Diabetess mellitus is a chronic disease that is characterized by upsets in saccharide, protein and lipid metabolism1. Its cardinal perturbation appears to affect an abnormalcy either in the secernment of or effects produced by Insulin although other factors besides may be involved. Diabetess mellitus is a metabolic upset in which saccharide metamorphosis is reduced while that of proteins and lipoids is increased2. The external secernment of the pancreas is digestive in map and the enteric secernments play a major function in the ordinance of metamorphosis. The endocrines which regulate the degree of blood sugar are chiefly two ; glucagon from the alpha-cells and Insulin from the I?-cells of the islets of Langerhans3. Insulin is used in the intervention of diabetes mellitus as a replacing therapy. Diabetes occurs in chiefly two idiopathic signifiers, type 1 and type 2. Both type 1 and type 2 are at least partly inherited. India has the highest instances of diabetes in the universe ( 32 million expected to increase to 78 million by 2030 harmonizing to WHO estimation ) 4. Harmonizing to World Health Organization estimations, by 2025, over 350 million would be affected and over 75 % of these diabetes instances will be in the development world5. As India has no subsidized, coordinated diabetes attention plans, cut downing intervention costs through raising public consciousness, regular monitoring and earlier diagnosing should be a cardinal objective6.
Table 1.1: Complications of Diabetes Mellitus: 7
Retinopathy, cataract formation, glaucoma and periodic ocular perturbations ; taking cause of new sightlessness.
Gingivitis, increased incidence of dental pits and periodontic disease.
Increased incidence of big babes, still-births, abortions, neonatal deceases and inborn defects.
Motor, sensory and autonomic neuropathy taking to impotence, neurogenic vesica, parathesias, sphacelus.
Large vas disease and micro angiopathy.
Numerous infections and specific lesions due to little vas disease, increased lipoids in blood and pruritus.
Diabetic glomerulosclerosis doing nephropathy.
Diabetics have a higher incidence of cystitis, TB and skin infections ; candidiasis is common in diabetic adult females.
1.1.1 Types of Diabetes Mellitus 8
On the footing of etiology three chief classs of diabetes are recognized, viz.
Type I ( Insulin Dependent Diabetes Mellitus ) ( IDDM )
Type II ( Maturity onset Diabetes Mellitus ) ( Non-Insulin Dependent Diabetes Mellitus ) ( NIDDM )
Gestationnel Diabetes Mellitus
1.1.2 Categorization of Anti diabetic Drugs: 9
Anti-diabetic drugs are classified as
First Generation Analogs
E.g. , Tolbutamide, Chlorpropamide, Acetohexamide, Tolazamide
Second Generation Analogs
E.g. , Glibenclamide, Glipizide, Gliclazide
E.g. , Phenformin, Metformin
E.g. , Acarbose, Guargum
Other Hypoglycemic Agents:
1.2 INTRODUCTION TO CONTROLLED DRUG DELIVRY SYSTEMS
Controlled-release unwritten bringing systems have been an built-in portion of pharmaceutical engineering for several decennaries. Within the pharmaceutical industry bringing systems and preparations have been developed which can supply a broad assortment of drug release profiles, including systems designed for immediate, uninterrupted, pulsatile and delayed disposal. In recent old ages, much of the focal point in unwritten controlled-release engineering has been directed towards site-specific bringing in the GI piece of land, chronobiology every bit related to unwritten bringing systems and the development of engineering to command the release and bringing of non-traditional drug campaigners, i.e. peptides and proteins. Included in these assorted engineerings are osmotically controlled devices, matrix tablets, hydrogels, polymeric systems, multi particulates and eroding systems regulated by geometric design. In malice of the handiness of legion engineerings to accomplish up to 24 Hs controlled drug release, comparatively few merchandises that are efficacious for once-a-day dosing have reached the market. One of the jobs associated with these merchandises is hapless colonic drug soaking up that limits the one time day-to-day efficaciousness of dose forms10.
1.2.1 Advantages & A ; Disadvantages of Oral Controlled Release Drug Delivery Systems:
The undermentioned advantages11 are offered by unwritten controlled release drug bringing systems
Avoids patient conformity jobs
Minimize or extinguish local and systemic side effects
Reduces dose frequence
Reduces fluctuations in blood degrees
Improve bioavailability of drugs
A smoother curative response over the dose interval
The undermentioned disadvantages12 are observed with unwritten controlled release drug bringing systems.
Administration of controlled release medicine does non allow the prompt expiration of therapy
The doctor has less flexibleness in seting the dose regimens
Controlled release signifiers are designed for the normal population.
So, Economic factors must besides be assessed
Patients may necessitate extra information for the proper usage of controlled release merchandises
Complexity of controlled release dose signifiers may take to stableness jobs
1.2.2 Drugs Which Are Unsuitable For Oral Controlled Release Drug Delivery Systems: 13-15
Long biological half life & gt ; 12 H ( E.g. , Diazepam, Phenytoin )
Not efficaciously absorbed in the lower bowel ( E.g. , Riboflavin )
Absorbed and excreted quickly ; short biological half life & lt ; 1 H ( E.g. , Penicillin G, Furosemide )
Large doses required ( E.g. , Sulfonamides ) .
Drugs with low curative index ( E.g. , Phenobarbital, Digoxin ) .
Precise dose to persons is required ( E.g. , Anti-coagulants, cardiac glycosides )
No clear advantage for sustained release preparation ( E.g. , Griseoflavin ) .
1.2.3 Approachs to Achieve Controlled Release Drug Delivery
In general, controlled release preparations can be divided into different classs based on the mechanism of drug release16
Dissolution controlled release
Matrix disintegration control
Reservoir disintegration control
Diffusion controlled release
Matrix diffusion control
Reservoir diffusion control
Osmotic controlled release
Ion exchange rosins
pH regulated systems
Fig 1.1: A conjectural plasma concentration-time profile from conventional multiple dosing and individual doses of sustained and controlled bringing preparations.
Fig 1.2: Pie of Pie Representation of Market Share of Controlled Drug Delivery Systems
1.3 INTRODUCTION TO ORAL MATRIX TABLETS
A matrix system consists of active and inactive ingredients, which are homogeneously dispersed and mixed in the dose signifier. It is by far the most normally used viva voce controlled release engineering and the popularity of the matrix systems can be attributed to several factors which will be discussed in the ulterior subdivision. The release from matrix type preparations governed by Fick ‘s first jurisprudence of diffusion17 and shown in eq.1
J= dQt = – D District of Columbia aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ ( 1 )
Where J is flux, or rate of diffusion, while Q is the sum diffused per unit of clip T, and D is diffusion coefficient.
1.3.1 Hydrophobic Matrix System
The polymers used in hydrophobic matrix are H2O indissoluble in nature. These ingredients include waxes, acylglycerols, fatty acids and polymeric stuffs such as ethyl cellulose, methyl cellulose and propenoate copolymer18. Soluble ingredients such as lactose incorporated into preparation to modulate drug release. The presence of indissoluble ingredient in the preparations helps to keep the physical dimension of hydrophobic matrix during drug release. Hydrophobic matrix systems by and large are non suited for indissoluble drug because the concentration gradient is excessively low to render equal drug release. As such, depending on existent ingredient belongingss or preparation design, uncomplete drug release within the GI theodolite clip is a possible hazard and demand to be delineated during the development.
1.3.2 Hydrophilic Matrix System
The hydrophilic matrix polymers swell on contact with aqueous solution and organize a gel bed on the surface of the system. When the release medium ( i.e. H2O ) is thermodynamically compatible with a polymer, the dissolver penetrates into the free infinites between macromolecular ironss. The polymer may undergo a relaxation procedure, due to the emphasis of the penetrated dissolver, so that the polymer chains become more flexible and the matrix swells. This allows the encapsulated drug to spread more quickly out of the matrix19. On the other manus, it would take more clip for drug to spread out of the matrix since the diffusion way is lengthened by matrix swelling. Furthermore, it has been widely known that swelling and diffusion are non the lone factors that determine the rate of drug release. For dissoluble polymer matrix, polymer disintegration is another of import mechanism that can modulate the drug bringing rate. While either swelling or disintegration can be the prevailing factor for a specific type of polymers, in most instances drug release dynamicss is a consequence of a combination of these two mechanisms. The penetrant concentration gradient, polymer concentration gradient and osmotic force behaviour are observed as a consequence of polymer web. Appropriate polymer can compensate normal Fickian diffusion by impeding the release of embedded drug, taking to an drawn-out period of drug bringing, and perchance zero-order release. Sing the mechanism of release, the consequences showed that in most instances the drug release was controlled by both diffusion and eroding depending on the polymer type and concentration. On the other manus, incorporation of H2O soluble fillers like polythene ethanediol, lactose and surfactant into gel organizing matrices can better phenomenon of deficient drug release, because these excipients can heighten the incursion of the dissolver or H2O into the interior portion of matrices, ensuing in drug release from the matrices20.
1.3.3 Advantages of Oral Matrix Tablets21
Matrix design can be manufactured utilizing conventional procedures and equipments
The development cost and clip associated with the matrix systems by and large less and no extra capital investing is required.
A matrix system is capable of suiting both low and high drug burden and active ingredients with a broad scope of physical and chemical belongingss.
1.3.4 Restrictions of The Matrix tablets22
Lack flexibleness in seting to invariably altering dose degrees as required by clinical surveies.
For some merchandises that require alone release profiles ( double release or delayed plus drawn-out release ) , more complex matrix-based engineerings such as superimposed tablets are required.
Dose dumping, less facile dosage accommodation, increased potency for hepatic first-pass metamorphosis, possible hold in oncoming of action and perchance hapless system handiness.
1.4. Introduction TO TRANSDERMAL DRUG DELIVERY SYSTEM:
These are locally applied medicated spots which delivers the drug ( s ) in to systemic circulation at a preset and controlled rate23. A drug is kept in a comparatively high dose inside of a spot, which is allowed to lodge to clamber surface for a specified period. The drugs enter in to systemic circulation by diffusion mechanism. The high concentration of drug in the spot and low in the blood makes the drug to spread into the blood for an drawn-out period of clip and maintains changeless drug concentration in the blood. This technique has many advantages than traditional methods. Compared to the unwritten path, transdermic drug bringing is barren of GI soaking up, enzymatic/pH associated inactivation and decreased pharmacological dosing due to the shortened metabolisation pathway compared to unwritten path. Transdermal therapy is multi-day therapy with a individual application and the therapy can be terminated merely by taking the patch24.
1.4.1 Advantages & A ; Disadvantages of Transdermal Drug Delivery Systems:
The undermentioned advantages25 are offered by transdermic spots.
Convenient to use
Increasing patient conformity
Bettering tolerability and dosing
The steady pervasion of drug across the tegument allows for more consistent serum drug degrees, frequently a end of therapy
The deficiency of extremums in plasma concentration can cut down the hazard of side effects
Drugs that require comparatively consistent plasma degrees are really good campaigners for transdermic drug bringing
If toxicity develops from a drug administered by transdermic path, the effects could be terminated by taking the spot
Transdermal drug bringing can be used as an alternate path of disposal to suit patients who can non digest unwritten dose signifiers
It is of great advantage in patients who are nauseated or unconscious
Drugs that cause GI disturbance can be good campaigners for transdermic bringing because this method avoids direct effects on the tummy and bowel
Drugs that are degraded by the enzymes and acids in the GI system may besides be good marks
First base on balls metamorphosis, an extra restriction to unwritten drug bringing, can be avoided with transdermic disposal
The undermentioned Dis advantages26 of transdermic spots.
Erythema, hydrops or local annoyance can be caused by the drug/ adhesive/ excipients used in the spot preparation
Many drugs with a hydrophilic construction permeate the tegument excessively easy to be of curative benefit. Drugs with a lipotropic character, nevertheless, are better suited for transdermic bringing
A stable concentration gradient to be maintained in the mechanism of dose signifier to acquire changeless drug degrees in blood
Some transdermic spots contain more sums of drug that will be easy absorbed during its usage. Thus, after remotion, these spots contain sufficient measure ( & gt ; 90 % ) of the entire sum of drug ab initio in the spot. So, opportunities of drug wastage
Any harm to a transdermic spot ( membrane/reservoir ) can ensue in hapless control over the drug release. So, patients should be directed to take the spot if any harm to the outer packaging/patch.
1.4.2 The Components of Transdermal Drug Delivery Systems
The basic constituents in transdermic devices are: 27
1. The Polymer
2. Active Pharmaceutical Ingredient ( The drug )
3. Permeation foils
1. The Polymer 28, 29
Table 1.2: Polymers used in Transdermal Drug Delivery Systems
Type of System
Ethyl Cellulose T-50
MDX -4-421 ( a silicone )
Carboxyl Vinyl polymer
Acrylic PSA emulsion
Soy lecithin ( Epikuron 200 )
Polyisobutylene solutions ( Vistanex LM-MH, Vistanex MML-100 )
Acrylic acid copolymer
HEMA, Styrene and N-vinyl pyrrolidone copolymer for membrane
HPMC ( Methocel K4M )
Urecryl MC 808
MDX4-4210 silicone elastomer
Acrylate copolymer ( Gelva-737 )
Silicone-2920 and 2675
2-Ethylhexyl propenoate and acrylic acid copolymer
2-Ethylhexyl propenoate and acrylamide copolymer
Polyvinyl intoxicant ( endorsing ) , HPMC ( matrix ) , Ethylene vinyl ethanoate ( rate-controlling
2. Active Pharmaceutical Ingredient:
The choice of drug in transdermic drug bringing system is really of import for successful development of transdermic spot. The drugs which are used in transdermic bringing should hold the undermentioned belongingss 30.
The molecular weight of the drug should be less than 1000 Daltons.
The drug should be amphiphilic. But, high grade of partitioning behaviour does n’t assist for the drug bringing through the tegument.
The drug should run at lesser temperatures.
Along with these belongingss the drug should be non-irritant, powerful, and have short half life.
3. Permeation Foils:
These promote drug permeableness through tegument by changing the skin surface.
These can be classified as follows: 31-33
I ) Solvents
Solvents increase incursion possibly by steeping the polar tract or by fluidizing lipoids. E.g. , Water, Methanol, Ethanol, Glycerol, propene ethanediol, Dimethyl sulfoxide, Dimethyl formamide, Pyrrolidones, silicone fluids and isopropyl palmitate etc.
two ) Wetting agents
They enhance the polar tract conveyance for hydrophilic drugs.
Anionic Wetting agents: e.g. , Sodium lauryl sulfate, Decodecylmethyl sulphoxide and Dioctyl sulphosuccinate, etc.
Nonionized Wetting agents: e.g. , Sodium taurocholate, Sodium deoxycholate, Sodium tauroglycocholate ( bile salts ) , Pluronic F68 and Pluronic F127 etc.
three ) Miscellaneous
E.g. , N, N-dimethyl-m-toluamide, di-o-methyl-?-cyclodextrin, Calcium thioglycolate, Eucalyptol, soyabean casein and Urea
I ) Adhesives:
The force per unit area sensitive adhesive is required for placement of the device on tegument. The adhesive systems should carry through the undermentioned requirements/ parametric quantities.
Should adhere forcefully to the tegument
Can be removed easy
Should non prohibit any residue on the tegument surface
Should non excite the uncomfortableness
Should non impact the drug pervasion
two ) Backing membrane:
They are flexible and steadfastly adhere to the dorsum of spot to forestall drug go forthing from the spot and easiness of publishing on the surface of the way.
E.g. , metal, plastic and aluminum foil etc.
1.4.3 Types of Transdermal Patches
Four Major Transdermal Systems 34-36
Fig 1.3 Single-layer Drug-in-Adhesive transdermic spot
This sort of spots contains the drug and tegument adhesive together. In transdermic system, the adhesive serves to stick on the spot to the tegument and explicating foundation, incorporating the drug and excipients. The release rate of drug from this system is by diffusion mechanism across the tegument. Single-layer Drug-in-Adhesive transdermic spot was shown in Fig 1.3.
The rate of drug release from single-layer Drug-in-Adhesive transdermic spot can be defined by eq.2.
dQ/dT = — — — — — — — — — — — — — – aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦..aˆ¦aˆ¦ ( 2 )
1/Pm + 1/Pa
Cr = drug concentration in the reservoir compartment
Pa = Permeability coefficient of the adhesive bed
Pm= Permeability coefficient of the rate commanding membrane
Pm = the amount of permeableness coefficients across the pores and the polymeric stuff, which can be defined by eq.3 and 4.
Pm = ___________ aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ . ( 3 )
Pa = _____________ aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦..aˆ¦ ( 4 )
Km/r = Partition coefficients of the drug in the reservoir and the membrane
Ka/m = Partition coefficients of the drug from the membrane to adhesive
Dm = Diffusion coefficients in the rate commanding membrane
Da= Diffusion coefficients in the adhesive bed
hectometer = Thicknesses of the rate commanding membrane
hour angle = Thicknesses of the adhesive bed.
Fig 1.4 Multi-layer Drug-in-Adhesive transdermic spot
In this the multi-layer consists of a membrane between two beds of drug-in-adhesive beds with a individual backup movie. Multi-layer Drug-in-Adhesive transdermic spot was shown in Fig 1.4.
The rate of drug release from these spots can be defined by eq.5.
dQ/dt = — — — — — — — — — — — — Cr aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ ( 5 )
Ka/r = Partition coefficient of the drug in the reservoir bed and the adhesive bed
Fig 1.5 Liquid Reservoir type transdermal spot
These spots were characterized by the inclusion of a drug solution/suspension and separated by a membrane and adhesive. The Liquid Reservoir type transdermal spot was shown in Fig 1.5.
The rate of drug release from drug reservoir type controlled system can be expressed as eq.6.
dQ/dt = — — — — — — — — — — – A ( hour angle ) aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ ( 6 )
hour angle ( T )
Fig 1.6 Matrix type transdermal spot
These spots consist of a semi solid matrix with a drug solution/suspension which is in contact with the release line drive. On top of the drug reservoir it consists of adhesive and endorsing bed severally. The Matrix type transdermal spot was shown in Fig 1.6.
The rate of drug release from these spots can be defined as eq.7.
dQ ACp Dp A?
— — — = — — — — — — — — aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ . ( 7 )
A= Initial drug burden dosage
Cp = Solubility of the drug in the polymer
Dp= Diffusivity of the drug in the polymer
1.4.4 Transdermal Permeation
The drug pervasion through tegument is majorly by Fick ‘s First Law of Diffusion37 given as eq.8. ( Skin can be considered a membrane )
m = D k A ( Cs – Cb ) T vitamin D — — — — — — — — — — — — — – ( 8 )
m = Mass of drug spreading in clip ‘t ‘
D = Drug ‘s diffusion coefficient
K = Partition coefficient ( SC and Sebum )
A = Area for soaking up through tegument thickness ‘d ‘
Cs =Concentration of drug in sebum
Cb =Concentration of drug in systemic circulation
Table 1.3: Marketed transdermic patches38-40
TheraTech/Proctol and Gamble
3M Pharmaceuticals/Berlex Labs
Ethical Holdings/Solvay Healthcare Ltd.
Cygnus Inc, Ltd.
Elan Corp./Lederle Labs
1.5 Aims of the survey
1.5.1 Objective of Matrix Tablets
Increased complications and disbursal involved in selling of new drug entities, has focused greater attending on development of sustained release ( SR ) , or controlled release ( CR ) drug bringing systems. Matrix system is the most widely used method in the development of controlled release preparations. This technique prolongs and controls the release of drug that is dissolved or dispersed. The aims of matrix tablets are as follows
Pre preparation surveies for Drug – Excipients Compatibility.
Preparation of standard curve for Glipizide and Glimepiride.
Preparation of assorted matrix tablets utilizing Aloe barbadensis Miller leaves mucilage, Guar gum and Povidone as polymers in different concentrations.
Evaluation of matrix tablets by following parametric quantities:
General visual aspect
Thickness and diameter
Weight fluctuation trial
Drug Content uniformity trial
Swelling index of the tablets
In-vitro Tablet Dissolution surveies
Comparison of Dissolution Characteristics of optimized formulated matrix tablet with Market tablets
In-vivo drug soaking up surveies
Stability surveies of optimized matrix tablets
The consequences are presented in tabular arraies and diagrammatically by utilizing assorted equations regulating release dynamicss. The aims of matrix transdermic spots are as follows
1.5.2 Objective of Transdermal Patches
Transdermal path has advantage because of they have increasing patient conformity and free from first base on balls metamorphosis. The transdermic path furnishes both controlled and sustained bringing. Technological finds, over the past old ages, have proved the feasibleness of utilizing several methods for heightening transdermic soaking up, with this the hereafter of transdermic drug bringing looks calendered. These finds are utile in the find of newer excipients and engineerings. The aims of matrix transdermic spots are as follows
Pre preparation surveies for Drug – Excipients Compatibility
Preparation of standard curve for Glipizide and Glimepiride
Preparation of assorted Trans cuticular spots utilizing Ficus bengalensis, Ficus Carica, Ficus glomerata fruit mucilage and Povidone as polymers in different concentrations
Evaluation of transdermic spots by following parametric quantities:
Uniformity of weight
Flatness and elongation brake
Determination of tensile strength
Drug content finding of movie
Skin annoyance trials.
In-vitro Skin pervasion trial
The consequences are presented in tabular arraies and diagrammatically by utilizing assorted equations regulating release dynamicss.