Penicillin G procaine suspension

An example of the second approach is penicillin G procaine suspensions, where an increase in the particle size resulted in prolongation of the therapeutic level (0.03 unit/mL) from 24 hours for particles at 1 to 2 am to more than 72 hours for particles at 150 to 250 pm.23... 

Penicillin G procaine suspension is an aqueous preparation of the crystalline salt that is only 0.4% soluble in water. Procaine combines with penicillin mole for mole a dose of 300,000 units thus contains approximately 120 mg procaine. When large doses of penicillin G procaine are given (e.g., 4.8 million units), procaine may reach toxic concentrations in the plasma. If the patient is believed to be hypersensitive to procaine, 0.1 mL of 1% solution of procaine should be injected intradermally as a test. The anesthetic effect of the procaine accounts in part for the fact that injections of penicillin G procaine are virtually painless. 

Penicillin G procaine suspension combines procaine with penicillin in equimolar ratios a dose of 300,000 units contains -120 mg procaine, which exerts local anesthetic effects when injected. 

Two basic methods are used to prepare parenteral suspensions (a) sterile vehicle and powder are combined aseptically, or (b) sterile solutions are combined and the crystals formed in situ. Examples of these procedures may be illustrated using Penicillin G Procaine Injectable Suspension USP and Sterile Testosterone Injectable Suspension USP. 

Parenteral preparations with antimicrobial activity, which depends on the causative pathogenic microorganism, and pharmacokinetic properties that meet most of these criteria include procaine penicillin G (aqueous suspension), amoxicillin trihydrate-clavulanate potassium combination (aqueous suspension), and enro-floxacin (solution). Enrofloxacin is not approved for use... 

Fig. 2. Flow curves of procain penicillin G aqueous suspension. Circle experiment. Curve A, calculated from (1) / = 0.49i -f 4.36 sinh 1.2s,

Penicillin G benzathine suspension is the aqueous suspension of the salt obtained by the combination of 1 mol of an ammonium base and 2 mol of penicillin G to yield A/,A -dibenzylethylenediamine dipenicilhn G. The salt itself is 0.02% soluble in water. The long persistence of penicillin in the blood after a suitable IM dose reduces cost, the need for repeated injections, and local trauma. The local anesthetic effect of penicillin G benzathine is comparable with that of penicillin G procaine. 

If the solubility of a drug is to be reduced to enhance stability or to prepare a suspension, the for-mulator may prepare water-insoluble salts. A classic example is procaine penicillin G, the decreased solubility (7 mg/mL) of which, when compared with the very soluble penicillin G potassium, is utilized to prepare stable parenteral suspensions. Another alternative to preparing an insoluble drug is to use the parent acidic or basic drug and to buffer the pH of the suspension in the range of minimum solubility. 

Buckwalter FJ, Dickison HL. The effect of vehicle and particle size on the absorption, by the intramuscular route, of procaine penicillin G suspension. J Am Pharm Assoc Sci Ed 1958 47 661. 

Randazzo SD, DiPrima G. Psicosi allucinatoria acuta da peniciUina-procaina in sospensione acquosa. [Acute hallucinatory psychoses caused by procaine penicillin in aqueous suspension.] Minerva Dermatol 1959 34(6) 422-8. 

Sabatini GR, Gulesich JJ. Formulation of a stable and palatable oral suspension of procaine penicillin G. / Am Pharm Assoc (Pract Pharm) 1956 17 806-808. 

Erythromycin suspension 50 mg/kg/d p.o. in four divided doses for 14 days) Erythromycin suspension 50 mg/kg/d p.o. in four divided doses for 14 days Acute epididymo-orchitis Amoxicillin 3.0 g p.o., or ampicillin 3.5 g p.o., or aqueous procaine penicillin G 4.8 million units IM at two sites (each along with probenecid 1.0 g p.o.), or spectinomycin 2.0 g IM or ceftriaxone 250 mg IM followed by tetracycline 500 p.o. four times daily for 10 days or... 

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