in the peak with a reduction in intensity and early onset indicates the reduction in drug crystallinity which confirms in PXRD pattern. The SEM of binary, as well as ternary, showed no aggregation, and there was a gap between the particles also indicating good redispersibility. The dissolution rate of the drug from the kneaded ternary complex with pectin was significantly rapid compared with the pure drug. The maximum drug release was observed at 85.21±1.84% at the end of 60 min. The ternary complex was found stable after 3 months stability studies. Conclusion: The results indicated that ternary inclusion complexation with natural polymers and β-CD was most useful for enhancement of solubility and dissolution rate of a poorly soluble drug like meloxicam.

The enhancement in solubility and dissolution rate of BCS class-II drug Nifedipine was achieved by simple physical mixture with sepitrap 80 & sepitrap 4000 in 1:1 & 1:2 proportion. The saturation solubility studies shows 263 % & 368 % increase in the solubility in physical mixture of Nifedipine with sepitrap 80 & sepitrap 4000 respectively. The physicochemical properties of pure Nifedipine compared to their physical mixtures with sepitrap 80 & sepitrap 4000 were determined using FTIR, DSC & PXRD. The FTIR and DSC studies shows no any interaction in Nifedipine and sepitrap, the marked broadening and distinct reduction in intensity with shifting of drug endotherm was displayed physical mixture with sepitrap demonstrate positive effect. The PXRD diffractograms shows distinctive peaks but reduction in peak intensity in terms of counts indicating conversion of drug in amorphous forms. The surface morphology of the prepared physical mixture was examined by SEM which indicating no significant change in its surface morphology due to no use any solvent during the preparation of physical mixture . Photostability studies shows that rate of photo degradation is very slow in Physical mixture with sepitrap as compared to pure Nifedipine. Dissolution studies in SGF & SIF shows that significant enhancement by use of novel solubilizer sepitrap 80 as well as sepitrap 4000 in 1:2 proportions. The physical mixture containing sepitrap 4000 was found stable as there was no any significant change in appearance and drug dissolution after three month stability studies.

The purpose of present investigation was to formulate bioadhesive pulsatile release tablet (BPRT) of lisinopril drug belong to antihypertensive category for chronotherapy of cardiac disorder. The concept behind this dosage form development is to investigate effect of coating polymer concentration on lag time and drug release from directly compressed tablet. The core tablets prepared by using various concentrations of disintegrants found suitable for complete release of drug in acidic medium indicating its solubility in gastric fluid. The FT-IR studies indicate that selected polymers are compatible with lisinopril since no interaction found in drug-excipient compatibility studies. The dissolution study clearly indicates that higher concentration of polymers which is HPMC K100M and Carbopol reduces free water volume and increase viscosity of the tablet coat causes reduction in drug release. The prepared Bioadhesive pulsatile release tablets showed desired hardness and good mucoadhesion strength. The obtained results showed capability of formulated bioadhesive pulsatile drug delivery system in a drug release for a programmable period of time to attain drug release after minimum 3 hr of Lag time. A stability results clearly indicate that developed pulsatile product was sufficiently stable under accelerated and controlled conditions. Thus, the developed pulsatile tablet can be considered to be a promising formulation for the relief of early morning surge in blood pressure and other cardiac disorders which follows a circadian rhythm.