Herbal formulation, Novel dosage forms (Part - 3), T.Y B.Pharm, Sem VI, Herbal drug technology, Unit - III, PCI Syllabus

NOVEL HERBAL DOSAGE FORMS (PART - 3)

Topics covered:-

• Microsphere
• Transferosomes
• Ethosomes
• TDDS
• Niosomes and Proniosomes

5. MICROSPHERES:-

Micro-spheres are small spherical particles, with diameter 1 μm to 1000 μm. They are spherical free flowing particles consisting of proteins or synthetic polymers which are biodegradable in nature. 

Microparticulate drug delivery systems are studied and taken on as a reliable one to rescue the drug to the target site with specificity, to assert the desired concentration at the situation of interest without untoward effects.

Micro - encapsulation is a useful method which extends the duration of drug effect significantly and improves patient compliance.

TYPES OF MICROSPHERE

A series of active ingredients of plants, such as rutin, camptothecin, zedoary oil,  tetrandrine, 

quercetine, and Cynara scolymus extract, has been made into microspheres.

In addition, reports on immune microsphere and magnetic microsphere are also usual in

recent years. Immune microsphere possesses the immune competence as a consequence of 

the antibody, and antigen was coated or adsorbed on the polymer microsphere.

[Some examples of herbal microsphere]

6. TRANSFEROSOMES:-

The term ‘Transfersome’ indicates ‘transferre’ means ‘to carry across’ and ‘some’ means ‘ for a body. A Transfersome carrier is an artificial vesicle or a cell engaged in exocytosis, and thus suitable for controlled and, potentially targeted drug delivery. 

Transferosomes are supramolecular entities that can pass through a permeability barrier and thereby transport material from the application to the destination.  These are complex, vesicular aggregates optimized to attain flexible and self-regulating membrane. They are more elastic than standard liposomes.

COMPOSITIONS OF TRANSFEROSOMES:- 

The transfersome is composed of two main aggregates namely, 

Firstly, an amphiphillic ingredient (phosphatidylcholine), in which the aqueous solvents self- assembles into lipid bilayer that closes into a simple lipid vesicle.

Secondly, a bilayer softening component (such as a biocompatible surfactant or
amphiphile drug) that increases lipid bilayer flexibility and permeability.

The development of novel approaches such as transfersomes have immensely contributed in 
overcoming problem faced by transdermal drug delivery such as unable to transport larger 
molecules, penetration through the stratum corneum is the rate limiting step, physicochemical properties of drugs hinder their own transport through skin.

These elastic vesicles can squeeze themselves through skin pores many times smaller than their own size and can transport larger molecules. Transfersomes are applied in a nonoccluded method to the skin, which permeate through the stratum corneum lipid lamellar regions as a result of the hydration or osmotic force in the skin.

It can be applicable as drug carriers for a orbit of small molecules, peptides, proteins and
herbal elements. Transfersomes can penetrate the stratum corneum and supply the nutrients, locally to maintain its functions resulting maintenance of skin

E.G: The transfersomes of Capsaicin shows the better topical   absorption in comparison to pure capsaicin.

7. ETHOSOMES:-

Ethosomes are ethanolic liposomes. The ethosomes are vesicular carriers consisting of hydroalcoholic or hydroglycolic phospholipids in which the concentration of alcohols or their combination is relatively high.

These are soft, malleable vesicles tailored for enhanced delivery of active agents.

Ethosomes which are novel permeation-enhancing lipid vesicles embodying high concentration (20–45%) of ethanol.

Ethosomal systems are made up of soya phosphatidylcholine, ethanol and water. They may form multilamellar vesicles and have a high entrapment capacity for particles of various lipophilicities.

Ethosome has a high deformability and entrapment efficiency and can penetrate through the skin completely and improve drug delivery through the skin. Likened to other liposomes, the physical and chemical properties of ethosomes make the legal transfer of the drug through the stratum corneum into a deeper skin layer efficiently or even into the blood circulation.  This property is very important as the topical drug carrier and transdermal delivery system. 

Moreover, the ethosomes carrier also can provide an efficient intracellular delivery for both hydrophilic and lipophilic drugs, percutaneous absorption of matrine an anti-inflammatory herbal drug is increased, it also permits the antibacterial Peptide to penetrate into the fibrocyte easily.

8. TRANSDERMAL DRUG DELIVERY SYSTEM (TDDS):-

TDDS are topically administered medicament in the form of patches that deliver drugs for systemic effects at predetermined and controlled rate.

Trans-dermal patch is an adhesive patch, that has a coating of medicine (drug), that is placed on the skin to deliver specific dose of the medicine, into the blood over a period of time.

TDDS has been an increased stake in the drug administration via the skin for both local therapeutic effects on diseased skin (topical delivery) as comfortably as for systemic delivery of drugs.

Transdermal delivery system provides the advantage of controlled drug delivery, enhanced bioavailability, reduction in side effects, and easy application.

Formulation of transdermal films incorporating herbal drug components such as boswellic acid (Boswellia serrata) and curcumin (Curcuma longa) is one of the first few attempts to utilize Ayurvedic drugs through TDDS, which utilizes skin as a site for continuous drug administration into the systemic circulation. Thus, this delivery system avoids the first-pass

metabolism of the drug without the annoyance associated with injection; moreover, the scheme offers a prolonged drug delivery with infrequent dosing via zero-order kinetics and the therapy can be easily fired at any time.

E.g:- Use of turmeric in TDDS for the local action of the drug at the site of administration can also be regarded as a young version of Ayurvedic turmeric poultice or leap.

9. NIOSOMES & PRONIOSOMES:-

Niosomes are synthetic microscopic vesicles consisting of an aqueous core enclosed in a bi layer consisting of cholesterol and one or more nonionic surfactants. Vesicles are prepared from self assembly of hydrated non ionic surfactants molecules.

Niosomes are multilamellar vesicles formed from nonionic surfactants of the alkyl or dialkylpolyglycerol ether class and cholesterol.

Niosomes are different from liposomes in that they offer certain advantages over liposomes. Liposomes face problems such as they are expensive, their ingredients such as phospholipids are chemically unstable because of their predisposition to oxidative degradation, they require special memory and handling, and purity of natural phospholipids is variable. Niosomes do not have any of these problems.

Proniosome is dry formulation using a suitable carrier coated with non-ionic surfactants and can be converted into niosomes immediately before use by hydration.

These proniosome-derived niosomes are as good as or even better than conventional niosomes.

Proniosome gel system is step forward to niosome, which can be utilized for various applications in delivery of actives at desired site. Proniosomal gels are the formulations, which on in situ hydration with water from the skin are converted into niosomes.

Proniosomes are water-soluble carrier particles that are coated with surfactant and can be hydrated to form niosomal dispersion immediately before use on brief agitation in hot aqueous media