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Lipase activity in various pharmaceuticals has been assayed with different methods expressing the results in different units. Conversion factors enabling comparison of the international and Wallersteins units in FIP units which is current way of pancreatin enzyme activity expression have been calculated. Lipase activity conversion factors are diversified and depend on the type of pharmaceutical preparation containing pancreatic extract. Conversion factors facilitate comparison of lipase activity in different Polish and foreign-made pharmaceutical preparations and proper dosage.

A comparative in vitro analysis was performed of the enzyme activities contained in five commercial pancreatic supplements available in New Zealand. there was considerable individual variation between each product. Lipase was regarded as the most important enzyme, as lipase deficiency is the most significant clinical factor in patients with exocrine pancreatic insufficiency. Viokase not only contained the most lipase per tablet, but was also the cheapest product.

A comparative enzyme analysis was performed on 3 pancreatic extracts generally used for dermal-epidermal separation, namely, crude trypsin (Difco), crude trypsin (Sigma) and pancreatin. A fourth pancreatic extract, crude lipase, was subjected to a corresponding analysis. The 4 extracts were assayed for activities of: protease (total), trypsin, chymotrypsin, carboxypeptidase-A, amylase, elastase, lipase, esterase, arylesterase and ribonuclease. Relative activities of the different proteolytic enzymes were individualized by utilizing specific inhibitors. Insignificant differences were observed between the enzyme activities of crude trypsin (Difco) and pancreatin. Crude lipase displayed similar enzyme activities as these two extracts in addition to high lipolytic, esterolytic and arylesterolytic activities. Crude trypsin (Sigma) exhibited higher tryptic and chymotryptic activities than the other extracts but lacked all further enzyme activities. Epidermal separation was performed using similar incubation conditions for each extract and skin from the same donor. Ultrastructural examination of the detached epidermis revealed that a more effective separation could be achieved by crude lipase.

Guinea-pig insulin was purified from pancreatic extracts either by carboxymethyl-cellulose cation-exchange chromatography with a sodium chloride gradient or by high-performance liquid chromatography (HPLC) on octadecyl silica with mixtures of acetonitrile and phosphate buffer. HPLC proved to be superior to ion-exchange chromatography in the purification of insulin with respect both to time saving and to the purity of the product.

A mechanism is proposed wherein an essential lysine in porcine pancreatic lipase is the acylable residue in the catalytic mechanism of the enzyme. This mechanism involves an initial interfacial activation step were acylation first takes place in a rate-limiting step on a serine residue assisted by histidine and a carboxyl-containing residue, aspartic acid or glutamic acid, and then in a fast subsequent step the acyl group is transferred to the essential lysine residue at the catalytic site. Indirect support for the mechanism is presented. When the essential lysine is made inactive by reductive methylation, the lipase is functionally converted to a proteinase, as predicted by the mechanism.

The object of this study was to detect low molecular weight zinc binders in Viokase, a porcine pancreatic preparation used in the treatment of variant acrodermatitis enteropathica (AE). Extracts were centrifuged and ultrafiltered to yield a soluble fraction containing solutes of molecular weights less than or equal to 500 daltons. These were studied by modified gel chromatography (MGC) using sealed Sephadex G-15-120 columns equilibrated with buffered solvent systems containing either 5 ppm copper (II) or 5 ppm zinc (II). Eluted fractions were assayed for these metals by atomic absorption and for amino acids by various techniques. MGC profiles of ultrafiltrates resulted in a peak consisting of glutamic acid and another peak consisting of several amino acids. A third peak was due to metal ions. Citrate and picolinate have been claimed to be important zinc-binding ligands in Viokase, but neither was detectable by MGC, although small amounts of citrate or similar compounds were detected by the Furth and Herrmann reaction. Since amino acid ligands are easily detectable by MGC, and metal distribution among ligands is competitive in nature, the possibility of a role for citrate or picolinate as a zinc transporter in Viokase is seriously reduced. Relief to the variant AE patient was probably not due to citrate- or picolinate-enhanced zinc uptake.

Mouse pancreatic proteases were analyzed by one- and two-dimensional electrophoresis. Active proteases that existed in the luminal fluid were separated into at least eight bands in 8% polyacrylamide gel. Pancreatic proteases activated by intestinal extract were separated into at least seven bands. The mobilities of these bands were exactly the same as those of proteases in the luminal fluid except for those of the most cathodal band. Two kinds of trypsin (Try-I group and Try-II) and one kind of chymotrypsin (Chy-I) were determined by specific and nonspecific protease staining. Try-I group and Try-II were derived from different trypsinogens (Try G-I group and Try G-II), whereas Chy-I was derived from a single chymotrypsinogen (Chy G). Although Try G-II was activated by both intestinal extract and by bovine trypsin, Try G-I group activated only by intestinal extract. Intestinal-activating factors were analyzed by two-dimensional electrophoresis. Mouse enterokinase (enteropeptidase EC 3.4.4.8), which can activate bovine trypsinogen, had a slow mobility. In the intestine of the mouse there are several activating factors in addition to enterokinase. Although it is unclear what intestinal-activating factors can activate Chy G, there is a factor that can convert chymotrypsinogen into chymotrypsin directly. These data suggest that intestinal-activating factors play an important role in the activating mechanisms of mouse pancreatic zymogens.

In-vitro activity of 14 commercial pancreatin preparations, commonly used in the Federal Republic of Germany, were tested. All had been declared by their manufacturers to contain more than 6000 FIP (Fédération International Pharmaceutique) units of lipase and to be acid resistant. The declared lipase and amylase amounts were found to be present in 11 of the 14 preparations. Three of the 14 preparations, said to be acid resistant were found not to be so in buffer with falling pH values between 4.0 and 2.5, so that there occurred an, at times marked, loss of enzyme activity. Most noticeable was the poor solubility of most preparations at pH 6.6. Only three of the 14 liberated their total enzyme content within 60 minutes, as they should for theoretical reasons, based on the relatively short duodeno-cecal transit time.

The authors studied the purity of the hormonal drugs by electrophoresis in polyacrylamide gel and isoelectrofocusing. Identified fractions found in insulin, glucagon, andecaline and in other preparations. Established that isoelectrofocusing has a higher separation power as compared with disc electrophoresis in polyacrylamide gel.

Of the 72 pancreatic preparations currently on the market 24 were randomly selected for study and compared with 3 US preparations with different dosage forms. The activities of amylase, lipase, and proteases were measured with natural substrates. Prospective bioavailability was determined using amylase as indicator enzyme. Total bile acid content and distribution pattern were analyzed. The risk of renal changes due to prolonged ingestion of purines was estimated by qualitative and quantitative determination of these contaminants. Enzyme activities differed up to 16-fold. At pH 6, the drugs released the indicator enzyme with very different velocities. The efficacy of the drugs varied between 0.78% and 80.9%. The bioavailability of capsules was generally better than that of coated tablets; pellet capsules were not absolutely superior in this regard. All pancreatic preparations contained the purine bases guanine and hypoxanthine; only one drug had no adenine. Fifteen drugs contained 2.2%-10.6% bile acids by weight. Monohydroxy bile acids, which should not be administered to patients with liver disease, were detected in eight of these preparations.

Immunoreactive oxytocin and vasopressin were found in human and rat pancreatic extracts. The pancreatic oxytocin and vasopressin eluted on Sephadex G-75 gel filtration chromatography and on reverse phase high pressure liquid chromatography in the same positions as their respective reference preparations. The immunoreactive oxytocin was biologically active in the rat milk ejection assay. The presence of oxytocin and vasopressin in human and rat pancreatic extracts suggests the possibility of local synthesis of both hormones. The neurohypophysial hormones are known to be endocrine mediators of insulin and glucagon release. The finding of oxytocin and vasopressin in the pancreas raises the possibility, although yet unproven, of local synthesis and perhaps a paracrine function for the neurohypophysial peptides upon pancreatic hormone release or for a local function upon the liver.

Lyophilized pancreas and pancreatic extracts are widely used in therapy of pancreatic exocrine function deficiencies. Among the measures for quality of the extracts, assay for lipolytic activity appears to be one of the best. However, assay precision is poor, because the specificity and mode of action of lipase requires careful optimization of the assay parameters, especially substrate and measurement conditions. In the method proposed here, substrate quality is improved by the use of sodium desoxycholate and a high-speed stirrer for more reproducible emulsions. Fatty acids are assayed by a titrimetric method, using an electronically monitored pH meter. A comparative statistical study of the U.S. Pharmacopeia method, the International Pharmaceutical Federation (FIP) method, and a modified FIP method showed the latter to have improved accuracy and reproducibility.

Glucagon-like immunoreactivity (GLI), which can be separated from glucagon by isoelectric focusing, has been detected in partially purified canine pancreatic extracts. Like gastrointestinal GLI, this insular GLI reacts with crossreacting antiserum 78J but not with glucagon "specific" antiserum 30K and has an isoelectric point (pl) of 9.5, whereas canine pancreatic glucagon has a pl of 6.25. When combined with glucagon, the GLI-glucagon mixture gives 48J assay values between GLI and this crossreacting antiglucagon serum and thus conceals it in glucagon-containing extracts.

An enzyme that catalyzes the conversion of bovine proinsulin to insulin has been purified from a bovine pancreatic extract. The product of conversion was identified as insulin by aminoacid analysis and determination of carboxyl terminal aminoacid residues. The purified enzyme preparation showed one major protein band on polyacrylamide gel disc electrophoresis; it had a molecular weight of about 70,000 and an isoelectric point (pI) at a pH of 4.82.