Suspensions phenytoin

Each teaspoonful of suspension contains 125 mg phenytoin, with a maximum alcohol content not greater than 

It also contains carboxymethylcellulose sodium citric acid, anhydrous flavors glycerin magnesium alu- 

Charge in a suitable stainless steel-j acketed vessel item 5 and heat to 90° to 95°C. 

Add and dissolve preservatives (e.g., parabens) stir to complete solution. 

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Phenytoin decreases folic add absorption, but folic acid replacement enhances phenytoin clearance and can result in loss of efficacy. Phenytoin tablets and suspension contain phenytoin acid, while the capsules and parenteral solution are phenytoin sodium, which is 92% phenytoin. Clinicians should remember that there are two different strengths of phenytoin suspension and capsules. 

A child weighing 28 lb is to receive 4 mg of phenytoin per kilogram of body weight daily as an anticonvulsant. How many milliliters of pediatric phenytoin suspension containing 30 mg per 5 mL should the child receive ... 

Examples of a few oral suspensions in which a specific and well-defined particle-size specification for the drug substance is important include phenytoin suspension, car-bamazepine suspension, trimethoprim and sulfamethoxazole suspension, and hydrocortisone suspension. It is therefore a good idea to indicate particle size in the raw material specification, even though it is meant for dissolving in the processing, to better validate the manufacturing process while avoiding scale-up problems. 

There is a difference in bioequivalence between capsules and phenytoin suspension. A 100-mg phenytoin capsule is equivalent to 90 mg of the suspension preparation. 

However, another study in healthy subjects found the absolute bioavailability of phenytoin suspension or phenytoin sodium solution given by nasogastric tube was not affected by an enteral feed product (Isocat) ... 

A woman with a history of seizures had acceptable serum phenytoin levels when phenytoin was given intravenously, but they fell from 19.1 micrograms/mL to less than 2.5 micrograms/mL when a comparable dose of phenytoin suspension was given in the presence of an enteral feed product (levity), given by jqunostomy tube. ... 

Phenytoin, Sodium Capsules (Prompt or Extended), Oral Suspension... 

Wood, R. W., Clemente, W., Lambert, McShane, J. (190ffi)gle Dose Pharmacokinetic Comparison of Oral Phenytoin Administered as a Novel Nanocrystal Dispei dE( lantin-125 Suspension or Dilantin Kapseals, 24th Annual Meeting ACCP... 

Further cases in which simple oily solutions or suspensions contributed to higher absorption are cinnarizine [23], phenytoin [24], and lipophilic steroid [25]. 

The method was applied successfully to the determination of phenytoin in capsules and suspensions. 

Shinkuma D, Hamaguchi T, Muro C, et al. Bioavailability of phenytoin from oil suspension and emulsion in dogs. Int ] Pharm 1981 9 17-28. 

Phendimetrazin Tablets (35 mg) Phenindion Tablets (50 mg) Phenolphthalein Tablet Cores (200 mg) Phenytoin Oral Suspension (5%) Phenytoin Sodium Tablets (100 mg),... 

The degree of dispersion of a lipid-based delivery system appears to have the most marked effect on the bioavailability of a co-administered drug, and this has stimulated many of the most recent articles in the literature. Clearly, by decreasing the particle size of a dispersed formulation, the surface area available for lipid digestion and drug release or transfer is enhanced. In this regard, the bioavailability of griseofulvin [32, 33], phenytoin [23], penclomedine [30], dana-zol [34], REV 5901 [35], and, more recently, ontazolast [36] has been shown to be enhanced after administration in an emulsion formulation compared with a tablet, aqueous solution, or suspension formulation. It is not clear in these cases how much more efficient the emulsion formulation would have been compared with a simple lipid solution. 

There have been a number studies of the growth kinetics of biochemicals in suspension crystallization. Rodriguez-Homeda et al. (1986) used an MSMPR crystallizer to obtain the growth rate kinetics for the drug, phenytoin, as a function of pH. They found the kinetics to be size-independent and to increase at lower pH. An MSMPR crystallizer study by Harano and Yamamato (1982) determined the growth rate of glutamic acid from the measured size distribution. 

Phenytoin is used orally for the prevention of generalized (grand mal) and partial complex seizures. Intravenous phenytoin is used to treat status epilepticus and occasionally as an antiarrhythmic agent. Oral formulations include suspensions, capsules, and tablet preparations. The brand Dilantin Kapseals exhibits delayed absorption characteristics not usually shared by generic products. 

Figure 9.2 Phenytoin concentrations in serum after a 600 mg oral dose in aqueous suspensions containing either micronized (G) or conventional (F) drug. The area under the serum level versus time curve is 40 and 66 mg L h for F and G, respectively. (With permission from Neuvonen etal. (1977).)...

An epileptic had a marked fall in his serum phenytoin levels aeeompa-nied by an increased seizure frequency when phenytoin was given at bedtime with 8 oz of a food supplement Ensure). Another patient had reduced phenytoin serum levels when phenytoin was given as an oral suspension with oral Fresubin liquidfood concentrated ... 

When an aqueous suspension is prepared, the air at the surface of the particles should be replaced by the aqueous phase. When a poorly wettable substance is used (0 > 90°) this will not happen. The particles can float when the air is not replaced. This phenomenon is called flotation. Poorly wettable and floating particles often adhere to the wall of the bottle neck. As a result, dosing is difficult with such systems. Pharmaceutical examples of poorly wettable substances are phenytoin, sulfur, zinc oxide and barium sulfate. By adding a surfactant, the interfacial pressure can be reduced by which wetting is improved. 

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