Presented byK. Teja kumar Reddy

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Chilkur balaji college Of Pharmacy, Hyderabad ,Telangana-500075

A more recent technique, “powdered solution technology” or “Liquisolid technology”, has been applied to prepare water-insoluble drugs into rapid-release solid dosage forms.

The term “ liquisolid compacts technique ” refers to process of preparation of immediate or sustained release tablets or capsules using the “liquisolid systems” combined with the inclusion of appropriate excipients required for tabletting or encapsulation.

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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.

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More effective than Various techniques which 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.

But this becomes less effective when they are formulated as tablets or encapsulations.

The most promising method for promoting dissolution is the formation of liquisolid tablets.

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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.

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Liquid medication Liquisolid compacts Liquisolid Microsystems Liquid load factor (Lf) Coating Material Ratio (R) Carrier material Coating Material

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For poorly soluble, insoluble, liquid drugs or lipophilic drug .

For poorly flowable powder admixtures. To aid direct compression. To improve efficiency of tablet manufacturing.

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Large number of Bio-Pharmaceutical classification class II and class IV.

Improvement of Bio-availability of an orally administered water insoluble drugs is achieved.

Drug is formulated in a tablet form or encapsulated dosage form and is held in solubilized liquid state, which confers developed or improved drug wetting pro perties thereby improving drug dissolution profiles.

production cost is low as compared to soft gelatin capsules.

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Simplicity. 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.

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Liquisolid technology as described by “Spireas” a liquid may be transformed into a free flowing, readily compressible and apparently dry powder by simple physical blending with selected excipients named the carrier and coating material.

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.

 

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Schematic representation of liquisolid systems.

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A. Based on the type of liquid medication contained. 1. Powdered drug solutions.

2. Powdered drug suspensions.3. Powdered liquid drugs.

B. Based on the formulation technique used.1. Liquisolid compacts.2. Liquisolid Microsystems.

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Liquisolid compact mainly includes:1. Non volatile solvent:

e.g., PEG 200 and 400, glycerin, polysorbate 80 and propylene glycol, Tween–80.

2. Disintegrant:e.g., SSG, Cross povidone, Sodium cross carmellose .

3. Carrier Materials e.g., MCC grade, granular amorphous cellulose, starch, lactose.4. Coating Materialse.g., silica (Cab-O-Sil ), Aerosil.

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:

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A. Increased drug surface areaB. Increased aqueous solubility of the drugC. Improved wetting properties

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PRE-FORMULATION STUDIES:

1. Determination solubility of drug in different non-volatile solvents.

2. Determination of angle of repose.3. Determination of flowable liquid retention

potential (Φ value).4. Calculation of liquid load factor (Lf).5. Liquisolid compressibility test.

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EVALUATIONS

A.Pre Compression Evaluations:

1. Angle of repose measurements.2. Bulk density. 3. Tapped density.4. Carr’s index.5. Hausner’s ratios: >1.6 less free flowing powders, <1.25

indicate good flow.

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B. Post compression Evaluations:

1. Content of uniformity.2. Hardness.3. Weight variation.4. Friability.5. Disintegration.6. In-vitro dissolution studies.

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C. Characterization of Liquisolid Systems

1. UV2. HPLC 3. Scanning electron microscopy (SEM) 4. Differential Scanning Calorimetry (DSC)5. X-ray diffraction (XRD)6. Fourier Transform Infrared spectroscopy(FTIR)

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Sr.No. Characterization Purpose

1. UV/HPLC Assay & uniformity content

2. Infrared Spectroscopy Interaction studies

3. Powder X-Ray Diffraction Analysis (XRD) Crystalline Properties

4. Differential Scanning calorimetry (DSC)

Interaction studies, polymorphism

5. HPLC/TLC Purity, interaction/degradation

6. In vitro Dissolution studies Release Properties of drug

Solubility and dissolution enhancement. 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.

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The Liquisolid technique is a promising alternative to enhance the absorption as well as dissolution rate their by it may enhance the bio-availability of a poorly soluble, liquid drugs, insoluble or lipophilic drugs.

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.

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1. Spiras S., Bolton S., “Liquisolid systems and methods for preparing same”,(2000), United States patent: 6,096,337.

2. Shashidher B., Madhusudhanrao Y., “The Liquisolid Technique: An Overview”, Brazilian Journal of Pharmaceutical Sciences, vol-47, (2011), p. n. 3.

3. Gavali S. M., Pacharane S. S., Sankpal S. V., “Liquisolid Compact: A New Technique for Enhancement of Drug Dissolution”, IJRPC, (2011), Department of Pharmaceutics, p.n. 705-710.

4. Dr. Leopold C. S., Dr. Geffken D., “Optimization of the Liquisolid Technology”, (2011), p.n. 2-27.

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Thank you….

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