Microemulsion - A Novel approach in Colloidal drug Delivery System
By Ms.Payal R.Dande - 11/01/2009
(21 votes)
Microemulsions are modern colloidal drug carrier system. They are isotropic, thermodynamically stable transparent (or translucent) systems of oil, water and surfactant, frequently in combination with a cosurfactant with a droplet size usually in the range of 10-100 nm. They can be classified as oil-in-water (o/w), water-in-oil (w/o) or bicontinuous systems depending on their structure and are characterized by ultra low interfacial tension between oil and water phases.
Microemulsion concept was introduced as early in the 1943 by Hoar & Schulman. These versatile systems are currently of great technological and scientific interest to the researchers because of their potential to incorporate a wide range of drug molecules (hydrophilic and hydrophobic) due to the presence of both lipophilic and hydrophilic domains.
Due to their special features, microemulsions offer several advantages for pharmaceutical use, such as ease of preparation, long term stability, improved dug delivery and high solubilization capacity for hydrophilic & lipophilic drugs. These adaptable delivery systems provide protection against oxidation, enzymatic hydrolysis and improve the solubilization of lipophilic drugs and hence enhance their bioavailability. In addition to oral and intravenous delivery, they are amenable for sustained and targeted delivery through ophthalmic, dental, pulmonary, vaginal and topical routes.
The enhancing activity is attributable to a variety of factors depending on the composition and the resulting microstructure of the formulation.
The objective of this presentation is to provide an overview of the structures and phase behavior of microemulsions, methods of microemulsion formation, and their potential of being the novel approach in drug delivery system. In addition, attention is focused on the application of microemulsions as delivery systems for delivery of bioactive compounds, and the links between microemulsions and increased bioavailability.
Author : http://www.pharmainfo.net/payal-dande
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Please give some examples
Please give some examples (names) of MEM preparations which are best in market at present?
http://www.pharmainfo.net/raghavendraswamy
Hello mam, Now a days
Hello mam,
Now a days microemultion is also preferred in the field of agree culture in the form of diff. pesticides? so how they act in that case? please give some examples?
Komal Nikam
http://www.pharmainfo.net/komal-nikam
Hy mam, Can u please tell me
Hy mam,
Can u please tell me which types of cosolvents are preferred in mfg of microemultion? what is selection criteria?
KOMAL.
Komal Nikam
http://www.pharmainfo.net/komal-nikam
Stability of microemulsion as colloidal drug delivery system
1. What do you mean by thermodynamic, kinetic and hydrodynamic stability of microemulsion as colloidal drug delivery system?
2. What is effect of these types of stabilities on self life of microemulsion as colloidal drug delivery system?
Dr.Sandeep Bhaskar Kale
http://www.pharmainfo.net/sanykale123
methods of microemulsion preparation
Hello Mam Payal,
Can u plz tell me which are the different methods by which we can prepare microemulsions?
Amit Sharma,- M.Pharm,PGDCR, (PhD)
http://www.pharmainfo.net/pharmamit
Nice presentation
Can a single surfactant be used to prepare microemulsion?
ABHERI DAS SARMA
http://www.pharmainfo.net/abherids86
phospholipid origin
Hello mam
as you said that Phospholipids are used as surfactatnts, phospholipids of which origin are widely used and which are more advantageous ?
good presentation
please give me the references to show that MEs are thermostable.
thermodynamic stability of MEM
Dear Roshan,
please note the reference for the same
Lalwani, A.N., Shah, T.J., Parmar, N.S. 2008. microemulsion as Drug Delivery System, Progress in Controlled and Novel drug Delivery system, CBS Publication, 14, 309-340.
http://www.pharmainfo.net/payal-dande
Dear Payal Does microemulsion
Dear Payal
Does microemulsion require the direction as 'shake well before use'?
Mr. Dixon Thomas, M. Pharm, M. S., RPh
http://www.pharmainfo.net/pharmacistdixon
Direction for using MEM
No, Mr.Dixon,
It does not require the stated direction due to its physical, chemical & thermodynamic stabilty at normal conditions.
http://www.pharmainfo.net/payal-dande
Fine Madam Thanks for the
Fine Madam
Thanks for the information. I have seen some mixtures which are solutions are also asked to be shaken before use to make a culture of shaking liquids for content uniformity. Well the practice may differe from place to place and person to person.
Best regards,
Mr. Dixon Thomas, M. Pharm, M. S., RPh
http://www.pharmainfo.net/pharmacistdixon
hello Mam
nice presentation .
i want to know about what are the basic difference between Nanoemulsion and Microemulsion-by considering appearance, Bioavailability...etc.
in addition to all this which is the best emulsion for colloidal drug delivery system and why?
http://www.pharmainfo.net/pankajpatel
uses
hello mam,
How microemulsion is useful in coating & textile industry?
MELC
hello mam,
what is microemulsion based HPLC & what are its applications in pharmacy..?
Is it a novel approach ?
1. Is there any necessity to use a co-solvent for the preparation of micro emulsion?
2. What is the usually employed concentration of surfactants to prepare micro emulsions?
3. How micro emulsions are evaluated.
Is it a novel approach ?
1. Is there any necessity to use a co-solvent for the preparation of micro emulsion?
2. What is the usually employed concentration of surfactants to prepare micro emulsions?
3. How micro emulsions are evaluated.
Dear madam,
Here in this presentation you have mentioned the steps for preparing the microemulsions, in that further additionof surfactant along with the co surfactant are added what is the reason to add further surfactant ,is it complusoryt.........
And can you tell me regarding the micellar solutio and also bicontinuos phase in detail............
regards ,
shilpa.s
Shilpa.Sambana
http://www.pharmainfo.net/shilpasambana
St ann's college of pharmacy
Vizianagaram
Andhra pradesh, India
Gene therapy!!
Were microemulsions previously applied for gene delivery?
conductivity measurement
Dear mam,
how conductivy measurement of a mem helps in distinguishing them weather it is w/o or o/w.
Regards.
Amit Sharma,- M.Pharm,PGDCR, (PhD)
http://www.pharmainfo.net/pharmamit
Question
Dear Payal,
Nice work
Can you tell me that what is the difference in the steps of formulation of emulsion and microemulsion?are they same?
Varsha Bansode
http://www.pharmainfo.net/varsha-bansode
Formulation of microemulsion
Thank you Varsha,
Well regarding the formulation of microemulsions, they are little difficult to formulate than ordinary emulsion. This is because their formulation is very specific process involving spontaneous interactions among the constituent molecules (componenents). The general components used in the formulation are-
1. An oil phase (Lipophilic system)
2. An aqueous phase (Hydrophillic system)
3. primary surfactant and
4. Co surfactant
The choice of Surfactant and co-surfactant is very crucial in formulation of microemulsion. This requires considerable amount of time and and labour which can be best reduced by using phase diagrams. Phase diagrams are typically constructed in three dimensions, either maintaining the fourth component constant or maintaining the ratio between two of the components fixed. This helps in finding microemulsion region in ternary or quaternary system and also helps in minimizing the amount of surfactant and co surfactant to be used.
http://www.pharmainfo.net/payal-dande
nanoemulsion is more stable than micro-emulsion or not??
can u tell me whether nanoemulsion is more stable than micro-emulsion or not??
and also please tell me about the different marketed formulations containing these micro emulsions in cosmetics...
In addition plz tell me about the evaluation methods for these micro-emulsions...
Shobha Deepthikompella
http://www.pharmainfo.net/shobhadeepthi
formulation and evaluation of microemulsion
Hello Shobha,
Please go through each point for your answers:
1. Although the physical appearance of nanoemulsion resembles that of microemulsion, an essential difference between the two is that nanoemulsion are at best kinetically stable while microemulsions are thermodynamically stable. As a consequence long term stability can be a problem with nanoemulsions. Some however may have sufficiently high level of stability to be proposed as vehicles for drug delivery.it is worth noting however, that the most stable naoemulsion are prepared using high energy input methods such as microfluidization, ultrasonication which makes them expensive.
2. There are many marketed preparations in cosmetics as skin care products, perfumes, hair shampoo, hair gels and hair fixatives prepared by this technique with added advantages. Recently there has been two patent one two-phase cosmetic or dermatological preparations containing a microemulsion and another as a perfume-containing water-in-oil microemulsion is provided which is capable of being mixed with an aqueous fabric softener base composition to provide perfume thereto. The use of the defined microemulsion enables the addition of perfume as well as other cosmetic attributes to an aqueous base composition under conditions of low shear while avoiding any problems of gelation or physical instability in the finished fabric softener product.
3. As given in my presentation microemulsion are evaluated for their physiochemical evaluation by measuring particle size, viscosity, electro conductivity, refractive index and percent transmittance and in vitro by drug diffusion studies.
http://www.pharmainfo.net/payal-dande
HELLO MAM,
HELLO MAM,
MICROEMULSION HAS GREAT STABILITY AS COMPARE TO EMULSION BUT IN LAB SCALE TO FORMULATE THIS IS SOMEWHAT DIFFICULT SO PLEASE SUGGEST ANY SIMPLE & RAPID TECH TO PREPARE THIS? ALSO HOW IT CAN BE PREPARED FROM CHEMICAL REACTIONS ONLY?
Komal Nikam
http://www.pharmainfo.net/komal-nikam
nano emulsion is better than micro emulsion ?
Dear Payal Madam,
Can u suggest some marketed product for such system?
Wheather nano emulsion is better than micro emulsion, give your opinion regarding this?
Regards,
Amol
Amol
http://www.pharmainfo.net/amolsmalpani
marketed products & microemulsion
Dear Amol,
please go through my answer to shobha where i have stated the difference between nanoemulsion and microemulsion. beside this there are many marketed products under patents for drug formulations and cosmetics.Recently Dow Corning ( a well known cosmetic company) launched Silicone Quat Microemulsion for hair care products. transdermal patches are being made using microemulsion technique for enhancing drug delivery system.
http://www.pharmainfo.net/payal-dande
Marketed preperation for MEM?
Hello, Paya
Nice PPTs, Now I have some query.
Can u give me marketed preperation for MEM?
Can we convert micro emulsion in to nano emulsion ?? if yes How ??
Regards,
Kinjal
KINJAL B. RATHOD
http://www.pharmainfo.net/kinjal
Size of globules in the microemulsion?
Madam,
The pictorial representations and flow diagrams were impressive.
I have a few questions for you,
1. What are the different techniques used to evaluate the size and size distribution of globules in the microemulsion?
2. Can we use microemulsions for controlled drug delivery?
3. Is it possible to formulate a microemulsion in the GIT?(I mean, is
there any formulation that gets converted into a microemulsion in the
GIT)
Regards,
SUHAAS.
Suhaas
delivery systems provide protection
hi dear nice PPT.....
can you tell me how adaptable delivery systems provide protection against oxidation ???????????
Amit Sharma,- M.Pharm,PGDCR, (PhD)
http://www.pharmainfo.net/pharmamit