DIAS R. To study formulation aspects of liquisolid systems. To get overview of evaluation and pharmaceutical applications of liquisolid compacts. Production of them is similar to that of conventional tablets.
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Thakare Navnath M. Thombre N. Nearly one-third of drugs in development are water insoluble and one-half fail in trials because of under pharmacokinetics. The dissolution rate is the rate limiting factor in drug absorption for class II low solubility and high permeability and class IV low solubility and low permeability drugs as defined in the Biopharmaceutics Classification System.
Various techniques have been employed to enhance the dissolution profile and, in turn, the absorption efficiency and bioavailability of water insoluble drugs. Micronization, adsorption on the high surface area carriers, lyophilization, co-precipitation, micro-encapsulation, solubilization by surfactants, solid dispersions, solid solutions. Micronization is the most common method to increase the drug surface area.
The most promising method for promoting dissolution is the formation of liquisolid tablets. A liquisolid system refers to formulations formed by conversion of liquid drugs, drug suspensions or drug solution in non-volatile solvents, into dry, non-adherent, free flowing and compressible powder mixtures by blending the suspension or solution with selected carriers and coating materials. These techniques are carefully selected on the basis of properties of drug , excipients and dosage forms.
Coating Material: Refers to a material possessing fine and highly adsorptive particles. For poorly flowable powder admixtures. To aid direct compression. To improve efficiency of tablet manufacturing. Improvement of Bio-availability of an orally administered water insoluble drugs is achieved.
This liquisolid system is specifically for powdered liquid medications. Greater drug surface area is exposed to the dissolution medium. These Liquisolid systems formulate into immediate release or sustained release dosage forms.
Capability of industrial production is also possible. Optimized sustained release Liquisolid tablets or capsules of water insoluble drugs demonstrate constant dissolution rates Zero Order Release. Excellent flowability and compressibility. Drug release can be modified using suitable formulation ingredients. The liquid portion, which can be a liquid drug, a drug suspension or a drug solution in suitable non-volatile liquid vehicles is incorporated into the porous carrier material.
Based on the type of liquid medication contained. Powdered drug solutions. Powdered drug suspensions. Powdered liquid drugs. Based on the formulation technique used.
Liquisolid compacts. Liquisolid Microsystems. Non volatile solvent: Inert , high boiling point, preferably water-miscible and not highly viscous organic solvent systems and compatible with having ability to solubilise the drug. Disintegrant: Increases the rate of drug release, water solubility and wettability of liquisolid granules. Carrier Materials: It should be porous material possessing sufficient absorption properties.
It retain only certain amounts of liquid and at the same time maintain acceptable flow and compression properties. Coating Materials: Fine and highly adsorptive particles.
It is required to cover the surface and maintain the powder flowability. Surface area of drug available for release is much greater than that of drug particles within directly compressed tablets. Increased aqueous solubility of the drug: Small amount of liquid vehicle in a liquisolid compact is not sufficient to increase the overall solubility of the drug in the aqueous dissolution medium. Improved wetting properties Wettability of these systems has been demonstrated by measurement of contact angles and water rising times.
Enhanced dissolution rate from the liquisolid compacts. Nonvolatile solvent facilitates the decreasing interfacial tension between dissolution medium and tablet surfac e. Determination of angle of repose. Calculation of liquid load factor Lf. Liquisolid compressibility test. Bulk density. Tapped density. Weight variation. In-vitro dissolution studies. Characterization Purpose 1. Infrared Spectroscopy Interaction studies 3.
Used efficiently for water insoluble solid drug or liquid lipophilic drug. Rapid release rates. Designed for control release tablet. Designed for sustained release of water soluble drug such as propranolol hydrochloride. Application in probiotics. Liquisolid tablets prepared were found in terms of faster disintegration time, dissolution profile, acceptable tablet properties and stability.
The technique is also used to design immediate release or sustained release systems. Therefore, this technique has the potential as safer and efficacious method, hence should considered to be manufactured on a large scale. Shashidher B. Gavali S. Leopold C. Geffken D. Spireas S. Izhar A. Pathak A.
Preparation and Characterization of Liquisolid Compacts for Improved Dissolution of Telmisartan
Thakare Navnath M. Thombre N. Nearly one-third of drugs in development are water insoluble and one-half fail in trials because of under pharmacokinetics. The dissolution rate is the rate limiting factor in drug absorption for class II low solubility and high permeability and class IV low solubility and low permeability drugs as defined in the Biopharmaceutics Classification System. Various techniques have been employed to enhance the dissolution profile and, in turn, the absorption efficiency and bioavailability of water insoluble drugs. Micronization, adsorption on the high surface area carriers, lyophilization, co-precipitation, micro-encapsulation, solubilization by surfactants, solid dispersions, solid solutions.
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article has been cited by other articles in PMC. Abstract The objective of the present work was to obtain pH independent and improved dissolution profile for a poorly soluble drug, telmisartan using liquisolid compacts. The formulations were evaluated for drug excipient interactions, change in crystallinity of drug, flow properties, and general quality control tests of tablets using Fourier transform infrared FTIR spectroscopy, differential scanning calorimetry DSC , X-ray diffraction XRD , angle of repose, and various pharmacopoeial tests. In vitro dissolution studies were performed at three pH conditions 1.