There are several drugs that can be damaged or become inactive because the gastric liquid or can irritate the gastric mucosa. Therefore, these drugs need to be coated with enteric coated to protect the tablet core so that was not destroyed in the acidic environment of the stomach, preventing damage to the active ingredient which is unstable at low pH, protecting the stomach from the irritating effects of certain drugs and to facilitate the delivery of drugs absorbed in the intestine.

Enteric-coated polymers include cellulose acetyl phtalate, polyvinyl acetyl phtalate, and acrylate. Polymers are often used for enteric coating is acrylate derivatives, some of which can use water as a solvent and carrier. Eudragit ® L 30 D-55 is a polymer of methacrylic acid and have the ability and high stability against gastric fluid resistance, began to dissolve at pH 5.5 to pH 7 and using water as a solvent.

Sodium Diclofenac: Mechanism of Action and Side Effects
Diclofenac is a prostaglandin synthesis inhibitor which potency is equivalent to indomethacin. Although the mechanism of action of diclofenac is to inhibit the synthesis of prostaglandins, diclofenac also cause a decrease by increasing retrieval lipoxygenase products of arachidonic acid into triglycerides. Common side effects are nausea, gastritis, skin erythema and headache, as were all NSAID drugs, the use of these drugs have to be careful in patients with peptic ulcers. Therefore, diclofenac sodium oral pharmaceuticals particularly tablets must be coated.

Diclofenac Sodium Enteric Coated Tablet Formula

Preparation of Tablet Core.
Tablet core made as many as 10,000 tablets by direct compression method (Direct compressed tablets), with the formula as follows:

Ingredient/Materialmg/tab10,000 tab     (kg)      % w/wFunction
Sodium Diclofenac500.519.6Active ingredient
Lactose510.5120Diluent/Filler
Microcrystaline Cellulose 102 q.s148.261.4858.15Diluent/Filler, Disintegrant
Silicon Dioxide5.10.512Glidant
Magnesium Stearate0.640.00640.25Lubricant
Total tablet weight2552.55100

Preparation:

  1. The materials have been sifted, weighed according to the weight of each.
  2. All the ingredients are mixed until homogeneous. Preparations then inserted into the appliance homogenizer for 15 minutes until a homogeneous preparation.
  3. mass examination tablets like humidity test (LOD = Lost On Drying), flow rate, angle recess, and the compressibility of powders. Mass then compressed into tablets, labored to obtain tablets with hardness greater than 70 N, small friability and disintegration time less than 15 minutes.

Evaluation of tablet core. The evaluation includes testing the core tablet weight uniformity, uniformity of size (diameter and thickness), hardness, brittleness (friability) and disintegration time.

Preparation of enteric coating suspension.
Enteric coating suspension consisting of enteric-coated polymer is Eudragit ® L30 D-55 and other additives with the formula as follows:



Ingredients% Weight
Eudragit® L30 D-5514
NaOH 1 N0.2
Talcum7
Triethyl citrate1.4
Poliethylene glycol 6000 (33%)0.6
Titanium dioxide1.4
Tartazine0.4
Water75

Preparation:
  1. Several Eudragit ® L 30 D-55 is inserted into the glass beaker.
  2. sodium hydroxide 1 N solution was gradually incorporated into the Eudragit ® L 30 D-55 with stirring in a homogenizer at low speed for 5 minutes.
  3. In another place, made a suspension of other additives : talcum, triethyl citrate, polyethylene glycol 6000, titanium dioxide, tartazine, and water by using a homogenizer for 20 minutes.
  4. Added suspension (3) into the mix (2) and in the back stirring for 5 minutes with a low speed. Suspension of the enteric coating polymer Eudragit ® L 30 D-55 ready to use.

Evaluation of coating suspension. Evaluation of coating suspension includes examining surface tension, viscosity and acidity (pH).

Enteric Coating Process
Weight gain of the coated tablet is equal to 6% (270 mg).


Evaluation of enteric coated tablet. The evaluation includes testing enteric coated tablet weight uniformity, uniformity of size (diameter and thickness), hardness, disintegration time and dissolution.

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