Subcutaneous absorption

K Hirano, H Yamada. Studies on the absorption of practically water-insoluble drugs following injection VI subcutaneous absorption from aqueous suspensions in rats. J Pharm Sci 71(5) 500-505, 1982. 

Mesiha, M.S., M.B. Sidhom, and B. Fasipe. 2005. Oral and subcutaneous absorption of insulin poly(isobutylcyanoacrylate) nanoparticles. Int J Pharm 288 289. 

Recent work with insulin provides evidence that the total lung volume at the end of the delivery impacts the kinetics of absorption of this peptide delivery of fine particle insulin aerosol resulted in faster absorption with a higher plasma peak level in humans when the inhalation was done with a deep breath (close to vital capacity), as compared with a more shallow breath (about 50% of the vital capacity).The kinetics following the latter was similar to subcutaneous absorption of insulin. The exact reasons for this observation are unknown. However, the lung does have the above-described water channels that could expand during breathing. If the size of the peptide or protein molecule approaches the diameter of these channels, it would be expected that the channel expansion would lead to faster absorption. For molecules whose size exceeds the channel diameter, the lung volume does not play a role in their pulmonary absorption rate. ... 

Yu CD, Kent JS. Effect of propylene glycol on subcutaneous absorption of a benzimidazole hydrochloride. ] Pharm Sci 1982 71 476-478. 

Cross SE and Roberts MS. Subcutaneous Absorption Kinetics of Interferon and other Solutes./P/iarm Pharmacol 1993 45 606-609. 

Self-association of the insulin molecule into oligomers and macromolecular aggregates leads to complications in the development of long-term insulin therapeutic systems and limits the rate of subcutaneous absorptions, a process which... 

Subcutaneous absorption parameters were estimated using the Phase 1 data and subsequently fixed when fitting the combined Phase 1 and Phase 2 data. 

Epi injection is available in 1 mg/mL (1 1000), 0.1 mg/niL (1 10,000), and 0.5 mg/mL (1 2000) solutions. The usual adult dose given subcutaneously ranges from 0.3 to 0.5 mg. The intravenous route is used cautiously if an immediate and reliable effect is mandatory. If the solution is given by vein, it must be adequately diluted and injected very slowly. The dose is seldom as much as 0.25 mg, except for cardiac arrest, when larger doses may be required. Epi suspensions are used to slow subcutaneous absorption and must never be injected intravenously. Also, a 1% (10 mg/mL 1 100) formulation is available for administration via inhalation every precaution must be taken not to confuse this 1 100 solution with the 1 1000 solution designed for parenteral administration inadvertent injection of the 1 100 solution can be fatal. Epi is unstable in alkaline solution when exposed to air or light, it turns pink from oxidation to adrenochrome and then brown from polymer formation thus, an antioxidant or acid must be included. 

Cross, S.E. and Roberts, M.S., Subcutaneous absorption kinetics and local tissue distribution of interferon and other solutes, J. Pharm. Pharmacol., 1993, 45, 606-609. 

Hddebrandt, P., Birch, K., Sestoft, L., and Volund, A., 1984a, Dose-dependent subcutaneous absorption of porcine, bovine and human NPH insulins, Acta Med. Scand 215 69-73. 

Hildebrandt, P., Berger, A., Volund, A., and Kiilil, C., 1985a, The subcutaneous absorption of human and bovine ultralente insulin formulations. Diabetic Med 2 355-359. 

Clodfelter DK, Pekar AH, Rebhun DM, Destrampe KA, Havel HA, Myers SR, Brader ML. Effects of non-covalent selfassociation on the subcutaneous absorption of a therapeutic peptide. Pharm Res 1998 15 254-262. 

---