Penicillin-G-potassium salt

The penicillin-G-potassium salt has been oxidized using supported polyoxo-metallates.62 Specifically, the oxidation of the sulfide group to give the sulfoxide was achieved, the product being an intermediate in the production of Cephalosporin antibiotics.63 The selective oxidation of benzenethiol to benzenesulfonic acid with hydrogen peroxide was effectively catalysed by phosphotungstic acid on y-alumina.62 This was in contrast to the homogeneous oxidation where the disulfide was produced in substantial yields. 

Besides the group of psychotropic compounds, we must quote here the antibiotics as drugs where a rapid recent development of techniques can be observed. D.c. polarographic techniques for the determination of chloramphenicol [242], tetracycline [243] and streptomycin [244] are available. The polarographic determination of penicillin G potassium salt is only indirect and is preceded by the introduction of a nitroso group [245]. The synthesis of chloramphenicol comprises the chemical reduc-... 

The following oxidations will be described the oxidation of penicillin-G potassium salt to the sulphoxide the oxidation of cyclooctene the oxidation of cyclohexanone and the oxidation of styrene. 

Penicillin G, potassium salt 8001, N-13imethylaniline 6001 Phosphorus pentachloride 3001 Dimethyldichloro-silane... 

A penicillin G potassium salt. A, was prepared and standards containing three different amounts of labelling were obtained. 130 000 pulses. 

Solvent Penicillin G (potassium salt) Benzyl- penicil- loic acid Benzyl- penil- loic acid Dev. time (h) ... 

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. 

The international unit (lU) of penicilhn is the specific penicillin activity contained in 0.6 pg of the crystalline sodium salt of penicillin G. One milhgram of pure penicillin G sodium thus equals 1667 units 1.0 mg of pure penicillin G potassium represents 1595 units. The dosage and the antibacterial potency of the synthetic penicillins are expressed in terms of weight. 

In the latter case, the Marketing Department forecasts that an additional 5 million pounds (about 3.6 billion units) of penicillin G potassium (potassium salt of benzyl penicillin acid) will be... 

Whereas the carboxylic acid is shown for many of these compounds, the majority of the commercial penicillins are sodium salts. Penicillin G is available as the calcium salt [973-53-5] C gH N20 S d/s Ca, and as the potassium salt [113-98-4] C2gH2yN20 S K. 

The pH of the mixture was adjusted to 7.5 by adding a saturated sodium bicarbonate solution. After being washed twice with diethyl ether, the reaction solution was acidified to pH 2 with dilute hydrochloric acid and extracted with ether. The ether solution containing the free penicillin was washed twice with water and then extracted with 50 ml of N potassium bicarbonate solution. After freeze drying of the obtained neutral solution, the potassium salt of o-azidobenzylpenicillin was obtained as a slightly colored powder (11.2 grams, 54% yield) with a purity of 55% as determined by the hydroxylamine method (the potassium salt of penicillin G being used as a standard). 

Gomez etal. [160] have studied specific adsorption of potassium penicillin G (salt K) on Hg electrode from electrocapillary and capacity measurements. The Frumkin isotherm has been found applicable to the quantitative description of the data repulsive interaction parameter equaled —3.5 and standard free Gibbs energy of adsorption at the zero charge was —38.6 kJ mol h depended linearly... 

Benzyl penicillin (Penicillin G sodium and potassium salt) 0.5-5 MU IM/IV... 

Table 7.5 also lists the coefficients obtained in the IL-based ATPS for proteins and short-chain linear alcohols [14]. The protein coefficients are two orders of magnitude higher than those obtained in the classical PEG 1000-K2HP04-water ATPS. The short-chain alcohols, a homologous series, have coefficients about one order of magnitude higher than their coefficient. The partitioning of Penicillin G was recently studied in the same ATPS and similar results were obtained (Table 7.5) [15]. These results indicate that the IL-rich phase of the [C4CiIm]Cl-K2HP04-acetonitrile-water system has a polarity much lower than the octanol phase of the reference system and also much lower than the PEG aqueous phase obtained with classical ATPS made with PEG 1000 and the same potassium hydrogeno phosphate salt [10,13,16].

The activity of penicillin G was originally defined in units. Crystalline sodium penicillin G contains approximately 1600 units per mg (1 unit = 0.6 meg 1 million units of penicillin = 0.6 g). Semisynthetic penicillins are prescribed by weight rather than units. The minimum inhibitory concentration (MIC) of any penicillin (or other antimicrobial) is usually given in mcg/mL. Most penicillins are dispensed as the sodium or potassium salt of the free acid. Potassium penicillin G contains about 1.7 mEq of K+ per million units of penicillin (2.8 mEq/g). Nafcillin contains Na +, 2.8 mEq/g. Procaine salts and benzathine salts of penicillin G provide repository forms for intramuscular injection. In dry crystalline form, penicillin salts are stable for years at 4°C. Solutions lose their activity rapidly (eg, 24 hours at 20°C) and must be prepared fresh for administration. 

The rates of absorption, clearance, and elimination of penicillin G are influenced by its formulation. Penicillin G is available in a number of different salts either with inorganic ions including sodium, potassium, or calcium or with organic cations including procaine and benzathine. These salts have differing solubilities and hence differing durations of action. 

The sodium and potassium salts are rapidly absorbed but give effective plasma concentrations for no more than 4 h. The procaine salt has a lower solubility and forms, on injection, a depot that slowly releases penicillin G, maintaining effective concentrations for up to 24 h. After intramuscular treatment of swine... 

The resulting solution was treated as described in Example 1 to give the potassium salt of a-azidobenzylpenicillin as a white powder (29.4 grams, 84% yield) with a purity of 83% as determined by the hydroxylamine method (the potassium salt of penicillin G being used as a standard). 

Approximately 1,000 g of phenoxymethylpenicillin acid (Penicillin V) is dissolved directly in about 5 liters of ethyl acetate to a concentration of 20% w/v. The resulting solution is filtered to remove any insoluble salts. The penicillin V acid (1,000 g) may also be obtained by extracting an aqueous solution of 1,110 g of the potassium salt of phenoxymethylpenicillin at a temperature of about 5°C, this solution being adjusted to pH 2-3 by the addition of 6 N sulfuric acid, twice with a total of 5 liters of ethyl acetate so that the final washed combined volume will have a concentration of about 20% w/v. The abovementioned ethyl acetate solution having a volume of about 5 liters is then dried with anhydrous Na2S04 and filtered to obtain a clear ethyl acetate solution of phenoxymethylpenicillin acid. 

The sodium and potassium salts of penicillin G are the only formulations suitable for i.v. administration. They are also the most rapidly absorbed... 

Penicillin G is available in injectable formulations. The sodium and potassium salts (crystalline penicillin) are water-soluble formulations and may be injected i.v., i.m. or s.c. They rapidly produce high plasma concentrations but have very short half-lives, so must be administered frequently. The potassium salt must be administered more carehilly than the sodium salt, as rapid i.v. administration can cause cardiac arrhythmias. These formulations are frequently used for their Grampositive activity in life-threatening diseases and conditions such as surgical colic, neonatal septicemia and clostridial myositis. 

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